9015930
Translation, cross-cultural adaptation and psychometric properties of the Nepali versions of numerical pain rating scale and global rating of change
BackgroundPain intensity and patients’ impression of global improvement are widely used patient-reported outcome measures (PROMs) in clinical practice and research. They are commonly assessed using the Numerical Pain Rating Scale (NPRS) and Global Rating of Change (GROC) questionnaires. The GROC is essential as an anchor for evaluating the psychometric properties of PROMs. Both of these PROMs are translated to many languages and have shown excellent psychometric properties. Their availability in Nepali would facilitate pain research and cross-cultural comparison of research findings. Therefore, the objectives of this study were to translate and cross-culturally adapt the NPRS and GROC into Nepali and to assess the psychometric properties of the Nepali version of the NPRS (NPRS-NP).MethodsAfter translating and cross-culturally adapting the NPRS and GROC into Nepali using recommended guidelines, NPRS-NP was administered to 104 individuals with musculoskeletal pain twice. The Nepali version of the GROC (GROC-NP) was administered at the follow-up for anchor-based assessment. (1) Test-retest reliability and minimum detectable change (MDC) among the stable group, (2) construct validity (by single sample t-test within the improved group and independent sample t-test between groups), and (3) concurrent validity were assessed. Receiver operating characteristic (ROC) curves were plotted to determine the responsiveness of the NPRS-NP using the area under the curve (AUC), and minimum important changes (MIC) for small, medium and large improvements.ResultsSignificant cultural adaptations were required to obtain relevant Nepali versions of both the NPRS and GROC. The NPRS-NP showed excellent test-retest reliability and a MDC of 1.13 points. NPRS-NP demonstrated a good construct validity by significant within-group difference in mean of NPRS score- t(63)= 7.57, P < 0.001 and statistically significant difference of mean score- t(98)= -4.24, P < .001 between the stable and improved groups. It demonstrated moderate concurrent correlation with the GROC-NP; r = 0.43, P < 0.01. Responsiveness of the NPRS-NP was shown at three levels with AUC = 0.68–0.82, and MIC = 1.17–1.33.ConclusionsThe NPRS and GROC were successfully translated and culturally adapted into Nepali. The NPRS-NP demonstrated good reliability, validity and responsiveness in assessing musculoskeletal pain intensity in a Nepali population.
53878680
Outcome measurement in clinical practice: practical and theoretical issues for health related quality of life (HRQOL) questionnaires
Abstract The defining characteristic of clinical outcome measurement tools is that they are intended to measure change over time. There is a range of practical issues that must be considered when choosing outcome measures for routine use in the clinical setting. Outcome measures should be: relevant to patients’ values and perceived needs; measure aspects of health and function that are relevant to the treatment offered; have sound psychometric properties; be quick and easy to complete and score; and, be intuitive to interpret. They should also provide clinically meaningful information useful to the clinician for decision-making regarding patient care. Outcome measures fall broadly into two types: measures of impairment of physical structures or functions; and measures of activities or participation as determined by health-related quality of life (HRQOL) questionnaires. Whilst recognizing that measures of physical impairments have an important role in patient assessment, this paper focuses on HRQOL measures. It is intended as a summary of the key attributes of HRQOL outcome measurement tools. The different types of outcome measures are reviewed along with the important scientific and practical considerations for the choice of an outcome measure. The determination of validity, reliability, responsiveness for outcome measures is explained, and the interpretation of changes in score for an outcome measure in terms of minimal important difference is outlined.
5560216
Core outcome measures for chronic pain clinical trials: IMMPACT recommendations
AbstractObjective. To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of d
35498639
OARSI Clinical Trials Recommendations: Design and conduct of clinical trials of rehabilitation interventions for osteoarthritis.
A Task Force of the Osteoarthritis Research Society International (OARSI) has previously published a set of guidelines for the conduct of clinical trials in osteoarthritis (OA) of the hip and knee. Limited material available on clinical trials of rehabilitation in people with OA has prompted OARSI to establish a separate Task Force to elaborate guidelines encompassing special issues relating to rehabilitation of OA. The Task Force identified three main categories of rehabilitation clinical trials. The categories included non-operative rehabilitation trials, post-operative rehabilitation trials, and trials examining the effectiveness of devices (e.g., assistive devices, bracing, physical agents, electrical stimulation, etc.) that are used in rehabilitation of people with OA. In addition, the Task Force identified two main categories of outcomes in rehabilitation clinical trials, which include outcomes related to symptoms and function, and outcomes related to disease modification. The guidelines for rehabilitation clinical trials provided in this report encompass these main categories. The report provides guidelines for conducting and reporting on randomized clinical trials. The topics include considerations for entering patients into trials, issues related to conducting trials, considerations for selecting outcome measures, and recommendations for statistical analyses and reporting of results. The focus of the report is on rehabilitation trials for hip, knee and hand OA, however, we believe the content is broad enough that it could be applied to rehabilitation trials for other regions as well.
116307366
Measurement in Medicine: A Practical Guide
1. Introduction 2. Concepts, theories and models, and types of measurements 3. The development of a measurement instrument 4. Field testing - item reduction and data structure 5. Reliability 6. Validity 7. Responsiveness 8. Interpretation 9. Systematic reviews of measurement properties Index.
8120020
The measurement of clinical pain intensity: a comparison of six methods
&NA; The measurement of subjective pain intensity continues to be important to both researchers and clinicians. Although several scales are currently used to assess the intensity construct, it remains unclear which of these provides the most precise, replicable, and predictively valid measure. Five criteria for judging intensity scales have been considered in previous research: (a) ease of administration of scoring; (b) relative rates of incorrect responding; (c) sensitivity as defined by the number of available response categories; (d) sensitivity as defined by statistical power; and (e) the magnitude of the relationship between each scale and a linear combination of pain intensity indices. In order to judge commonly used pain intensity measures, 75 chronic pain patients were asked to rate 4 kinds of pain (present, least, most, and average) using 6 scales. The utility and validity of the scales was judged using the criteria listed above. The results indicate that, for the present sample, the scales yield similar results in terms of the number of subjects who respond correctly to them and their predictive validity. However, when considering the remaining 3 criteria, the 101‐point numerical rating scale appears to be the most practical index.
206369218
Studies comparing Numerical Rating Scales, Verbal Rating Scales, and Visual Analogue Scales for assessment of pain intensity in adults: a systematic literature review.
CONTEXT
The use of unidimensional pain scales such as the Numerical Rating Scale (NRS), Verbal Rating Scale (VRS), or Visual Analogue Scale (VAS) is recommended for assessment of pain intensity (PI). A literature review of studies specifically comparing the NRS, VRS, and/or VAS for unidimensional self-report of PI was performed as part of the work of the European Palliative Care Research Collaborative on pain assessment.


OBJECTIVES
To investigate the use and performance of unidimensional pain scales, with specific emphasis on the NRSs.


METHODS
A systematic search was performed, including citations through April 2010. All abstracts were evaluated by two persons according to specified criteria.


RESULTS
Fifty-four of 239 papers were included. Postoperative PI was most frequently studied; six studies were in cancer. Eight versions of the NRS (NRS-6 to NRS-101) were used in 37 studies; a total of 41 NRSs were tested. Twenty-four different descriptors (15 for the NRSs) were used to anchor the extremes. When compared with the VAS and VRS, NRSs had better compliance in 15 of 19 studies reporting this, and were the recommended tool in 11 studies on the basis of higher compliance rates, better responsiveness and ease of use, and good applicability relative to VAS/VRS. Twenty-nine studies gave no preference. Many studies showed wide distributions of NRS scores within each category of the VRSs. Overall, NRS and VAS scores corresponded, with a few exceptions of systematically higher VAS scores.


CONCLUSION
NRSs are applicable for unidimensional assessment of PI in most settings. Whether the variability in anchors and response options directly influences the numerical scores needs to be empirically tested. This will aid in the work toward a consensus-based, standardized measure.
30827096
Postoperative pain assessment based on numeric ratings is not the same for patients and professionals: a cross-sectional study.
BACKGROUND
Numeric pain scores have become important in clinical practice to assess postoperative pain and to help develop guidelines for treating pain. Professionals need the patients' pain scores to administer analgesic medication. However, do professionals interpret the pain scores in line with the actual perception of pain by the patients?


OBJECTIVE
The study aim was to assess which Numerical Rating Scale (NRS) pain score was considered bearable on a Verbal Rating Scale (VRS) by patients and professionals.


METHODS
This prospective study examined the relationship between the Numerical Rating Scale and a Verbal Rating Scale. The patients (n=10,434) rated their pain the day after surgery on the 11-point NRS (0=no pain and 10=worst imaginable pain) and a VRS comprising five descriptors: "no pain"; "little pain"; "painful but bearable"; "considerable pain"; and "terrible pain". The first three categories together ("no pain", "little pain" and "painful but bearable") were considered "bearable" and the last two categories ("considerable pain" and "terrible pain") were deemed as "unbearable" pain. The professionals (n=303) were asked to relate the numbers of the NRS to the words of the VRS.


RESULTS
Most patients considered NRS 4-6 as "bearable" pain. Among professionals, anesthesiologists, Post Anaesthesia Care nurses, and ward nurses interpreted NRS scores in the same way as the patients. Only the Acute Pain Nurses interpreted the scores differently; they considered NRS of 5 and higher to be not bearable.


CONCLUSIONS
Some care providers and patients differ in their interpretation of the postoperative NRS scores. A risk of overtreatment might arise when health care providers rigidly follow guidelines that prescribe strong analgesics for pain scores above 3 or 4 without probing the patient's preference for pharmacological treatment.
72072214
Pain measurement: Visual Analogue Scale (VAS) and Verbal Rating Scale (VRS) in clinical trials with OTC analgesics in headache
Aim: The aim was to assess the performance of the Visual Analogue Scale (VAS) in patients recruited in a clinical trial with over the counter analgesics in headache. Methods: The Thomapyrin Study showed the significant superiority of the fixed combination of acetylsalicylic acid + paracetamol + caffeine over the combination without caffeine, the single preparations, and placebo in the treatment of headache. Patients enrolled into the study were trained in the handling of the VAS by naming categories of a 6-point Verbal Rating Scale (VRS). These data were used to evaluate the level of order consistency between the VAS and VRS, to deduce cut-off points for rescaling the continuous VAS into a discrete ordinal scale using the receiver operating characteristic methodology, and to assess the test-retest performance. Results: Approximately 75% of the patients recorded the pain intensity on the VAS in the same order as given on the VRS. However, in 12.6% of patients, the German terms ‘leicht’ (mild) and ‘mäßig’ (moderate) were mixed up regarding their order on the VAS. Substantial overlapping of the frequency distributions of the VAS assessment were found for the VRS categories mild and moderate pain as well as severe and very severe pain. Grouping of the VAS assessments into a discrete ordinal scale necessitated a non-equidistant rescaling based on the categories of the VRS. By means of analysis of the receiver operating characteristic curves, the following cut-off points were determined on a 100 mm VAS: no pain 0–2 mm, mild pain 2–17 mm, moderate pain 17–47 mm, severe pain 47–77 mm, very severe pain 77–96 mm, most severe pain imaginable 96–100 mm. Repeated assessment up to several months after the first assessment demonstrated a test-retest agreement on the VAS in 61.0–91.4% of the patients, depending on the VRS category. Conclusions: This study shows that the VRS categories cannot be presented in an equidistant manner on the VAS, and that contrary to previous assumptions, the pain intensity descriptors are less clear and can have different meanings in different languages. Therefore, both in the 3rd edition of the International Headache Classification (ICHD-III) and in the guidelines for clinical trials of patients with headache illnesses, rather than a 4-grade VRS, a 6-grade or higher level VRS or a VAS should be recommended, with correspondingly broadly defined anchor points.
23985784
Minimum important differences for the patient-specific functional scale, 4 region-specific outcome measures, and the numeric pain rating scale.
STUDY DESIGN
Multicenter, prospective, longitudinal cohort study.


OBJECTIVES
To investigate the minimum important difference (MID) of the Patient-Specific Functional Scale (PSFS), 4 region-specific outcome measures, and the numeric pain rating scale (NPRS) across 3 levels of patient-perceived global rating of change in a clinical setting.


BACKGROUND
The MID varies depending on the external anchor defining patient-perceived "importance." The MID for the PSFS has not been established across all body regions.


METHODS
One thousand seven hundred eight consecutive patients with musculoskeletal disorders were recruited from 5 physical therapy clinics. The PSFS, NPRS, and 4 region-specific outcome measures-the Oswestry Disability Index, Neck Disability Index, Upper Extremity Functional Index, and Lower Extremity Functional Scale-were assessed at the initial and final physical therapy visits. Global rating of change was assessed at the final visit. MID was calculated for the PSFS and NPRS (overall and for each body region), and for each region-specific outcome measure, across 3 levels of change defined by the global rating of change (small, medium, large change) using receiver operating characteristic curve methodology.


RESULTS
The MID for the PSFS (on a scale from 0 to 10) ranged from 1.3 (small change) to 2.3 (medium change) to 2.7 (large change), and was relatively stable across body regions. MIDs for the NPRS (-1.5 to -3.5), Oswestry Disability Index (-12), Neck Disability Index (-14), Upper Extremity Functional Index (6 to 11), and Lower Extremity Functional Scale (9 to 16) are also reported.


CONCLUSION
We reported the MID for small, medium, and large patient-perceived change on the PSFS, NPRS, Oswestry Disability Index, Neck Disability Index, Upper Extremity Functional Index, and Lower Extremity Functional Scale for use in clinical practice and research.
13504953
Systematic review of endometriosis pain assessment: how to choose a scale?
BACKGROUND
Numerous studies concerning endometriosis and pain have been reported. However, there is no consensus on the best method to evaluate pain in endometriosis and many scales have been used. Moreover, there are only a few descriptions of minimal clinically important differences after treatment (MCID) to evaluate variations in pain. In our study, we aim to identify pain scales used in endometriosis pain treatment, to address their strong and weak points and to define which would be the ideal scale to help clinicians and researchers to evaluate endometriosis-related pain.


METHODS
A search of the MEDLINE and EMBASE databases was carried out for publications in English, French or Portuguese from 1980 to December 2012, for the words: endometriosis, treatment, pain. Studies were selected if they studied an endometriosis treatment and a pain scale was specified. A quantitative and a qualitative analysis of each scale was performed to define strong and weak points of each scale (systematic registration number: CRD42013005336).


RESULTS
A total of 736 publications were identified. After excluding duplications and applying inclusion criteria 258 studies remained. We found that the visual analog scale (VAS) is the most frequently used scale. Both VAS and the numerical rating scale (NRS) show a good balance between strong and weak points in comparison with others such as the Biberoglu and Behrman scale. Concerning MCID, only VAS, NRS and Brief Pain Inventory scales have reported MCID and, among these, only VAS MCID has been studied in endometriosis patients (VAS MCID = 10 mm). Adding the Clinical Global Impression score (CGI) to the pain scale allows calculation of the MCID.


CONCLUSIONS
When using pain scales their strengths and weaknesses must be known and included in the analysis. VAS is the most frequently used pain scale and, together with NRS, seems the best adapted for endometriosis pain measurement. The use of VAS or NRS for each type of typical pain related to endometriosis (dysmenorrhea, deep dyspareunia and non-menstrual chronic pelvic pain), combined with the CGI and a quality-of-life scale will provide both clinicians and researchers with tools to evaluate treatment response.
29270313
Self-Report Measures of Hand Pain Intensity: Current Evidence and Recommendations.
Successful management of problems related to the hands and upper extremities begins with a comprehensive assessment of the pain experience and related factors. Pain intensity is the domain most commonly assessed, and pain relief is often the primary goal of treatment. Because pain is a private and subjective experience, self-report is considered the gold standard of pain measurement. This article describes and discusses the strengths and weaknesses of the most commonly used self-report scales used to measure hand pain intensity, and gives recommendations to help clinicians select from among the various options for measuring the intensity of hand pain.
25344473
Mind the MIC: large variation among populations and methods.
OBJECTIVE
There is no consensus on the best method to determine the minimal important change (MIC) of patient-reported outcomes. Recent publications recommend the use of multiple methods. Our aim was to assess whether different methods lead to consistent values for the MIC.


STUDY DESIGN AND SETTING
We used two commonly used anchor-based methods and three commonly used distribution-based methods to determine the MIC of the subscales: pain and physical functioning of the Western Ontario and McMaster University Osteoarthritis Index questionnaire in five different studies involving patients with hip or knee complaints. We repeated the anchor-based methods using relative change scores, to adjust for baseline scores.


RESULTS
We found large variation in MIC values by the same method across studies and across different methods within studies. We consider it unlikely that this variation can be explained by differences between disease groups, disease severity, or lengths of follow-up. The variation persisted when using relative change scores. It was not possible to conclude whether this variation is because of true differences in MIC values between populations or to conceptual and methodological problems of the MIC methods.


CONCLUSION
To better disentangle these two possible explanations, the MIC methodology should be improved and standardized. In the meantime, caution is needed when interpreting and using published MIC values.
23640093
A Comprehensive Method for the Translation and Cross-Cultural Validation of Health Status Questionnaires
The FACIT (Functional Assessment of Chronic Illness Therapy) translation methodology has been in use for nearly 10 years and, during the course of that time, has emphasized a universal translation approach that includes multicountry review, the use of qualitative and quantitative methods in testing, and the exploration of new methods such as differential item functioning (DIF) analysis using item response theory to evaluate item equivalence. The FACIT translation methodology aims to establish equivalence of meaning and measurement between different country versions through the use of the decentered model of translation and advanced statistical methods.
4516888
The COSMIN checklist for assessing the methodological quality of studies on measurement properties of health status measurement instruments: an international Delphi study
BackgroundAim of the COSMIN study (COnsensus-based Standards for the selection of health status Measurement INstruments) was to develop a consensus-based checklist to evaluate the methodological quality of studies on measurement properties. We present the COSMIN checklist and the agreement of the panel on the items of the checklist.MethodsA four-round Delphi study was performed with international experts (psychologists, epidemiologists, statisticians and clinicians). Of the 91 invited experts, 57 agreed to participate (63%). Panel members were asked to rate their (dis)agreement with each proposal on a five-point scale. Consensus was considered to be reached when at least 67% of the panel members indicated ‘agree’ or ‘strongly agree’.ResultsConsensus was reached on the inclusion of the following measurement properties: internal consistency, reliability, measurement error, content validity (including face validity), construct validity (including structural validity, hypotheses testing and cross-cultural validity), criterion validity, responsiveness, and interpretability. The latter was not considered a measurement property. The panel also reached consensus on how these properties should be assessed.ConclusionsThe resulting COSMIN checklist could be useful when selecting a measurement instrument, peer-reviewing a manuscript, designing or reporting a study on measurement properties, or for educational purposes.
6830546
Three ways to quantify uncertainty in individually applied "minimally important change" values.
OBJECTIVE
Determining "minimally important change" (MIC) facilitates the interpretation of change scores on multi-item instruments. This article focuses on how MIC values should be interpreted when applied to individual patients.


STUDY DESIGN AND SETTING
The MIC value of a hypothetical questionnaire "Q" was determined in a sample of 400 patients who improved and 100 patients who did not improve, using the receiver operating characteristic (ROC) method, and three methods to quantify the uncertainty.


RESULTS
The MIC value on questionnaire Q was 10.5. Firstly, the 95% confidence interval (CI) of the MIC value (for questionnaire Q: 5.6-14.2) quantifies the uncertainty of the estimation of the MIC value. Secondly, "how sure we are that this MIC value holds for every patient" is quantified by the values for sensitivity (74%) and specificity (91%). Thirdly, the smallest detectable change (SDC) on questionnaire Q is calculated (16.0) to consider whether the MIC value (10.5) falls outside or within the measurement error.


CONCLUSION
For application in clinical research and practice, MIC values are always considered at the individual level, but determined in groups of patients. The interpretation comes with different forms of uncertainty. To appreciate the uncertainty, knowledge of the underlying distributions of change scores is indispensable.
26733706
Guidelines, Criteria, and Rules of Thumb for Evaluating Normed and Standardized Assessment Instruments in Psychology.
In the context of the development of prototypic assessment instruments in the areas of cognition, personality, and adaptive functioning, the issues of standardization, norming procedures, and the important psychometrics of test reliability and validity are evaluated critically. Criteria, guidelines, and simple rules of thumb are provided to assist the clinician faced with the challenge of choosing an appropriate test instrument for a given psychological assessment. Clinicians are often faced with the critical challenge of choosing the most appropriate available test instrument for a given psychological assessment of a child, adolescent, or adult of a particular age, gender, and class of disability. It is the purpose of this report to provide some criteria, guidelines, or simple rules of thumb to aid in this complex scientific decision. As such, it draws upon my experience with issues of test development, standardization, norming procedures, and important psychometrics, namely, test reliability and validity. As I and my colleagues noted in an earlier publication, the major areas of psychological functioning, in the normal development of infants, children, adolescents, adults, and elderly people, include cognitive, academic, personality, and adaptive behaviors (Sparrow, Fletcher, & Cicchetti, 1985). As such, the major examples or applications discussed in this article derive primarily, although not exclusively, from these several areas of human functioning.
39489899
Pain intensity assessment: a comparison of selected pain intensity scales for use in cognitively intact and cognitively impaired African American older adults.
The purpose of this study was to determine the reliability and validity of selected pain intensity scales including the Faces Pain Scale (FPS), the Verbal Description Scale, the Numeric Rating Scale, and the Iowa Pain Thermometer to assess pain in cognitively impaired minority older adults. A descriptive correlational design was used, and a convenience sample of 57 volunteers age 58 and older residing in the South was recruited for this study. The sample consisted of 8 males and 49 females with a mean age of 76. Fifty-nine percent of the sample completed an 11th grade education or less, and 59% completed high school or college. Seventy-seven percent (n = 44) of the sample scored 24 or less on the mental status exam, indicating some degree of cognitive impairment. The remaining 23% (n = 13) were cognitively intact. All of the participants were able to use each of the scales to rate their pain. Concurrent validity of the scales was supported with Spearman rank correlation coefficients ranging from.74 to.83 in the cognitively impaired group and.81 to.96 in the cognitively intact group. Test-retest reliability at a 2-week interval was acceptable in the cognitively intact group (Spearman rank correlations ranged from.73 to.83) and to a lesser degree in the cognitively impaired group (correlations ranged from.52 to.79). When asked about scale preference, both the cognitively impaired and the intact group indicated a preference for the FPS. Findings from this study suggest that cognitive impairment did not inhibit older minority participants' ability to use a variety of pain intensity scales. Additionally, options should be provided that address individual needs of older adults considering specific cognitive level and disability, education, gender, ethnicity, and cultural influences concerning perceptions of the various pain intensity scales.
969983
Psychometric properties of the Neck Disability Index and Numeric Pain Rating Scale in patients with mechanical neck pain.
OBJECTIVE
To examine the psychometric properties including test-retest reliability, construct validity, and minimum levels of detectable and clinically important change for the Neck Disability Index (NDI) and the numeric rating scale (NRS) for pain in a cohort of patients with neck pain.


DESIGN
Single-group repeated-measures design.


SETTING
Outpatient physical therapy (PT) clinics.


PARTICIPANTS
Patients (N=137) presenting to PT with a primary report of neck pain.


INTERVENTIONS
Not applicable.


MAIN OUTCOME MEASURES
All patients completed the NDI and the NRS at the baseline examination and at a follow-up. At the time of the follow-up, all patients also completed the global rating of change, which was used to dichotomize patients as improved or stable. Baseline and follow-up scores were used to determine the test-retest reliability, construct validity, and minimal levels of detectable and clinically important change for both the NDI and NRS.


RESULTS
Test-retest reliability was calculated using an intraclass correlation coefficient (ICC) (NDI ICC=.50; 95% confidence interval [CI], .25-.67; NRS ICC=.76; 95% CI, .51-.87). The area under the curve was .83 (95% CI, .75-.90) for the NDI score and .85 (95% CI, .78-.93) for the NRS score for determining between stable and improved patients. Thresholds for the minimum clinically important difference (MCID) for the NDI were 19-percentage points and 1.3 for the NRS.


CONCLUSIONS
Both the NDI and NRS exhibit fair to moderate test-retest reliability in patients with mechanical neck pain. Both instruments also showed adequate responsiveness in this patient population. However, the MCID required to be certain that the change in scores has surpassed a level that could be contributed to measurement error for the NDI was twice that which has previously been reported. Therefore the ongoing analyses of the properties of the NDI in a patient population with neck pain are warranted.
13470640
A note on the use of the intraclass correlation coefficient in the evaluation of agreement between two methods of measurement.
The intraclass correlation coefficient (rI) has been advocated as a statistic for assessing agreement or consistency between two methods of measurement, in conjunction with a significance test of the difference between means obtained by the two methods. We show that neither technique is appropriate for assessing the interchangeability of measurement methods. We describe an alternative approach based on estimation of the mean and standard deviation of differences between measurements by the two methods.
4546971
How to regress and predict in a Bland-Altman plot? Review and contribution based on tolerance intervals and correlated-errors-in-variables models.
Two main methodologies for assessing equivalence in method-comparison studies are presented separately in the literature. The first one is the well-known and widely applied Bland-Altman approach with its agreement intervals, where two methods are considered interchangeable if their differences are not clinically significant. The second approach is based on errors-in-variables regression in a classical (X,Y) plot and focuses on confidence intervals, whereby two methods are considered equivalent when providing similar measures notwithstanding the random measurement errors. This paper reconciles these two methodologies and shows their similarities and differences using both real data and simulations. A new consistent correlated-errors-in-variables regression is introduced as the errors are shown to be correlated in the Bland-Altman plot. Indeed, the coverage probabilities collapse and the biases soar when this correlation is ignored. Novel tolerance intervals are compared with agreement intervals with or without replicated data, and novel predictive intervals are introduced to predict a single measure in an (X,Y) plot or in a Bland-Atman plot with excellent coverage probabilities. We conclude that the (correlated)-errors-in-variables regressions should not be avoided in method comparison studies, although the Bland-Altman approach is usually applied to avert their complexity. We argue that tolerance or predictive intervals are better alternatives than agreement intervals, and we provide guidelines for practitioners regarding method comparison studies. Copyright © 2016 John Wiley & Sons, Ltd.
4493951
Psychometric properties of the shortened disabilities of the Arm, Shoulder, and Hand Questionnaire (QuickDASH) and Numeric Pain Rating Scale in patients with shoulder pain.
PURPOSE
To examine the psychometric properties of the Shortened Disabilities of the Arm, Shoulder, and Hand Questionnaire (QuickDASH) and the Numeric Pain Rating Scale (NPRS) in patients with shoulder pain.


METHODS
Single-group repeated measures design in which 101 patients presenting to physical therapy completed the QuickDASH and the NPRS at the baseline examination and at a follow-up visit. At the follow-up all patients also completed the Global Rating of Change (GRC), which was used to dichotomize patients as improved or stable. Baseline and follow-up scores were used to determine the test-retest reliability, construct validity and minimal levels of detectable and clinically important change for both the QuickDASH and NPRS.


RESULTS
Test-retest reliability was 0.90 for the QuickDASH and 0.74 for the NPRS. The minimal clinically important difference (MCID) was 8.0 points for the QuickDASH and 1.1 for the NPRS.


CONCLUSION
The NPRS and QuickDASH exhibit good test-retest reliability and responsiveness in patients with shoulder pain.
27699725
Evaluating measurement responsiveness.
Strategies to improve responsiveness of quantitative questionnaires and methods for evaluating responsiveness are reviewed. Current methods of evaluating responsiveness are not standardized and are themselves unevaluated. A conceptual model of assessing responsiveness is proposed.
24532480
Reproducibility and responsiveness of health status measures. Statistics and strategies for evaluation.
Before being introduced to wide use, health status instruments should be evaluated for reliability and validity. Increasingly, they are also tested for responsiveness to important clinical changes. Although standards exist for assessing these properties, confusion and inconsistency arise because multiple statistics are used for the same property; controversy exists over how to measure responsiveness; many statistics are unavailable on common software programs; strategies for measuring these properties vary; and it is often unclear how to define a clinically important change in patient status. Using data from a clinical trial of therapy for back pain, we demonstrate the calculation of several statistics for measuring reproducibility and responsiveness, and demonstrate relationships among them. Simple computational guides for several statistics are provided. We conclude that reproducibility should generally be quantified with the intraclass correlation coefficient rather than the more common Pearson r. Assessing reproducibility by retest at one-to-two week intervals (rather than a shorter interval) may result in more realistic estimates of the variability to be observed among control subjects in a longitudinal study. Instrument responsiveness should be quantified using indicators of effect size, a modified effect size statistic proposed by Guyatt, or the use of receiver operating characteristic (ROC) curves to describe how well various score changes can distinguish improved from unimproved patients.
11875257
Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale
&NA; Pain intensity is frequently measured on an 11‐point pain intensity numerical rating scale (PI‐NRS), where 0=no pain and 10=worst possible pain. However, it is difficult to interpret the clinical importance of changes from baseline on this scale (such as a 1‐ or 2‐point change). To date, there are no data driven estimates for clinically important differences in pain intensity scales used for chronic pain studies. We have estimated a clinically important difference on this scale by relating it to global assessments of change in multiple studies of chronic pain. Data on 2724 subjects from 10 recently completed placebo‐controlled clinical trials of pregabalin in diabetic neuropathy, postherpetic neuralgia, chronic low back pain, fibromyalgia, and osteoarthritis were used. The studies had similar designs and measurement instruments, including the PI‐NRS, collected in a daily diary, and the standard seven‐point patient global impression of change (PGIC), collected at the endpoint. The changes in the PI‐NRS from baseline to the endpoint were compared to the PGIC for each subject. Categories of ‘much improved’ and ‘very much improved’ were used as determinants of a clinically important difference and the relationship to the PI‐NRS was explored using graphs, box plots, and sensitivity/specificity analyses. A consistent relationship between the change in PI‐NRS and the PGIC was demonstrated regardless of study, disease type, age, sex, study result, or treatment group. On average, a reduction of approximately two points or a reduction of approximately 30% in the PI‐NRS represented a clinically important difference. The relationship between percent change and the PGIC was also consistent regardless of baseline pain, while higher baseline scores required larger raw changes to represent a clinically important difference. The application of these results to future studies may provide a standard definition of clinically important improvement in clinical trials of chronic pain therapies. Use of a standard outcome across chronic pain studies would greatly enhance the comparability, validity, and clinical applicability of these studies.
25578192
Defining the clinically important difference in pain outcome measures
&NA; The purpose of this study was to determine the levels of change on standard pain scales that represent clinically important differences to patients. Data from analgesic studies are often difficult to interpret because the clinical importance of the results is not obvious. Differences between groups, as summarized by a change in mean values over time, can be difficult to apply to clinical care. Baseline scores vary widely and group mean differences could reflect large changes in a few patients, small changes in many patients, or any combination of these outcomes. Determination of the proportion of patients who have a clinically important improvement in their pain would provide a more interpretable result with direct clinical implications. However, determining a clinically important outcome requires information about the degree of change over time that is clinically important. Data from the titration phase of a multiple cross‐over randomized clinical trial of oral transmucosal fentanyl citrate (OTFC) for the treatment of cancer‐related breakthrough pain were re‐analyzed to examine the differences in pain scores between treatment episodes that did and did not yield adequate pain relief. The scales evaluated were absolute pain intensity difference (PID, 0–10 scale), percentage pain intensity difference (PID%, 0–100% scale), pain relief (PR, 0 (none), 1 (slight), 2 (moderate), 3 (lots), 4 (complete)), sum of the pain intensity difference (SPID over 60 min), percentage of maximum total pain relief (% Max TOTPAR over 60 min), and global medication performance (0 (poor), 1 (fair), 2 (good), 3 (very good), 4 (excellent)). Adequate relief was defined by the patient's decision not to use another dose of opioid medication as a rescue, in addition to the study medication, to treat each painful episode. One hundred thirty OTFC naive patients contributed data on 1268 episodes of breakthrough pain. The scales that were converted to a percentage change yielded the best accuracy in predicting adequate relief, with balanced sensitivity and specificity. The best cut‐off point for both the % Max TOTPAR and the PID% was 33%. The best cut‐off points for the absolute scales were absolute pain intensity difference of 2, pain relief of 2 (moderate), and SPID of 2. The global medication performance of 2 (good) had excellent values as well. This study presents data‐derived cut‐off points for the changes in several pain scales, each reflecting the clinically important improvement for patients treating breakthrough cancer pain episodes with OTFC. Confirmation in other patient populations and different pain syndromes will be needed. The use of consistent clinically important cut‐off points as the primary outcome in future pain therapy clinical trials will enhance their validity, comparability, and clinical applicability.
35218849
Minimal Clinically Important Change for Pain Intensity, Functional Status, and General Health Status in Patients With Nonspecific Low Back Pain
Study Design. Cohort study. Objectives. To estimate the Minimal Clinically Important Change (MCIC) of the pain intensity numerical rating scale (PI-NRS), the Quebec Back Pain Disability Scale (QBPDS), and the Euroqol (EQ) in patients with low back pain. Summary of Background Data. MCIC can provide valuable information for researchers, healthcare providers, and policymakers. Methods. Data from a randomized controlled trial with 442 patients with low back pain were used. The MCIC was estimated over a 12-week period, and three different methods were used: 1) mean change scores, 2) minimal detectable change, and 3) optimal cutoff point in receiver operant curves. The global perceived effect scale (GPE) was used as an external criterion. The effect of initial scores on the MCIC was also assessed. Results. The MCIC of the PI-NRS ranged from 3.5 to 4.7 points in (sub)acute patients and 2.5 to 4.5 points in chronic patients with low back pain. The MCIC of the QBPDS was estimated between 17.5 to 32.9 points and 8.5 to 24.6 points for (sub)acute and chronic patients with low back pain. The MCIC for the EQ ranged from 0.07 to 0.58 in (sub)acute patients and 0.09 to 0.28 in patients with chronic low back pain. Conclusion. Reporting the percentage of patients who have made a MCIC adds to the interpretability of study results. We present a range of MCIC values and advocate the choice of a single MCIC value according to the specific context.
15560944
Words that describe chronic musculoskeletal pain: implications for assessing pain quality across cultures
Background People from different cultures who speak different languages may experience pain differently. This possible variability has important implications for evaluating the validity of pain quality measures that are directly translated into different languages without cultural adaptations. The aim of this study was to evaluate the impact of language and culture on the validity of pain quality measures by comparing the words that individuals with chronic pain from Nepal use to describe their pain with those used by patients from the USA. Methods A total of 101 individuals with chronic musculoskeletal pain in Nepal were asked to describe their pain. The rates of the different pain descriptor domains and phrases used by the Nepali sample were then compared to the published rates of descriptors used by patients from the USA. The content validity of commonly used measures for assessing pain quality was then evaluated. Results While there was some similarity between patients from Nepal and the USA in how they describe pain, there were also important differences, especially in how pain quality was described. For example, many patients from Nepal used metaphors to describe their pain. Also, the patients from Nepal often used a category of pain descriptor – which describes a physical state – not used by patients from the USA. Only the original McGill Pain Questionnaire was found to have content validity for assessing pain quality in patients from Nepal, although other existing pain quality measures could be adapted to be content valid by adding one or two additional descriptors, depending on the measure in question. Conclusion The findings indicate that direct translations of measures that are developed using samples of patients from one country or culture are not necessarily content valid for use in other countries or cultures; some adaptations may be required in order for such measures to be most useful in new language and culture.
25669042
Choice of external criteria in back pain research: Does it matter? Recommendations based on analysis of responsiveness
Abstract Understanding a change score is indispensable for interpretation of results from clinical studies. One way of determining the relevance of change scores is through the use of transition questions that assesses patients’ retrospective perception of treatment effect. Unfortunately, results from studies using transition questions are difficult to compare since wording of questions and definitions of important improvements vary between studies. The objectives of this study were to determine the consequence of using different transition questions on pain and disability measures and make proposals for a standardised use of such questions. Two hundred and thirty‐three patients with low back pain and/or leg pain were recruited. Participants were followed over an 8‐week period and randomised to two groups receiving a 7‐ (TQ1) and 15‐point (TQ2) transition question, respectively, in addition to a numeric rating scale evaluating the importance of the perceived change. Four external criteria were generated using both stringent and less stringent standards to dichotomise patients. Discrimination was determined using area under the receiver operating characteristic curve (ROCauc) and responsiveness using standardised response mean (SRM). Results demonstrated small variations in ROCauc across the external criteria for all outcome measures. 7% more patients were classified as improved in the group receiving the 15‐point TQ compared to the 7‐point TQ (stringent standard). SRMs were higher for the retrospective TQs in primary sector patients compared to the serial measures with no difference between TQ1 and TQ2. On the basis of our findings we have outlined a proposal for a standardised use of transition questions.
4230514
The psychometric properties of an Arabic numeric pain rating scale for measuring osteoarthritis knee pain
Abstract Purpose: The aims of this study were to translate the numeric rating scale (NRS) into Arabic and to evaluate the test–retest reliability and convergent validity of an Arabic Numeric Pain Rating Scale (ANPRS) for measuring pain in osteoarthritis (OA) of the knee. Methods: The English version of the NRS was translated into Arabic as per the translation process guidelines for patient-rated outcome scales. One hundred twenty-one consecutive patients with OA of the knee who had experienced pain for more than 6 months were asked to report their pain levels on the ANPRS, visual analogue scale (VAS), and verbal rating scale (VRS). A second assessment was performed 48 h after the first to assess test–retest reliability. The test–retest reliability was calculated using the intraclass correlation coefficient (ICC2,1). The convergent validity was assessed using Spearman rank correlation coefficient. In addition, the minimum detectable change (MDC) and standard error of measurement (SEM) were also assessed. Results: The repeatability of ANPRS was good to excellent (ICC 0.89). The SEM and MDC were 0.71 and 1.96, respectively. Significant correlations were found with the VAS and VRS scores (p <0.01). Conclusions: The Arabic numeric pain rating scale is a valid and reliable scale for measuring pain levels in OA of the knee. Implications for Rehabilitation The Arabic Numeric Pain Rating Scale (ANPRS) is a reliable and valid instrument for measuring pain in osteoarthritis (OA) of the knee, with psychometric properties in agreement with other widely used scales. The ANPRS is well correlated with the VAS and NRS scores in patients with OA of the knee. The ANPRS appears to measure pain intensity similar to the VAS, NRS, and VRS and may provide additional advantages to Arab populations, as Arabic numbers are easily understood by this population.
12262731
Using ROC Curves to Choose Minimally Important Change Thresholds when Sensitivity and Specificity Are Valued Equally: The Forgotten Lesson of Pythagoras. Theoretical Considerations and an Example Application of Change in Health Status
Background Receiver Operator Characteristic (ROC) curves are being used to identify Minimally Important Change (MIC) thresholds on scales that measure a change in health status. In quasi-continuous patient reported outcome measures, such as those that measure changes in chronic diseases with variable clinical trajectories, sensitivity and specificity are often valued equally. Notwithstanding methodologists agreeing that these should be valued equally, different approaches have been taken to estimating MIC thresholds using ROC curves. Aims and objectives We aimed to compare the different approaches used with a new approach, exploring the extent to which the methods choose different thresholds, and considering the effect of differences on conclusions in responder analyses. Methods Using graphical methods, hypothetical data, and data from a large randomised controlled trial of manual therapy for low back pain, we compared two existing approaches with a new approach that is based on the addition of the sums of squares of 1-sensitivity and 1-specificity. Results There can be divergence in the thresholds chosen by different estimators. The cut-point selected by different estimators is dependent on the relationship between the cut-points in ROC space and the different contours described by the estimators. In particular, asymmetry and the number of possible cut-points affects threshold selection. Conclusion Choice of MIC estimator is important. Different methods for choosing cut-points can lead to materially different MIC thresholds and thus affect results of responder analyses and trial conclusions. An estimator based on the smallest sum of squares of 1-sensitivity and 1-specificity is preferable when sensitivity and specificity are valued equally. Unlike other methods currently in use, the cut-point chosen by the sum of squares method always and efficiently chooses the cut-point closest to the top-left corner of ROC space, regardless of the shape of the ROC curve.
6566608
Likert scales, levels of measurement and the “laws” of statistics
Reviewers of research reports frequently criticize the choice of statistical methods. While some of these criticisms are well-founded, frequently the use of various parametric methods such as analysis of variance, regression, correlation are faulted because: (a) the sample size is too small, (b) the data may not be normally distributed, or (c) The data are from Likert scales, which are ordinal, so parametric statistics cannot be used. In this paper, I dissect these arguments, and show that many studies, dating back to the 1930s consistently show that parametric statistics are robust with respect to violations of these assumptions. Hence, challenges like those above are unfounded, and parametric methods can be utilized without concern for “getting the wrong answer”.
15212162
Validity of four pain intensity rating scales
Summary The validity of 4 common pain intensity measures is supported, although the 0–10 Numerical Rating Scale and Visual Analogue Scale evidenced the most responsivity. Abstract The Visual Analogue Scale (VAS), Numerical Rating Scale (NRS), Verbal Rating Scale (VRS), and the Faces Pain Scale‐Revised (FPS‐R) are among the most commonly used measures of pain intensity in clinical and research settings. Although evidence supports their validity as measures of pain intensity, few studies have compared them with respect to the critical validity criteria of responsivity, and no experiment has directly compared all 4 measures in the same study. The current study compared the relative validity of VAS, NRS, VRS, and FPS‐R for detecting differences in painful stimulus intensity and differences between men and women in response to experimentally induced pain. One hundred twenty‐seven subjects underwent four 20‐second cold pressor trials with temperature order counterbalanced across 1°C, 3°C, 5°C, and 7°C and rated pain intensity using all 4 scales. Results showed statistically significant differences in pain intensity between temperatures for each scale, with lower temperatures resulting in higher pain intensity. The order of responsivity was as follows: NRS, VAS, VRS, and FPS‐R. However, there were relatively small differences in the responsivity between scales. A statistically significant sex main effect was also found for the NRS, VRS, and FPS‐R. The findings are consistent with previous studies supporting the validity of each scale. The most support emerged for the NRS as being both (1) most responsive and (2) able to detect sex differences in pain intensity. The results also provide support for the validity of the scales for use in Portuguese samples.
6113129
A comparison of three self-report pain scales in adults with acute pain.
BACKGROUND
Several pain rating methods are used to quantify pain. Although these instruments have been extensively studied, their inter-agreement, especially in emergency department (ED) settings, has yet to be determined.


OBJECTIVE
This study was designed to assess the agreement between Visual Analog Scale (VAS), Color Analog Scale (CAS), and verbally administered Numeric Rating Scale (NRS) in the emergency setting.


METHODS
A sample of 150 adult patients presenting with acute pain to two EDs was recruited. Patients' pain severity at presentation, 30 and 60 min later was assessed using the three pain scales. The agreement between pain scales was assessed using Bland-Altman method and Spearman correlation. We described a composite measure to serve as the gold standard and to be compared with each score. Factor analysis was also performed to assess the underlying construct.


RESULTS
Spearman correlation coefficients between NRS and CAS, NRS and VAS, and CAS and VAS were 0.95, 0.94, and 0.94, respectively (p < 0.001). On a scale of 0 to 10, the 95% limits of agreement between the paired NRS and VAS, VAS and CAS, and CAS and NRS as measured by Bland-Altman method ranged from -2.0 to 2.6, from -2.7 to 2.0, and from -2.1 to 2.0, respectively. The Kaiser-Meyer-Oklin measure of sampling adequacy was 0.785 and Bartlett's test for sphericity was significant (p < 0.001).


CONCLUSIONS
The three pain scales were strongly correlated at all time periods. The findings suggest that NRS, CAS, and VAS can be interchangeably applied for acute pain measurement in adult patients.