To develop and validate a specific individual burden questionnaire, BONe'S (Burden of Osteoarthritis New Scale), assessing osteoarthritis (OA) patients in the broadest sense.
Items included in BONe'S were identified by literature review, and patient/healthcare practitioner interviews, and refined via item reduction and exploratory factor analysis (EFA). Internal consistency was calculated using Cronbach's α; concurrent validity was assessed by calculating the correlation between BONe'S and the Short Form (SF)-12 Health Survey and Psychological General Well-Being Index (PGWBI). Discriminant validity was analyzed by age, gender and number of OA locations.
From an initial list of 56 items, the final BONe'S questionnaire consisted of 20 questions (5 dimensions) based on EFA. BONe'S was evaluated in patients with OA (n = 200; mean age 69.4 ± 7.0 years, 86% of patients aged >60 years, 91.5% women). BONe'S demonstrated excellent internal coherence (Cronbach's α: 0.86). Individual BONe'S dimensions correlated well with the overall BONe'S score (highest: 'Independence' [r = 0.91]; lowest: 'Hygiene & Beauty' [r = 0.56]), and to each other dimension, and also correlated well (inversely) with the SF-12 and, to a slightly lesser extent, the PGWBI. The only exception was 'Budget', but this dimension was important and relevant in the subpopulation of active OA patients (r = 0.40). The mean BONe'S score for subjects with one or two affected joints was significantly lower than for subjects with three or more affected joints. The BONe'S score also differed according to gender and age. The original French BONe'S has also been adapted (linguistically and culturally) to English, Russian and Portuguese. Limitations include the fact that BONe'S was developed in a predominantly female population, in patients receiving a pharmacological intervention, has not been evaluated in a large population and has not been compared with other OA tools, including WOMAC, Lequesne and KOOS.
The BONe'S questionnaire is a short (20-item) validated tool for evaluating the specific individual burden of OA in a holistic manner.