Physicians often classify patients' osteoarthritis (OA) severity subjectively. As treatment decisions are influenced by severity classifications, it is important to understand the factors that influence physicians' OA severity ratings. This research sought to empirically identify physician and patient characteristics that lead to a patient being perceived as having more severe OA.
Data were analyzed from the OA IX Disease Specific Program, a large cross-sectional survey of OA physicians and patients in Germany, the UK, and USA between September 2011 and January 2012. Eligible, consenting physicians completed a Patient Record Form (PRF) for 10 consecutive OA patients. The PRF asked physicians to report the patient's demographics [age, gender, body mass index (BMI), ethnicity], their assessment of the patients' symptom severity, treatment, probability for surgery, to rate their overall OA severity (mild, moderate or severe) and the factors that had influenced the rating. Chi-squared tests and analysis of variance were used to identify patient characteristics that significantly impacted physicians' OA severity ratings. Controlling for the significant patient characteristics, we then examined the impact of physician specialty on physician's OA severity ratings. Finally, we investigated the differences in physician-reported factors that influenced the physicians' rating of patients' severity between physician specialties.
Three hundred and sixty-three physicians [220 primary care physicians (PCPs), 48 rheumatologists, 95 orthopedic surgeons] recruited 3561 patients. Patients with greater age and BMI, worse symptoms and greater health care use were given higher OA severity ratings. Controlling for these factors, orthopedic surgeons rated their OA patients as more severe than PCPs and rheumatologists [adjusted odds ratio (OR) 1.8, 95% confidence interval (CI) 1.4-2.4]. Specialists (rheumatologists and orthopedic surgeons) were more likely than PCPs to use joint spaced narrowing based on X-ray and severity of joint deterioration radiographic severity to assess patients' OA severity (joint space narrowing: 79% and 78% vs 55%, P < 0.0001).
Patient age, BMI, presence and severity of symptoms and health care use significantly impacted physicians' OA severity ratings, but radiographic changes appeared to be given greater weight among orthopedic surgeons and rheumatologists than PCPs when assessing patient severity. Whether these differences translate into different treatment recommendations for similar patients is unknown, and warrants study.