Impact of physician specialty on classification of physician-perceived patient severity for patients with osteoarthritis

Abstract

Purpose: To identify physician and patient characteristics that lead to a patient being perceived as having more severe OA. Methods: All data were analyzed from the Osteoarthritis IX Disease Specific Programme, a large cross-sectional non-hypothesis driven survey conducted in Germany, UK, and USA, collecting robust real-world data. Physicians recruited up to 10 consecutive consulting patients presenting with OA from September 2011 to January 2012. An ordinal logistic regression, controlling for physician clustering, was performed using a backward stepwise approach on preselected physician-reported patient attributes identified in the initial univariate selection process. This process produced an initial model identifying which attributes significantly effected physicians’ rating of OA severity. Refinement to the model included physician specialty and physician attributes (gender, qualification date) and use of diagnostic tools or techniques. McFadden's pseudo R-squared values were used to compare the fit of each model. Results: 363 physicians (220 primary care physicians (PCPs), 95 Rheumatologists (Rheums), 48 orthopedic surgeons (ORURGS)) recruited 3,561patients 24.9% of whom were assessed as mild, 52.0% moderate, and 23.1% severe; of these, 3332 (93.6%) had completed data for analysis. All physician-reported patient characteristics (demographics, pain rating, functionality rating, number of joints, analgesia level, symptoms ever suffered, concomitant condition), with the exception of patient gender, loss of movement, and number of autoimmune diseases, differed significantly between severity groups (p<.0001) at a univariate level. The multivariate model indicated that OSURGs (odds ratio 1.6, 95% Confidence interval 1.2 to 2.2) were more likely to perceive patients as more severe compared to PCPs and RHEUMs combined. The model also indicated that a greater age, body mass index (BMI), use of diagnostics [joint space narrowing based on X-ray, severity of pain symptom(s), impairment in the ability to function (e.g. walk, activities of daily living), severity of joint deterioration], and ever suffering from one or more of the symptoms (pain on movement, pain at rest, nocturnal wakening, loss of movement), are associated with greater severity. McFadden's R-squared increased from 0.35 to 0.37. Conclusions: Patient age, BMI, reported symptoms, disability and radiographic grade influenced physicians’ assessment of OA severity. Controlling for patient factors, OSURGs rated patient's severity as worse compared to RHEUMs and PCPS. Our results suggest that this effect could in part be due to a greater influence of radiographic findings on OA severity rating (potentially deemed more important by OSURGs in severity assessment). Further research is needed to understand other potential explanations for this difference.