Relationship between patient-reported disease severity and other clinical outcomes in osteoarthritis: a European perspective.

Objective: To determine how patient-rated osteoarthritis (OA) severity correlates with other patient-reported and clinical outcomes in the European clinical setting.

Methods: We used the Adelphi Arthritis VII (2008) Disease Specific Program (DSP). OA severity was patient-rated using the question 'How bad would you say your arthritis is now?' with responses of 'mild,' 'moderate,' and 'severe.' Patient-reported outcomes included a 0-100 mm pain visual analogue scale (VAS); questions on daily functioning; Work Productivity and Activity Impairment (WPAI) scale; and EuroQoL (EQ-5D). Regression models and chi-square analyses evaluated relationships between self-rated OA severity and other outcomes.

Results: Patient-reported data were available from 1739 individuals (63.1% female, mean age 64.4 [standard deviation 11.9] years) from France, Germany, Italy, Spain, and the UK. With increasing OA severity; mild (24.5%), moderate (56.3%), severe (19.2%), statistically significant differences (p<0.05) were observed with higher pain VAS scores (28.3, 49.9, 69.2, respectively), reduced function, and greater overall work impairment due to OA (24.3%, 38.5%, 68.6%, respectively). Significant associations of patient-reported OA severity with function and health status were indicated, including the EQ-5D health state index; 0.77 (mild), 0.62 (moderate), 0.30 (severe) (p<0.0001). Physicians tended to overestimate patients who rated their OA as mild, and underrate patients who rated their OA as severe.

Conclusions: In five European countries, patient-rated OA severity was associated with other patient-reported outcomes, and may be of benefit in the clinical setting when choosing treatment options aimed at improving pain, function and productivity, providing an accurate and tangible assessment of patient's perceptions of their disease.