Objectives To investigate patterns in patient-reported and physician-reported disease outcomes in patients with rheumatoid arthritis (RA) from countries with different level of socioeconomic development.

Methods Data from a cross-sectional multinational study (COMOrbidities in RA) were used. Contribution of socioeconomic welfare (gross domestic product (GDP); low vs high) of country of residence to physician-reported (tender joint count, swollen joint count (SJC), erythrocyte sedimentation rate, disease activity score based on 28 joints assessment (DAS28)-3v based on these three components and physician global assessment) and patient-reported (modified Health Assessment Questionnaire (mHAQ), patient global assessment and fatigue) disease outcomes was explored in linear regressions, adjusting for relevant confounders.

Results In total, 3920 patients with RA from 17 countries (30 to 411 patients per country) were included, with mean age of 56 years (SD13) and 82% women. Mean SJC varied between 6.7 (Morocco) and 0.9 (The Netherlands), mean mHAQ ranged between 0.7 (Taiwan) and 1.5 (The Netherlands). Venezuela had the lowest (1.7) and the Netherlands the highest score on fatigue (5.0). In fully adjusted models, lower GDP was associated with worse physician-reported outcomes (1.85 and 2.84 more swollen and tender joints, respectively, and 1.0 point higher DAS28-3v), but only slightly worse performance-based patient-reported outcome (0.15 higher mHAQ), and with better evaluation-based patient-reported outcomes (0.43 and 0.97 points lower on patient global assessment and fatigue, respectively).

Conclusions In patients with RA, important differences in physician-reported and patient-reported outcomes across countries were seen, with overall a paradox of worse physician-reported outcomes but better patient-reported outcomes in low-income countries, while results indicate that these outcomes in multinational studies should be interpreted with caution. Research on explanatory factors of this paradox should include non-disease driven cultural factors influencing health.