Prediction of mortality in rheumatoid arthritis based on disease activity markers

The risks and predictors for mortality in patients with rheumatoid arthritis (RA) were examined in a cohort of 152 consecutive outpatients (119 women, 33 men) seen in a 2 month period.

We evaluated 4 measures of disease activity: erythrocyte sedimentation rate (ESR), physician and patient global assessment of disease activity, and the Ritchie Articular Index (RAI) as mortality predictors, adjusting for disease severity, treatment, and cardiovascular disease (CVD) comorbidity.

During followup from 1978 through 1998, 111 patients (86 women, 25 men) died, and only one was lost to followup. The standardized mortality ratio for women was 161 (95% confidence interval 129-199), for men 152 (95% CI 99-223), and for both sexes combined 156 (95% CI 128-188). In a proportional hazards model adjusted for age and sex, at the beginning of the period and for the whole group, significant predictors of mortality were Steinbrocker functional class, Larsen index, CVD comorbidity, use of corticosteroids ever, ESR, and the physician and patient global assessment of disease activity; but the rheumatoid factor (RF), RAI, and use of disease modifying antirheumatic drugs were not significant predictors. When evaluating the 4 assessments of disease activity adjusting for confounders, only physician global assessment hazard ratio (HR) = 1.32 per 1 SD (95% CI 1.00-1.74) and ESR HR = 1.47 per 1 SD (95% CI 1.11-1.93) were significant predictors.

This longterm followup study of a single clinical patient cohort showed a significant increase in mortality among patients with RA compared to the general population in Malmö. In addition to disease damage and CVD comorbidity, measures of disease activity independently predicted mortality, which supports the hypothesis that improving these variables may also improve longterm outcome.