Mortality Decreases in Patients with Rheumatoid Arthritis: a 15-Year Prospective Cohort Study

Background/Purpose Patients with rheumatoid arthritis (RA) have a higher mortality risk than the general population, with similar patterns over the last decades. However, more recent studies show conflicting results. Given these conflicting results, there is an obvious need to evaluate the risk of mortality in patients with RA, over a long period, using more recent mortality data. Objectives To investigate a) the mortality in a clinical cohort of patients with established rheumatoid arthritis in comparison with the general Dutch population over 15 years, b) the trend in the mortality ratio during the study period, and c) the causes of death and compare these with the general population. Methods In 1997, a sample of 1222 patients was randomly selected from the register of a large rheumatology outpatient clinic in Amsterdam. Their mortality and causes of death between 1997 and 2012 were obtained from Statistics Netherlands. The Standardized Mortality Ratio (SMR) for all-cause mortality and the number of life-years lost in the study period were calculated. Linear poisson regression analysis was performed to evaluate change in all-cause SMR over time. Finally, the SMRs for cause-specific mortality were calculated. Results The mean age of the population at baseline was 60.4 (SD 15.4) years and 72.6% of the patients were women. The estimated SMR (95% CI) for all-cause mortality was 1.54 (1.41, 1.67) with about one life-year lost over the study period. The SMR decreased with 2% annually (p = .05). Mortality increased for diseases of the circulatory system, respiratory system, musculoskeletal system, and digestive system (p <.05). Conclusion The observed mortality among patients with RA was more than 50% higher than in the general population. More than one life-year was lost over 15 years and the mortality seemed to decrease over time. The most frequent causes of death were the same as those in the general population. (...) Annual Standardized Mortality Ratio and 95% Confidence Interval.