How many life years are lost in patients with rheumatoid arthritis? Secular cause‐specific and all‐cause mortality in rheumatoid arthritis, and their predictors in a long‐term Australian cohort study

Abstract

There is an excess of mortality in patients with rheumatoid arthritis (RA) but no long-term Australian cohort data. To determine median life years lost, all-cause standardised mortality ratio (SMR) and cause-specific SMR, their predictors and secular change in Australian patients with RA. Study population was all patients seen by a rheumatologist between 1990 and 1994. Record linkage with Australian National Death Index was performed to determine fact and cause of death up to 2004. All-cause and cause-specific SMR, and median life years lost were determined. There were 35 (31%) deaths in the early 1990s cohort (n = 113), SMR 1.31 (95% 0.93, 1.80). There were 216 (44%) deaths in the pre-1990s established cohort (n = 495), SMR 1.73 (1.49, 1.95). Median life years lost in the early cohort was 6 years for males and 7 years for females compared with 8 and 10 years, respectively, in the established cohort. Patients with low disease activity score at baseline (DAS < 3.2), SMR was 0.8 (0.3, 2.2) and 1.5 (1.1, 2.2) for the early and established cohorts, and if DAS ≥3.2, SMR was 1.4 (1.02, 1.98) and 1.8 (1.5, 2.1) respectively. Primary cause of death was cardiovascular disease (SMR 1.43 (1.17, 1.74). Patients at most risk were those age 45-54 years. RA was listed as a comorbid condition on the death certificate in only 16% of patients. Within a period of 14 years, median life expectancy of patients with RA with disease onset in the early 1990s is reduced by 6-7 years. However, our results also suggest a secular reduction in excess mortality.