Trends in all-cause and cardiovascular mortality in patients with incident rheumatoid arthritis: a 20-year follow-up matched case-cohort study

Abstract

Objectives: To examine all-cause and cardiovascular disease (CVD) mortality in consecutive cohorts of patients with incident RA, compared with population comparators.

Methods: The Oslo RA register inclusion criteria were diagnosis of RA (1987 ACR criteria) and residency in Oslo. Patients with disease onset 1994-2008 and 10 matched comparators for each case were linked to the Norwegian Cause of Death Registry. Hazard ratios for all-cause and CVD mortality were calculated for 5, 10, 15 and 20 years of observation using stratified cox-regression models. Mortality trends were estimated by multivariate cox-regression.

Results: 443, 479 and 469 cases with disease incidence in the periods 94-98, 99-03 and 04-08 were matched to 4430, 4790 and 4690 comparators, respectively. For cases diagnosed between 1994 and 2003, the all-cause mortality of cases diverged significantly from comparators after 10 years of disease duration [hazard ratio (95% CI) 94-98 cohort 1.42 (1.15-1.75): 99-03 cohort 1.37 (1.08-1.73)]. CVD related mortality was significantly increased after 5 years for the 94-98 cohort [hazard ratio (95% CI) 1.86 (1.16-2.98) and after 10 years for the 99-03 cohort 1.80 (1.20-2.70)]. Increased mortality was not observed in the 04-08 cohort where cases had significantly lower 10-year all-cause and CVD mortality compared with earlier cohorts.

Conclusion: All-cause and CVD mortality were significantly increased in RA patients diagnosed from 1994 to 2003, compared with matched comparators, but not in patients diagnosed after 2004. This may indicate that modern treatment strategies have a positive impact on mortality in patients with RA.

Keywords: cardiovascular disease; epidemiology; mortality; rheumatoid arthritis; treat to target.