A Narrowing Mortality Gap: Temporal Trends of Cause-Specific Mortality in a National Matched Cohort Study in US Veterans With Rheumatoid Arthritis.

Abstract

To examine temporal trends in all-cause and cause-specific mortality in patients with rheumatoid arthritis (RA) in the Veterans Health Administration (VHA). We conducted a matched cohort study in the VHA from January 1, 2000 to December 31, 2017. Incident RA patients were matched up to 1:10 on age, sex, and VHA enrollment year to non-RA patients, then followed until death or end of study period. Cause of death was obtained from the National Death Index. Multivariable Cox regression models stratified by RA diagnosis years were used to examine trends in RA-related risk of all-cause and cause-specific mortality. Among 29,779 incident RA patients (matched to 245,226 non-RA patients), 9,565 deaths occurred. RA patients were at increased risk of all-cause (adjusted hazard ratio [HR_adj ] 1.23 [95% confidence interval (95% CI) 1.20-1.26]), cardiovascular (HR_adj 1.19 [95% CI 1.14-1.23]), cancer (HR_adj 1.19 [95% CI 1.14-1.24]), respiratory (HR_adj 1.46 [95% CI 1.38-1.55]), and infection-related mortality (HR_adj 1.59 [95% CI 1.41-1.80]). Interstitial lung disease was the cause of death most strongly associated with RA (HR_adj 3.39 [95% CI 2.88-3.99]). Nearly 70% of excess deaths in RA were attributable to cardiopulmonary disease. All-cause mortality risk related to RA was lower among those diagnosed during 2012-2017 (HR_adj 1.10 [95% CI 1.05-1.15]) compared to 2000-2005 (HR_adj 1.31 [95% CI 1.26-1.36]), but still higher than for non-RA controls (P < 0.001). Cause-specific mortality trends were similar. Excess RA-related mortality was driven by cardiovascular, cancer, respiratory, and infectious causes, particularly cardiopulmonary diseases. Although our findings support that RA-related mortality risk is decreasing over time, a mortality gap remains for all-cause and cause-specific mortality in RA.