Increased case fatality rates following a first acute cardiovascular event in patients with rheumatoid arthritis

Abstract

Objective: Among patients with rheumatoid arthritis (RA), cardiovascular mortality is increased compared with the rate among unaffected peers. In this study, 30-day mortality rates following a first acute cardiovascular event (myocardial infarction or stroke) were compared between RA patients and the general population.

Methods: All cases of a first acute cardiovascular event between July 1, 2001 and November 30, 2003 in Victoria, Australia were identified from hospital discharge data. Individuals were classified as having RA when an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) or an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification code for RA was recorded at the index admission or during the previous 5 years. Thirty-day mortality rates were determined from linkage to the state death registry.

Results: A total of 29,924 patients experienced a first cardiovascular event during the study period, 359 (1.2%) of whom had RA. Thirty-day cardiovascular mortality was 17.6% in RA patients versus 10.8% in non-RA patients. In fully adjusted models, the odds ratio (OR) for cardiovascular death in RA patients following a first acute cardiovascular event was 1.6 (95% confidence interval [95% CI] 1.2-2.2). Analysis of index event subgroups revealed that this increased case fatality rate in patients with RA was accounted for almost entirely by excess deaths following myocardial infarction. The adjusted ORs for cardiovascular death in RA after myocardial infarction and stroke were 1.9 (95% CI 1.3-2.7) and 1.2 (95% CI 0.7-2.0), respectively.

Conclusion: RA patients have a substantially increased risk of 30-day case fatality following myocardial infarction, but not stroke, compared with non-RA patients. This higher case fatality rate is likely to contribute to the observed overall excess of cardiovascular deaths in RA populations.