Myocardial infarction and mortality following joint surgery in patients with rheumatoid arthritis: a retrospective cohort study

BACKGROUND: Rheumatoid arthritis (RA) is associated with an increased risk of myocardial infarction (MI) and post-MI fatality compared with the general population. In a previous study examining post-MI treatment in RA compared with controls we noted that a higher proportion of the RA patients had experienced MI following a surgical procedure. The aim of this study was to compare the risk of MI and mortality at 6 weeks and 12 months following joint surgery in patients with RA compared with the general population. METHODS: Individuals who had undergone joint surgery in Victoria, Australia between 1 July 2000 and 30 June 2007 were identified from routinely collected hospital administrative data. Logistic regression analysis was performed to examine odds of 6 week and 12 month MI and mortality in RA versus non-RA patients with adjustment for age, sex, comorbidities, socioeconomic status, patient type and admission type. Subgroup analysis of total hip and knee arthroplasty episodes was undertaken. RESULTS: A total of 308,589 episodes of joint surgery occurred among 240,571 individuals, with 3654 (1.2 %) occurring among patients with RA. At 6 weeks post joint surgery the adjusted odds ratio (OR) for MI was 1.50 (95 % CI 0.96-2.33), all-cause death was 1.85 (95 % CI 1.09-3.13) and cardiovascular death was 1.90 (95 % CI 1.07-3.37). At 12 months post joint surgery the adjusted OR of MI was 1.70 (95 % CI 1.27-2.28), all-cause death was 2.18 (95 % CI 1.66-2.86) and cardiovascular death was 2.30 (95 % CI 1.65-3.22). On analysis of joint surgeries other than hip or knee arthroplasty, people with RA were at greater risk of MI within 6 weeks (adjusted OR 2.32; 95 % CI 1.24-4.34) and 12 months (adjusted OR 2.20; 95 % CI 1.47-3.30) compared to those without RA, but no difference in odds of short term mortality were found. CONCLUSIONS: Following an episode of joint surgery RA patients have a significantly increased risk of death at 6 weeks, and MI and death at 12 months, compared to