Does rheumatoid arthritis equal diabetes mellitus as an independent risk factor for cardiovascular disease? A prospective study

OBJECTIVE: Rheumatoid arthritis (RA) is associated with an increased risk of cardiovascular disease (CVD), but longitudinal observations are limited and the precise magnitude is unknown. We prospectively assessed the incidence of CVD in patients with RA compared with patients with type 2 diabetes mellitus (DM) and the general population. METHODS: The 3-year incidence rate of CVD was determined in a prospective cohort (the Cardiovascular Research and Rheumatoid Arthritis Study) of 353 outpatients with RA, and was compared with that in 1,852 population-based cohort study participants (155 had type 2 DM). We investigated fatal and nonfatal CVD (according to International Classification of Diseases, Ninth Revision criteria) and used Cox proportional hazards models to assess the incidence of CVD in RA, type 2 DM, and the general population. RESULTS: The 3-year incidence of CVD was 9.0% in patients with RA and 4.3% in the general population, corresponding with an incidence rate of 3.30 per 100 patient-years (95% confidence interval [95% CI] 2.08-4.25) and 1.51 per 100 person-years (95% CI 1.18-1.84), respectively. Compared with the general population, the age- and sex-adjusted hazard ratio (HR) for RA was 1.94 (95% CI 1.24-3.05, P = 0.004). Neither exclusion of patients with prior CVD at baseline nor adjustment for cardiovascular risk factors significantly influenced this. Compared with the nondiabetic population, nondiabetic patients with RA and those with type 2 DM had comparable HRs, 2.16 (95% CI 1.28-3.63, P = 0.004) and 2.04 (95% CI 1.12-3.67, P = 0.019), respectively. CONCLUSION: The risk of CVD in RA was significantly elevated compared with the general population, and comparable with the magnitude of risk in type 2 DM.