How much of the increased incidence of heart failure in rheumatoid arthritis is attributable to traditional cardiovascular risk factors and ischemic heart disease?

OBJECTIVE: To compare the proportion of the risk for the development of heart failure (HF) that is attributable to traditional cardiovascular (CV) risk factors, ischemic heart disease (IHD), and alcohol abuse between subjects with and subjects without rheumatoid arthritis (RA). METHODS: A population-based inception cohort of RA patients was assembled along with a similar cohort of subjects without RA. All individuals were followed up through their complete medical records, until HF incidence, death, migration, or January 1, 2001. The attributable risk of HF was estimated as the difference between the observed cumulative incidence of HF in each cohort (estimated from multivariable Cox models and adjusted for the competing risk of death) and the predicted cumulative incidence of HF in the absence of risk factors, with results expressed as a percentage of the observed cumulative incidence. RESULTS: A total of 575 RA subjects and 583 non-RA subjects (mean age 57 years, 73% women) without HF at incidence/index date had a mean followup of 15.1 and 17.0 years, respectively. During that period, 165 RA and 115 non-RA subjects had a first episode of HF, with a cumulative incidence of 36.3% and 20.4%, respectively, at age 80 years. Among non-RA subjects, 77% of the HF at age 80 years was attributable to CV risk factors, IHD, and alcohol abuse combined, whereas among RA subjects, only 54% of the HF at age 80 years was attributable to these factors (P < 0.01). CONCLUSION: The excess risk of HF among RA patients is not explained by an increased frequency or effect of CV risk factors and IHD.