SAN ANTONIO — Rheumatoid arthritis patients develop heart failure more frequently than the general population, and this increase does not appear to be explained by traditional risk factors, Cynthia Crowson said at the annual meeting of the American College of Rheumatology.
There have been many studies of heart disease in rheumatoid arthritis, but no one has previously looked at heart failure in particular, said Ms. Crowson, a statistician at the Mayo Clinic, Rochester, Minn.
The study followed 575 rheumatoid arthritis patients and 583 control subjects from the time they were 50–60 years of age (mean age 57 years) for 11–15 years, to see how many developed heart failure and what role was played by known cardiovascular risk factors.
Over the course of the study, 165 of the rheumatoid arthritis (RA) patients developed heart failure, as did 115 of the control subjects.
A statistical analysis of the subjects with heart failure—one that took into account each individual's risk factors—indicated that risk factors such as sedentary lifestyle and smoking played less of role in the heart failure of the RA patients than did that of the controls. Instead, the pathogenesis of RA itself may be to blame for the rates of heart failure, Ms. Crowson suggested.
Overall, the analysis indicated that 83% of the heart failure in the control subjects could be attributed to known cardiovascular risk factors and ischemic heart disease. By comparison, 45% of the heart failure in the rheumatoid arthritis patients could be attributed to such factors.
In the control subjects, 64% of the risk of heart failure was attributable to hypertension, but only 18% of the risk was associated with hypertension in the rheumatoid arthritis patients.
A history of ischemic heart disease (myocardial infarction, silent myocardial infarction, angina, or a revascularization procedure) was present in 26% of the control subjects, but only 17% of the risk in the RA patients.
Smoking accounted for 14% of the attributable risk in the control subjects, but only 3% in RA patients.
Body mass index tended to be fairly similar in the two groups; 23% of the RA patients had a BMI greater than 30, compared with 24% of the controls.
Smoking or a history of smoking was more common in the RA patients, but not dramatically so (55% versus 45%).