The inflammatory markers interleukin-6 and C-reactive protein as well as macroalbuminuria are independently predictive of heart failure, according to a study that followed nearly 7,000 Americans for a median of 4 years.
Each standard deviation increase in serum interleukin-6 or CRP level raised the risk of heart failure (HF) by 50% and 38%, respectively, while the presence of macroalbuminuria increased the risk 4.3-fold (J. Am. Coll. Cardiol. 2008;51:1775–83).
These associations were strong “even after adjustment for established risk factors, LV [left ventricular] dysfunction, and interim MI,” wrote Dr. Hossein Bahrami of Johns Hopkins University, Baltimore, and colleagues.
The community-based Multi-Ethnic Study of Atherosclerosis is a multicenter cohort study of 6,814 whites, blacks, Hispanics, and Chinese Americans with no history of symptomatic cardiovascular disease. Overall, 79 participants developed HF during the study period and 26 of those individuals (33%) had an interim MI. Participants who developed HF were more likely to be older, male, obese, and current smokers and to have hypertension and diabetes.
The presence of metabolic syndrome at baseline (seen in 35% of participants) more than doubled the risk of HF. Specifically, the absolute risk of HF in obese individuals was 16/1,000, compared with 10/1,000 in the nonobese. However, the association between obesity and incident HF was no longer significant after the model was adjusted to include the two inflammatory markers, they reported.
Very few participants (1.3%) had left ventricular ejection fraction (LVEF) below 50%, though 10% of participants had left ventricular hypertrophy (LVH) at baseline by Framingham criteria. Among the individuals who developed HF, rates of LVEF below 50% and LVH were 15% and 32%, respectively.
LVEF was the strongest predictor of incident HF and was therefore incorporated into the multivariate analysis. Among the 60 participants with LV function data at time of HF diagnosis, 87% had LVEF of 30% or greater, 65% had LVEF of 40% or greater, and 55% had LVEF of 50% or greater, the investigators wrote.