Is diabetes mellitus a heart disease equivalent in women? Results from an international study of postmenopausal women in the Raloxifene Use for the Heart (RUTH) Trial

BACKGROUND: Several studies have concluded that diabetes mellitus and heart disease carry similar risk for future cardiovascular disease (CVD). Most of these studies were too small to quantify independent risks specific to women. The purpose of this study was to determine whether diabetes mellitus is a coronary heart disease (CHD) risk equivalent for prediction of future CHD and CVD events in women.

METHODS AND RESULTS: The Raloxifene Use for the Heart (RUTH) trial was an international, multicenter, double-blind, randomized, placebo-controlled trial of raloxifene and CVD outcomes in 10 101 postmenopausal women selected for high CHD risk. Of these, 3672 had a history of diabetes mellitus without known CHD, and 3265 had a history of CHD without known diabetes mellitus. Cox proportional hazard models were used to compare cardiovascular outcomes in these 2 groups. Mean age at baseline was 67.5 years; median follow-up was 5.6 years. There were 725 deaths, including 450 cardiovascular deaths. In age-adjusted analyses, diabetic women had an increased risk of all-cause mortality compared with women with CHD. Although the overall risk of CHD and CVD was lower in diabetic women compared with women with CHD, the risk of fatal CHD, fatal CVD, and all-cause mortality was similar (hazard ratio [95% confidence interval]: 0.85 [0.65-1.12], 0.99 [0.78-1.25], and 1.18 [0.98-1.42], respectively, after adjusting for age, lifestyle factors, CHD risk factors, statin use, and treatment assignment).

CONCLUSIONS: In the RUTH trial, diabetes mellitus was a CHD risk equivalent in women for fatal, but not nonfatal, CHD and CVD.