Long-term Absolute Risk for Cardiovascular Disease Stratified by Fasting Glucose Level

Abstract

Objective: To estimate the long-term absolute risk for cardiovascular disease (CVD) according to fasting glucose (FG) levels below the threshold of diabetes.

Research design and methods: We pooled data from seven observational cohorts of U.S. black and white men and women followed from 1960 to 2015. We categorized FG as follows: <5.0, 5.0-5.5, 5.6-6.2, 6.3-6.9 mmol/L, and diabetes (FG ≥7.0 mmol/L or use of diabetes medications). CVD was defined as fatal/nonfatal coronary heart disease and fatal/nonfatal stroke. We estimated the risk of CVD by FG category at index age 55 years using a modified Kaplan-Meier survival analysis, adjusted for the competing risk of non-CVD death. We also assessed risk for incident CVD according to change in FG before 50 years of age, specifically among the categories <5.6 mmol/L, 5.6-6.9 mmol/L, and diabetes.

Results: Our sample included 19,630 individuals (6,197 blacks and 11,015 women) without a prior CVD event. Risk for CVD through 85 years of age ranged from 15.3% (<5.0 mmol/L) to 38.6% (diabetes levels) among women and from 21.5% (5.0-5.5 mmol/L) to 47.7% (diabetes levels) among men. An FG of 6.3-6.9 mmol/L was associated with higher long-term CVD risk compared with the lowest FG among men but not women. Increases in glucose during midlife with conversion to diabetes were associated with higher cardiovascular risk (1.3- to 3.6-fold) than increases in glucose below the diabetes threshold.

Conclusions: Middle-age individuals with diabetes have high long-term absolute risk for CVD. These data strongly support the importance of blood glucose monitoring in midlife for CVD prevention.

Figure 1

Absolute risk (with 95% confidence limits) for incident CVD over 20 years from 55 years of age according to subgroup of normal (FG <5.6 mmol/L and HbA_1c <5.7 [<39 mmol/mol]), prediabetes (FG 5.6–6.9 mmol/L or HbA_1c 5.7–6.4% [39–47 mmol/mol]), and diabetes (FG ≥7.0 mmol/L or HbA_1c ≥6.5% [≥48 mmol/mol] or diabetes medication use) for black and white women and men.