β-Cell Function as a Predictor of Coronary Heart Disease, Death, and Costs
Abstract Number: 241-OR
Authors: LESLEY CURTIS, BRADLEY HAMMILL, M. ANGELYN BETHEL, LAWRENCE LIAO, KEVIN SCHULMAN.
Institutions: Durham, NC.
Results: An association between impaired glucose tolerance, increased cardiovascular risk, and death exists, but the relationship of β-cell function to outcomes is unclear. In a prospective, population-based elderly cohort from the NHLBI Cardiovascular Health Study, we examined the impact of β-cell function on incident coronary heart disease (CHD), death, and costs A total of 4,555 subjects not taking insulin and for whom lab data were present were available for analysis. The computer-based homeostasis model assessment was used to calculate indices of β-cell function (HOMA-B) and insulin sensitivity (HOMA-S) using baseline fasting glucose and insulin levels. Subjects without CHD at baseline (n=3593) were included in the incident CHD analysis. All subjects were included in the mortality analysis, and 4359 subjects were linked to Medicare claims for the cost analysis. All subjects were followed from 1992 through 1998 or until death. We used a discrete-time survival model to assess the effect of ß-cell function on CHD and death, and semiparametric estimators to calculate mean 6-year costs. The mean HOMA-B was 98 (SD 39.4) and the median was 92 (IQR 74-116), reflecting a healthy cohort. The mean HOMA-S was 81 (SD 37.8) and the median was 76 (IQR 52-108). Controlling for HOMA-S, a 20% decrease in HOMA-B was associated with a 9% increased odds of developing CHD (OR 1.09, 95% CI 1.05-1.14) and a 10% increased odds of death (95% CI 1.07-1.14). The relationships persisted after the addition of sociodemographic and clinical confounders (CHD OR=1.08, 95% CI 1.03-1.12 and death OR=1.09, 95% CI 1.06-1.13). Mean 6-year costs were $23,030 (SD $23,003). Controlling for HOMA-S, a 20% decrease in HOMA-B was associated with a 3% increase in costs (95% CI, 0.7%-5.1%). The significant association did not persist when confounders were added. We conclude that β-cell function is a significant predictor of incident CHD and death after controlling for HOMA-S and confounders. We continue to explore the relationship between β-cell function and health care costs.