Study shows that insulin resistant can be an independent risk factor for cardiovascular disease. The goal of the study was to clarify if insulin resistance (IR) would predict cardiovascular disease (CVD) independent of the metabolic syndrome (MetSyn). Although the cause of MetSyn is not well defined, IR has been proposed to be an important cause. Only a small number of population-based studies have sought to clarify if IR predicts CVD independent of MetSyn.
This was a prospective population-based study of 2,493 men and women, age 41 to 72 years, without major CVD at baseline. We defined MetSyn according to both the International Diabetes Foundation (IDF) and the National Cholesterol Education Program (NCEP) criteria, and we quantified IR by the homeostasis model assessment (HOMA-IR). Prevalence of MetSyn was 21% according to IDF criteria and 16% according to NCEP criteria. Accordingly, we defined IDF-HOMA-IR as belonging to the highest 21% of the HOMA-IR distribution, and NCEP-HOMA-IR as belonging to the highest 16% of the HOMA-IR distribution.
Over a median follow-up of 9.4 years, the incidence of CV end points (CV death, nonfatal ischemic heart disease, and nonfatal stroke) amounted to 233 cases. In proportional hazard models, adjusting for age, gender, smoking, and low-density lipoprotein cholesterol, and with IDF-HOMA-IR and IDF-MetSyn included in the same model, the relative risk of an end point was 1.67 (95% confidence interval [CI] 1.22 to 2.29) for IDF-HOMA-IR and 1.16 (95% CI 0.84 to 1.60) for IDF-MetSyn. The corresponding figures for NCEP-HOMA-IR and NCEP-MetSyn included in the same model were 1.49 (95% CI 1.07 to 2.07) and 1.56 (95% CI 1.12 to 2.17).
The present study provided interesting results: 1) IR predicted incident CVD independent of the MetSyn based on either IDF or NCEP criteria; 2) adjusted for IR, the MetSyn based on NCEP criteria was a significant predictor of CVD, whereas the MetSyn based on IDF criteria was not; 3) the MetSyn and IR were significant risk factors of CVD in the nondiabetic population; 4) IR, defined as belonging to the highest 20.6% of the HOMA-IR distribution, predicted incident CVD independent of the Framingham risk score with an approximate 1.5-fold increased risk; and 5) the rate of concordance among those individuals with the MetSyn and IR amounted to around 50%.
Although IR has been proposed as an important cause of the MetSyn, the present results showed that other causes must be present. Accordingly, the rate of concordance among those individuals with the MetSyn and IR only amounted to around 50%, and the correlation coefficients between HOMA-IR and the continuously distributed components of the MetSyn were not that high either. However, based on the medical literature,[2-4] it is reasonable to believe that IR is a major cause of the MetSyn, although the exact percentage of MetSyn cases caused by IR remains to be defined.
In conclusion from this study it was determined that, both HOMA-IR and NCEP-MetSyn were independent predictors of incident CVD.
R. Kahn, J. Buse, E. Ferrannini, M. Stern. The metabolic syndrome: time for a critical appraisal. Joint statement from the American Diabetes Association and the European Association for the Study of Diabetes. Diabetologia; 48 (2005), 1684-1699
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BLACK patients approximately 30% less likely than whites to receive treatment such as angioplasty after heart attack, compared to white patients, black patients were 23% less likely to be transferred to hospitals that provide specialized services, and overall they were about thirty-percent less likely to get those services. The risk of death for black patients was lower than for white patients during the first 30 days after hospital admission, but was up to 17% higher at one year. Ioana Popescu, M.D., M.P.H.University of Iowa