The prevalence of type 2 diabetes is increasing worldwide, and diabetes is a strong adverse prognostic factor among patients with cardiovascular (CV) disease. Four classes of drugs that are commonly used for CV risk reduction, statins, niacin, thiazide diuretics, and ß-blockers, have been shown to increase the risk of new-onset diabetes (NOD) by 9% to 43% in meta-analyses or large-scale clinical trials. Clinical predictors for drug-related NOD appear to be similar to the predictors that have been described for NOD unrelated to drugs: fasting blood glucose N100 mg/dL and features of the metabolic syndrome such as body mass index N30 kg/m 2 , serum triglycerides N150 mg/dL, and elevated blood pressure, among others. The mechanisms whereby these drugs increase the risk of NOD are incompletely understood, although different hypotheses have been suggested. Lifestyle intervention consisting of diet and exercise has been shown in multiple studies to reduce the risk of NOD by approximately 50%, with persistent benefit during long-term follow-up. In patients at high risk for NOD, niacin should be avoided, and for hypertension, an angiotensin-converting enzyme inhibitor or even a ß 1 -selective blocker might be a better choice than a standard ß-blocker. For thiazide diuretics and particularly statins, benefit in terms of CV event reduction outweighs the risk of NOD. (Am Heart J 2014;167:421-8.) Worldwide, the prevalence of type 2 diabetes continues to increase rapidly, with more than 371 million cases in the year 2012.1 Diabetes is thus becoming a more prevalent risk factor for cardiovascular (CV) disease, and a higher proportion of patients with CV disease have diabetes. Among patients with CV disease, diabetes is a strong adverse prognostic factor. Controlling for blood pressure, low-density lipoprotein cholesterol, and glycosylated hemoglobin (HbA 1C ) levels reduces CV risk in patients with diabetes; however, only a minority of them successfully attains these multiple goals, 2 despite recent increasing use of drug treatment.
3Within this context, it is troublesome that some of the drugs used to reduce CV risk have been shown either to increase the risk of new-onset diabetes (NOD) or to interfere with glucose control in patients with established diabetes. The purpose of this article is to review clinical trial data for 4 commonly used classes of drugs, statins, niacin, thiazide diuretics, and ß-blockers. For each drug class, an attempt will be made to quantify the benefit of treatment and potential harm based on clinical trial results and meta-analyses of trials. The data from these sources documenting the increased risk of NOD with these drugs are summarized in Figure 1.
Predictors of NODStudies in different populations have consistently identified the same cluster of risk factors for NOD. Impaired fasting glucose (IFG; defined as a fasting blood sugar from 100 to 125 mg/dL), a family history of diabetes, and features of the metabolic syndrome are associated with an increased risk of NOD.4 Lifestyle factors, low bo...