Background: In patients with established CHD the cardiovascular (CV) prevention guidelines recommend random hypolipidemic treatment and administration of ACE inhibitors and betablockers. However, similar or even stronger risk factor than hyperlipidemia and elevated blood pressure in these patiens may represent diabetes and even prediabetes.
Purpose: To analyse the epidemiology and CV risk of prediabetes in patients with established CHD and draw conclusions.
Methods: Prospective cohort analysis of pooled sample of four independent surveys of patiens with stabilized manifest CHD performed in 1995 - 2013 (Czech samples of EUROASPIRE I, II, III and IV surveys, pts interviewed at least 6 months after hospitalization for acute coronary syndrome and/or revascularization). Mortality data were obtained from National mortality registry. Series of multivariate regression analyses to assess CV mortality risk associated with basic CV risk factors, with metabolic syndrome (MS) defined by harmonised definition and with its single components were performed.
Results: 1692 pts were followed. In due time prevalence of diabetes (fasting glycaemia >7 mmol/L or use of antidiabetic treatment) increased from 26% to 47% and prevalence of increased fasting glycemia (>5,6 mmol/L) increased from 7,1 to 9,3% respectively. Pts with MS had significantly higher 5-years CV mortality: adjusted HRR 2.01 [95% CI: 1.26–3.22]; p=0.003 than subjects without MS. The majority of attributable mortality risk was driven by raised fasting glycaemia (HRR 2.69 [96% CI: 1.29–5.62]; p=0.009), in non diabetic patients even more: HRR 3.39 [96% CI: 1.51–7.64]; p=0.003. In non diabetic pts increased fasting glycaemia was the most signifiant mortality risk factor, only increased waist circumference (HRR 1.77 [CI: 1.1–2.87]; p=0.025) and low LDL (HRR 1.65 [CI: 1.1–2.49]; p=0.016) retained, as risk factor, the statistical significance.
Conclusions: Prevalence of impaired glucose metabolism and of diabetes in pts with established CHD is increasing and relatively modest effect of concomitant hyperlipidaemia on mortality risk is overcome by impaired glucose metabolism. Not only diabetes, but already increased fasting glycaemia is a strong indicative of mortality risk and should be considered as treatment target by oral antidiabetic agents (avoiding hypoglycaemia) in secondary prevention of CHD. However, data from controlled treatment trials are still scarce.