Usefulness of total cholesterol/HDL-cholesterol ratio in the management of diabetic dyslipidaemia

Aims Our aim was to evaluate the usefulness of the total cholesterol/HDL-cholesterol ratio (TC/HDL) in predicting the cardiovascular risk of Type 2 diabetic patients. Methods Prospective cohort study with inclusion of 418 Type 2 diabetic individuals with follow-up until the appearance of a cardiovascular event. The predictive power of updated mean lipid values during follow-up was analysed by means of Cox proportional hazard models. An estimate was made of the relative risk (RR) conferred by high levels of TC/HDL stratified by LDL-cholesterol levels. Results Sixty-six cardiovascular events occurred during an average follow-up of 4.7 years (SD 1.5). The main lipid predictor of vascular events was mean TC/HDL ratio [hazard ratio (HR)=1.46; 95% confidence interval (CI) 1.25, 1.7; P<0.0001]. In the multivariate model with simultaneous inclusion of mean TC/HDL and mean LDL-cholesterol, both were significant predictors of cardiovascular disease [HR (1 unit)=1.37; 95% CI 1.16, 1.62; P=0.0003 and HR (1 mmol/l)=1.5; 95% CI 1.04, 2.18; P=0.03, respectively]. The LDL adjusted RR for cardiovascular events due to high TC/HDL ratio, with 4.5 cut-off point, was 2.5 (95% CI 1.4, 4.3; P=0.0007). For the stratum of subjects with average LDL cholesterol <3.5 mmol/l, RR was 1.2 (95% CI 0.5, 2.8; P=NS) and for the stratum of average LDL cholesterol >3.5 mmol/l, RR was 4 (95% CI 1.8, 9; P=0.00013), with heterogeneity among strata (P=0.044). Conclusions It could be useful to include the TC/HDL ratio in treatment guides for diabetic dyslipidaemia, given their high predictive value and strong interaction with LDL cholesterol.