Statin use reduces cardiovascular events and all-cause mortality amongst Chinese patients with type 2 diabetes mellitus: a 5-year cohort study

BACKGROUND The benefit of statin on the management of Type 2 Diabetes Mellitus (T2DM) among Chinese patients in primary care is not clear nor fully implemented in clinical practice. This study aimed to evaluate and quantify the benefit of statin on the overall cardiovascular risk and all-cause mortality in patients with T2DM. METHODS Uncomplicated diabetic patients with baseline low-density-lipoprotein cholesterol (LDL-C) > 2.6 mmol/L and without statin use before baseline in 2010 were followed-up for 5 years for cardiovascular disease (CVD) events and all-cause mortality. Propensity score matching analysis was conducted to identify patients who were newly prescribed statin at baseline and then compared to non-statin users with similar baseline characteristics. Subgroup analysis was done within the statin group to detect any difference in outcomes between patients achieving target LDL-C of <2.6 mmol/L and not. Multivariable Cox proportional hazards regression with adjustment of all baseline covariates was used to evaluate the effect of statin on outcome events. Hazard ratio (HR) and its 95% confidence intervals were reported. RESULTS 10,104 pairs of diabetic patients were propensity score matched. Statin users had an extra drop of 1.21 mmol/L in LDL-C than non-users. Statin group had a CVD incidence rate of 16.533 per 1000 person-years whereas comparison group had 32.387 per 1000 person-years (HR: 0.458) during a median follow-up period of 50.5 months. Statin group had a mortality rate of 8.138 deaths per 1000 person-years whereas comparison group had 19.603 deaths per 1000 person-years (HR: 0.378). For patients prescribed with statin, the HR was 0.491 for CVD and 0.487 for all-cause mortality if target of LDL-C < 2.6 mmol/L achieved compare to those not achieved. CONCLUSIONS Use of statin was associated with a significant decrease in CVD risk and all-cause mortality among diabetic patients in primary care, and the risk reduction was most significant if the target of LDL-C less than 2.6 mmol/L was achieved.