Change in high-density lipoprotein cholesterol and risk of subsequent hospitalization for coronary artery disease or stroke among patients with type 2 diabetes mellitus

The association between the changes in high-density lipoprotein (HDL) cholesterol and the risk of cardiovascular (CVD) or cerebrovascular hospitalization among patients with type 2 diabetes remains unclear. We conducted a retrospective observational cohort study of 30,067 members of the Kaiser Permanente Northwest and Georgia regions, who had type 2 diabetes and 2 HDL cholesterol measurements 6 to 24 months apart in 2001 to 2006. We followed up the cohort for ≤8 years (through 2009) to determine whether the change in HDL cholesterol was associated with subsequent CVD hospitalization. We examined the HDL cholesterol change continuously and by 3 categories: HDL cholesterol increased ≥6.5 mg/dl, decreased ≥6.5 mg/dl, or remained within ±6.4 mg/dl. The Cox regression models were adjusted for the baseline HDL cholesterol and demographic and clinical risk factors. During a mean follow-up of 55.8 ± 23.8 months, 3,023 patients (10.1%) experienced a CVD hospitalization. After multivariate adjustment, each 5 mg/dl of baseline HDL cholesterol was significantly associated with a 6% lower CVD hospitalization risk (hazard ratio 0.94 per 5 mg/dl, 95% confidence interval 0.92 to 0.95, p <0.0001) and each 5-mg/dl increase in HDL cholesterol was associated with a 4% CVD risk reduction (hazard ratio 0.96, 95% confidence interval 0.94 to 0.99, p <0.003). In the categorical analysis, a ≥6.5-mg/dl HDL cholesterol decrease was associated with an 11% increased CVD risk (hazard ratio 1.11, 95% confidence interval 1.00 to 1.24, p = 0.047) and a ≥6.5-mg/dl increase was associated with an 8% CVD risk reduction (hazard ratio 0.92, 95% confidence interval 0.84 to 1.01, p = 0.077) relative to those with stable HDL cholesterol. In conclusion, our results add to the growing body of evidence that increasing the HDL cholesterol levels might be an important strategy for CVD risk reduction. The prevention of HDL cholesterol decreases could be equally important.