The impact of serum lipids on risk for microangiopathy in patients with type 2 diabetes mellitus

BACKGROUND Few large-scale, real-world studies have assessed the relative associations of lipid fractions with diabetic microvascular events. The main objective of this study was to evaluate the association of the lipid profile components, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), and non-high density lipoprotein cholesterol (non-HDL-C) with microvascular complications (MVCs) in type 2 diabetes mellitus (T2DM) patients. METHODS This observational cohort study queried the HealthCore Integrated Research Database (HIRDSM) for newly-diagnosed (Index Date) 18-64-year-old patients with diabetes mellitus between 01/01/2005-06/30/2010. Inclusion required ≥ 12 months pre-index continuous health plan eligibility and ≥ 1 pre-index lipid profile result. Patients with polycystic ovary syndrome and prior MVCs were excluded. Incident complications were defined as the earliest occurrence of diabetic retinopathy, peripheral neuropathy, and/or nephropathy post-index. Cox proportional models and Kaplan-Meier (KM) curves were used to evaluate associations among variables. RESULTS Of the patients (N=72,267), 50.05% achieved HDL-C, 64.28% LDL-C, 59.82% TG, and 56.79% non-HDL-C American Diabetes Association goals at baseline. During follow-up (mean, 21.74 months), there were 5.21 microvascular events per 1,000 patient-months. A 1-mg/dL increase in HDL-C was associated with 1% decrease in any MVC risk (P< .0001), but for LDL-C, TG, and non-HDL-C, 1-mg/dL increase resulted in increases of 0.2% (P< .0001), 0.1% (P<0.001) and 0.3% (P<0.001) in MVC risk. Patients achieving HDL-C goals had a 11% lower risk of MVC versus non-achievers (RR 0.895, [95% CI, 0.852-0.941], P< .0001). Similarly, TG goal attainment was associated with a lowered risk for any MVC (RR 0.849, [95% CI, 0.808-0.892], P< .0001). Evaluation of KM survival curves demonstrated no significant difference in the risk of MVCs between patients achieving vs. not achieving LDL-C goals, but did demonstrate a difference in MVC risk between patients achieving vs. not achieving non-HDL-C goals. CONCLUSION This study demonstrates significant independent associations among lipid fractions and risk for microangiopathy. These findings suggest that attaining established ADA goals for HDL-C, TG, and non-HDL-C may reduce risk for microvascular events among patients with diabetes.