Cholesterol and Cardiovascular Risk in Type 2 Diabetes: The Role of Kidney Function.

Objective: The association of lipid parameters with cardiovascular disease (CVD) and the impact of kidney function on this association have not been thoroughly evaluated in patients with type 2 diabetes mellitus (T2DM).

Methods: Using the Korean National Health Insurance Service Cohort database, we identified 2,343,882 subjects with T2DM in 2015-2016. Baseline lipid levels and kidney function were evaluated and followed up until December 2020. Subjects were classified into three groups according to their estimated glomerular filtration rate (eGFR): ≥60, 30-59, or <30 mL/min/1.73 m². We analyzed the diabetes group with eGFR ≥60 and low-density lipoprotein cholesterol (LDL-C) <70 mg/dL as a reference group.

Results: The risk of CVD began to increase at LDL-C ≥100 mg/dL in the eGFR ≥60 mL/min/m² group. The risk of CVD in the eGFR 30-59 mL/min/m² group was increased by 43%, even in the LDL-C <70 mg/dL, and the risk increased progressively with LDL-C category. Among subjects with eGFR 30-59 mL/min/m², LDL-C 70-99, 100-129, 130-159, and ≥160 mg/dL were significantly associated with the risk of CVD, with hazard ratio (95% confidence interval) of 1.48 (1.43-1.53), 1.54 (1.49-1.60), 1.55 (1.48-1.63), and 1.88 (1.77-2.00), respectively. In the eGFR <30 mL/min/m² group, a 3.3-fold increased risk of CVD was seen, even at LDL-C <70 mg/dL.

Conclusion: The cutoff levels of LDL-C that increase CVD risk in patients with T2DM depend on kidney function, which influences the relationship between LDL-C and CVD risk in patients with T2DM.