Circulating apolipoprotein B levels in statin-treated type 2 diabetic patients with coronary artery disease: Implications for coronary atheroma progression and instability

BACKGROUND Type 2 diabetic patients exhibited an increased secretion of triglyceride-rich lipoproteins and low HDL-C levels with a greater amount of small dense LDL. Given that apolipoprotein B (ApoB), a proatherogenic lipoprotein, exists at both triglyceride-rich lipoproteins and LDL particles, circulating ApoB may associate with diabetic coronary atherosclerosis. METHODS The OPTIMAL study was a prospective randomized-controlled study which employed serial NIRS/IVUS imaging to evaluate the efficacy of glycemic control on coronary atherosclerosis in 94 statin-treated type 2 diabetic patients with CAD (UMIN000036721). Of these, 78 patients with both serial ApoB levels and NIRS/IVUS images at baseline and week 48 were analyzed. NIRS/IVUS-derived plaque measures were compared in those with and without any reduction of ApoB levels. RESULTS All of study subjects received a statin, and 60.6% of study subjects exhibited any reduction of ApoB levels. There was no significant difference in the atheroma progression rate between two groups (-0.27±0.15% vs. -0.33±0.51%, p=0.44). However, patients with any reduction of ApoB levels exhibited a greater frequency of change in maxLCBI 4mm (-13.4±22.2% vs. 70.3±28.7%, p=0.03) and maxLCBI 4mm regression (61.1±0.08 vs. 31.0±0.09%, p=0.02). Multivariate analysis demonstrated change in ApoB as an independent factor associated with maxLCBI 4mm regression (OR=0.92, 95%CI=0.87-0.98, p=0.01). CONCLUSIONS In statin-treated type 2 diabetic patients with CAD, a greater delipidation of coronary atherosclerosis was observed in association with a reduction of ApoB levels. The current findings indicate a potential anti-atherosclerotic effect of lowering ApoB levels, which may ultimately mitigate a future coronary events' risks in statin-treated type 2 diabetic patients with CAD.