Impact of body mass index on repeat coronary revascularization rates in patients with LDL-C below 55 mg/dL and LDL-C below 70 mg/dL: a 42-month cohort study in Korea

Background: Previous studies revealed a linear relationship between body mass index (BMI) and repeat coronary revascularization rate in patients who underwent percutaneous coronary intervention (PCI). However, this relationship has not been demonstrated in Korean patients who meet old and new target low-density lipoprotein cholesterol (LDL-C) levels of Korean dyslipidemia guidelines. Therefore, we conducted this study to find out the effect of BMI on repeat coronary revascularization rate in patients with LDL-C <55 mg/dL and patients with LDL-C <70 mg/dL. Methods: This cohort study was followed for 42 months in Daegu Catholic Medical Center, Korea. We included 429 patients with LDL-C <70 mg/dL 1 year after PCI. We compared repeat revascularization rates using Kaplan-Meier survival curves between the normal weight group (18.5 kg/m(2) <= BMI < 23 kg/m(2)) and the pre-obesity and obesity group (23 kg/m(2) <= BMI) in patients with LDL-C <55 mg/dL and patients with LDL-C <70 mg/dL. Results: During a follow-up period, there was no significant difference in repeat coronary revascularization-free survival between a group with LDL-C <55 mg/dL and a group with LDL-C <70 mg/dL (79.6% vs. 76.2%, P=0.32). In normal weight patients, LDL-C <55 mg/dL group showed higher repeat coronary revascularization-free survival than LDL-C <70 mg/dL group (89.3% vs. 77.1%, P=0.05). There was no significant difference in repeat revascularization-free survival between the normal weight group and the pre-obesity and obesity group in patients with LDL-C <70 mg/dL (77.1% vs. 75.7%, P=0.67). However, the normal weight group showed significantly higher repeat revascularization-free survival compared to the pre-obesity and obesity group in patients with LDL-C <55 mg/dL (89.3% vs. 74.3%, P=0.03). Normal body weight and LDL-C <55 mg/dL [hazard ratio (HR): 0.421, 95% confidence interval (CI): 0.193-0.916, P=0.02] was the only independent predictor for repeat revascularization. Conclusions: In Korean PCI patients with normal body weight whose LDL-C level is less than 70 mg/dL, but more than 55 mg/dL, should be treated with more intensive therapy to lower LDL-C to less than 55 mg/dL. For obese patients who have succeeded in reducing LDL-C below 55 mg/dL, it seems that weight loss should be attempted to a normal body weight level.