Obesity paradox among elderly patients with coronary artery disease undergoing non-cardiac surgery

Lu CHE; Li XU; Ming-Ya WANG; Yu-Guang HUANG

doi:10.11909/j.issn.1671-5411.2018.09.004

摘要：Background High body mass index (BMI) is a risk factor for chronic cardiac disease.However,mounting evidence supports that high BMI is associated with less risk of cardiac morbidity and mortality compared with normal BMI,also known as the obesity paradox.There-fore,we sought to determine the existence of the obesity paradox in regard to perioperative 30-day cardiac events among elderly Chinese patients with known coronary artery disease undergoing non-cardiac surgery.Methods A post-hoc analysis of a prospective,multi-institutional cohort study was performed.Patients aged ＞ 60 years with a history of coronary artery disease and undergoing non-cardiac surgery were grouped according to BMI:underweight (＜ 18.5 kg/m2),normal weight (18.5-24.9 kg/m2),overweight (25-29.9 kg/m2) and obese (≥ 30 kg/m2).Demographic information,perioperative clinical variables and incidence of 30-day postoperative cardiac adverse event were retrieved from a research database.Results We identified 1202 eligible patients (BMI:24.3 ± 3.8 kg/m2).Across BMI groups,a U-shaped distribution pattern of incidence of 30-day postoperative major cardiac events was observed,with the lowest risk in the overweight group.When using the normal-weight group as a reference,no difference was found in either the obesity or overweight groups in terms of a major cardiac adverse event (MACE).However,risk of a 30-day postoperative MACE was significantly higher in the underweight group (odds ratio [OR] 2.916,95％ confidence interval [CI]:1.072-7.931,P =0.036).Conclusion Although not statistically significant,the U-shaped relation between BMI and cardiac complications indicates the obesity paradox possibly exists.