Association between body mass index and clinical outcomes in patients with out-of-hospital cardiac arrest undergoing extracorporeal cardiopulmonary resuscitation: A multicenter observational study

Abstract

BackgroundWe examined the association between body mass index (BMI) and outcomes in patients with out-of-hospital cardiac arrest (OHCA) undergoing extracorporeal cardiopulmonary resuscitation (ECPR). MethodsWe retrospectively analyzed the database of an observational multicenter cohort in Japan. Adult patients with OHCA of cardiac etiology who received ECPR between 2013 and 2018 were categorized as follows: underweight, BMI < 18.5; normal weight, BMI = 18.5–24.9; overweight, BMI = 25–29.9; and obese, BMI ≥ 30 kg/m2. The primary outcome was in-hospital mortality; secondary outcomes were unfavorable neurological outcomes at discharge (cerebral performance category ≥ 3) and ECPR-related complications. BMI’s association with outcomes was assessed using a logistic regression model adjusted for age, sex, comorbidities, witness/bystander CPR, initial rhythm, prehospital return of spontaneous circulation, and low-flow time. ResultsIn total, 1,044 patients were analyzed. Their median age was 61 (IQR, 49–69) years; the median BMI was 24.2 (21.5–26.9) kg/m2. The overall rates of in-hospital mortality, unfavorable neurological outcome, and ECPR-related complications were 62.2%, 79.9%, and 31.7%, respectively. In multivariate analysis, the overweight and obese groups had higher in-hospital mortality odds than the normal BMI group (odds ratio [95%CI], 1.37 [1.02–1.85], p = 0.035; and 2.09 [1.31–3.39], p < 0.001, respectively). The odds ratio for unfavorable neurological outcomes increased more in the obese than in the normal BMI group (3.17 [1.69–6.49], p < 0.001). ECPR-related complications were not significantly different among groups. ConclusionsIn OHCA patients undergoing ECPR, a BMI ≥ 25 kg/m2 was associated with increased in-hospital mortality, and a BMI ≥ 30 kg/m2 was also associated with a worse neurological outcome.