The impact of body mass index on post resuscitation survival after cardiac arrest: A meta-analysis

Background: Observational studies examining the association between body mass index (BMI) and the outcome of cardiac arrest (CA) shows controversial results. Methods: We reviewed literature for studies assessing the impact of BMI on survival and neurological outcome following CA. Eligible studies were subsequently meta-analyzed and pooled odds ratios and their corresponding 95% confidence intervals for post CA survival and neurological status were derived. Results: A total of 7 studies with 24,651 patients were evaluable for this meta-analysis. The studies were also categorized by location of the CA and the use of therapeutic hypothermia. Our results suggested that BMI between 25 and 29.9 kgr/m2had a favorable impact on survival after CA (OR = 1.172, 95% CI, 1.109-1.236) in comparison to normal weight subjects. Likewise, overweight patients presented increased odds for a favorable neurological outcome after CA (OR = 1.112, 95% CI, 1.020-1.213). On the contrary, underweight subjects presented decreased odds of surviving after CA as compared to normal BMI subjects (OR = 0.781, 95% CI, 0.652-0.935). Finally, BMI >30 kgr/m2was not associated with improved survival or neurological outcome as compared to BMI 18.5-24.9 kgr/m2. Conclusions: Overweight patients have a favorable prognosis after CA in terms of both survival and neurological outcome. This effect was amplified when the analysis is restricted in in-hospital cardiac arrest and in patients non-treated with therapeutic hypothermia.