Impact of obesity on outcomes in patients receiving extracorporeal membrane oxygenation: A systematic review and meta-analysis

Given the growing obesity pandemic, the impact of obesity on outcomes of Extracorporeal Membrane Oxygenation (ECMO) would be increasingly relevant to our daily practise. This meta-analysis aims to evaluate the impact of obesity on ECMO outcomes, integrating the latest evidence. Systematic literature search was conducted from inception until December 2024 on MEDLINE, Embase and the Cochrane Library using the terms ‘ECMO’, ‘obesity’, and their related terms. Twenty-eight studies were included from 2013 to 2024, including a total of 74,330 ECMO patients (Mean age 52.84 ± 13.55 years). Obese patients had a similar risk of in-hospital or 30-day mortality when compared to non-obese patients (Risk difference −2%, 95%CI −5% to −1%, I 2 = 85%, p = 0.25). Subgroup analysis of patients on V-V-ECMO showed a trend towards lower mortality in obese patients which did not reach statistical significance (risk difference −6%, 95%CI −13% to 0%, I 2 = 53%, p = 0.06). Subgroup analysis of patients on V-A-ECMO showed significantly higher mortality in obese patients (risk difference 5%, 95%CI 1% to 9%, I 2 = 54%, p = 0.007). Regarding secondary outcomes, obesity had no significant association with major bleeding or thrombotic complications (Risk difference 0%, 95%CI −1% to 2%, I 2 = 15%, p = 0.63). Obesity was associated with significantly shorter hospital length-of-stay (Mean difference −2.92 days, 95% CI −5.03 to −0.80, I 2 = 74%, p = 0.007), but had no impact on ECMO duration (Mean difference 0.35 days, 95%CI −0.03 to 0.74, I 2 = 41%, p = 0.07). In summary, our meta-analysis showed that obesity was a favourable prognostic factor in V-V-ECMO. However, obesity increased mortality in V-A-ECMO patients. The modality of ECMO support should be taken into consideration when evaluating ECMO candidacy in individual obese patients.