Association of obesity with morbidity and mortality in critically ill children: a systematic review and meta-analysis of observational studies

Recent studies have suggested that obesity might be protective in specific conditions such as critical illness; however, there are controversial data in critically ill children with obesity. The aim of this study was to investigate the association of obesity with mortality and other outcomes in these patients. We conducted a systematic review of observational studies investigating obesity in critically ill children, published by August 2017 in PubMed and Scopus. After screening documents, 15 articles with 142119 patients were included in the systematic review and meta-analysis. The results were reported with odds ratio (OR) or standard mean difference (SMD). The primary outcome was mortality and the secondary outcomes were length of ICU stay (ICU LOS), length of hospital stay (hospital LOS), and duration of mechanical ventilation (MV). The analysis showed that critically ill children without obesity had lower risk of mortality compared to patients with obesity (OR 0.79, 95% CI 0.64 to 0.97, P = 0.025, I-2 = 35.2%). Hospital LOS was also significantly lower in children without obesity (pooled SMD -0.12, 95% CI -0.21 to -0.04, P = 0.004, I-2 = 8.1%). There were no differences in ICU LOS (95% CI -0.19 to 0.01, P = 0.083) and duration of MV (95% CI -0.22 to 0.03, P = 0.136) between critically ill children with and without obesity. In conclusion, the current systematic review and meta-analysis revealed that critically ill children with obesity have higher risk of mortality and length of hospital stay compared to the group without obesity. Further prospective studies are essential to elucidate the role of obesity and underlying mechanisms in predicting outcomes of critically ill children.