Relationship between body mass index and mortality of burns patients: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to evaluate the relationship between body mass index (BMI) and mortality of burn patients. A comprehensive, systematic search was conducted in different international electronic databases, such as Scopus, PubMed, Web of Science and Persian electronic databases such as Iranmedex, and Scientific Information Database (SID) using keywords extracted from Medical Subject Headings such as "Body mass index", "Burns" and "Mortality" from the earliest to the April 1, 2023. The quality of the studies included in this systematic review was evaluated using the appraisal tool for cross-sectional studies (AXIS tool). Finally, six articles were included in this systematic review and meta-analysis. A total of 16 154 burn patients participated in six studies. Their mean age was 46.32 (SD = 1.99). Of the participants, 71.7% were males. The mean length of hospitalization was 18.80 (SD = 8.08) days, and the average TBSA in burn patients was 38.32 (SD = 2.79) %. Also, the average BMI in burn patients was 27.10 (SD = 1.75). Results found mortality in patients with abnormal BMI (overweight to morbidity BMI) was 0.19 more than normal BMI (ES: 1.19, 95%CI: 0.76-1.87, Z = 0.75, I² : 71.8%, p = 0.45). Results of linear dose-response showed each 5 kg/m² increase in BMI was associated with a 5% increase in mortality that was marginally significant (ES: 1.05, 95%CI: 1.00-1.11, Z = 1.99, I² : 22.2%, p = 0.047). There was a non-linear relationship between levels of BMI and mortality (Prob > χ²  = 0.02). There was an increase in mortality from percentile 10 to 50, although it was not significant (Correlational coefficient: 0.01, p = 0.85). Also, there was an increase in mortality rate from percentile 50 to 90 that was statistically significant (correlational coefficient: 0.06, p = 0.047). Finally, the results of the study indicated BMI can increase the chance of mortality by 0.19, although it was not significant. As a result, more studies are needed to better judge the relationship between BMI and mortality in burn victims.