Higher BMI was associated with reduced in-hospital mortality in patients with COVID-19, with the BMI-based Random Forest predictive model demonstrating strong predictive capabilities (ROC 0.84).
Key Findings
Results
BMI consistently demonstrated a protective effect against in-hospital mortality across all three analytical models.
Crude model: OR (95% CI) = 0.84 (0.77-0.92), P < 0.05
Adjusted model 1: OR (95% CI) = 0.84 (0.77-0.92), P < 0.05
Propensity Score Matching (PSM) model: OR (95% CI) = 0.85 (0.74-0.97), P < 0.05
BMI was the only weight-derived marker to consistently demonstrate a protective effect among all markers examined
Results
Restricted Cubic Spline regression revealed significant nonlinear associations between BMI, Weight, LBM, and WBFM with in-hospital mortality.
P for overall < 0.05 for BMI, Weight, Lean Body Mass (LBM), and Whole-Body Fat Mass (WBFM)
No significant nonlinear associations were observed between Body Fat Percentage (BFP) and in-hospital mortality
No significant nonlinear associations were observed between Basal Metabolic Rate (BMR) and in-hospital mortality
Results
The BMI-based Random Forest model effectively forecasted in-hospital mortality in COVID-19 patients.
ROC (95% CI) = 0.84 (0.76-0.92) for the BMI-based Random Forest model
Four machine-learning models were developed: Decision Tree Classifier, Random Forest, Gaussian Naive Bayes, and Gradient Boosting Classifier
The Random Forest model demonstrated the strongest predictive capability among the models assessed
Methods
A total of 509 COVID-19 patients were included, with body composition markers calculated from height, weight, gender, and age.
Sample size: 509 patients with COVID-19
Weight-derived markers examined included Weight, BMI, Body Fat Percentage (BFP), Whole-Body Fat Mass (WBFM), Lean Body Mass (LBM), and Basal Metabolic Rate (BMR)
All body composition variables were derived from height, weight, gender, and age
In-hospital mortality served as the primary clinical outcome
Associations were evaluated using a crude model, a logistic model adjusted for confounders, and a PSM model
Li Y, Song S, Ruan H, Gong C, Chen Y. (2026). Associations of weight-derived markers with mortality in patients with Corona virus disease 2019: evidence from hospitals and patients.. BMC pulmonary medicine. https://doi.org/10.1186/s12890-025-04049-2