Lung-to-Body Weight Ratio as a Supplemental Predictor of the Fresh Water Drowning Diagnosis at Autopsy

Background Drowning remains a diagnosis of exclusion in forensic pathology due to a lack of sensitivity and specificity in currently identified drowning signs. This study aimed to assess the diagnostic value of combined lung weight (LW) and lung-to-body ratio (LBR = LW/body weight × 1000) in differentiating drowning deaths from nondrowning deaths. Methods A retrospective case–control study was conducted using autopsy records from the Peoria County Coroner's Office (2011–2025), including 96 freshwater drowning cases and 99 age- and sex-matched nondrowning controls. Deidentified variables analyzed included LW, LBR, age, sex, body weight, degree of decomposition, and cardiopulmonary resuscitation (CPR) status and toxicology results (the presence or absence of drugs). Statistical analyses compared variables between cases and controls and evaluated the effects of covariates on LW and LBR within groups. Results Both LW and LBR were significantly higher in drowning cases than in controls ( p < 0.001). Subgroup analyses demonstrated that LBR was influenced by age but not by sex, CPR status, decomposition category, or the presence of drugs (within cases). LW, on the other hand, was affected by sex and age in controls, and by decomposition category, CPR status, and drug presence in drowning cases. Conclusions While both LW and LBR appear to be significantly elevated in drowning deaths, LBR may serve as a more reliable metric than LW when assessing the likelihood of drowning, as it is less affected by confounding factors.