Development and internal validation of a multivariable model for the prediction of the probability of 1-year readmission to the emergency department for acute alcohol intoxication

To develop and internally validate a multivariable logistic regression model (LRM) for the prediction of the probability of 1-year readmission to the emergency department (ED) in patients with acute alcohol intoxication (AAI). We developed and internally validated the LRM on a previously analyzed retrospective cohort of 3304 patients with AAI admitted to the ED of the Sant'Orsola-Malpighi Hospital (Bologna, Italy). The benchmark LRM employed readmission to the same ED for AAI within 1 year as the binary outcome, age as a continuous predictor, and sex, alcohol use disorder, substance use disorder, at least one previous admission for trauma, mental or behavioral disease, and homelessness as the binary predictors. Optimism correction was performed using the bootstrap on 1000 samples without replacement. The benchmark LRM was gradually simplified to get the most parsimonious LRM with similar optimism-corrected overall fit, discrimination and calibration. The 1-year readmission rate was 15.7% (95% CI 14.4-16.9%). A reduced LRM based on sex, age, at least one previous admission for trauma, mental or behavioral disease, and homelessness, performed nearly as well as the benchmark LRM. The reduced LRM had the following optimism-corrected metrics: scaled Brier score 17.0%, C-statistic 0.799 (95% CI 0.778 to 0.821), calibration in the large 0.000 (95% CI - 0.099 to 0.099), calibration slope 0.985 (95% CI 0.893 to 1.088), and an acceptably accurate calibration plot. An LRM based on sex, age, at least one previous admission for trauma, mental or behavioral disease, and homelessness can be used to estimate the probability of 1-year readmission to ED for AAI. To begin proving its clinical utility, this LRM should be validated in external cohorts.