Development and validation of a predictive model for short-term symptom relief after organophosphate poisoning

Background Acute organophosphate (OP) poisoning outcomes vary significantly despite standard atropine/pralidoxime (PAM) therapy. Early identification of patients likely to improve rapidly could optimize resource allocation and individualized care. Methods This retrospective study analyzed 138 adult acute OP poisoning cases (2018–2023). Patients were randomly split into training ( n = 96) and validation ( n = 42) cohorts. LASSO regression analyzed 14 potential predictors (demographics, clinical presentation, labs) to select features with non-zero coefficients at the 1-SE λ threshold. These were used in multivariable logistic regression to develop a nomogram predicting clinical improvement (any reduction in the poisoning symptom score (PSS) within 48 h post-admission). Model validation included discrimination (ROC/AUC), calibration [calibration plots and mean absolute error (MAE)], and clinical utility (decision curve analysis, DCA). Results Four independent predictors were identified: baseline PSS, admission serum cholinesterase, admission Glasgow Coma Scale (GCS) score, and major comorbidities. The nomogram showed strong discrimination (optimism-corrected AUC 0.930 in the training cohort; AUC 0.905 in the validation cohort) and good calibration (MAE 0.034 and 0.066). Decision-curve analysis showed positive net benefit over treat-all and treat-none across clinically relevant thresholds. Conclusion We developed and validated a practical nomogram predicting 48-h symptom relief in acute OP poisoning. This tool can enhance early risk stratification, guide clinical decisions, and support efficient ICU resource utilization.