A clinical nomogram incorporating hyperhomocysteinemia for predicting severe delayed encephalopathy after acute carbon monoxide poisoning: a retrospective single-center study.

BACKGROUND

Severe delayed encephalopathy after acute carbon monoxide poisoning (s-DEACMP) is a disabling complication associated with substantial long-term neurological impairment, yet reliable predictors for risk stratification during acute hospitalization remain limited. This study aimed to identify predictors associated with s-DEACMP and to develop a preliminary predictive model.

METHODS

In this retrospective single-center cohort study, 200 patients with acute carbon monoxide poisoning (ACMP) admitted between 2017 and 2024 were analyzed. Patients were categorized into DEACMP (n = 140) and non-DEACMP (n = 60) groups; the DEACMP group was further stratified into severe (s-DEACMP, n = 97) and mild-to-moderate (m-DEACMP, n = 43) subgroups based on Activities of Daily Living scores assessed at peak disease severity during hospitalization. Clinical characteristics were compared between the s-DEACMP group and a combined control group (n-DEACMP + m-DEACMP). Independent predictors were identified using multivariate logistic regression. A nomogram was constructed and internally validated using receiver operating characteristic (ROC) curves, calibration analysis, and decision curve analysis (DCA).

RESULTS

Patients with s-DEACMP were significantly older and had longer duration of disturbance of consciousness, higher prevalence of hypertension and hyperhomocysteinemia, elevated D-dimer levels, and lower serum albumin concentrations compared with controls (all P < 0.05). Multivariate analysis identified age >40 years (OR = 31.90, 95% CI = 3.93-259.14), disturbance of consciousness >24 h (OR = 3.06, 95% CI = 1.58-5.94), hypertension (OR = 1.99, 95% CI = 1.02-3.90), and hyperhomocysteinemia (OR = 2.57, 95% CI = 1.24-5.31) as factors independently associated with s-DEACMP. The nomogram demonstrated acceptable discrimination and calibration.

CONCLUSION

The proposed nomogram may assist in identifying patients at increased risk for s-DEACMP during acute hospitalization. External multicenter validation is required before broader clinical application.