Frostbite in Northeastern China: Risk factors for amputation and readmission burden - A retrospective cohort study

Frostbite leads to significant morbidity, yet comprehensive studies from Northeast China are limited. This study aimed to characterize the clinical features of frostbite inpatients, identify risk factors for amputation, and assess the burden and patterns of readmission.

This single-center retrospective study analyzed 252 frostbite admissions (2001-2023). Descriptive statistics, t-tests/chi-square tests, correlation analyses, Firth penalized maximum-likelihood logistic regression, and multiple linear regression were used. Readmission patterns and costs were evaluated.

Median age was 39.5 years and 84.5% of admissions were male. The amputation rate was 21.4% (54/252). With grade II as the reference, grade III (odds ratio [OR] 3.55, 95% CI 1.36-10.31) and grade IV (OR 7.45, 95% CI 2.68-22.96) frostbite independently increased amputation risk, as did infection (OR 3.34, 95% CI 1.55-7.24); the model showed moderate discrimination (apparent AUC 0.788; bootstrap-corrected 0.754). Amputation independently prolonged length of stay by approximately 20 days (P < 0.001), whereas infection was associated with longer stays only in univariable analysis. The readmission rate was 7.7%; readmitted patients had 2.9-fold longer mean cumulative length of stay and 2.5-fold higher mean cumulative costs (P < 0.01) and a significantly elevated risk of amputation at readmission (P = 0.009). Costs were higher in the alcohol-intoxication subgroup (P = 0.012).

Frostbite in Northeast China carries a substantial amputation burden and considerable readmission-related resource use. Frostbite severity and infection were independent clinical predictors of amputation, and amputation was an independent determinant of prolonged hospitalization. Enhanced follow-up for high-risk groups (alcohol intoxication, psychiatric disorders, winter peaks) warrants consideration.