Assessing the accuracy of the LACE index to predict 30-day readmissions in regional Victoria, Australia

Abstract

Background: Unplanned 30-day hospital readmissions are a key quality indicator and pose a significant burden on health systems. Risk stratification tools such as the LACE index (Length of stay, Acuity of admission, Charlson comorbidity index, Emergency department visits) help identify high-risk patients for targeted interventions. Still, their performance in regional populations is less well understood. Objective: To assess the predictive accuracy of the LACEi for 30-day unplanned readmission or death among adult medical patients discharged from a regional health service in Victoria, Australia. Methods: We conducted a retrospective cohort study of all adult medical patients discharged alive from South West Healthcare in Warrnambool, Victoria, between 1 April 2021 and 31 March 2023. LACEi scores were derived from administrative data. The primary outcome was unplanned readmission or death within 30 days of discharge. Discriminatory performance was evaluated using C-statistics, and odds and hazard ratios were calculated for patients classified as high-risk (LACEi > = 10). Results: Out of 4167 admissions, 360 (8.6%) experienced an unplanned readmission within 30 days. Patients readmitted had longer hospital stays, greater comorbidity burden, and higher LACE scores. Using a standard cut-off of > = 10, the index demonstrated moderate predictive accuracy (C-statistic = 0.69; 95% CI 0.67–0.73), with an adjusted OR of 10.4 (95% CI 8.3–12.6) and HR of 8.5 (95% CI 7.0–11.0). Most readmissions (68.1%) occurred within 14 days of discharge. Conclusion: In this regional cohort, the LACEi demonstrated moderate accuracy in predicting 30-day unplanned readmission or death. Scores > = 10 identified patients at higher risk, supporting its use as a simple, low-resource risk stratification tool. Future research should evaluate LACE-guided interventions to reduce early readmissions.