Prediction of 30-day unplanned hospital readmission among elderly patients using patient and ward level factors

Hospital readmission among elderly patients in sub-Saharan Africa, where health systems are constrained, is a critical yet poorly understood challenge. Although patient-level risk factors are established, the role of modifiable ward-level organizational factors remains largely unexplored in this context. This study aimed to investigate the patient- and ward-level determinants of 30-day unplanned readmission among elderly Ethiopian patients. A prospective study was conducted from January 2023 to February 2025; involving 504 patients aged ≥ 65 years. Data on patient demographics, clinical characteristics, and ward-level factors were collected from medical records. A GLMM was employed to identify predictors of readmission, presenting adjusted odds ratios (aORs) with 95% confidence intervals (CIs). The overall 30-day readmission rate was 44.8%. The GLMM revealed significant ward-level clustering, with an intra-class correlation coefficient (ICC) of 0.186, indicating that 18.6% of the variation in readmission odds was attributable to differences between wards. Significant patient-level predictors included a higher Charlson Comorbidity Index (aOR 1.27, 95% CI 1.13–1.42), more previous hospitalizations (aOR 1.24, 95% CI 1.08–1.43), longer length of stay (aOR 1.05, 95% CI 1.01–1.09), and cognitive impairment (aOR 1.89, 95% CI 1.21–2.94). Being discharged from a ward with a standardized discharge protocol was associated with a 45% lower odd of readmission (aOR 0.55, 95% CI 0.32–0.94). A significant cross-level interaction showed that this protective effect was strongest for patients with cognitive impairment. In this setting, readmission is driven by a combination of patient-level clinical vulnerability and ward-level organizational capacity. The substantial ward-level variation highlights a key opportunity for intervention. The implementation of discharge protocols represents a powerful, low-cost strategy to significantly reduce readmissions, particularly for the most vulnerable elderly patients with cognitive impairment, thereby improving the quality of care in resource-limited hospitals.