Multimorbidity and 30-Day Hospital Readmission in Older Adults

Introduction

Multimorbidity, the co-occurrence of two or more chronic conditions, is highly prevalent among older adults and is closely linked to functional decline, polypharmacy, and heightened healthcare use. However, its specific impact on early 30-day hospital readmission rates in older adults ( 65 years old) has not been synthesized with recent literature (2022 onwards). This review evaluates the association between multimorbidity and 30-day readmission in older adults, investigating whether risk scales proportionally with condition count or overall burden.

Methods

A systematic search of PubMed was conducted for literature published up to March 2026 using targeted terms for multimorbidity, 30-day readmission, and older populations. Observational studies (cross-sectional, prospective, or retrospective cohorts) focusing on adults aged  65 were eligible if they defined multimorbidity by a concurrent condition count ( 2) or a validated burden index (e.g., Charlson Comorbidity Index [CCI] or Elixhauser Comorbidity Measure) and reported 30-day readmission data.

Results

Eight studies met the inclusion criteria. Seven reported a significant positive association between multimorbidity and 30-day hospital readmission in older adults, with six demonstrating a dose-response relationship where risk increased alongside condition number or burden. Reported 30-day readmission rates spanned from 7.8% to 24.6%, yielding a pooled mean readmission rate of 17.3%. One study cited lower readmission rates in specialized geriatric wards compared to general medical wards, which was attributed to distinct medical practices for older adults in the study’s location.

Conclusions

Multimorbidity was associated with higher 30-day hospital readmission rates in older adults, with risk escalating alongside condition severity and count. However, variations in the definitions of multimorbidity across literature limit direct cross-study comparisons. Future research should evaluate whether current discharge protocols adequately safeguard multimorbid older adults during care transitions.