Abstract / Summary
Intermediate care units (IMCUs) provide a level of care between general wards and intensive care units (ICUs), offering enhanced monitoring and selected organ support at lower staffing intensity than ICUs. Their expansion across countries has prompted growing interest about their effectiveness, cost-efficiency, and optimal patient selection. However, existing evidence regarding their impact has been inconsistent, in part due to the substantial heterogeneity in IMCU organisation, nomenclature, and clinical purpose. This systematic review synthesises comparative evidence published between 2013 and 2025 to evaluate the contribution of ICMUs to patient outcomes and hospital resource use. The review aimed to assess IMCU effects on mortality, length of stay (LOS), hospital readmissions, ICU readmissions, costs, and adverse events in adult patient populations. Three databases were systematically searched for comparative studies in Organisation for Economic Co-operation and Development (OECD) countries. Screening was performed in duplicate, and data were extracted using a standardised template. Methodological quality was evaluated with relevant NIH assessment tools. Twenty‑eight studies met inclusion criteria. The findings across studies were heterogeneous. Mortality patterns did not point in a single direction: some research suggested potential benefits of IMCU care, others reported no clear differences or highlighted potential risks. These discrepancies were often linked to differences in case-mix and admission criteria. LOS outcomes were similarly inconsistent, with some studies associating IMCUs with shorter hospital stays, and others reporting minimal or no improvement. Readmission rates generally did not differ substantially between IMCU patients and those managed in alternative levels of care, and advantages in reducing ICU readmissions were uncommon. In contrast, cost savings were more consistently observed, with many studies indicating lower hospital expenditure when patients were managed in IMCUs, though occasionally accompanied by unfavourable clinical trade‑offs in specific patient groups. Adverse event rates were generally comparable across settings. Overall, IMCU effects on mortality and LOS remain inconclusive due to methodological and organisational heterogeneity. However, evidence for cost savings is more consistent. IMCUs appear beneficial for selected moderate‑risk populations, but their suitability for high‑risk patients is uncertain. Standardised definitions, clearer admission criteria, and improved reporting are essential to strengthen future evidence. Not applicable.