Comparing Outcomes in Post-Acute Care: A Systematic Literature Review of IRFs vs SNFs

To synthesize existing evidence comparing patient outcomes between inpatient rehabilitation facilities (IRFs) and skilled nursing facilities (SNFs) and assess whether higher-cost IRF care is associated with improved outcomes.

Systematic review conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Study quality was assessed using an internal and external validity framework, with particular attention to methods addressing selection bias and unobserved confounding. Due to heterogeneity in study designs and populations, results were synthesized qualitatively.

Studies of adult patients receiving post-acute care in the United States that quantitatively compared patient-level outcomes between IRF and SNF care, published in English between 2000 and 2024.

A systematic search of PubMed and Google Scholar was conducted, with the final search completed on March 10, 2025. Outcomes of interest included rehospitalization, mortality, community discharge, functional improvement, and long-term nursing home placement.

A total of 31 studies met the inclusion criteria. Twenty studies reported better outcomes for patients treated in IRFs, including lower rehospitalization rates, higher community discharge rates, and greater functional improvement. Three favored SNFs, 6 reported mixed results, and 2 found no significant difference. The majority of studies relied on observational designs, which are limited in their ability to address unmeasured confounding. Studies employing more rigorous quasi-experimental methods, such as instrumental variable approaches, supported these findings but were sensitive to assumptions regarding instrument validity.

While the literature suggests better outcomes in IRFs compared with SNFs, substantial methodological limitations restrict causal interpretation. The evidence base is limited by reliance on observational study designs, which are vulnerable to unmeasured confounding and selection bias. Given the higher cost of IRF care, more rigorous research that addresses unobserved heterogeneity is needed to inform Medicare payment policy and optimize cost-effective post-acute care delivery.