Emulating 3 Clinical Trials That Compare Stroke Rehabilitation at Inpatient Rehabilitation Facilities With Skilled Nursing Facilities

Published:March 01, 2022DOI:



      To inform the design of a potential future randomized controlled trial (RCT), we emulated 3 trials where patient-level outcomes were compared after stroke rehabilitation at inpatient rehabilitation facilities (IRFs) with skilled nursing facilities (SNFs).


      Trials were emulated using a 1:1 matched propensity score analysis. The 3 trials differed because facilities from rehabilitation networks with different case volumes were compared. Rehabilitation network case volumes were based on the number of patients with stroke that each hospital discharged to each specific IRF or SNF. Trial 1 included 60,529 patients from all networks, trial 2 included 34,444 patients from networks with medium and large case volumes (ie, ≥5 patients), and trial 3 included 19,161 patients from networks with large case volumes (ie, ≥10 patients). The E values were calculated to estimate the minimum strength that an unmeasured confounder would need to be to nullify the results.


      A national sample of IRFs and SNFs from across the United States.


      Fee-for-service Medicare patients with acute stroke who received IRF or SNF based rehabilitation.


      Not applicable.

      Main Outcome Measures

      One-year successful community discharge (home for >30 consecutive days) and all-cause mortality.


      Overall, 29,500, 15,156, and 7450 patients were matched for trials 1, 2, and 3. For 1-year successful community discharge, absolute risk differences for IRF patients were 0.21 (95% CI, 0.20-0.22), 0.17 (95% CI, 0.16-0.19), and 0.12 (95% CI, 0.10-0.14) in trials 1, 2, and 3, respectively. For 1-year all-cause mortality, corresponding risk differences were −0.11 (95% CI, −0.12 to −0.11), −0.11 (95% CI, −0.12 to −0.09), and −0.08 (95% CI, −0.10 to −0.06). The E values indicated that a moderately sized unmeasured confounder, with a relative risk of 1.6-2.0 would nullify differences in successful community discharge.


      IRF patients had superior outcomes, but differences were attenuated when IRFs and SNFs from larger rehabilitation networks were compared. The vulnerability of the findings to unmeasured confounding supports the need for an RCT.


      List of abbreviations:

      aOR (adjusted odds ratio), ASD (absolute standardized difference), HR (hazard ratio), HTE (heterogeneity of treatment effect), IRF (inpatient rehabilitation facility), LTNH (long-term nursing home), PS (propensity score), RCT (randomized controlled trial), RD (risk difference), RR (risk ratio), SNF (skilled nursing facility)
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