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

Abstract

ObjectiveTo 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). DesignTrials 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. SettingA national sample of IRFs and SNFs from across the United States. ParticipantsFee-for-service Medicare patients with acute stroke who received IRF or SNF based rehabilitation. InterventionsNot applicable. Main Outcome MeasuresOne-year successful community discharge (home for >30 consecutive days) and all-cause mortality. ResultsOverall, 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. ConclusionsIRF 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.