An exploration of the association between very early rehabilitation and outcome for the patients with acute ischaemic stroke in Japan: a nationwide retrospective cohort survey

Background: Very early rehabilitation is expected to improve functional outcomes after stroke, although its effectiveness has not been fully evaluated. The purpose of this study was to investigate the association between very early intervention (VEI), and patient outcomes at discharge by using nationwide large data and statistical treatment for selection bias. Methods: In this study, we defined VEI as rehabilitation commencing within 3 days of stroke admission. The data were derived from a nationwide survey of acute-care hospitals conducted in 2007 for designing a reimbursement scheme and from a concurrent survey on rehabilitation services among a convenient subgroup of hospitals participating in the above survey. We included patients with a diagnosis code of ischaemic cerebrovascular disease with acute onset who underwent any rehabilitation services during hospitalisation. Surgery cases, those with no functional deficit, and those with a severe consciousness deficit upon admission were excluded. A total of 5,482 patients were enrolled from 294 hospitals. To correct for any potential selection bias, we used Friday admission as an instrumental variable (IV) and conducted a bivariate probit model analysis. Results: We found that VEI for acute stroke patients was significantly associated with a lesser degree of disability at discharge. Even after considering endogenous problems due to treatment selection, VEI improved the chance of reducing disability by 15.3% (p < 0.001). There was no significant association between VEI and in-hospital mortality, suggesting that VEI was not likely to lead to an adverse outcome. Conclusions: These data suggest that VEI may lead to a better outcome with no increase in adverse events compared to delayed rehabilitation.