Association between volume of patients undergoing stroke rehabilitation at acute care hospitals and improvement in activities of daily living.

Background: This study aimed to determine the relationship between the annual volume of patients undergoing rehabilitation per hospital and the outcomes of patients admitted for acute stroke.

Methods: This observational study used nationwide administrative data. Data on stroke patients aged ≥ 20 years who underwent rehabilitation were extracted from 1,182 acute care hospitals in Japan. The exclusion criteria were extended hospital stay exceeding 180 days and death during hospitalization. Hospital volumes were divided into four quartiles of total patients per hospital. The primary outcome was an improvement in activities of daily living from admission to discharge measured using the Barthel index. Poisson regression analysis of activities of daily living improvement was performed using inverse probability of treatment weighting.

Results: High rehabilitation volume was significantly correlated with improvements in activities of daily living using the "very low group" as a reference (risk ratio [95% confidence interval]): 1.06 [1.05-1.08], P<0.001). Low volume was also significantly associated with activities of daily living improvement (risk ratio [95% confidence interval]: 1.04 [1.03-1.06], P<0.001).

Conclusions: The annual volume of stroke patients undergoing multidisciplinary rehabilitation at a specific hospital may be a factor in the degree of patient improvement in activities of daily living.