Association between frequency of rehabilitation therapy and long-term mortality after stroke : a nationwide cohort study

Background Poststroke rehabilitation reportedly improves functional outcomes and minimizes disability. However, previous studies have demonstrated conflicting results regarding the effects of rehabilitation therapy on post-stroke mortality. Therefore, we aimed to investigate the association between rehabilitation therapy within the first six months after stroke and long-term all-cause mortality in patients with stroke using data from the Korean National Health Insurance System. Methods A total of 10,974 patients newly diagnosed with stroke using ICD-10 codes (I60-I64) between 2013 and 2019 were enrolled and followed-up for all-cause mortality until 2019. Post-stroke patients were categorized into three groups according to the frequency of rehabilitation therapy: no rehabilitation therapy, ≤ 40 sessions, and > 40 sessions. Cox proportional hazard models were used to assess the mortality risk according to rehabilitation therapy stratified by disability severity. Results Higher frequency of rehabilitation therapy was associated with significantly lower post-stroke mortality in comparison to no rehabilitation therapy (HR=0.88, 95% CI 0.79-0.9 9), especially among individuals with severe disability after stroke (HR=0.74, 95% CI 0.62-0.87). An inverse association between number of rehabilitation therapy sessions and mortality was identified in a multivariate Cox regression model with restricted cubic splines. In the context of stroke type, higher frequency of rehabilitation therapy was associated with reduced mortality rates compared to no rehabilitation therapy only in patients with hemorrhagic stroke (HR=0.60, 95% CI 0.49-0.74). While socioeconomic factors were not associated with mortality, older age, male sex, and pneumonia were associated with increased mortality risk, regardless of disability severity. Conclusions Post-stroke rehabilitation therapy within six months of stroke onset seems to play a substantial role in reducing long-term mortality after stroke. A higher frequency of rehabilitation therapy is recommended for post-stroke patients, particularly among those with severe disability.