Study Design and Participants
This retrospective cohort study was conducted in adherence to the STROBE statement. This study included 2,151 consecutive patients with subacute stroke admitted to Tokyo Bay Rehabilitation Hospital between April 1, 2015 and March 31, 2020. The inclusion criterion was a first occurrence of subacute stroke. The exclusion criteria were age < 20 years (n = 5), entered the facility before stroke onset (n = 19), subarachnoid hemorrhage (n = 250), infratentorial lesions (n = 204), bilateral cerebral lesions (n = 40), disturbance of consciousness (n = 55), aphasia (n = 215), hospital transfer (n = 86), death (n = 4), and loss of data (n = 44). After applying the selection criteria, 1,229 patients were finally included in this study (Fig. 1). This study was conducted in accordance with the Declaration of Helsinki [22] and was reviewed and approved by the Ethics Committee of Tokyo Bay Rehabilitation Hospital (approval number. #246). The opt-out method was applied to obtain informed consent in this study.
Data collection
The following demographic characteristics and measures were collected from the patients’ medical records: age, sex, body mass index (BMI), stroke type (cerebral infarction or cerebral hemorrhage), brain side affected, duration from stroke onset to admission, hospital duration, living situation (alone or not), and discharge destination (home or facility). Hospital duration and discharge destination were collected at discharge, while the other data were collected at admission.
Mini-Mental State Examination
Mini-Mental State Examination (MMSE) is a questionnaire for evaluating cognitive function [23]. It consists of 11 items as follows (maximum score of each item): orientation to time (5), orientation to place (5), registration of three words (3), attention and calculation (serial sevens or spelling) (5), recall (3), naming (2), repetition (1), comprehension of verbal (3), comprehension of written (1), writing (1), and construction (1). The maximum score is 30 points, with a higher score representing greater cognitive function. Occupational therapists administered the MMSE and determined the score at admission.
Stroke Impairment Assessment Set
Motor function was assessed using the stroke impairment assessment set-motor function (SIAS-m) [24, 25], which consists of two tests for the upper extremity (knee-mouth and finger function tests) and three tests for the lower extremity (hip flexion, knee extension, and foot pat tests). Each test was rated on a 6-grade ordinal scale rating from 0 (no movement at all) to 5 points (normal). The total scores of the upper and lower extremities were 0–10 and 0–15 points, respectively [26]. Physical and occupational therapists administered the SIAS-m and determined the score at admission.
Grip strength
Upper-body muscle strength was measured using grip strength, which has established reliability in patients with stroke [27]. Grip strength was measured for each participant’s non-paralyzed upper limb using a handgrip dynamometer (TKK 5401; Takei Scientific Instruments, Tokyo, Japan). Representative grip strength was calculated as the average of two trials. Each measurement was assessed by trained physical or occupational therapists.
Functional Independence Measure
FIM version 3.0 is an observational evaluation tool for functional disability [28]. The FIM consists of 13 motor subscales (FIM motor) and five cognitive subscales (FIM cognitive). The FIM motor consists of the following four categories: self-care (eating, grooming, bathing, dressing-upper body, dressing-lower body, and toileting), sphincter control (bladder management and bowel management), transfers (bed/chair/wheelchair, toilet, and tub/shower), and locomotion (walk/wheelchair and stairs). The FIM cognitive consists of two categories: communication (comprehension and expression) and social cognition (social interaction, problem-solving, and memory). Each item has a 7-grade scale ranging from 1 (total assistance or not testable) to 7 points (complete independence). The total score is 18–126 points, 13–91 points, and 5–35 points for the total FIM, FIM motor, and FIM cognitive, respectively, with a higher score representing greater functional independence. Nurses evaluated FIM scores at admission and discharge.
Statistical Analyses
The normality of the data was assessed using the normal Q-Q plot. We classified participants into home discharge and facility discharge groups. Patient characteristics were compared between groups using the chi-squared test, unpaired t-test, or Mann-Whitney U test, as appropriate. Finally, a multivariate logistic regression analysis was performed to assess the factors affecting home discharge after controlling simultaneously for potential confounders. The dependent variable was the discharge destination (home or facility), and the independent variables were the factors at admission with a P ≤ 0.05 in the univariate analysis. All statistical analyses were performed using IBM SPSS Statistics (version 27.0; IBM, Tokyo, Japan). Statistical significance was set at P ≤ 0.05.