BACKGROUND: Hospital-associated disability (HAD), a decline in the ability to perform activities of daily living (ADL) during hospitalization, is a modifiable target in integrated care for older adults. The aim of this study was to determine the impact of inpatient cardiac rehabilitation (CR) on the development of HAD in older patients with aortic stenosis undergoing transcatheter aortic valve implantation (TAVI). METHODS: Older patients undergoing TAVI were extracted from the Japanese nationwide database (JROAD-DPC) from April 2014 to March 2021 and were divided into patients receiving inpatient CR (CR group) and a non-CR group. HAD was defined as a decrease in the Barthel Index (BI) score ≥5 points at discharge compared with the score at admission. RESULTS: Of 19,789 eligible patients, 17,066 (86%) underwent inpatient CR. The overall prevalence of HAD was 9.6%, with a lower incidence in the CR group than in the non-CR group (8.8% vs. 14.2%, p <
0.001). Random forest analysis revealed key features associated with HAD risk including BI score at admission, inpatient CR participation, age, body mass index (BMI), and chronic kidney disease. The results of multivariate logistic regression analysis showed that participation in inpatient CR was associated with a lower odds ratio (OR) of HAD (OR, 0.62
95% confidence interval, 0.54-0.70), with similar results in inverse probability of treatment weighting-adjusted logistic regression analyses (OR, 0.82
95% confidence interval, 0.77-0.88). Analyses in subgroups of interest showed heterogeneity in the effects of inpatient CR with possible loss in patients with a BMI of <
18.5 kg/m CONCLUSIONS: The data suggest a beneficial effect of inpatient CR participation on the prevention of HAD in older patients undergoing TAVI, but the effect may be limited in lean patients with disability for ADL before TAVI.