Supplementary Material for: Home Healthcare Massage for Disabled Older Adults in Japan: Factors Associated with Improvement and Adverse Events

Background: Home healthcare massage is widely used in Japan under insurance coverage, yet scientific evidence on its effectiveness and adverse events remains limited. Objective: To examine effectiveness and predictors of improvement in disabled older adults receiving home healthcare massage and to describe adverse events. Methods: A retrospective cohort study included 469 participants (mean age 80.2 years; 65.7% women) from 10 clinics. Outcomes at baseline and one year were the level of nursing care required, the degree of independent living, and 15 basic activities of daily living (ADL). Participants were classified as improved, unchanged, or worsened. Logistic regression identified predictors of improvement. Adverse events during one year were recorded. Results: Improvement was associated with a mild level of nursing care required at baseline (OR=0.865), muscle atrophy (OR=1.87), and no use of services other than massage (OR=0.439). Maintenance without deterioration was also considered clinically meaningful. Ninety-six adverse events (20.5%) were reported, most frequently pain, followed by abrasions/contusions/bruises and numbness. Severity, causality, and temporal course were not collected. Conclusion: Home healthcare massage may contribute to functional improvement under specific conditions, though most participants received combination therapies. These findings reflect real-world practice in Japan and support the need for large-scale prospective studies.