Inverse Dose-Response Relationship Between Home Health Care Services and Rehospitalization in Older Adults

(1) To examine the impact of specific services [skilled nursing (SN), physical therapy (PT), occupational therapy (OT), and home health aide (HA)] in Medicare-certified home health care (HHC) on subsequent rehospitalization among older patients during a 60-day HHC episode and (2) to test the moderating effect of functional limitation on these services. Secondary analysis of data from the Outcome and Assessment Information Set (OASIS) and HHC administrative records of a statewide not-for-profit HHC agency from January 1, 2016, to December 31, 2016. Participants were ≥65 years old and were admitted to HHC within 48 hours of hospital discharge. Outcome was time to rehospitalization during the 60-day HHC episode (ie, number of days). Independent variables were visit intensity (number of visits/week) of SN, PT, OT, and HA, respectively. Functional limitation was measured by a composite score generated from 9 OASIS items on physical function. Multivariate Cox Proportional hazard analyses were conducted. Subgroup analysis (high vs low functional limitation) was conducted to examine the moderating effect of functional limitation on specific HHC services. Ad hoc analysis was conducted to examine potential interaction between specific HHC services that were significantly related to rehospitalization. The sample included 1377 participants, among whom 11.5% were rehospitalized during the 60-day HHC episode. At the threshold dose of 1 PT or 2 SN visits/week, higher visit intensity significantly reduced the hazard of rehospitalization in these patients by up to 82% for PT (2.30 visits/week; hazard ratio [HR] = 0.18, P value