Using a Claims-Based Frailty Index to Investigate Frailty, Survival, and Healthcare Expenditures among Older Adults Hospitalized for COVID-19 at an Academic Medical Center

BACKGROUND: Frailty is associated with mortality in older adults hospitalized with COVID-19, yet few studies have quantified healthcare utilization and spending following COVID-19 hospitalization. OBJECTIVE: To evaluate whether survival and follow-up healthcare utilization and expenditures varied as a function of claims-based frailty status for older adults hospitalized with COVID-19. DESIGN: Retrospective cohort study PARTICIPANTS: 136 patients aged 65 and older enrolled in an Accountable Care Organization (ACO) risk contract at an academic medical center and hospitalized for COVID-19 between March 11, 2020 - June 3, 2020 MEASUREMENTS: We linked a COVID-19 Registry with administrative claims data to quantify a frailty index and its relationship to mortality, healthcare utilization, and expenditures over 6 months following hospital discharge. Kaplan Meier curves and Cox Proportional Hazards models were used to evaluate survival by frailty. Kruskal-Wallis tests were used to compare utilization. A generalized linear model with a gamma distribution was used to evaluate differences in monthly Medicare expenditures. RESULTS: Much of the cohort was classified as moderate to severely frail (65.4%), 24.3% mildly frail, and 10.3% robust or pre-frail. Overall, 27.2% (n=37) of the cohort died (n=26 during hospitalization, n=11 after discharge) and survival did not significantly differ by frailty. Among survivors, inpatient hospitalizations during the 6-month follow-up period varied significantly by frailty (p=0.02). Mean cost over follow-up was $856.37 for the mild and $4914.16 for the moderate to severe frailty group, and monthly expenditures increased with higher frailty classification (p <.001). CONCLUSIONS: In this cohort, claims-based frailty was not significantly associated with survival but was associated with follow-up hospitalizations and Medicare expenditures. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.14283/jfa.2023.15 and is accessible for authorized users.