{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,17]],"date-time":"2026-10-17T02:41:14Z","timestamp":1792204874254,"version":"4.4.0"},"reference-count":30,"publisher":"Oxford University Press (OUP)","issue":"11","license":[{"start":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T00:00:00Z","timestamp":1789689600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"name":"National Institute on Aging of the National Institutes of Health","award":["R56AG084578"],"award-info":[{"award-number":["R56AG084578"]}]},{"name":"National Institute on Aging of the National Institutes of Health","award":["K24AG073527"],"award-info":[{"award-number":["K24AG073527"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Despite growing enrollment in Medicare Advantage (MA) plans, the performance of claims-based frailty algorithms, which were developed for Medicare fee-for-service (FFS), remains unclear in MA.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We calculated the Kim claims-based frailty index (CFI), Veterans Affairs-Frailty Index (VA-FI), and Hospital Frailty Risk Score (HFRS) using the National Health and Aging Trends Study linked to Medicare FFS and MA data. We evaluated their performance against the comprehensive geriatric assessment-based frailty index (CGA-FI) and the frailty phenotype (FP) in Round 11 and Round 9.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Among 1527 FFS and 1457 MA beneficiaries in Round 11, frailty prevalence was 34.2% and 35.5%, respectively, by CGA-FI \u22650.25, and 13.3% and 16.2%, respectively, by FP. Across FFS and MA populations, the CFI, which prioritizes specificity and positive predictive value, classified 10%-12% of the overall population and 30%-36% of those with prior hospitalization as frail, whereas the VA-FI and HFRS, which emphasize sensitivity, classified 53%-71% of the overall population and 56%-87% of those with prior hospitalization as frail. Although claims-based frailty measures performed similarly across FFS and MA populations, their discriminatory ability was higher for CGA-FI \u22650.25 (C-statistics: CFI, 0.79-0.82; VA-FI, 0.77-0.82; HFRS, 0.63-0.77) than for FP (CFI, 0.71-0.77; VA-FI, 0.67-0.75; HFRS, 0.60-0.74). Performance was consistent by race and survey rounds, with modestly better discrimination in women than men.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Claims-based frailty measures are scalable tools for contemporary FFS and MA populations. However, applying published thresholds led to differences in frailty prevalence and model performance. Thresholds should therefore be tailored to the intended.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/gerona\/glag229","type":"journal-article","created":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T11:08:40Z","timestamp":1789384120000},"source":"Crossref","is-referenced-by-count":0,"title":["Performance of claims-based frailty indices in Medicare Advantage and fee-for-service populations"],"prefix":"10.1093","volume":"81","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0779-2808","authenticated-orcid":false,"given":"Lan","family":"Luo","sequence":"first","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3836-2440","authenticated-orcid":false,"given":"Kevin","family":"Pritchard","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1880-048X","authenticated-orcid":false,"given":"Chan Mi","family":"Park","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]},{"name":"Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiecheng","family":"Chen","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eunji G","family":"Kim","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1705-6249","authenticated-orcid":false,"given":"Ellen P","family":"McCarthy","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]},{"name":"Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7290-6838","authenticated-orcid":false,"given":"Dae Hyun","family":"Kim","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]},{"name":"Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, Massachusetts,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6801-5602","authenticated-orcid":false,"given":"Sandra M","family":"Shi","sequence":"additional","affiliation":[{"name":"Frailty Research Center, Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife , Boston, Massachusetts,","place":["United States"]},{"name":"Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, Massachusetts,","place":["United 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