Impact of Lookback Duration on the Performance of a Claims‐Based Frailty Proxy in Women With Stage I– III Breast Cancer
Year: 2025
Type: article
Abstract: BACKGROUND: Frailty is an important prognostic indicator in older women with breast cancer. The Faurot frailty index, a validated claims-based frailty proxy measure, uses healthcare billing codes during a user-specified ascertainment window to predict frailty. We assessed how the duration of frailty ascertainment affected the ability of the Faurot frailty index to predict one-year mortality in women with stage I-II breast cancer. METHODS: We included 128 857 women (66+ years) with stage I-III breast cancer in the SEER-Medicare database (2003-2019). The Faurot frailty index was calculated using 3-, 6-, 8-, and 12-month ascertainment windows prior to diagnosis or using all-available lookback. Associations between the Faurot frailty index using each window and one-year all-cause mortality were estimated using Kaplan-Meier curves. Discrimination of one-year mortality risk was assessed using C-statistics. RESULTS: Five percent of women died during the year following diagnosis. Higher Faurot scores were associated with increased mortality risk for all frailty ascertainment windows. Differences in one-year mortality risk for women with high vs. low Faurot frailty scores were reduced when using all-available lookback (16% vs. 2%, difference = 15%, 95% CI 0.14-0.15) compared to shorter windows (e.g., 8 months: 25% vs. 2%, difference = 23%, 95% CI 0.22-0.24). C-statistics ranged from 0.758 (all-available lookback) to 0.770 (12 months) and were robust in subgroups defined by age, race, ethnicity, region, stage, and cancer subtype. CONCLUSIONS: The Faurot frailty index performed well across 3- to 12-month frailty ascertainment windows in women with breast cancer. Researchers should employ this index to address confounding by frailty in studies of cancer populations.
DOI: 10.1002/pds.70103
Language: English
Topic: Frailty in Older Adults
Subfield: Geriatrics and Gerontology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,650
Funders: California Department of Public Health, University of Southern California, National Institutes of Health, Centers for Disease Control and Prevention, University of North Carolina at Chapel Hill, National Institute on Aging, National Cancer Institute, National Center for Chronic Disease Prevention and Health Promotion, National Center for Advancing Translational Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, School of Medicine, University of North Carolina at Chapel Hill
Awards: G1289825209, G1393855433, G2238803135, G2612351997, G2639781304, G3014186981, G3161224617, G3190882026, G3223130445, G3509688676, G4203349661, G4322373146, G4393609197, G480705112, G5309353569, G5333917095, G5433357946, CALIFORNIA COORDINATED CANCER PREVENTION & CONTROL PROGRAM, G5570217171, North Carolina Translational and Clinical Science Institute (NC TraCS), G6795547015, G793654858, G8247152613, G8923144227, Carolina Center for Population Aging and Health, Propensity scores and preventive drug use in the elderly, Mid-Career Mentoring Award For Patient-Oriented Research in Frailty and Health Outcomes, Cancer Care Quality Training Program, North Carolina Translational and Clinical Sciences Institute (NC TraCS)
OpenAlex ID: W4406542648