Abstract
BACKGROUND: Falls are a major source of morbidity in older adults and may be particularly consequential for breast cancer survivors, who face vulnerabilities from aging, treatment side effects, and comorbidities. Sarcopenia, the progressive loss of skeletal muscle mass and strength, may exacerbate fall risk but is rarely incorporated into oncology-focused fall risk assessments. OBJECTIVE: To evaluate the association between sarcopenia and the risk of first and repeated falls in older breast cancer patients using real-world electronic health record data. METHODS: We conducted a retrospective cohort study using the TriNetX platform, including women aged 60-89 years diagnosed with breast cancer between 2010 and 2024. Sarcopenia was identified using ICD-10 code M62.84. Outcomes included first fall, repeated falls, time to fall, and fall frequency. Analyses included unadjusted comparisons, propensity score matching, and multivariable Cox regression adjusting for demographics, comorbidities, treatments, and prior falls. RESULTS: Among 884,123 patients (768 with sarcopenia, 883,355 without), crude fall rates were markedly higher in those with sarcopenia (first fall: 24% vs. 2%; repeated falls: 13% vs. < 1%; p < 0.0001). Kaplan-Meier analyses showed an eightfold higher risk of first fall and a fourteenfold higher risk of repeated falls. After propensity score matching, fall rates were nearly identical. In fully adjusted Cox models, sarcopenia remained a significant predictor of first fall (HR 1.93, 95% CI 1.61-2.31). Other independent predictors included older age, hypertension, diabetes, obesity, opioid use, and prior falls. CONCLUSION: Sarcopenia is a strong crude marker of fall risk in older breast cancer survivors, but much of the excess risk reflects comorbidities. Incorporating sarcopenia screening with comorbidity management may enhance fall prevention in survivorship care.