Comparison of the Simplified sWHI and the Standard CHS Frailty Phenotypes for Prediction of Mortality, Incident Falls, and Hip Fractures in Older Women

Abstract

Background We compared the simplified Women's Health Initiative (sWHI) and the standard Cardiovascular Health Study (CHS) frailty phenotypes in predicting falls, hip fracture, and death in older women. Methods Participants are from the WHI Clinical Trial. CHS frailty criteria included weight loss, exhaustion, weakness, slowness, and low physical activity. The sWHI frailty score used two items from the RAND-36 physical function and vitality subscales, one item from the WHI physical activity scale plus the CHS weight loss criteria. Specifically, level of physical function was the capacity to walk one block and scored as severe (2-points), moderate (1-point), or no limitation (0). Vitality was based on feeling tired most or all of the time (1-point) versus less often (0). Low physical activity was walking outside less than twice a week (1-point) versus more often (0). A total score of 3 resulted in a frailty classification, a score of 1 or 2 defined pre-frailty, and 0 indicated nonfrailty. Outcomes were modeled using Cox regression and Harrell C-statistics were used for comparisons. Results Approximately 5% of the participants were frail based on the CHS or sWHI phenotype. The sWHI frailty phenotype was associated with higher rates of mortality (hazard ratio [HR] = 2.36, p ≤.001) and falls (HR = 1.45, p =.005). Comparable HRs in CHS-phenotype were 1.97 (p