Background Frailty, an important prognostic indicator in heart failure (HF), may be defined as a biological phenotype or an accumulation of deficits. Each method has strengths and limitations, but their utility has never been evaluated in the same community HF cohort. Methods Southeastern Minnesota residents with HF were recruited from 2007 to 2011. Frailty according to the biological phenotype was defined as 3 or more of: weak grip strength, physical exhaustion, slowness, low activity and unintentional weight loss >10 lb in 1 year. Intermediate frailty was defined as 1 to 2. The deficit index was defined as the proportion of deficits present out of 32 deficits. Results Among 223 patients (mean age 71 ± 14, 61% male), 21% were frail and 48% intermediate frail according to the biological phenotype. The deficit index ranged from 0.02-0.75, with a mean (SD) of 0.25 (0.13). Over a mean follow-up of 2.4 years, 63 patients died. After adjustment for age, sex and ejection fraction, patients categorized as frail by the biological phenotype had a 2-fold increased risk of death compared to those with no frailty, whereas a 0.1 unit increase in the deficit index was associated with a 44% increased risk of death. Both measures predicted death equally (C-statistics: 0.687 for biological phenotype and 0.700 for deficit index). Conclusion The deficit index and the biological phenotype equally predict mortality. As the biological phenotype is not routinely assessed clinically, the deficit index, which can be ascertained from medical records, is a feasible alternative to ascertain frailty.
Bibliographical noteFunding Information:
This study was supported by the National Heart, Lung and Blood Institute of the National Institute of Health (R01HL72435 to VLR) and study data were obtained from the Rochester Epidemiology Project, which is supported by the National Institute on Aging of the National Institutes of Health under Award Number R01AG034676. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the manuscript, and its final contents.