Frailty as a Novel Predictor of Mortality and Hospitalization in Individuals of All Ages Undergoing Hemodialysis

Abstract

Objectives To quantify the prevalence of frailty in adult patients of all ages undergoing chronic hemodialysis, its relationship to comorbidity and disability, and its association with adverse outcomes of mortality and hospitalization. Design Prospective cohort study. Setting Single hemodialysis center in Baltimore, Maryland. Participants 146 prevalent hemodialysis patients enrolled between January 2009 and March 2010 and followed through August 2012. Measurements Frailty, comorbidity, and disability on enrollment into the study and subsequent mortality and hospitalizations. Results At enrollment, 50.0% of older (age≥65) and 35.4% of younger (age<65) hemodialysis patients were frail; 35.9% and 29.3% were intermediately frail, respectively. The 3-year mortality was 16.2% for non frail, 34.4% for intermediately frail, and 40.2% for frail participants. Intermediate frailty and frailty were associated with a 2.68-fold (95% CI: 1.02-7.07, P=0.046) and 2.60-fold (95%CI: 1.04-6.49, P=0.041) higher risk of death independent of age, sex, comorbidity, and disability. In the year after enrollment, median number of hospitalizations was 1 (IQR 0-3). The proportion with 2 or more hospitalizations was 28.2% for non frail, 25.5% for intermediately frail, and 42.6% for frail participants. While intermediate frailty was not associated with the number of hospitalizations (RR=0.76, 95%CI:0.49-1.16, P=0.21), frailty was associated with a 1.43-fold (95%CI:1.00-2.03, P=0.049) higher number of hospitalizations independent of age, sex, comorbidity, and disability. The association of frailty with mortality and hospitalizations did not differ between older and younger participants (Interaction P=0.64 and P=0.14, respectively). Conclusions Adults of all ages undergoing hemodialysis have a very high prevalence of frailty, more than 5-fold higher than community dwelling older adults. In this population, regardless of age, frailtyis a strong, independent predictor of mortality and number of hospitalizations.

Association of Performance-Based and Self–Reported Function–Based Definitions of Frailty with Mortality among Patients Receiving Hemodialysis

“…Thus, we can compare the prevalence of frailty in this population with that observed in previous studies. We found a similar prevalence among patients on HD using the performancebased definition as McAdams-DeMarco et al (5) found in a cohort of patients from the Baltimore area. However, the prevalence was more than threefold higher than that in community-dwelling elders in the Cardiovascular Health Study (3) and the Women's Health Initiative (7), although our population was not restricted to individuals age .65 years old.…”

“…We and others have previously shown that a substantial percentage of patients receiving dialysis is frail (5,8,12) and that the prevalence depends on how frailty is defined (12). This study begins to explore the potential utility of two definitions of frailty as predictors of mortality in this already high-risk population.…”

“…We and other investigators have invoked frailty definitions that substitute alternative criteria for some or all of the original five (7)(8)(9)(10)(11). Not surprisingly, such substitution has led to variations in the reported prevalence of frailty across studies (4)(5)(6)(8)(9)(10)(11)(12)(13). Specifically, frailty is more prevalent when patients' self-reported physical function are used in the definition than when physical performances are measured (11,12).…”

“…For physical activity, grip strength, and gait speed, we used the thresholds established by Fried et al (3), which were on the basis of the lowest sex-specific quintiles among community-dwelling elderly and have now been used as standard thresholds in other populations, including ESRD (Supplemental Table 1) (5,6,17).…”

“…The Fried frailty definition has become a standard of physical frailty that has been applied to not only older community-dwelling adults, in whom it was first described, but also, older patients undergoing elective surgery, patients with CKD (4), and patients with ESRD undergoing hemodialysis (HD) (5,6). We and other investigators have invoked frailty definitions that substitute alternative criteria for some or all of the original five (7)(8)(9)(10)(11).…”