Individual Frailty Components and Mortality in Kidney Transplant Recipients

Abstract

Frailty increases early hospital readmission and mortality risk among kidney transplantation (KT) recipients. Although frailty represents a high-risk state for this population, the correlates of frailty, the patterns of the 5 frailty components, and the risk associated with these patterns are unclear. Six hundred sixty-three KT recipients were enrolled in a cohort study of frailty in transplantation (12/2008-8/2015). Frailty, activities of daily living (ADL)/instrumental ADL (IADL) disability, Centers for Epidemiologic Studies Depression Scale depression, education, and health-related quality of life (HRQOL) were measured. We used multinomial regression to identify frailty correlates. We identified which patterns of the 5 components were associated with mortality using adjusted Cox proportional hazards models. Frailty prevalence was 19.5%. Older recipients (adjusted prevalence ratio [PR], 2.22; 95% confidence interval [CI], 1.21-4.07) were more likely to be frail. The only other factors that were independently associated with frailty were IADL disability (PR, 3.22; 95% CI, 1.72-6.06), depressive symptoms (PR, 11.31; 95% CI, 4.02-31.82), less than a high school education (PR, 3.10; 95% CI, 1.30-7.36), and low HRQOL (fair/poor: PR, 3.71; 95% CI, 1.48-9.31). The most common pattern was poor grip strength, low physical activity, and slowed walk speed (19.4%). Only 2 patterns of the 5 components emerged as having an association with post-KT mortality. KT recipients with exhaustion and slowed walking speed (hazards ratio = 2.43; 95% CI, 1.17-5.03) and poor grip strength, exhaustion, and slowed walking speed (hazard ratio, 2.61; 95% CI, 1.14-5.97) were at increased mortality risk. Age was the only conventional factor associated with frailty among KT recipients; however, factors rarely measured as part of clinical practice, namely, HRQOL, IADL disability, and depressive symptoms, were significant correlates of frailty. Redefining the frailty phenotype may be needed to improve risk stratification for KT recipients.