Walking Ability and Brain Natriuretic Peptide Are Highly Predictive of Kidney Transplant Waiting List Removal

Abstract

Background: Kidney transplant waitlist management is complex because waiting time is long, and the patients have significant comorbidities. Identification of patients at highest risk for waiting list removal for death and medical complications could allow better outcomes and allocation of resources. Methods: Demographics, functional and frailty assessment‚ and biochemical data were retrospectively analyzed on 313 consecutive patients listed for kidney transplant. Troponin, brain natriuretic peptide, components of the Fried frailty metrics, pedometer activity, and treadmill ability were measured at the time of transplant evaluation and at subsequent re-evaluations. Cox proportional hazards models were used to identify factors associated with death or waiting list removal for medical reasons. Multivariate models were created to identify significant predictor sets. Results: Among 249 patients removed while waitlisted, 19 (6.1%) died and 51 (16.3%) were removed for medical reasons. Mean follow-up duration was 2.3 y (±1.5 y). 417 sets of measurements were collected. Significant (P < 0.05) non–time-dependent variables associated with the composite outcome identified on univariate analysis included N-terminal probrain natriuretic peptide (BNP), treadmill ability, pedometer activity, diagnosis of diabetes and the Center of Epidemiological Studies Depression Scale question asking how many days per week could you not get going. Significant time-dependent factors included BNP, treadmill ability, Up and Go, pedometer activity, handgrip, 30 s chair sit-stand test, and age. The optimal time-dependent predictor set included BNP, treadmill ability, and patient age. Conclusions: Changes in functional and biochemical markers are predictive of kidney waitlist removal for death and medical reasons. BNP and measures of walking ability were of particular importance.