Abstract
RATIONALE & OBJECTIVE: Concerns about nonadherent behaviors often prevent dialysis patients from entering waitlists for transplant even though there is an inconsistent association of these behaviors with posttransplant outcomes. We examined the association between plausible metrics of nonadherence related to dialysis treatment and posttransplant outcomes. STUDY DESIGN: Retrospective cohort. We linked national dialysis treatment data with transplant registry data. SETTING AND PARTICIPANTS: Adult patients receiving maintenance hemodialysis from January 1, 2004, through December 31, 2014, who received a kidney transplant at a US center. EXPOSURES: We examined 5 nonadherence metrics: serum potassium level (≥5.2 mEq/L), serum phosphorus level (>5.5 mg/dL), interdialytic weight gain (IDWG; ≥5 L), shortened treatments (≥30 min), and missed treatments (≥1); missed treatment data were available only for 2004-2009. These metrics were characterized per proportion of time under observation. Dialysis observation time was divided into 3-month intervals (quarters), and the number of nonadherent measurements in each domain was calculated for each quarter. OUTCOMES: Allograft loss, mortality, and acute rejection in the first posttransplant year. ANALYTICAL APPROACH: Using Cox proportional hazards and logistic regression, we estimated the hazard ratios for graft loss and mortality and odds ratios for rejection. RESULTS: 9,543 patients met inclusion criteria. In our primary model, hyperphosphatemia (adjusted hazard ratio [aHR], 1.27 [95% CI, 1.08-1.49]), large IDWG (aHR, 1.39 [95% CI, 1.23-1.59]), and shortened treatments (aHR, 1.54 [95% CI, 1.12-2.13]) were associated with greater rates of allograft loss, but hyperkalemia was not. Large IDWG (aHR, 1.49 [95% CI, 1.29-1.73]) and shortened treatments (aHR, 1.34 [95% CI, 1.13-1.58]) were associated with mortality, whereas hyperkalemia and hyperphosphatemia were not. Only shortened treatments were associated with an increased risk of acute rejection (adjusted odds ratio, 3.88 [95% CI, 1.98-7.58]). In models limited to the years 2004-2009 that included missed treatments, missed treatments were associated only with mortality. LIMITATIONS: Unmeasured confounding (eg, dietary data); adherence metrics used may have multiple, complex causes. CONCLUSIONS: Plausible measures of dialysis nonadherence have long-term associations with allograft and patient survival. Behavioral metrics were more closely associated with outcomes than laboratory markers were. The implications of nonadherent behaviors for dialysis patients must be carefully considered before patients are excluded from transplantation.