Original Investigation
Dialysis Nonadherence and Kidney Transplant Outcomes: A Retrospective Cohort Study

https://doi.org/10.1053/j.ajkd.2021.09.011Get rights and content

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.

Section snippets

Study Design and Data Sources

We performed a retrospective cohort study. Included in the study were incident and prevalent cases in adults (age ≥18 years) receiving outpatient in-center maintenance hemodialysis between January 1, 2004, and December 31, 2014, at facilities managed by a large national dialysis provider (DaVita) who were waitlisted and received a transplant during the study period (Fig S1). The study was limited to in-center hemodialysis to harmonize data-collection time points among study participants. To

Results

We identified 9,543 hemodialysis patients who met our inclusion criteria; patient clinical characteristics are presented in Table 1. Many patients met criteria for nonadherence (Table S1). We found that 41.3% of patients had at least 1 quarter with hyperkalemia; compared with those without hyperkalemia, they were younger (median age, 51 vs 53 years; P < 0.001), more often Latino (23.8% vs 12.3%), had a lower body mass index, had Medicaid as their primary insurance (9.3% vs 6.3%), and tended to

Discussion

Through a novel linkage of transplant registry data to dialysis treatment records, we have demonstrated that nonadherence with elements of the dialysis prescription is common even in patients who receive a kidney transplant and that dialysis behaviors such as shortened or missed treatments were more consistently associated with posttransplant patient and allograft survival than laboratory measurements were. Furthermore, the act of reducing the duration of dialysis treatments was associated with

Article Information

Authors’ Full Names and Academic Degrees

Deirdre Sawinski, MD, Hanna Lindner, MS, Robert Fitzsimmons, MS, Justine Shults, PhD, Jayme E. Locke, MD, MPH, Jordana B. Cohen, MD, MSCE, Paul A. MacLennan, PhD, and Peter P. Reese, MD, MSCE.

Authors’ Contributions

Contributed to the design of the study: DS, HL, JS, JEL, PAM, JBC, PPR; conducted the statistical analysis: DS, HL, RF; contributed to interpretation of the data: DS, HL, JS, JEL, PAM, JBC, PPR. Each author contributed important intellectual content during manuscript drafting or revision and agrees to be

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