Association Between Weight Loss Before Deceased Donor Kidney Transplantation and Posttransplantation Outcomes

Abstract

Rationale & objective: There is debate on whether weight loss, a hallmark of frailty, signals higher risk for adverse outcomes among recipients of deceased donor kidney transplantation (DDKT).

Study design: Retrospective cohort study.

Setting & participants: Using national Organ Procurement and Transplantation Network data, we included all DDKT recipients in the United States between December 4, 2004, and December 3, 2014, who were adults (aged ≥ 18 years) when listed for DDKT.

Exposures: Relative pre-DDKT weight change as a continuous predictor and categorized as <5% weight change from listing to DDKT, ≥5% to <10% weight loss, ≥10% weight loss, ≥5% to <10% weight gain, and ≥10% weight gain.

Outcomes: We examined 3 post-DDKT outcomes: (1) transplant hospitalization length of stay (LOS) in days, (2) all-cause graft failure, and (3) mortality.

Analytic approach: Unadjusted fractional polynomial methods, multivariable log-gamma models, and multivariable Cox proportional hazards models.

Results: Among 94,465 recipients of DDKT, median pre-DDKT weight change was 0 (interquartile range, -3.5 to +3.9) kg. There were nonlinear unadjusted associations between relative pre-DDKT weight loss and longer transplant hospitalization LOS, higher all-cause graft loss, and higher mortality. Compared with recipients with <5% pre-DDKT weight change (n = 49,366; 52%), recipients who lost ≥10% of their listing weight (n = 10,614; 11%) had 0.66 (95% CI, 0.23-1.09) days longer average transplant hospitalization LOS (P = 0.003), 1.11-fold higher graft loss (adjusted HR [aHR], 1.11; 95% CI, 1.06-1.17; P < 0.001), and 1.18-fold higher mortality (aHR, 1.18; 95% CI, 1.11-1.25; P < 0.001) independent of recipient, donor, and transplant factors. Pre-DDKT dialysis exposure, listing body mass index category, and waiting time modified the association of pre-DDKT weight change with hospital LOS (interaction P < 0.10), but not with all-cause graft loss and mortality.

Limitations: Unmeasured confounders and inability to identify volitional weight change. Also, the higher significance level set to increase the power of detecting interactions with the fixed sample size may have resulted in increased risk for type 1 error.

Conclusions: DDKT recipients with ≥10% pre-DDKT weight loss are at increased risk for adverse outcomes and may benefit from augmented support post-DDKT.

Keywords: Renal transplantation; deceased donor kidney transplantation (DDKT); end-stage kidney disease (ESKD); frailty; graft failure; mortality; obesity; outcomes; protein-wasting malnutrition; sarcopenia; wasting; weight loss.

Figure 1

Box and Whisker Plots Depicting the Distribution of Absolute Weight Change (in Kilograms) from Listing to Transplantation among Deceased Donor Kidney Transplant Recipients in the United States by Year. Black bars in the middle of the white boxes indicate the median values. The bottoms and tops of the boxes represent the interquartile ranges (IQRs), and the tops and bottoms of the whiskers represent values for weight change that extend from the boxes by no more than the interquartile range X 1.5.

Figure 2

Non-linear Associations between Relative Pre-DDKT Weight Change and Post-Transplantation Outcomes among US DDKT Recipients. Figure displays results of fractional polynomial methods to model the non-linear, unadjusted association of pre-DDKT relative weight change, relative to no weight change, with transplantation hospital length of stay (Panel A), all-cause graft loss (Panel B), and post-transplantation mortality (Panel C). Histograms in light green display overall cohort distribution of pre-transplantation relative weight change. Black line indicates unadjusted estimates for each outcome of interest. Blue areas represent 95% Confidence Intervals.

Figure 3

Cumulative Incidence Curves for All-Cause Graft Loss (Panel A) and Mortality (Panel B) by Relative Pre-Transplantation Weight Change from Listing to Transplantation among US Deceased Donor Kidney Transplant Recipients from 2004–2014. The log-rank p-values for the contrasts between weight change categories were <0.001 for all-cause graft loss and post-transplantation mortality, respectively. At five years post-transplantation, all-cause graft loss occurred among 25% of recipients with <5% weight change and 5–9.9% weight gain, respectively, among 26% of recipients with 5–9.9% weight loss, among 27% of recipients with ≥10% weight gain, and among 28% of recipients with ≥10% weight loss. At five years, mortality occurred among 16% of recipients with weight gain 5–9.9% and ≥10%, respectively, among 17% of recipients with <5% weight change and weight loss 5–9.9%, respectively, and among 19% of recipients with weight loss ≥10%.