The interplay of socioeconomic status, distance to center, and interdonor service area travel on kidney transplant access and outcomes

Abstract

Background and objectives: Variation in kidney transplant access across the United States may motivate relocation of patients with ability to travel to better-supplied areas.

Design, setting, participants, & measurements: We examined national transplant registry and U.S. Census data for kidney transplant candidates listed in 1999 to 2009 with a reported residential zip code (n = 203,267). Cox's regression was used to assess associations of socioeconomic status (SES), distance from residence to transplant center, and relocation to a different donation service area (DSA) with transplant access and outcomes.

Results: Patients in the highest SES quartile had increased access to transplant compared with those with lowest SES, driven strongly by 76% higher likelihood of living donor transplantation (adjusted hazard ratio [aHR] 1.76, 95% confidence interval [CI] 1.70 to 1.83). Waitlist death was reduced in high compared with low SES candidates (aHR 0.86, 95% CI 0.84 to 0.89). High SES patients also experienced lower mortality after living and deceased donor transplant. Patients living farther from the transplant center had reduced access to deceased donor transplant and increased risk of post-transplant death. Inter-DSA travel was associated with a dramatic increase in deceased donor transplant access (HR 1.94, 95% CI 1.88 to 2.00) and was predicted by high SES, white race, and longer deceased-donor allograft waiting time in initial DSA.

Conclusions: Ongoing disparities exist in kidney transplantation access and outcomes on the basis of geography and SES despite near-universal insurance coverage under Medicare. Inter-DSA travel improves access and is more common among high SES candidates.

Figure 1.

Cumulative incidence of live donor transplant access according to SES quartile at initial listing censored at deceased donor transplantation. SES quartiles at transplant were distributed as ≤41, 42 to 45, 46 to 49, and ≥50.

Figure 2.

Adjusted associations of prelisting SES and distance to center with the likelihood of transplant access by multivariable Cox regression. Time to deceased donor transplant was censored at receipt of a live donor allograft. Time to live donor transplant was censored at receipt of a deceased donor allograft. Regression models were adjusted for baseline demographic, clinical, and geographic factors at initial listing, as displayed in Table 1A. Results were similar after stratification by DSA of initial listing.

Figure 3.

Incidence of inter-DSA travel after initial listing according SES quartile and according to median DSA-specific waiting time. Inter-DSA traveling was defined as transfer of care to a center outside of a candidate's initial DSA after initial listing, censored at death, waitlist removal because of illness, and end of study. Median waiting blood-type-specific waiting time for deceased donor transplant was defined for initial DSA at year of listing.

Figure 4.

Adjusted associations of pretransplant SES and distance to center with post-transplant outcomes by multivariable Cox regression. Regression models were adjusted for baseline demographic, clinical, and geographic factors at the time of transplant as displayed in Table 1B.