Development and Validation of a Socioeconomic Kidney Transplant Derailers Index

Abstract

Background. Socioeconomic barriers can prevent successful kidney transplant (KT) but are difficult to measure efficiently in clinical settings. We created and validated an individual-level, single score Kidney Transplant Derailers Index (KTDI) and assessed its association with waitlisting and living donor KT (LDKT) rates. Methods. The dataset included 733 patients presenting for KT evaluation in a transplant center in California. Exploratory factor analysis was used to identify socioeconomic barriers to KT (derailers) to include in the index. Potential KT derailers included health insurance, employment, financial insecurity, educational attainment, perception of neighborhood safety, access to a vehicle, having a washer/dryer, and quality of social support. Validity was tested with associations between KTDI scores and the following: (1) the Area Deprivation Index (ADI) and (2) time to KT waitlisting and LDKT. Results. Nine derailers were retained, omitting only social support level from the original set. The KTDI was scored by summing the number of derailers endorsed (mean: 3.0; range: 0–9). Black patients had higher estimated KTDI scores than other patient groups (versus White patients, 3.8 versus 2.1; P < 0.001, effect size = 0.81). In addition, the KTDI was associated with the ADI (γ = 0.70, SE = 0.07; P < 0.001). Finally, in comparison to the lower tertile, patients in the upper and middle KTDI tertiles had lower hazard of waitlisting (upper tertile hazard ratio [HR]: 0.34, 95% confidence interval [CI]: 0.25-0.45; middle tertile HR: 0.54, 95% CI: 0.40-0.72) and receiving an LDKT (upper tertile HR: 0.15, 95% CI: 0.08-0.30; middle tertile HR: 0.35, 95% CI: 0.20-0.62). These associations remained significant when adjusting for the ADI and other patient characteristics. Conclusions. The KTDI is a valid indicator of socioeconomic barriers to KT for individual patients that can be used to identify patients at risk for not receiving a KT.