County socioeconomic characteristics and pediatric renal transplantation outcomes

Existing risk adjustment models for solid organ transplantation omit socioeconomic status (SES). With limited data available on transplant candidates' SES, linkage of transplant outcomes data to geographic SES measures has been proposed. We investigate the utility of county SES for understanding differences in pediatric kidney transplantation (KTx) outcomes.

We identified patients < 18 years of age receiving first-time KTx using United Network for Organ Sharing registry data in two eras: 2006-2010 and 2011-2015, corresponding to periods of county SES data collection. In each era, counties were ranked by 1-year rates of survival with intact graft, and by county SES score. We used Spearman correlation (ρ) to evaluate the association between county rankings on SES and transplant outcomes in each era and consistency between these measures across eras. We also evaluated the utility of county SES for improving prediction of individual KTx outcomes.

The analysis included 2972 children and 108 counties. County SES and transplant outcomes were not correlated in either 2006-2010 (ρ = 0.06; p = 0.525) or 2011-2015 (ρ = 0.162, p = 0.093). County SES rankings were strongly correlated between eras (ρ = 0.99, p < 0.001), whereas county rankings of transplant outcomes were not correlated between eras (ρ = 0.16, p = 0.097). Including county SES quintile in individual-level models of transplant outcomes did not improve model predictive utility.

Pediatric kidney transplant outcomes are unstable from period to period at the county level and are not correlated with county-level SES. Appropriate adjustment for SES disparities in transplant outcomes could require further collection of detailed individual SES data.