Nationwide Study of County Health Rankings and Lung Transplant Outcomes

Abstract

There is limited information about whether social determinants of health affect lung transplant outcomes. In this study we aimed to examine associations between nationwide County Health Rankings (CHR) and its domain specific sub-ranks and lung transplant graft and patient survival. United Network for Organ Sharing and CHR datasets were linked by using transplant recipient's zip code of residence. Patient- and county-level characteristics were assessed for all adult lung transplant recipients from 2010-2018. CHR were calculated across all 3149 US counties and averaged across the eight study years and counties were assigned to a tertile for each of two overall ranks and six domain-specific sub-ranks. Mixed effects Cox proportional hazards models were used to examine associations between County Health Rankings and graft survival and patient survival post-lung transplant. Out of 15909 Lung Transplant recipients, 7084 resided in best, 6072 in middle and 2753 in worst terile. The Health Outcomes rank, Length of Life sub-rank, Quality of Life sub-rank, Clinical Care sub-rank, Social and Economic Factors sub-rank, and Physical Environment sub-rank were independently associated with both graft and patient survival (between 7 and 15% increased risk among counties in the worst tertiles compared to the best). However, these associations did not remain statistically significant when models were adjusted for all relevant patient characteristics, center lung transplant volume, and random effects for transplant center and county. While county-level differences do affect lung transplant outcomes, these differences are largely accounted for by individual patient and transplant-specific characteristics. Further research is needed to ascertain whether these factors act as mediator factors.