Geographic disparities in lung transplant rates

Abstract

In November 2017, in response to a lawsuit from a New York City lung transplant candidate, an emergency change to the lung allocation policy eliminated the donation service area (DSA) as the first geographic tier of allocation. The lawsuit claimed that DSA borders are arbitrary and that allocation should be based on medical priority. We investigated whether deceased-donor lung transplant (LT) rates differed substantially between DSAs in the United States before the policy change. We estimated LT rates per active person-year using multilevel Poisson regression and empirical Bayes methods. We found that the median incidence rate ratio (MIRR) of transplant rates between DSAs was 2.05, meaning a candidate could be expected to double their LT rate by changing their DSA. This can be compared directly to a 1.54-fold increase in LT rate that we found associated with an increase in lung allocation score (LAS) category from 38-42 to 42-50. Changing a candidate's DSA would have had a greater impact on the candidate's LT rate than changing LAS categories from 38-42 to 42-50. In summary, we found that the DSA of listing was a major determinant of LT rate for candidates across the country before the emergency lung allocation change.

Keywords: Scientific Registry for Transplant Recipients (SRTR); clinical research/practice; disparities; donors and donation: deceased; health services and outcomes research; lung disease; lung transplantation/pulmonology; organ allocation; organ procurement and allocation.

Figure 1:

Distribution of incidence rate ratios (IRRs) and MIRR. For each pair of DSAs, the IRR is the ratio of the higher LT rate to the lower LT rates and thus IRRs were always greater than 1. MIRR was the median of all these IRRs. DSA, donation service area; IRR, incidence rate ratio; LT, lung transplant; MIRR, median incidence rate ratio.

Figure 2.

Unadjusted (observed) LT rates per active person-year in the United States, by DSA. Darker colors represented higher LT rates, while lighter colors represented lower LT rates. Gray represents DSAs that did not have a lung transplant program during the study period. LT, lung transplant; DSA, donation service area.

Figure 3.

Adjusted LT rates per active person-year in each donation service area. LT rates were adjusted for LAS and blood type. LAS, lung allocation score; LT, lung transplant.

Figure 4.

MIRR was calculated for each year from 2006 through 2016. Simple linear regression showed that the MIRR has been increasing by 0.04 per year (slope=_0.020.04_0.06, P < 0.001). MIRR, median incidence rate ratio.