Patterns of geographic variability in mortality and eligible deaths between organ procurement organizations.

Eligible deaths are currently used as the denominator of the donor conversion ratio to mitigate the effect of varying mortality patterns in the populations served by different organ procurement organizations (OPOs). Eligible death is an OPO-reported metric rather than a product of formal epidemiological analysis, however, and may be confounded with OPO performance. Using Scientific Registry of Transplant Recipients and Centers for Disease Control and Prevention data, patterns of mortality and eligible deaths within each OPO were analyzed with the use of formal geostatistical analysis to determine whether eligible deaths truly reflect the geographic patterns they are intended to mitigate. There was a 2.1-fold difference in mortality between the OPOs with the highest and lowest rates, with significant positive spatial autocorrelation evident in mortality rates (Moran I = .110; P < .001), meaning geographically proximate OPOs tended to have similar mortality rates. The eligible death ratio demonstrated greater variability, with a 4.5-fold difference between the OPOs with the highest and lowest rates. Contrary to the pattern of mortality rates, the geographic distribution of eligible deaths among OPOs was random (Moran I = -.002; P = .410). This finding suggests geographic patterns do not play a significant role in eligible deaths, thus questioning its continuing use in OPO performance comparisons.