"You can't get there from here": Critical obstacles to current estimates of the ESRD risks of young living kidney donors.

Short studies that generate lifetime end-stage renal disease (ESRD) risks for young living kidney donors have conflicted with the knowledge and practice of nontransplant specialists. A widely accepted online risk calculator (OLRC) is no exception. It uses 6.4 year observations and an ostensibly empiric methodology to predict low lifetime risks for normal young candidates. But the nonspecific ESRD risk factors identified in this study are likely features of kidney diseases that were already underway at study entry. No practicing nephrologist would use their absence to predict any specific kidney disease that had yet to begin, which is essential for excluding high-risk individuals. The OLRC's risk estimates are particularly low because it also does not assign to young adults about 70% of the lifetime ESRD that they will experience as they age, which is part of their risk. It reinforces traditional concepts of low donor risk, minimizing the potential relevance of recent, sometimes concerning, long-term outcome data. These data suggest many similarities between postdonation ESRD and ESRD in the general population, about which much is already known. Despite our best efforts, the heterogeneity and exponential accumulation of end-stage kidney diseases over time prevent long-term predictions of risk for young kidney donors.