Long-term renal allograft survival: have we made significant progress or is it time to rethink our analytic and therapeutic strategies?

Impressive renal allograft survival improvement between 1988 and 1995 has been described using projections of half-lives based on limited actual follow up. We aimed, now with sufficient follow up available to calculate real half-lives. Real half-lives calculated from Kaplan-Meier curves for the overall population as well as subsets of repeat transplants and African Americans recipients were examined. Real half-lives were substantially shorter than projected half-lives. As a whole, half-lives have improved by about 2 years between 1988 and 1995 as compared to the earlier projected 6 years of improvement. The improvement seems to be driven primarily by the improvement in graft survival of re-transplants. First transplants showed a cumulative increase in graft survival of less than 6 months. Projected half-lives are a risky estimation of long-term survival especially when based on short actual follow up. First transplant survival has only marginally improved during the early years of post transplant follow up while no significant improvement in long-term survival could be detected between 1988 and 1995. Redirection of attention from early endpoints towards the process of long-term graft loss may be necessary to sustain early gains in the long term.