Clinical determinants of multiple acute rejection episodes in kidney transplant recipients

Background. Recipients with multiple (more than one) acute rejection (AR) episodes have significantly lower graft survival rates than those with no AR or only one treated episode. However, fewer than 50% of recipients treated for one AR episode will have another episode. Methods. We studied recipients with at least one AR episode to determine whether any clinical features could identify risk factors for multiple AR. Results. Between January 1, 1984, and June 30, 1997, a total of 1793 recipients underwent a kidney transplant at our institution. Of these, 354 were treated for one AR episode, 307 for more than one. By multivariate analysis, recipients at highest risk for multiple AR episodes were those with initial delayed or slow graft function (relative risk=1.5, P=0.05), those with initially severe AR (as judged by vascular involvement or steroid resistance), and those with an initial early AR episode (<6 months posttransplant). The remaining variables tested were not significant. Graft survival in recipients with more than one AR episode was significantly lower than in those with only one AR episode. Graft survival at 5 years posttransplant was 52.5% in recipients with more than one AR episode and 85.1% in recipients with one AR episode (P=0.0001). Chronic rejection as a cause of graft loss was significantly more common in recipients with more than one vs. only one AR episode (34.8% vs. 8.9%, P=0.001). Conclusion. Clinical features may be used to identify recipients at higher risk for multiple AR episodes. These recipients can then be targeted with more aggressive or novel immunosuppressive regimens in an attempt to reduce the likelihood of another AR episode.