Balancing rejection and infection with respect to age, race, and gender: clues acquired from 17 years of cardiac transplantation data.

BACKGROUND: Donor and recipient risk factors for rejection and infection have been well characterized. The contribution of demographic factors, especially age at the time of transplantation to morbidity and mortality due to rejection and infection, is much less well understood. METHODS: Using parametric hazard analysis and multivariate risk-factor equations for infection and rejection events, we quantitatively determined the relationship of fundamental demographic variables (age, race and gender) to infection and rejection. These analyses were conducted with respect to date of transplant and age at the time of transplantation. The patient group consisted of all primary heart transplants performed at the University of Alabama at Birmingham during the years 1990 to 2007 (n = 526). RESULTS: Risk factors for rejection within 12 months post-transplantation were date of transplant (p < 0.0001) and age at the time of transplantation (young adults 10 to 30 years of age, p < 0.0001). Risk factors for infection were date of transplant (p < 0.0001) and age at the time of transplantation (young children and older adults, p < 0.0001). There were three immunosuppressive eras in 1990 to 2007. Notably, although the proportion of patients experiencing rejection and infection events decreased during each successive immunosuppressive era, the relative relationship of infection to rejection, as well as age at the time of transplantation, remained similar into the most recent era. The maximal frequency of rejection events and rejection death occurred among patients transplanted at ages 10 to 30 years. Conversely, the frequency of infection events was minimal within the same group. In the oldest and youngest patients receiving transplants, infection was the predominant cause of death and rates of rejection events decreased. CONCLUSIONS: These data show that evolving immunosuppressive strategies have successfully reduced rejection and infection frequencies, and those patients transplanted at 30 to 60 years of age have the lowest frequency of rejection/infection events. However, individuals transplanted at younger or older ages, especially non-white recipients in the 10- to 30-year age group, experience significantly more infection or rejection. Therefore, programs should increase the level of surveillance in these patients and consider modification of immunosuppressive regimens in order to lower the frequency of infection and rejection events.

Racial disparities in renal allograft survival: a public health issue?

BACKGROUND: Racial disparities in renal transplantation outcomes have been documented with inferior allograft survival among African Americans compared with non-African Americans. These differences have been attributed to a variety of factors, including immunologic hyperresponsiveness, socioeconomic status, compliance, HLA matching, and access to care. The purpose of this study was to examine both immunologic and nonimmunologic risk factors for allograft loss with a goal of defining targeted strategies to improve outcomes among African Americans. STUDY DESIGN: We retrospectively analyzed all primary deceased-donor adult renal transplants (n = 2,453) at our center between May 1987 and December 2004. Analysis included the impact of recipient and donor characteristics, HLA typing, and immunosuppressive regimen on graft outcomes. Data were analyzed using standard Kaplan-Meier actuarial techniques and were explored with nonparametric and parametric methods. Multivariable analyses in the hazard-function domain were done to identify specific risk factors associated with graft loss. RESULTS: The 1-year allograft survival in recipients improved substantially throughout the study period, and 3-year allograft survival also improved. Risk factor analyses are shown by type of allograft and according to specific time periods. Risk of immunologic graft loss (acute rejection) was most prominent during the early phase. During late-phase, immunologic risk persists (chronic rejection), but recurrent disease, graft quality, and recipient's comorbidities have an increasingly greater role. CONCLUSIONS: Advances in immunosuppression regimens have contributed to allograft survival in both early and late (constant) phases throughout all eras, but improvement in longterm outcomes for African Americans continues to lag behind non-African Americans. The disparity in renal allograft loss between African Americans and non-African Americans over time indicates that beyond immunologic risk, the impact of nonimmunologic variables, such as time on dialysis pretransplantation, diabetes, and access to medical care, can be key issues.