Racial differences in renal allograft survival: The role of systemic hypertension

The rate of decline in the number of functioning renal allografts beyond the first year after transplantation has changed little in the last 25 years, and during long-term follow-up most allografts are lost due to chronic transplant rejection or patient death. The recipient race correlates with allograft survival, and African American recipients have a lower allograft survival than Caucasians. The goal of the present study was to identify clinical variables present during the first six months after transplantation that predict the loss of renal allografts beyond six months after transplantation, and in particular to determine the role of systemic hypertension on renal allograft survival in black and white recipients. This study includes 547 recipients of first cadaveric renal allografts performed at The Ohio State University. All patients were treated with a uniform immunosuppressive protocol and had a follow-up of at least three years. By multivariate analysis the following variables correlate with poor allograft survival than elevated serum creatine concentration measured six months after transplantation (SCr(6mo)) (P < 0.0001); black race (P < 0.0001); increasing numbers of acute rejection episodes (ATR) (P = 0.002); and young recipients (P = 0.026). Allograft survival is significantly worse in black (mean allograft half-life of 7.7 ± 1.3 years) than in white recipients (24 ± 3 years) (P < 0.0001). Black recipients also have a significantly higher six month average mean arterial blood pressure (MAP) (105 ± 8 mm Hg) than white recipients (102 ± 7 mm Hg) (P = 0.002). However, the prevalence of hypertension is not significantly different in black (33%) than in white recipients (26%). Furthermore, increasing MAP levels correlate with a shorter allograft half-life in black recipients (P = 0.0002), but not in white recipients (P = 0.84). Allograft survival was eight times shorter in hypertensive black (3.1 ± 0.7 years) than in hypertensive white recipients (24.6 ± 7 years). In contrast, allograft survival was not statistically different between normotensive black and white patients. In conclusion, the presence of poorly controlled systemic hypertension, early after renal transplantation, correlates with poor allograft survival in black recipients. Thus, systemic hypertension may explain, in part, differences in renal allograft survival between black and white patients.