Factors Affecting Renal Allograft Function in Long-Term Recipients

Abstract

The natural history of renal allograft function in long-term recipients is not known. To characterize renal allograft function and the factors that affect it, we reviewed the records of all patients who received a renal allograft at the University of Wisconsin between 1965 and 1981 and selected those who had annual data on renal function for at least 10 years. We identified 155 patients—78 with living-related donors and 77 with cadaveric donors. All patients were adults receiving azathioprine and prednisone. Renal function was estimated by calculated creatinine clearances (Ccr), which correlated well with measured 24-hour creatinine clearances. The creatinine clearance data for each patient were plotted versus time. In 73% of patients, the creatinine clearance increased for several years before reaching a peak value. After the peak, the creatinine clearance declined in a linear manner. Stepwise regression analyses indicated that allografts from cadaveric donors had a greater increase in creatinine clearance from the value at year 1 to the peak than allografts from living-related donors (0.35 ± 0.25 v 0.21 ± 0.23 mL/s [21.4 ± 15.0 v 12.7 ± 13.8 mL/min); P < 0.001). The average time to reach the peak value of creatinine clearance was longer in cadaveric allografts (6.8 ± 3.5 v 4.6 ± 4.0 years; P < 0.001). Postpeak, the rate of decline in creatinine clearance was faster in cadaveric allografts than in living-related ones (0.06 ± 0.05 v 0.04 ± 0.04 mL/s/yr [3.50 ± 2.99 v 2.55 ± 2.16 mL/min/yr); P < 0.05). The presence of diastolic hypertension (average > 89 mm Hg) was associated with a more rapid rate of decline in creatinine clearance. The presence of diabetes mellitus or hypercholesterolemia was not associated with a more rapid decline in renal function. These data indicate that the natural history of renal allograft function in longterm recipients was to increase for several years and then to decline linearly. Allografts from cadaveric donors showed the most functional hypertrophy and had faster rates of decline. From these data, the average estimated life span of a successful renal allograft was 30 years for a cadaveric donor and 40 years for a living-related donor.