Failure of predicted creatinine clearance equations in HIV-seropositive patients

The Cockcroft and Gault (CG) [1976] method of predicted creatinine clearances (CCR) accurately predicts measured 24-hour CCR values in healthy volunteers. The present study compared the relationship between measured and predicted CCR through 5 methods: CG, J1 [Jelliffe 1971], J2 [Jelliffe 1973], M [Mawer et al. 1972], and H [Hull et al. 1981], in 42 HIV-seropositive patients: 21 ARC/21 AIDS, 35M/7F, 26 homosexual/16 intravenous drug users, age: 37 +/- 7 years, actual body weight: 74 +/- 14 kg, CD4: 0.286 +/- 0.185 x 10(9) cells per liter (mean +/- SD). Measured CCR values poorly correlated with serum creatinine levels (r = -0.35; p < 0.01). The average measured CCR was 106 +/- 29 ml/min compared with 94 +/- 21 (CG; r = 0.49), 78 +/- 13 (J1; r = 0.41), 77 +/- 14 (J2; r = 0.44), 97 +/- 21 (M; r = 0.51) and 95 +/- 17 ml/min (H; r = 0.32). Standardization to body surface area or lean body weight or stratification by patient factors (gender, disease stage, risk factors, drug treatment) did not improve correlations. However, patients with normal microalbumin excretion rates had more predictable CCR values compared with those who had excess excretion, suggesting the influence of HIV-associated nephropathy on CCR estimation. Since all predicted CCR equations consistently underestimated actual values, these equations should be used with caution in estimating measured CCR in HIV-seropositive patients.