Monitoring Renal Function in Hypertensive Pregnancy

Objective. In hypertensive pregnancy, to compare 24hr creatinine clearance (CrCl) with formulae-derived renal function (Cockcroft-Gault (CG) or Modified Diet in Renal Disease (MDRD)). Study design. Retrospective review (198 women, 63% preeclampsia) using paired t-test (significant p < 0.008) and intraclass correlation coefficients (acceptable > 0.70) to compare 24hr and CG CrCl. The 24hr CrCl was compared with each of the CG and MDRD formulae by Bland-Altman plots. Results. For 24hr CrCl, uncorrected values were similar to corrected using pre-pregnancy weight (p = 0.04); other weights gave consistently different CrCl (p < 0.0001). Limits of agreement were wide when CG and MDRD formulae were compared with 24hr CrCl. Compared with 24hr CrCl, MDRD estimates were consistently lower, and CG CrCl higher (current weight) or lower (pre-pregnancy or lean weight). Conclusion. MDRD and CG formulae should not be used in hypertensive pregnancy. Use of serum creatinine is advocated. If 24hr CrCl is performed, any correction should utilize pre-pregnancy weight. Neither the Cockcroft-Gault nor Modified Diet in Renal Disease formulae for glomerular filtration rate estimation are alternatives to 24hr creatinine clearance in hypertensive pregnancy.