Estimation of glomerular filtration rate with and without height: effect of age and renal function level.

Abstract

The current glomerular filtration rate (GFR) equation (CKiD) may be less accurate in adolescents and children with higher GFR. This was a retrospective study (n = 161, 247 (99)mTc DTPA-GFRs). Six equations were evaluated for bias, accuracy, and low GFR diagnosis: (1) CKiD; (2) historic center; (3) Hoste(age); (4) Hoste(height); (5) modified Pottel; (6) Gao. Children with ≥ vs. <90 ml/min/1.73 m(2)) and < vs. ≥16 years were compared. Two adult equations were evaluated in children ≥16 years. Most equations underestimated GFR by 1-14 % in the higher GFR group, least so for Hoste(age). In the low GFR group, Hoste(age) and historic center overestimated GFR significantly more than CKiD (p < 0.05). Accuracy (within 30 % GFR) was similar across equations and GFR subgroups (66-86 %). In the ≥16 years group, CKiD underestimated GFR by ∼10 %, vs. ∼3 % for Hoste(height). Accuracy was 5-10 % lower in the older group and most equations were more sensitive than specific for detecting low GFR; this discrepancy was less for the Hoste equations. Adult equations were highly inaccurate. GFR estimation in older children and with higher GFR is suboptimal. The Hoste(height) may be an alternative GFR estimation method; Hoste(age) may allow for height-independent GFR estimation in patients with normal GFR.