Adaption and validation of a glomerular filtration rate estimation equation for Chinese children: a cross-sectional analysis of pooled data.

Background: This study aimed to adapt the existing Q-based equation for glomerular filtration rate (GFR) estimation using serum creatinine (SCr) to Chinese children by modification of certain parameters, and to establish the pediatric reference intervals (RIs) for estimated GFR in China accordingly.

Methods: The Q-based equation had the form eGFR = M/(SCr/Q), where the parameter M was estimated from 328 children with measured GFR in Wuhan Children's Hospital, and the parameter Q was fitted among 11,713 healthy children volunteers who had SCr recruited from 11 provinces of China. The Q-based equation was applied to 60,524 inpatients in Beijing Children's Hospital to assess the impact of estimated GFR on the clinical diagnosis of acute kidney injury (AKI). Then, the Q-based equation was used to estimate GFR in a large representative population of healthy Chinese children for RI establishment.

Results: The parameter M was estimated separately in children aged less than 2 years (100.2) and 2 years or above (107.3). The parameter Q was modeled as a linear function of age in boys (19.5 + 3.2Age) and girls (23.6 + 2.2Age), respectively. The GFR estimated by the Q-based equation could well identify AKI, with a significantly higher risk of in-hospital mortality in AKI patients than non-AKI patients (OR, 5.69; 95% CI, 4.80-6.74). The RI of estimated GFR for children aged 2 years or above ranged from 82.5 to 145.2 ml/min/1.73 m², comparable to that for young adults (80 to 140 ml/min/1.73 m²).

Conclusions: The Q-based equation is simple and practical for GFR estimation in Chinese children.