Comparison of three formulae for estimation of glomerular filtration rate in severely malnourished children at tertiary care facility

Objectives: First objective was to compare eGFR by Updated Schwartz (US) and Simple Height Independent (SHID) formula with Original Schwartz (OS) in children with Severe Acute Malnutrition (SAM). The second objective was to compare eGFR in children below and above two years.

Methods: This analytic study on estimation of GFR was based on retrospective data collected from 78 children with SAM at Nutritional Rehabilitation Unit from October 2014 - March 2015. Glomerular filtration rate was calculated using serum creatinine (S. Cr) and height in Original Schwartz, US and by age in SHID equation and compared with OS as standard. Data was analyzed using descriptive statistics.

Results: There were 78 children in this study. Males were 39(50%). Mean age of patients was 18±15.53 months with 62(79.48%) ≤24 months. Mean weight, height and Mid Upper Arm Circumference was 5.69±2.42kg, 68.52+13.59 cm and 10±1.57 cm respectively. Mean eGFR by OS, US and SHID formula was 71.45±49.89, 58.06±3.91 and 59.33±3.73ml/min/1.73m2 respectively. There was significant difference (0.001) in mean eGFR calculated by three different formulae. Majority of children (73%) had subnormal GFR (<90 ml/min /1.73 m2). There was a significant difference in GFR ≥90ml calculated by US compared to OS (0.025) and by SHID with OS (0.04) in children below two years and no difference in children above two years. But there was no difference in other categories of eGFR calculated by either of formula in both age groups.

Conclusion: We found a significant difference in eGFR in ranges above 90 ml/min/1.73 m2 by US compared to OS as well as by SHID with OS in children below two years and no difference in children above two years. Also, there was no difference in GFR categories below 90 ml/min /1.73 m2 calculated by either of formula in both age groups. So, we may conclude that either of formula can be used in clinical practice for eGFR in mild to severe renal dysfunction in severely malnourished children.