Assessment of renal function in persons with motor complete spinal cord injury-cystatin C as an accurate single marker

Abstract

Study design: Observational cohort.

Aim: To show that Cystatin C is an accurate single marker to estimate GFR in motor complete persons with SCI.

Objectives: To assess if Cystatin C is an accurate for estimating GFR in persons with SCI with no preserved motor power. To study if use of Serum creatinine for estimation of GFR in this population significantly overestimates GFR, thereby inaccurate.

Setting: Tertiary care hospital and Medical College, Vellore, South India.

Methods: 30 persons with SCI (ASIA A and B) fulfilling the inclusion criteria were recruited. Serum Creatinine and Serum Cystatin C values were obtained, and eGFR was calculated based on available formulae. 24-h urine for urine creatinine clearance-based eGFR was used as a reference value.

Results: Analysis with a Bland-Atman plot showed that eGFR estimated with Serum Cystatin C was more accurate than Serum Creatinine, using 24-h urine creatinine as a reference value. eGFR using Serum Creatinine significantly overestimated GFR by over 50.6%. Estimated GFR using Serum Cystatin C showed a meager mean difference of 0.5% from the reference 24-h urine creatinine clearance (mean difference of -2.56%).

Conclusion: Serum Cystatin C is a much more accurate marker for estimating GFR in SCI, compared to serum Creatinine which overestimates GFR.