Comparison of Measured Glomerular Filtration Rate Versus Estimated Glomerular Filtration Rate in Indian Cirrhotic Patients: Report of a Pilot Study

Background: Renal impairment significantly affects morbidity and mortality rates of cirrhosis patients. Studies on glomerular filtration rate (eGFR) estimation did not include cirrhosis patients. These equations are erroneous and unreliable in cirrhosis due to sarcopenia. Further, the accuracy of eGFR equations varies across different ethnic groups. Measurement of GFR by iohexol clearance is a gold standard method of accurate determination of GFR. There is scarce data on iohexol GFR in cirrhosis and none in Indian population.

Methodology: This was prospective observational study. Consecutive adult patients with cirrhosis with stable renal function for prior 1 month were included. Iohexol weight-based dosage was given and timed blood samples were taken to measure iohexol clearance. Plasma iohexol levels was measured by high performance liquid chromatography (HPLC) and Cystatin-C was measured by ELISA in plasma samples.

Results: Thirty-five patients were enrolled in the study. Hepatitis B (n = 5), hepatitis C (n = 4); alcoholic liver disease (n = 20), metabolic dysfunctional associated steatotic liver disease (n = 2), others/overlap (n = 3). The average eGFR by MDRD4, MDRD6, CKD-EPI Creat, CKD EPI Cys C, CKD EPI Creat-Cys C, RFHand GRAIL formulae were 105.24(24.2),104.75(23.5),102.14(15.9),68.91(16.5),82.91(15.21), 67.27 (14.08) and 112.9 (19.5) ml/min ml/min/1.73m², respectively. The average mGFR measured by iohexol method was 73.44 (16.8)ml/min/1.73 m². 30% agreement with mGFR was found with eGFR by MDRD4 in 38.2% (n = 13), MDRD6 38.2% ((n = 13), CKD-EPI Creat in 35.2% (n = 12), CKD EPI Cys C in 79.41% (n = 27), CKD EPI Creat-Cys C in 76.42% (n = 26), RFH 76.4% (n = 26) and GRAIL 20.5% (n = 7).

Conclusion: The eGFR equations using creatinine are imprecise and less accurate in Indian patients with cirrhosis. All equations overestimate GFR. Equations especially developed for cirrhosis patients like MDRD6 are also not precise. Cystatin C based equations are better than creatinine-based equations. Further studies with large sample size are needed to establish an accurate method of GFR assessment in Indian patients with cirrhosis.