Increased prevalence of reduced estimated glomerular filtration rate in chronic Hepatitis C patients

Background To investigate the prevalence and severity of reduced estimated glomerular filtration rate (eGFR) in patients with chronic hepatitis C (CHC). Methods Medical record review of 831 consecutive CHC patients seen in our clinic between July 2000 and August 2003; eGFR was estimated using the abbreviated Modification of Diet in Renal Disease (aMDRD) equation. The stage of kidney disease was determined based on eGFR expressed in milliliters per minute per 1.73 m²: stage 1 (signs of kidney damage but normal or elevated (eGFR ≥90), stage 2 (eGFR 60-89), stage 3 (30-59), stage 4 (eGFR 15-29), stage 5 (eGFR<15 or dialysisdependent). Results A total of 522 patients had available data with using the aMDRD equation, 51% had abnormal eGFR (stage 1, 4.6%; stage 2, 36.4%; stage 3 or 4, 6.1%; stage 5, 3.8%). Of 190 patients with stage 2 kidney disease, 189 patients (99.5%) had normal serum creatinine and only one patient (0.5%) had elevated creatinine concentrations (<1.4 mg/dl). Of the 32 patients with stage 3 or 4 disease, 20 (62.5%) had a normal serum creatinine concentration. Of 349 patients without diseases known to cause renal insufficiency, 38% had stage 2-4 renal disease. In a subset of these patients, 95/522 (18%) the measured creatinine clearance showed good correlation with their aMDRD (R = 0.47, (p<0.0001). Conclusions In CHC patients, a normal serum creatinine concentration does not assure normal kidney function. Estimation of eGFR with the aMDRD equation is a more accurate method of identifying patients with chronic kidney disease and reduced eGFR. Therefore, CHC patients should be screened more rigorously for chronic kidney disease because of the high prevalence of reduced eGFR. Lastly, in all CHC patients, the aMDRD eGFR should beused in each encounter with these patients when assessing their renal function irrespective of their serum creatinine.