SAULI VUOTI (1), KATI KAARTINEN (2), EERO HONKANEN (2), MARTTI FÄRKKILÄ (3)

Affiliates

(1) MSD Finland, Espoo, Finland (2) Helsinki University Hospital, Abdominal center, Department of Nephrology, Helsinki, Finland (3) Helsinki University and Helsinki University Hospital, Clinic of Gastroenterology, Helsinki, Finland

Abstract

Background: Hepatitis C (HCV) infection is known to cause kidney deficiencies. Both glomerular and tubolointerstitial damage have been described in the literature, but their mechanism has not been extensively studied. Renal disease associated with hepatitis C is often silent and it has been suggested that subclinical and under-diagnosed glomerulopathy is frequently present in the course of the HCV infection. Renal derangements are typically discovered at a late stage, and urine test is not used systematically to screen patients for early findings. The impact of HCV eradication on renal disease is variable and dependent on the extent of kidney damage according to literature.

The primary objective of the HCVKID-study was to assess the prevalence of renal manifestations among patients suffering from chronic HCV in Finland and compare those findings to HCV-negative controls complemented by long-term analysis to identify changes from baseline. The patient population was also characterized based on genotype, estimated time with chronic infection, stage of fibrosis, liver function parameters and routine clinical blood tests.

Methods: 148 HCV-PCR-positive male and female patients (≥ 18 years old) evaluated by the Clinic of Gastroenterology were eligible for the study. The HCV-negative control group (n= 208) was enrolled by an occupational healthcare provider. Exclusion criteria were HIV or Hepatitis B positivity and other underlying diseases that may influence kidney function. The patients were considered to have a renal manifestation if s-creatinine was >UNL or eGFR< LLN (< 60 ml/min/1.73m2) or spot urine analysis revealed hematuria (u-erythrocytes ≥ 20 x10(E6)/l), tubular proteinuria (u -A1Miglo ≥ 12 mg/l) or glomerular proteinuria (u-AlbCrea in men ≥ 2.5 mg/mmol, in women ≥ 3.5 mg/mmol).
Results: Results of the interim analysis showed that the prevalence of any renal finding was significantly increased in HCV+ -population compared to healthy controls (19.8 % vs. 4 %, p < 0.001). EGFR was lower in the HCV+ population (eGFR calculated according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)-equation) 107 vs. 115 ml/min/1.73m2, p<0.001. Occurrence of abnormal proteinuria (combined analysis of dipstick test, u -A1Miglo and u-AlbCrea) was significantly more prevalent in the HCV+ -population compared to control group (dipstick test), p < 0.001. The mean age for HCV+ population was 43 years, healthy controls were younger (p<0.001), which may partly explain eGFR result. The main genotypes were 1 (45 %) and 3 (43 %) and stage of fibrosis F0-F2 (80 %) and F3-F4 (20 %).
Conclusions: The prevalence of abnormal proteinuria was significantly more frequent in the HCV+ -population, albeit the level of proteinuria did not generally exceed the level necessitating kidney biopsy. It is possible to identify patients with a higher risk to develop extrahepatic kidney manifestations with the aid of urine test for early treatment consideration.