What is the prevalence and clinical profile of Hepatitis C (HCV) in patients undergoing Hemodialysis (HD)?

Prevalence and Clinical Profile of Hepatitis C in Hemodialysis Units

The prevalence of Hepatitis C virus (HCV) infection in hemodialysis patients remains significantly higher than in the general population, with a global prevalence of approximately 10% as of 2012-2015, ranging from 4% in Belgium to as high as 20% in the Middle East. 1, 2

Epidemiology and Prevalence

• HCV prevalence in US hemodialysis units decreased from 11.5% to 6.9% over the 1996-2015 period, but still affects approximately 31,000 patients on hemodialysis in the United States 1
• Regional variations are significant:
  • Low prevalence (4%) in Belgium
  • High prevalence (20%) in Middle Eastern countries
  • Intermediate prevalence in China, Japan, Italy, Spain, and Russia 1, 2
• The prevalence of HCV at the initiation of hemodialysis is approximately 5%, which has remained relatively stable over the past two decades 1
• Incidence of new HCV infections in hemodialysis units has decreased from 2.9 to 1.2 per 100 patient-years in countries participating in the DOPPS study 2

Risk Factors for HCV Acquisition in Hemodialysis

• Duration of hemodialysis treatment (longer time = higher risk) 3, 2
• High HCV prevalence within the dialysis unit (powerful facility-level risk factor) 3, 2
• History of blood transfusions (especially before 1992) 4
• Prior injection drug use 4
• Nosocomial transmission through:
  • Blood contamination on staff hands
  • Contaminated medications, supplies, and equipment
  • Lapses in infection control practices 3, 4

Clinical Profile and Manifestations

• Most HCV-infected hemodialysis patients are asymptomatic 1
• Clinical manifestations include:
  • Diminished quality of life scores 1
  • Higher risk of hospitalization and mortality 1
  • Increased risk of cirrhosis and hepatocellular carcinoma 3
  • Liver enzyme abnormalities (though ALT levels are generally within normal limits or only slightly elevated) 1
• Renal manifestations:
  • HCV increases risk of CKD development and progression 1
  • Renal deposition of immune complexes causing glomerular inflammation 1
  • 2-fold higher risk of membranoproliferative glomerulonephritis (MPGN) 1
  • 17-fold higher risk of cryoglobulinemia 1
  • Direct cytopathic effect on the kidney is suspected 1

Diagnostic Approach

1. Initial Screening:

   • All patients should be screened for HCV upon initiation of in-center hemodialysis or transfer from another facility 1
   • Recommended testing: NAT alone or immunoassay followed by NAT if immunoassay is positive 1

2. Ongoing Surveillance:

   • Screen every 6 months with immunoassay or NAT 1
   • Monthly ALT monitoring (baseline at initiation, then monthly) 1
   • In units with new HCV infection, test all patients and increase frequency of subsequent testing 1
   • Patients with resolved HCV infection should undergo repeat testing every 6 months using NAT to detect possible re-infection 1

3. Special Considerations:

   • NAT samples should be drawn before dialysis (hemodialysis reduces viremia levels) 1
   • A newly elevated ALT level has a sensitivity of 83% and specificity of 90% for acute HCV infection 1
   • Anti-HCV antibody testing may have false negatives due to delayed seroconversion or impaired antibody production in hemodialysis patients 5

Liver Assessment in HCV-Infected Hemodialysis Patients

• All HCV-infected patients with CKD should be assessed for liver fibrosis 3
• Noninvasive methods recommended for initial staging of liver fibrosis:
  • Transient elastography (Fibroscan)
  • Aspartate aminotransferase platelet ratio index
  • Fibrotest/fibrometer
  • FIB4 index 1, 3
• Transient elastography has been shown to be superior to aspartate aminotransferase platelet ratio index in detecting advanced hepatic fibrosis and cirrhosis in hemodialysis patients 1

Prevention and Control Measures

• Report any new HCV infection to appropriate public health authorities 1
• Strict adherence to infection control practices:
  • Proper hand hygiene
  • Safe handling of injectable medications
  • Thorough equipment disinfection 3
• In units with high prevalence, consider:
  • Physical separation of HCV-positive and HCV-negative patients
  • Dedicated staff for HCV-positive patients 3
• Regular screening and surveillance as outlined above

Pitfalls and Caveats

1. Delayed antibody response: Seroconversion may be delayed or absent in hemodialysis patients, making NAT testing crucial for accurate diagnosis 5

2. Cluster outbreaks: Despite overall declining prevalence, 10% of hemodialysis units experience 3 or more cases over a median of 1.1 years, highlighting the need for vigilance 2

3. Normal ALT levels: ALT levels may be within normal range even in HCV-infected hemodialysis patients, though typically slightly higher than in HCV-negative patients 1

4. Isolation effectiveness: Use of isolation stations for HCV-positive patients has not been associated with significantly lower seroconversion rates 2

5. Pre-dialysis testing: HCV RNA testing should be performed before dialysis sessions as hemodialysis can reduce viremia levels 1

The high prevalence and significant clinical impact of HCV infection in hemodialysis patients necessitate rigorous screening, surveillance, and infection control practices to reduce transmission and improve outcomes in this vulnerable population.