Epidemiology of viral hepatitis among patients undergoing hemodialysis at nephrology center Benghazi

Introduction: During hemodialysis, patients are at-risk of acquiring blood-borne viruses and pathogenic bacteria. Within dialysis units, prevention of infection is of paramount importance. The nursing staff must take adequate precaution to prevent the spread of infection within this high-risk environment. Patients and Methods: All patients undergoing hemodialysis for the period of 7 days were interviewed once during dialysis, using a closed-ended questionnaire. Patients’ files were checked for seropositivity. Results: The prevalence of the hepatitis C virus (HCV) was 34% (male 39% and female 21.4%). The prevalence of the hepatitis B virus (HBV) was 7% in male and 3 % in female. A small number had a double infection. Conclusion: In this study of 186 patients on dialysis, 34% were infected with HCV and 5% with HBV. The most important risk factors were multiple blood transfusions and the duration of dialysis.

Keywords: Hemodialysis, hepatitis C virus (HCV), risk factors

Infection in the dialysis unit

Hemodialysis systems include hemodialysis machines, water supply, water-treatment systems, and distribution systems. During hemodialysis, patients have acquired blood-borne viruses and pathogenic bacteria. Within dialysis units, prevention of infection is of paramount importance. Nursing staff must take adequate precautions to prevent the spread of infection within this high-risk environment. This is achieved through the use of universal precautions, and the isolation of patient and machines, if required. Each dialysis unit must have an infection control policy. ^[1]

Hepatitis B infection

The hepatitis B virus (HBV) was highly prevalent 20 years ago in hemodialysis patients, but now has been minimized in most developed countries by the implementation of universal precautions: Screening of blood products for hepatitis B surface antigen (HBsAg), vaccination of the dialysis patient, isolation of HBsAg-positive patients, and use of a dedicated machine for infected patients. Acute HBV infection is usually asymptomatic, manifesting only as a rise in serum transaminases. Chronic carriage is common in infected dialysis patients, and increased in those with high serum ferritin levels. All patients on dialysis should be screened regularly (once every 3 months) for HBsAg, and serum transaminases monitored (often monthly), which is especially important in patients returning from holiday dialysis in countries with a higher prevalence of HBV (increase screening to once every 2 months). ^[2] Patients positive for HPV require treatment in isolation and with a designated machine. Protective clothing must be used at all times. Special care must be taken when dealing with blood spillages. Members of the nursing staff who have not been vaccinated against HBV should not work in a high-risk area. A vaccination program should be in place for patients (ideally predialysis) and staff.

Hepatitis C infection

Prevalence rates in dialysis patient vary around the world from 0-73% (0.4-15% in United States). ^[3] Most renal units do not isolate patients, but dedicated machines are often used. Patient-to-patient spread can occur, so care must be taken to avoid and clear blood spillages, and prevent blood sprays. Symptomatic acute illness is rare, but infection may cause a rise in serum transaminase. Transmission is mainly by blood products and shared needles. Increasing evidence for horizontal spread (patient-to-patient) within dialysis units by environmental blood contamination is seen. Being dialysed next to a hepatitis C virus-infected (HCV) patient significantly increases the re-use of machines.

Diagnosis of HCV is ascertained by the detection of antibodies (3 ^rd generation assays high sensitivity and specificity) or viral RNA in serum by polymerase chain reaction. Antibody response may take several months to develop after infection, and are blunted in dialysis patients. Patient should be screened every 3 months (more frequently on return from holiday dialysis in high-risk countries).

Disinfection in the hemodialysis unit

Cleaning and disinfection are important components of infection control in a hemodialysis center. The Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) regulate disinfectants used to reprocess hemodialyzers, hemodialysis machines, and water-treatment systems.

Non-critical surfaces (e.g., dialysis bed or chair, countertops, external surfaces of dialysis machines, and equipment such as scissors, hemostats, clamps, blood pressure cuffs, and stethoscopes) should be disinfected with an EPA-registered disinfectant unless the item is visibly contaminated with blood; in that case a tuberculocidal agent (or a disinfectant with specific label claims for HBV and the human immunodeficiency virus [HIV]) or a 1:100 dilution of a hypochlorite solution (500-600 ppm free chlorine) should be used. This procedure accomplishes two goals: It removes soil on a regular basis and maintains an environment that is consistent with good patient care. Hemodialyzers are disinfected with peracetic acid, formaldehyde, glutaraldehyde, heat pasteurization with citric acid, and chlorine-containing compounds. Hemodialysis systems usually are disinfected by chlorine-based disinfectants (e.g., sodium hypochlorite), aqueous formaldehyde, heat pasteurization, ozone, or peracetic acid. All products must be used according to the manufacturers’ recommendations. Some dialysis systems use hot-water disinfection to control microbial contamination. ^[4] At its high point, 82% of U.S. chronic hemodialysis centers were reprocessing i.e., reusing, dialyzers for the same patient using high-level disinfection. However, one of the large dialysis organizations decided to phase out reuse and by 2002, the percentage of dialysis facilities reprocessing hemodialyzers had decreased to 63%. Two commonly used disinfectants to reprocess dialyzers were peracetic acid and formaldehyde; 72% used peracetic acid and 20% used formaldehyde to disinfect hemodialyzers. Another 4% of the facilities used either glutaraldehyde or heat pasteurization in combination with citric acid. Infection-control recommendations, including disinfection and sterilization and the use of dedicated machines for HBsAg-positive patients, in the hemodialysis setting were detailed in two reviews. The Association for the Advancement of Medical Instrumentation (AAMI) has published recommendations for the reuse of hemodialyzers. ^[4],[5]

The following is a general guide to infection control in dialysis units:

1. Use of disposable gloves when dealing with patients;
2. Removal of gloves and washing hand between patients;
3. Items used on a treatment station should be either disposable or for single use, and reserved for a single patient;
4. Clean areas should be designated and used for the preparation and handling of medications and should be separated from contaminated area;
5. Multi-dose medication vials should be prepared for use away from the patient;
6. Use of new external venous and arterial pressure transducer filters for each patients treatment, to prevent blood contamination of the dialysis machine pressure monitor;
7. Cleaning and disinfecting of the dialysis station between patients (including chair, table, bed, and machine), and especially the dialysis machine control panel and discarding fluids carefully and cleaning/ disinfecting all containers. ^[6]

This study was conducted to estimate the prevalence of HBV and HCV infection among patients and to find out the risk factors for infection among the patient on dialysis.

All patients undergoing hemodialysis within a period of 7 days were interviewed once during dialysis, using a closed ended questionnaire. Patients’ files were checked for seropositivity.

Statistical analysis

Data was entered into a SPSS computer package (SPSS Version 11.5, IBM Corporation) and analyzed, results are presented as percentage. A chi-square test was done.

In the study majority of patient were middle-aged. In this sample, 60% of patients were male and 40% were female [Table 1]. The prevalence of the HCV was 34% (male 39% and female 21.4%). In the study done in Iran, HCV prevalence was 8% while in Jordan it was 28%. ^[7] In the present study, HBV prevalence was 7% in males and 3 % in females. A small number had double infection [Table 2].

HBV is usually found in health care workers (HCW). In this study we found HBV to be more common in housewives (6%). HCV was also more common among housewives (37%). There was only one lab technician who also had both infections [Table 3].

We also observe that increase in the number of dialysis lead to increased incidence of infection. The majority (51%) of infections was seen among those with more than 500 dialysis sessions [Table 4].

In the Iranian study, the duration of treatment by hemodialysis was significantly associated with HBV and HCV positivity. ^[2] The incidence of infection increased with the duration of dialysis in the current study [Table 5].

The married group has more people with HBV and HCV about 35% [Table 6].

Blood transfusions are the most common risk factor, followed by a past history of surgery. Patients having dialysis outside the center previously were more prone for infection.

Renal transplantation patients had significantly higher risk of HCV infection [Table 7].

In this study of 186 patients on dialysis, 34% were infected with HCV and 5% with HBV. The most important risk factors were multiple blood transfusions and the duration of dialysis. The promotion of safe blood transfusions and decreasing the duration of dialysis by providing renal transplant facilities are some measures that could bring down the incidence of infections.

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1755-6783.154826

[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]