Management of hepatitis C in decentralised versus centralised drug substitution programmes and minimally invasive point-of-care tests to close gaps in the HCV cascade.

BACKGROUND

In Switzerland, intravenous drug use accounts for the majority of hepatitis C virus (HCV) infections. Early HCV treatment prevents further transmissions and reduces morbidity and mortality due to decompensated liver cirrhosis and hepatocellular carcinoma. Nevertheless, patients in drug substitution programmes are often insufficiently screened and treated.

AIM

The aim was to compare the current state of HCV management in centralised and decentralised drug substitution programmes of the canton Aargau. Objectives were human immunodeficiency virus (HIV) and HCV prevalence, compliance with guidelines and gaps in the HCV cascade, as well as feasibility/acceptance/validity of HIV/HCV rapid tests on finger-prick blood and noninvasive liver fibrosis assessment with Fibroscan®.

METHODS

For the cross-sectional study, in June 2013, questionnaires and free rapid tests for HIV (Determine®) and HCV (OraQuick®) that used capillary blood (finger-stick) were sent to 161 physicians providing drug substitution treatment for 631 patients. Free liver fibrosis assessment with Fibroscan® by a member of the study team was offered to all patients. Additionally, patients were directly recruited by the study team in the heroin substitution programme and several addiction clinics visited every 4-6 months, as well as in the Infectious Diseases Outpatient Clinic (questionnaire, rapid tests and Fibroscan® in the same session).

RESULTS

Between July 2013 and July 2015, 205 (32.5%) of the 631 patients receiving opioid substitution in the canton Aargau were enrolled, 192 (93.7%) with HIV/HCV rapid tests and 167 (81.5%) with Fibroscan®. Acceptance of Fibroscan® was higher when offered in the same session (94.1 vs 69.2%). Overall, 77.8% had ever used intravenous drugs. HCV seroprevalence was 53.7% (109/203), HCV RNA prevalence 27.8%. Overall, 7.4% (15/202) were HIV infected, all of whom were HCV co-infected and under antiretroviral treatment. Of the 205 patients included, 104 (50.7%) were recruited in a decentralised setting (family practice / pharmacy) and 101 (49.3%) in a centralised setting (heroin programme, addiction clinic, Infectious Diseases Outpatient Clinic). Compliance with guidelines (regular HIV/HCV screening, workup of HCV-positive patients, availability of HAV/HBV serology) was consistently lower in the decentralised setting, characterised by a higher proportion of females, longer median time in the programme, lower percentage of daily attendance, ever-use of intravenous drugs and HIV and HCV infections. We identified several gaps in the HCV cascade: 23.9% (49/205) had never been HCV screened; 18.9% (18/95) of the HCV positive patients had no HCV RNA test. Of the 61 patients developing chronic HCV infection, 19.7% (12) were not HCV genotyped, 52.5% (32) had no liver fibrosis assessment (liver biopsy) and 54.1% (33) never received treatment; 25.0% (7/28) did not achieve a sustained virological response with interferon-based treatment. The 192 HCV rapid tests showed a sensitivity of 90.4% (94/104; 95% confidence interval 84.7-96.1%) and a specificity of 100% (88/88), and provided 14 new HCV diagnoses. Eight of ten patients with a false-negative HCV rapid test were HCV RNA negative (2 unknown). Among the 88.6% (39/44) currently HCV RNA-positive individuals with valid Fibroscan® results, 24 (61.5%) had a liver stiffness <7.5 kPa. Both HIV co-infection and alcohol overconsumption doubled the risk of severe fibrosis/cirrhosis in HCV positive patients.

CONCLUSION

In contrast to HIV, HCV transmission among intravenous drug users is still ongoing. The management of hepatitis C in drug substitution patients needs improvement, especially in family practices. Minimally invasive "point-of-care" diagnostics such as the HCV antibody rapid test using capillary blood and mobile Fibroscan® can close some of the gaps in the HCV cascade. HCV RNA determination in capillary blood is still an unmet need. A "one-stop strategy" might improve linkage to care. Restricting the new, highly efficient (90-100% sustained virological response for all genotypes) direct-acting antivirals to patients with at least stage F2 fibrosis withholds treatment from two thirds of the chronically infected and prevents us from reaching the WHO goal of 80% treatment uptake necessary to eliminate hepatitis C by 2030.