While viral clearance or treatment initiation data may serve as reasonable surrogate in measuring treatment success among insured US adults with hepatitis C virus infections when only one data source is available, combining laboratory and pharmacy data could provide the most rigorous assessment of posttreatment viral clearance.
In a retrospective cohort study using the HealthVerity database, which links longitudinal laboratory results, pharmacy claims, and insurance enrollment information, investigators included US adults who underwent hepatitis C virus testing between January 30, 2019, and June 30, 2022. Eligible patients had evidence of hepatitis C virus (HCV) infection, continuous insurance enrollment from 60 days prior to through 360 days following the index date, and no evidence of direct-acting antiviral (DAA) treatment during the 60 days prior to the index date. Among more than 4.5 million patients tested, 91,491 had evidence of HCV infection, including 51,068 patients with initial active infection. The investigators assessed three care cascade outcomes: laboratory-confirmed viral clearance, DAA treatment initiation, and viral clearance following treatment initiation, which served as a proxy for sustained virologic response.
Among patients with initial infection, 40% achieved laboratory-confirmed viral clearance, 36% initiated DAA treatment, and 26% had documented viral clearance following treatment initiation.
Among the 18,246 patients who initiated treatment, 73% subsequently had a negative HCV RNA result, whereas 4% had a positive RNA result and 23% had no documented follow-up RNA testing. Among those without follow-up testing, 91% had received at least 56 days of DAA therapy. Conversely, among patients without documented treatment initiation, 21% subsequently had a negative RNA result, suggesting spontaneous viral clearance or treatment that was not captured in the pharmacy claims data.
The investigators noted that laboratory-based measures may underestimate viral clearance because many patients do not undergo follow-up RNA testing after treatment. Conversely, pharmacy-based measures may overestimate cure because treatment initiation does not confirm drug adherence. Viral clearance following treatment initiation most closely aligned with the definition of sustained virologic response, although it may have also underestimated cure when follow-up testing was incomplete.
The study had several limitations. Treatments received outside insurance claims may not have been captured, evolving screening recommendations may have influenced testing patterns, the requirement for continuous insurance enrollment may have excluded patients with unstable coverage, and reliance on available laboratory data may have resulted in misclassification of infection status or care outcomes.
Overall, the findings suggested that integrating laboratory and pharmacy data may provide the most complete assessment of HCV care outcomes, although viral clearance or treatment initiation alone may serve as reasonable surrogate measures when only one data source is available.
"Our findings suggest that improving follow-up RNA testing and integrating laboratory and pharmacy data will enhance accuracy and bridge gaps in [HCV] testing and treatment," wrote lead study author Hasan Symum, PhD, of the Division of Viral Hepatitis at the National Center for HIV, Viral Hepatitis, STD, and Tuberculosis Prevention, at the Centers for Disease Control and Prevention, and colleagues.
Co study author William A. Meyer III, PhD, reported receiving consulting fees from Quest Diagnostics outside the submitted work. The study authors reported no other conflicts of interest.
Source: JAMA Network Open