Nearly one in four adults treated for HCV had no follow-up RNA testing

# What the study measured

# Main findings Among the cohort, 82,422 individuals (90.1%) received at least one HCV RNA test. Of those tested, 62% (51,068 people) had initial infection. Key outcome measures:

• 35.7% of those with initial infection initiated DAA therapy.
• 26.1% achieved viral clearance after treatment initiation as documented by laboratory RNA testing.
• Of individuals who initiated treatment, 73.2% had a negative follow-up RNA result, 3.7% had a positive result, and 23.2% had no evidence of follow-up RNA testing.

Importantly, 90.8% of people with no documented follow-up testing had pharmacy records showing at least 56 days of DAA prescriptions, which the authors interpret as likely indicating treatment completion and probable cure despite absent lab confirmation.

# Why this matters for HCV surveillance Sustained virologic response (SVR), defined as no detectable HCV RNA at least 12 weeks after completing therapy, is the clinical standard for cure. Surveillance systems that rely on laboratory-only or pharmacy-only data can miss cases where the other data stream would confirm outcomes. This study reveals concrete gaps:

• Pharmacy claims alone may indicate treatment but cannot confirm viral clearance without RNA results.

The authors argue that integrating lab and pharmacy data would improve measurement of treatment success and tracking toward HCV elimination goals.

# How the data break down for untreated and treated groups Among those with initial infection who did not start treatment (32,822 people):

• 21.3% later had a negative follow-up RNA result, consistent with spontaneous clearance or undocumented treatment.
• 32.1% had a positive follow-up result.
• 46.7% had no follow-up test documented.

For the treated subgroup (18,246 who initiated therapy):

• 73.2% had negative follow-up RNA results (documented SVR).
• 3.7% had positive follow-up RNA results.
• 23.2% had no documented follow-up RNA testing, though most had extended DAA prescriptions.

# Limitations reported by the authors The researchers acknowledged specific limitations present in the data:

• Insurance claims for treatment may not have been filed or captured in the database.
• Infection status and outcomes could be misclassified when relying on single-source records.
• Individuals with unstable insurance coverage were excluded, which may bias results toward those with more stable access to care.

# Practical implications Health systems and public health programs that monitor HCV at the population level should consider linking laboratory and pharmacy datasets to reduce misclassification of treatment and cure. Where only one data source exists, the study suggests using documented viral clearance or treatment initiation as reasonable, though imperfect, proxies for cure.

# Bottom line The study identifies a measurable surveillance gap: nearly one in four adults who started DAAs lacked documented follow-up RNA testing, yet most of them had prescriptions consistent with completed therapy. Integrating lab and pharmacy records would give a clearer picture of HCV treatment outcomes and progress toward elimination targets.