Adherence to Hepatitis C Virus Therapy and Early Virologic Outcomes

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Clin Infect Dis. 2008 Dec 16. [Epub ahead of print]

Adherence to Hepatitis C Virus Therapy and Early Virologic Outcomes.

Lo Re Iii V, Amorosa VK, Localio AR, O'Flynn R, Teal V, Dorey-Stein Z, Kostman

JR, Gross R.

1Division of Infectious Diseases, Department of Medicine, 2Department of

Biostatistics and Epidemiology and Center for Clinical Epidemiology and

Biostatistics, and 3Center for Education and Research on Therapeutics,

University of Pennsylvania School of Medicine and 4Philadelphia Veterans Affairs

Medical Center, Philadelphia, Pennsylvania.

Background. @nbsp; Suboptimal drug exposure attributable to physician-directed

dosage reductions of pegylated interferon and/or ribavirin are associated with

decreased sustained virologic response rates. However, data are limited with

regard to suboptimal drug exposure that is attributable to missed doses by

patients with chronic hepatitis C virus (HCV) infection. We examined the

relationship between adherence to pegylated interferon and ribavirin therapy,

measured by pharmacy refill, and HCV suppression during the initial 12 weeks of

therapy. Methods. @nbsp; We conducted a cohort study involving 188 patients with

chronic HCV infection who were treated with pegylated interferon plus ribavirin.

Adherence was calculated using pharmacy refill data and could exceed 100%. The

primary outcome was decrease in HCV load at 12 weeks; early virologic response

was a secondary outcome. Mixed-effects regression models estimated the

association between adherence and HCV suppression during the initial 12 weeks.

Subanalyses were performed among patients who received optimal weight-based

dosages. Results. @nbsp; The mean decrease in HCV load at 12 weeks was 0.66 log

IU/mL greater for patients with>/=85% adherence than for those with /=85%

adherence (3.32 vs. 2.32 log IU/mL; [Formula: see text]). Early virologic

response was more common among patients with>/=85% adherence than it was among

those with /=85% to pegylated interferon and ribavirin treatment was associated

with increased HCV suppression. Decreases in HCV load became greater when

patients with>/=85% adherence to their regimen continued to receive their

recommended weight-based ribavirin dosage.

PMID: 19086908 [PubMed - as supplied by publisher]