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1. Adherence to HCV Therapy:Relation with Virologic Outcomes andChanges in Adherence Over Time Vincent Lo Re, MD, MSCE
V. Teal, R. Localio, V. Amorosa, D. Kaplan, R. Gross
Division of Infectious Diseases
Center for Clinical Epidemiology and Biostatistics
University of Pennsylvania School of Medicine
2. Hepatitis C Virus (HCV) Therapy Pegylated interferon (PEG-IFN) + ribavirin
Complex treatment regimen
Frequent monitoring of laboratory results
Office visits to evaluate for adverse effects
Suboptimal adherence ? ? response
3. Adherence to HCV Therapy Prior data:
? drug exposure from dosage reductions: ? SVR
Few data: ? drug exposure from missed doses
=85% adherence: ? wk 12 HCV RNA declines*
Unanswered questions:
Differences between PEG-IFN, ribavirin
Levels of adherence for virologic response
Changes in antiviral adherence over time
4. Specific Aims Aim 1: Evaluate relation between adherence to PEG-IFN, ribavirin and virologic response
Hypothesis: ? adherence ? ? HCV response
Aim 2: Assess changes in adherence over course of HCV treatment
Hypothesis: Adherence ? with time
5. Study Design / Setting Retrospective cohort study
Setting: U.S. VA Hepatitis C Case Registry
Extract of VA records from HCV+ veterans
Demographic, administrative, lab data
Dispensing data on meds
Advantages:
Majority receive meds through VA*
Initiate contact for refills (not automatic)
Dispensing of antivirals not linked
6. Study Subjects Inclusion criteria:
HCV RNA+, HCV genotype 1 – 4
PEG-IFN + ribavirin rx: Jan 2003 ? Dec 2006
HCV viral load prior to, after treatment start
Exclusion criteria:
Clinical trial, switched IFN formulation, HIV
Selection: first treatment course
7. Adherence: Pharmacy Refills Calculated over 12-wk intervals:
0 – 12 wks
13 – 24 wks
25 – 36 wks
37 – 48 wks
Initial fills: closest to wks 13, 25, 37
Included in analyses: fill during interval
8. Data Analysis:Calculation of Adherence
9. Study Outcomes Early virologic response (EVR)
=2 log ? in HCV RNA copies/ml at 12 wks
Defined wk 12 HCV RNA: wks 9 – 15
Sustained virologic response (SVR)
Undetectable HCV RNA in all follow-up viral load tests 24 wks after treatment end date
Collected HCV viral loads ? Dec. 2008
10. Data Analysis Calculated adherence separately
Adherence categorized into 4 strata
Examined virologic response in each stratum
Chi-square tests for trend
Mixed effects regression models
Changes in adherence (each med) over time
11. Results: Subject Selection
12. Results: Patient Characteristics
13. Ribavirin Adherence and EVR:Genotypes 1 / 4
14. Ribavirin Adherence and EVR:Genotypes 2 / 3
15. Ribavirin Adherence and SVR:Genotypes 1 / 4, EVR+
16. Adherence Over Time
17. Potential Limitations Overestimate actual adherence
Patients may not take meds after refill
Assoc. with biological surrogate that only responds to antiviral therapy
Retrospective design
No standardized HCV RNA testing
Generalizability
18. Conclusions ? EVR and SVR with higher levels of adherence to PEG-IFN and ribavirin
PEG-IFN adherence higher than ribavirin
Adherence to both anti-HCV drugs ? over time
Greater decline in ribavirin adherence
19. Implications / Future Directions Addition of direct acting antivirals:
Increase complexity
? adherence ? antiviral resistance
Methods to measure adherence in real time
Identify non-adherence as soon as it occurs
Future research emphasis:
Identify risk factors for non-adherence
Develop interventions
20. Acknowledgements Center for Clinical Epi:
Robert Gross, MD, MSCE
Russell Localio, PhD
Valerie Teal, MS
Infectious Diseases:
Valerianna Amorosa, MD
Gastroenterology:
David E. Kaplan, MD
22. Results: Virologic Response