Comparing drug interaction frequencies of various hepatitis C treatment regimens among monoinfected patients.

INTRODUCTION AND OBJECTIVES: Four regimens are recommended for treating hepatitis C (HCV) genotype 1 infection. Study aims were to (1) compare frequencies of contraindicated drug interactions (XDDIs) when each HCV regimen is added to medication profiles of HCV-monoinfected patients, (2) quantify the proportion of patients with XDDIs to all four regimens and (3) determine covariates independently associated with having a XDDI to all four regimens. MATERIALS AND METHODS: A cross-sectional study was performed within Upstate New York Veterans Healthcare Administration. INCLUSION CRITERIA: (1) age ≥18 years, (2) HCV monoinfection and (3) available medication list. Data extracted were: demographics, comorbidities, and medication list. Primary outcome was XDDIs involving patient's home medications and each HCV regimen. University of Liverpool drug interaction website was used to define XDDIs. Two-way comparisons of regimens were performed using McNemar's test where p<0.0083 was considered statistically significant. Multivariate regression analyses were performed to determine predictors. RESULTS: Of the 4047 subjects, mean±standard deviation age was 59.8±7.6. Median (interquartile range) number of medications used was 7 [4-11]. Frequencies of XDDIs after the addition of each regimen ranged from 2.8% to 17.8% and were mostly statistically different from one another. There were 95 (2.3%) patients with XDDIs to all four regimens. Predictors of having XDDIs to all four regimens were ≥6 medications and HCV infection ≥10 years. CONCLUSION: The frequencies of XDDIs varied between HCV regimens. Number of medications and duration of HCV infection were predictors of having XDDIs to all four regimens.

Relationship Between Single Tablet Antiretroviral Regimen and Adherence to Antiretroviral and Non-Antiretroviral Medications Among Veterans' Affairs Patients with Human Immunodeficiency Virus.

Several antiretrovirals (ART) have been coformulated as single tablet regimens (STR). Study objectives were to compare ART and non-ART adherence between STR and multiple tablet regimens (MTR) recipients, determine whether STR independently predicts ART adherence, and determine whether ART adherence influences non-ART adherence. A retrospective cohort study was performed among Upstate New York Veterans' Healthcare Administration (VISN-2) patients from 2000 to 2013. Inclusion criteria were age ≥18 years, human immunodeficiency virus (HIV) infection, receipt of ≥3 ART medications for ≥3 months, and available pharmacy refill records. The two study outcomes were adherence to ART medications and non-ART medications. Adherence was determined with pharmacy refill records that were used to calculate medication possession ratios. Among the 1202 subjects, there were 165 (13.7%) STR and 1037 (86.3%) MTR recipients. Mean ± standard deviation (SD) ART adherence was significantly higher for STR recipients (81.5% ± 15.3%) than MTR recipients (66.1% ± 21.1%), p < 0.001. Use of STR [adjusted odds ratio (aOR): 5.76, 95% confidence interval (CI): 3.84-8.65, p < 0.001] was independently associated with optimal (≥90%) adherence to ART. Mean ± SD non-ART adherence did not differ between STR (78.8% ± 15.6%) and MTR recipients (80.8% ± 16.0%), p = 0.17. Optimal adherence to ART medications (aOR: 2.30, 95% CI: 1.57-3.38, p < 0.001) was independently associated with optimal adherence to non-ART medications. The use of STRs are associated with optimal adherence to ART medications, but not directly associated with adherence to non-ART medications.

Prevalence of drug-drug interactions upon addition of simeprevir- or sofosbuvir-containing treatment to medication profiles of patients with HIV and hepatitis C coinfection.

The objectives were to (1) compare the frequency of contraindicated drug-drug interactions (XDDI) when simeprevir (SIM)- and sofosbuvir (SOF)-containing regimens are theoretically added to a patient's medication profile; (2) identify which hepatitis C (HCV) regimen is associated with the lowest frequency of XDDIs within different types of antiretroviral treatment (ART) regimens; and (3) determine the risk factors for XDDIs with each regimen. A cross-sectional study was performed among adult HIV/HCV-coinfected patients. Demographics, comorbidities, and medication lists were collected from medical records. Medication lists were entered into Lexi-Interact drug interaction software and XDDI before/after the addition of SIM- and SOF-containing therapy was documented. Classification and regression tree (CART) analyses identified breakpoints in continuous variables. Before the addition of any HCV therapy, XDDIs were present in 20% of the 335 included patients. After the addition of SIM-containing therapy, the frequency of XDDIs significantly increased to 88.4% (p<0.001). After adding SOF-containing therapy, the prevalence of XDDIs increased to 24.5% (p<0.001). The prevalence of XDDIs was significantly lower for SOF-containing HCV therapy within various types of ART regimens. Use of ≥7 non-HIV medications (CART breakpoint) was the only variable to predict XDDIs before the addition of any HCV therapy. Similarly, this was the only variable to predict XDDIs after the addition of SOF-containing therapy (PR: 4.80; 95% CI: 2.57-8.96, p<0.001). Variables independently associated with XDDIs after the addition of SIM-containing therapy were NNRTI regimen (prevalence ratio, PR: 1.62; 95% confidence interval, CI: 1.38-1.91, p<0.001), PI regimen (PR: 1.64; 95% CI: 1.40-1.93, p<0.001), and ≥7 non-HIV medications (PR: 1.06; 95% CI: 1.00-1.14, p=0.09). The addition of SOF-containing therapy was associated with a lower prevalence of XDDI than SIM-containing therapy.