Discontinuation of new hepatitis C drugs among Medicare patients

OBJECTIVES: To examine factors associated with discontinuation of new hepatitis C drugs—second-generation direct-acting antivirals (DAAs)—among Medicare beneficiaries with chronic hepatitis C. STUDY DESIGN: A retrospective analysis using 2014-2016 Medicare claims. METHODS: The study population was patients with chronic hepatitis C in fee-for-service Medicare with Part D who initiated a DAA therapy between January 1, 2014, and September 1, 2016. We defined discontinuation of DAA therapy as filling prescriptions for fewer weeks than the expected duration of the DAA identified. We estimated adjusted odds ratios (aORs) of DAA discontinuation by patient characteristics using multivariable logistic regression. We estimated the model separately for patients with a Part D low-income subsidy (LIS) and those without an LIS. RESULTS: Of 82,056 patients who initiated a DAA therapy during the study period, 5171 (6.3%) did not complete the therapy. Discontinuation rates varied across DAAs, ranging from 4.7% (elbasvir/grazoprevir) to 11.8% (ombitasvir/ paritaprevir/ritonavir/dasabuvir). Women with an LIS were more likely to discontinue DAA therapy than men with an LIS (aOR, 1.16; 95% CI, 1.08-1.25; P <.01). Non-LIS black and Hispanic patients had higher odds of discontinuation than non-LIS white patients (black: aOR, 1.49; 95% CI, 1.28-1.73; P <.01; Hispanic: aOR, 1.56; 95% CI, 1.01-2.44; P <.05). High comorbidity index score increased the odds of DAA discontinuation among patients with an LIS. CONCLUSIONS: Real-world discontinuation of DAA therapy was low, but it was 3 times more likely than in clinical trials and varied by patient characteristics. Efforts to increase DAA adherence would help lower patients’ risk of developing resistance to future treatments and reduce potential waste of resources.