Patients being treated for chronic hepatitis C become less likely to take their medications over time, according to a new study from the Perelman School of Medicine at the University of Pennsylvania. Since the study also showed better response to the drugs when they're taken correctly, the researchers say the findings should prompt clinicians to assess patients for barriers to medication adherence throughout their treatment, and develop strategies to help them stay on track. The study is published online this month in Annals of Internal Medicine.
"Our findings are particularly timely since many chronic hepatitis C patients are now being prescribed direct-acting antiviral drugs, which have a complex dosing regimen that may be even harder for patients to maintain than the two-drug standard therapy," said lead author Vincent Lo Re, MD, MSCE, an assistant professor of Infectious Disease and Epidemiology. "These data show us that we need to develop and test interventions to help patients be more successful at taking their medicine and have the best chance at being cured."
Literacy issues, financial hurdles, and socioeconomic problems such as unstable living situations can all hamper patients' abilities to properly maintain their drug regimen. The authors suggest that refilling patients' pill boxes for them, creating easy-to-follow dosing and refill schedules, and helping them set alarms to remind them to take their medicine may all help improve adherence.
The Penn researchers studied 5,706 chronic hepatitis C patients who had been prescribed the standard treatment for the virus -- pegylated interferon (given as a single weekly shot) and ribavirin (a twice-daily oral medicine) -- using pharmacy refill data and test results for virologic response during treatment. They found that patients who refilled their prescriptions on time had a higher likelihood of being cured of the infection. However, over the course of patients' treatment, adherence waned, and more often for ribavarin. That pattern, Lo Re notes, is similar to that among patients taking drugs for other chronic conditions, during which patients often develop so-called "pill fatigue."
The newer, more powerful direct-acting antiviral drugs, which must be taken every 8 hours, will add to the complexity, and cost, of chronic hepatitis C treatment. In addition, if the newer direct-acting antiviral drugs aren't taken properly, the hepatitis C virus may become resistant to treatment, compromising the chance of cure. Hepatitis C is a communicable disease spread via blood, from needle-sharing during IV drug use, tattooing or piercing, or even from more casual contact like sharing razors and toothbrushes. Worldwide, approximately 180 million people have the disease, about 4 million of them in the United States.
Monitoring for and treating drug-related side effects may also be a key factor in boosting adherence, Lo Re says. The study results showed that patients who received medication for thyroid dysfunction, anemia, or low white blood cell counts common side effects associated with hepatitis C drugs were more likely to remain adherent to their antiviral therapy. Although those drugs added more steps into their self care, Lo Re said the resulting relief for symptoms, including depression, fatigue and irritability, and more frequent visits to health care providers typically required with administration of these drugs, may play a role in patients' ability to maintain the regimen overall.
"We know that a major barrier to adherence is side effects of these drugs. People don't feel good when they're on them," he said. "If we can identify those problems and treat them when they occur, patients may be more motivated and feel well enough to continue with their prescribed regimen."
The study was funded by the National Institutes of Health, the Agency for Healthcare Research and Quality, and the Department of Veterans Affairs.