At the end of two years, researchers found that adherence to DMARD and steroid regimens was low: Just 21 percent of patients took DMARDs correctly and only 41 percent took prednisone correctly at least 80 percent of the time.

Poor medication adherence – defined as not taking the correct dose or not following recommended dosing regimens – was associated with higher levels of disease activity and joint damage; the opposite was true for patients who more closely followed drug regimens.  

Dr. Suarez-Almazor says the study is the most comprehensive examination of RA medication use to date. She notes that previous research suffered from limited follow-up – a few weeks to months – making it impossible to know the long-term consequences of poor medication adherence. "To see the impact on health outcomes, studies need to be long-term," she explains.

It's equally important to understand why patients are unable or unwilling to take medications as directed, and the MD Anderson team investigated that, too. Results of that study are yet to be published, but Dr. Suarez-Almazor says input from separate focus group corroborated what researchers found.

"Some barriers are external – patients may not understand the indications [for use] or explanations as to why medications are important," she explains. "Other barriers are internal and relate to attitudes and beliefs. In our focus groups, patients often didn't think medications were beneficial. That happens frequently in RA because drugs can take a while to be effective. Patients are also worried about side effects and risks. They might hear something negative about a drug and stop taking it without telling their doctor."

Ultimately, though, many adherence problems stem from poor communication between providers and patients. Office visits are short, and patients often don't get to ask important questions. And doctors, for their part, almost never ask about adherence.

"'Are you taking your medications? Is anything making it hard for you to take them?' That's a conversation that doesn't happen nearly as often as it should," Dr. Suarez-Almazor says.

Still, she thinks that the growing emphasis on patient-centered care is changing that scenario.

"Honest communication is essential if a patient isn't adherent. It's the patients' choice at the end of the day to take medication or not, but they should be able to ask questions without fear of the physician getting angry or thinking they're dumb. There should be a language of caring, not condescension," she says.

Eric L. Matteson, MD, rheumatology chair at Mayo Clinic in Rochester, Minn., agrees, noting the study "stresses the importance of patients understanding why it is important to take medications as prescribed, and perhaps even more, the need for providers to explore with patients their actual use – and beliefs – regarding their medications."

He adds, "The findings may also help us understand why medications seem to fail in some patients, leading perhaps to unneeded changes in medications, including to more expensive ones."