Many patients with rheumatoid arthritis (RA) don't take their oral medications – specifically disease-modifying antirheumatic drugs (DMARDs) and prednisone – as prescribed, leading to poor health outcomes, according to a study published in the June issue of Arthritis & Rheumatism.

Researchers at the University of Texas MD Anderson Cancer Center in Houston found that among a group of patients – primarily low-income and minority  – only about one-fifth adhered to their drug regimen 80 percent of the time or more. Patients who didn't take their medications correctly had greater disease activity, more joint damage and a poorer quality of life after two years than those who did.

The researchers note that “our patient population had low socioeconomic status and was ethnically diverse, and most patients were underinsured. Thus the results cannot be generalized to the population at large.” Yet previous studies have found poor drug adherence is a problem among patients in all walks of life.

A total of 107 patients participated in the study. Sixty-five percent were Hispanic, 19 percent were African-American and 16 percent were white. Almost half (45 percent) had not completed high school and 67 percent made less than $20,000 a year. Many spoke only Spanish. On average, they had experienced RA symptoms for eight years.

All participants agreed to have their medications electronically monitored for 24 months using bottles that automatically recorded the date and time of each opening.

"In the past, the gold standard for measuring adherence was pill counting," says senior author Maria E. Suarez-Almazor, MD, chief of the section of rheumatology at the University of Texas MD Anderson Cancer Center. "But it was easy for patients to throw pills away. This new electronic system is very good – it allows a [small] margin of error in time between doses. And because we followed people for two years, it is unlikely they opened the bottle every single day just to trick investigators."

The majority of study participants (81 percent) were taking methotrexate pills, the most common disease-modifying antirheumatic drug (DMARD). Slightly more than half were using more than one DMARD and nearly 70 percent were taking the corticosteroid prednisone. (Fifty-seven percent were taking a biologic drug, but for the study, only corticosteroid and DMARD use was monitored.)

Although biologic drugs such as etanercept (Enbrel) and adalimumab (Humira), are more powerful than traditional DMARDs and have been available for more than a decade, methotrexate remains the first-line therapy for RA. If it doesn’t work well enough, it is sometimes replaced by another DMARD, or prescribed in combination with other DMARDs or a biologic drug.  Like with other diseases, drugs to treat RA are most effective when used as prescribed.

In addition to medication use, patients were assessed for disease activity, pain, radiologic changes and general health at the beginning of the study (baseline) and at various intervals over the next 24 months. The authors note that patients who took medications correctly before the study had better control over disease activity and better radiographic scores at baseline than those who didn't.