Study finds lack of medication adherence among people with RA and lupus

American College of RheumatologyNov 9 2010

People with rheumatic diseases don't take their medication on a regular basis, and this leads to poor outcomes in their disease treatment, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Atlanta.

Treatment adherence (consistently and correctly following the treatment plan outlined by a health care professional) is a crucial part of successfully managing rheumatic diseases such as rheumatoid arthritis and lupus. Although there are multiple ways health care professionals can monitor if their patients are taking medications as prescribed, electronic monitoring is considered one of the most accurate.

Recently researchers conducted two studies to look at adherence rates among people with RA and lupus to determine how well they follow their prescribed treatment plans. Throughout the course of the studies, researchers followed 110 participants with RA and 74 patients with lupus. The participants with RA were predominately Hispanic (67 percent) females (86 percent) with an average age of 49 years and who had suffered from RA for roughly seven years. The participants with lupus were predominately Black (49 percent) females (89 percent) with an average age of 36 years and who had suffered from lupus for roughly six years.

Both studies were two years long and recruited participants from two publicly-funded hospitals. With the permission of the participants, researchers monitored adherence using MEMS® caps, which are medicine bottle caps with a microchip that records the time and date of bottle openings. Each time a participant refilled a prescription, the researchers downloaded MEMS cap information. They calculated adherence to daily medications (such as disease modifying anti-rheumatic drugs and steroids) by determining the percentage of days with the correct dosage taken, and they calculated the adherence to weekly methotrexate by determining the percentage of doses taken within a week's time. Finally, researchers used MEMS cap data to estimate the percentage of prescribed doses taken by each participant.

"MEMS caps are the closest approach to a 'gold standard' to measure adherence, other than direct observation of the patients taking their medications - which in this context and with our study duration is not feasible, and which is also thought to bias patients by increasing compliance when observed directly," explains Christian A. Waimann, MD and Maria F. Marengo, MD who are both at MD Anderson Cancer Center in Houston and who are the lead authors in the studies. Drs. Waimann and Marengo go on to explain that the MEMS caps system assumes that each opening of the bottle truly indicates the taking of the pill in the correct dose as prescribed by the physician.

The researchers noted the types of medications each participant was taking and evaluated each participant for physical pain and inflammation as well as social support and mental health at intervals of three, six, 12, 18 and 24 months.

Ninety-one percent of the participants with RA, and 81 percent of the participants with lupus completed the full course of their study. For those who didn't complete their study, researchers used what data they had to draw their conclusions.

Overall, the adherence rates in both study groups were low. The adherence rate for doses taken on schedule each day and/or week was 59 percent for participants in the RA study taking DMARDS and 64 percent for participants in the lupus study taking prednisone. Overall, only 61 percent of the participants in the RA study correctly took their medications, and the number ranged from 46 to 62 percent in the lupus study.

Additionally, researchers found that only one in five participants in both studies had an average adherence rate of 80 percent or higher. Although a small group, these participants reported better disease activity.

In the RA study, more participants were successful at taking the correct dosage of their medications than were successful at taking their medications on time each day and week (this was especially true with methotrexate). Participants in this study who had worse overall health and better mental health were found to be more adherent to their treatment plans. Finally, researchers noted that participants who lived alone, and those who were separated or were widowed showed less adherence, and those with social support might actually show more adherence.

In the lupus study, depression was associated with lower adherence, and better mental health increased the likelihood that participants would follow treatment plans. Also, researchers noted lower levels of disease activity among those participants who adhered to the correct dosages of their medication.

These results led researchers to conclude that there is poor treatment adherence among people with RA and lupus, at least in the populations studied, and that this lower adherence can affect those people's health in negative ways.

"It is important to ascertain if patients are taking their prescribed therapy as indicated before determining that a treatment is ineffective," explains Drs. Waimann and Marengo. "Physicians need to understand why patients may not take their medications as prescribed, and explain to patients the importance of taking medications as prescribed in order to reach treatment goals."