SAN DIEGO – Fewer than one in three Medicaid beneficiaries with systemic lupus erythematosus are adhering to their recommended treatment regimens at least 80% of the time, results from a large national analysis demonstrated.
"As a physician who spends my professional time taking care of people with lupus, these data are highly concerning," Dr. Jinoos Yazdany said in an interview prior to the annual meeting of the American College of Rheumatology, where the study was presented. "For many individuals with lupus, treatment is very effective and has a proven track record of preventing life-threatening complications and long-term organ damage such as kidney failure. The fact that less than one in three patients are adhering with treatment is alarming and should serve as a call to action for those of providing care to these patients."
Dr. Jinoos Yazdany
Dr. Yazdany, associate director of the lupus clinic at the University of California-San Francisco Medical Center, and her colleagues used MAX (Medicaid Analytic eXtract) data from 2000 to 2006 to identify 23,187 patients with systemic lupus erythematosus (SLE) who were taking at least one immunosuppressive or antimalarial drug. They used pharmacy claims to assess adherence to drugs over a period of 180 days by calculating a medication possession ratio (MPR), defined as the proportion of days covered by the total days’ supply dispensed after the first claim for each drug. The researchers also evaluated the proportion of patients who had an MPR of 80% or greater. The oral drugs studied were hydroxychloroquine, azathioprine, methotrexate, mycophenolate mofetil, cyclosporine, tacrolimus, cyclophosphamide, and leflunomide.
The mean age of the 23,187 patients was 38 years, 94% were female, and the racial and ethnic makeup was diverse (40% black, 34% white, 16% Hispanic, 5% Asian, and 5% other). The highest proportion of SLE patients lived in the southern United States (36%).
Dr. Yazdany reported that the average MPR ranged from 31.1% for tacrolimus to 56% for hydroxychloroquine. In addition, for most drugs, fewer than one in three patients had an MPR of at least 80%. Overall adherence was poorest among those taking tacrolimus (14%) and highest among those taking mycophenolate mofetil (40%).
Across all medications, blacks had lower adherence, compared with whites, and adherence was highest for those residing in the Northeast.
"Our findings underscore the need to understand the reasons behind low adherence in this high-risk and vulnerable group of patients," Dr. Yazdany said. "And we urgently need to develop interventions to improve adherence. Physicians may be unaware of their patient’s adherence with medication, and patients may not be forthcoming about this issue. Concerns about side effects, inadequate understanding of the benefit, and the medication’s cost may be barriers for patients. Treatment-associated side effects may be another important barrier. We need better patient-physician communication around the issue of adherence."
The Medicaid administrative data allowed for an otherwise unobtainable nationwide view of adherence in SLE, but Dr. Yazdany acknowledged certain limitations of the study, including the fact that treatment "may be interrupted for clinically appropriate reasons, so the medication possession ratios in our study may underestimate actual adherence. Also, pharmacy claims are imperfect proxies for whether patients actually take medications that are dispensed, which might lead to an overestimation of adherence."
Dr. Yazdany disclosed that her research is funded by the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases. She had no other relevant financial conflicts to disclose.