"Many Patients With Osteoporosis Do Not Continue Their Bisphosphonate Therapy: Presented at ACR"
By Paula Moyer
SAN DIEGO, CA -- November 21, 2005 -- Women with osteoporosis adhere poorly at best to their bisphosphonate therapy, according to investigators speaking here at the American College of Rheumatology Annual Scientific Meeting (ACR).
"Difficulties following the instructions for taking bisphosphonates, and the frequency of dosing, only compounded the reluctance this population has with a long-term medication regimen they already question," said Paul Thompson, MD, at a briefing on November 15[th.
He noted that the instructions about eating and maintaining an upright position made treatment seem very complicated for some women.
The women were reluctant to take a long-term medication due to concerns about tolerance or fear of addiction, balanced against "only the most conservative expectations for benefit," said Dr. Thompson, consultant rheumatologist, Poole Hospital National Health Services Trust, Poole, United Kingdom. "These mental hurdles are going to have to be overcome to gain any increased level of compliance in bisphosphonate therapy."
Current evidence on the level of patient adherence to bisphosphonate therapy is limited. Dr. Thompson and colleagues therefore conducted their study to identify factors that would influence adherence to bisphosphonate therapy among postmenopausal women in the United Kingdom.
They conducted telephone interviews with 533 postmenopausal women who were more than 50 years old, had been diagnosed with osteoporosis, and who had taken bisphosphonate therapy.
The interview consisted of a validated questionnaire, in which the interviewer collected detailed information about adherence, including medication-taking behaviors and patients' beliefs and expectations about osteoporosis and treatment. The investigators used the utility-based rating scale to determine patient preferences for different dosing frequencies (0, worst health state imaginable; 100, best health state imaginable).
Of the 533 women interviewed, 42% had sustained a previous fracture due to osteoporosis, and 63% were currently taking bisphosphonate therapy. More than half of them (54%) said they took less of the treatment than prescribed.
Reported barriers to adherence included difficulty following the instructions and confusion about medication scheduling. Approximately 33% believed that if they took their bisphosphonates regularly, the medications would lose their efficacy, Dr. Thompson reported. While 40% were concerned about becoming addicted to the treatment if taken on a long-term basis.
Many women were skeptical about treatment outcomes; 44% believed that the treatment would help prevent fractures over the long term.
Among those interviewed, 77% said they would prefer to take bisphosphonates monthly rather than daily or weekly. The average values for dosing frequency on the rating scale were 46.84 for daily dosing, 68.20 for weekly dosing, and 77.96 for monthly dosing. The most highly valued treatment strategy, given an average value of 81.35, combined a monthly dosing schedule with a patient support program.
"A variety of factors work against adherence to bisphosphonate therapy," Dr. Thompson said. "These factors and beliefs need to be addressed if adherence, and therefore clinical outcomes, of bisphosphonate therapy are to be improved."
The study was funded by GlaxoSmithKline, which manufactures ibandronate (Boniva) in partnership with Roche. The medication is a once-daily bisphosphonate formulation.
[Presentation title: Factors Influencing Adherence to Bisphosphonates for Osteoporosis. Abstract 625]
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