Disease-modifying drugs (DMDs) are injected medications used to slow the progression of multiple sclerosis (MS), and have been shown to reduce the frequency and severity of relapses. But according to a new study led by St Michael's Hospital and the Institute for Clinical Evaluative Sciences, adherence to all disease-modifying drugs is low, with less than half of patients, or 44%, continually adherent after 2 years.
"There are a number of reasons why adherence to therapies of proven value might be low," says Dr Paul O'Connor, director of the Multiple Sclerosis Clinic at St Michael's Hospital. "These drugs don't work in everyone and some patients may stop them because they don't feel they are experiencing benefits. In some cases, patients may stop treatment because of side-effects. It is important that patients understand the need for continuing treatment in order to prevent some of the long-term consequences of MS."
The study, published in the May edition of The Canadian Journal of Neurological Sciences, aimed to determine differential adherence to these drugs in Ontario given that they are each marketed as differential efficacy, side effects, or convenience.
The study found:
• 682 Ontarians filling prescriptions through Ontario's Public Drug Programs were newly treated with a disease-modifying drug for multiple sclerosis between April 2006 and March 2008
• Although disease-modifying drugs differ with respect to frequency of injection, costs, and side-effect profiles, there is no indication that adherence to these medications varies substantially in Ontario
• Despite their efficacy, adherence to all disease-modifying drugs is low, with less than half of patients (44%) continually adherent after 2 years.
"This study shows that adherence to treatment with DMDs is low, which is concerning given their proven effectiveness in slowing the progression of MS. We need to increase the appreciation of the long-term benefits of these medications to ensure that MS patients are receiving the best treatment available," says co-author Tara Gomes, an epidemiologist at the Institute for Clinical Evaluative Sciences .
The use of these drug therapies for the treatment of multiple sclerosis has risen 30% between 2002 and 2007, with associated costs rising from $187 to $287 million in Canada.
Source: News Release
St. Michael's Hospital
May 10, 2011