For some patients with multiple sclerosis (MS), adhering to a strict disease-modifying therapy (DMT) regimen can be challenging. Some DMTs for the treatment of relapsing-remitting MS are injectable and require long-term use, so it’s understandable that some patients may not adhere well to these treatments. Kyla McKay, PhD candidate and epidemiology researcher with Dr. Helen Tremlett’s Pharmacoepidemiology in Multiple Sclerosis Research Group, set out to discover why.

“We aimed to evaluate patient characteristics that might be associated with non-adherence to the injectable DMTs,” says McKay, who was recently awarded a Rising Star research award from the Vancouver Coastal Health Research Institute and the Frederick Banting and Charles Best Canada Graduate Scholarship Doctoral Award from the Canadian Institutes of Health Research.

“We assessed 949 patients from four MS clinics across Canada at three time points over two years between 2010 and 2013,” explains McKay. “We asked participants about their DMT use and how many injections they had missed in the previous month. We considered those who missed more than 20 per cent of their doses to be ‘non-adherent.’”

Over the course of the study, 485 participants reported use of an injectable DMT. Over one in five participants were non-adherent and over half reported missing at least one dose of their DMT over the study period.

“It’s important to know why this is happening, and to support patients who are missing a substantial proportion of their doses,” says McKay. “Medication may not be effective if it’s not being taken as prescribed.”

The study found that some of the characteristics associated with non-adherence included mild MS disability, longer disease duration (more than five years), alcohol dependence, and self-reported cognitive difficulties.

“Enhancing communication between health professionals and patients and addressing modifiable risk factors, such as alcohol dependence could improve health outcomes in individuals with MS and ultimately reduce costs to health systems,” says McKay.

The study was funded by the Canadian Institutes of Health Research and the Rx&D Health Research Foundation (PI: Ruth Ann Marrie, University of Manitoba; co-PI Helen Tremlett, University of British Columbia). Dr. Tremlett is the Canada Research Chair in Neuroepidemiology and Multiple Sclerosis.

Citation: McKay KA, Tremlett H, Patten SB, Fisk JD, Evans C, Fiest K, Campbell T, Marrie RA. Determinants of non-adherence to disease-modifying therapies in multiple sclerosis: A cross-Canada prospective study. Mult Scler. 2016 [E-pub ahead of print].