Beliefs about Medicines Questionnaire Specific
The BMQ-S consists of 10 items, with 5 items for beliefs about necessity
(e.g. “My health in de future will depend on these medicines”) and 5
items about concerns (e.g. “Having to take these medicines worries
me”). All items are rated on a 5-point Likert Scale from 1 (strongly
disagree) to 5 (strongly agree), hence a sum scale score of 5 to 25 for
necessity and concern beliefs subscales. The difference between
necessity and concern sum scale scores (NC-differential) is between -20
and +20, with a total positive score meaning that advantages of DOAC use
outweigh disadvantages. On the basis of the necessity and concern
scores, patients are also categorized as accepting (necessity
>16, concern ≤13), ambivalent (necessity >16,
concern >13), sceptical (necessity ≤16, concern
>13) or indifferent (necessity ≤16, concern ≤13) [21].
The BMQ consists of one more item that is not used in the shorter BMQ-S
for calculating necessity and concern beliefs scores. Because this item
(question 11) is about a concern believe about side effects of DOACs
(“These medicines have unpleasant side effects”) we have included it
as well to compare with results obtained from the side effect burden
questionnaire [17].