Letter to the Editor

To the Editor:

I applaud my colleagues for undertaking the SIngulair in Mild asthma: comPLiance and Effectiveness (SIMPLE) study (1) because real-world studies are crucial to our understanding of asthma care. Given the trial design and patient characteristics, I believe that their conclusions are misleading. The authors indicate that in the survey phase, 75.9% of patients were not adherent to inhaled corticosteroid (ICS) therapy and, at baseline, 58.1% of patients reported not missing any ICS doses during the previous two weeks. The authors should reconcile these different adherence reports. It is also important to know why the majority of patients in the survey phase did not progress to the treatment phase. If the reason for this discrepancy was related to well-controlled asthma, it should be stated and included in the discussion because this would influence how the reader interprets the data from a clinical perspective; if this was the case, then only a minority of patients not well controlled with ICS benefited from montelukast as an alternative therapy.

Furthermore, because more than 40% of patients at baseline were not adherent to ICS, it does not appear reasonable that the group – as a whole – should serve as a control, particularly because we do not know if those patients who were compliant were receiving adequate doses of ICS. The latter comments and the lack of ICS and placebo arms make it very difficult – if not impossible – to interpret the results of the SIMPLE study in a clinically meaningful way, although the conclusions suggest that “montelukast is an effective…alternative to ICS treatment in patients with mild asthma who are uncontrolled… with low-dose ICS therapy”. I am troubled by the fact that inappropriate use of ICS is compared with a therapeutic intervention that is not considered first line (2). I do not believe that it is appropriate (given some critical design limitations of the study) to compare real world-driven outcomes measured at baseline with protocol (clinical trial) -driven outcomes given the influence that clinical trial participation may have on patient behaviour. The authors should have clarified what proportion of the survey population receiving ICS failed to make it to treatment because of well-controlled asthma, because this would have conveyed an important and reassuring message to family physicians about the effectiveness of ICS in this population. The theme in the discussion should have focused more on the importance of compliance with ICS, rather than presenting second-line therapy as a therapeutic equivalent.