Interventions supporting long term adherence and decreasing cardiovascular events after myocardial infarction (ISLAND): pragmatic randomised controlled trialBMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1731 (Published 10 June 2020) Cite this as: BMJ 2020;369:m1731
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Re: Interventions supporting long term adherence and decreasing cardiovascular events after myocardial infarction (ISLAND): pragmatic randomised controlled trial
Ivers et al. should be commended on performing a randomised control trial of this scale aimed at improving patient compliance to secondary prevention.
In their discussion, the authors appropriately consider the major limitations of their study – the large drop-out rate, and their reliance on self-reporting by participants. Despite this, it would have been pertinent for the authors to have discussed these in more detail. Of particular interest is the considerably higher drop out rate in the ‘Mail & Phone Call’ group (39.5%) compared to the ‘Mail Only’ and control groups (28.5% & 26.6% respectively). This shows the burden of the intervention was, perhaps, far greater than the authors predicted, calling into question the reliability of available data from the ‘Mail & Phone Call’ group. Participants would quickly learn that answering truthfully to automated phone calls (had they been non-compliant) would result in a further call from a lay healthcare worker. Participants may then change their answers to give a false impression of compliance to avoid additional calls. This could explain the moderate increase in compliance with cardiac rehabilitation seen in the ‘Mail & Phone Call’ group.
The authors also claim they ‘used a previously validated approach to ask patients about the percentage of prescribed cardiac rehabilitation sessions attended’ (pg. 3, Data Collection). However, it should be noted the study which the authors reference here differs greatly to the present study (1); having sent only two mailed questionnaires in a nine month period to consenting participants. Comparing this to the five letters plus minimum five calls over a 44 week period in the ‘Mail & Phone Call’ group (in which consent was also waived), demonstrates the vast differences between the present study and the ‘previously validated approach’ they claim to use. Can the authors really downplay their reliance on self-reporting by quoting this previous study?
Furthermore, the authors fail to discuss how their significant result relies solely on data from respondents, ignoring drop-outs. Their results are far less impressive if viewed with the (perhaps conservative) assumption that the 39.5% who did not respond were not fully compliant.
Admirably the authors wanted their intervention to be practical and scalable. Perhaps when scaling up their intervention, it would be more pragmatic to target only those willing to accept (and thus, consent to) this number of mailings and phone calls.
(1) Kayaniyil S, Leung YW, Suskin N, Stewart DE, Grace SL. Concordance of self- and program-reported rates of cardiac rehabilitation referral, enrollment and participation. Can J Cardiol 2009;25:e96-9. doi:10.1016/S0828-282X(09)70063-
Competing interests: No competing interests