SeriesSystematic review of randomised trials of interventions to assist patients to follow prescriptions for medications
Introduction
Non-adherence with prescribed treatments is very common. Typical adherence rates for prescribed medications are about 50% with a range from 0% to over 100%.1 To the extent that treatment response is related to dose, non-adherence reduces treatment benefits2 and can bias assessment of the efficacy of treatments.3 With increasing numbers of efficacious self-administered treatments, the need is apparent for better understanding and management of non-adherence.
In previous reviews, we have examned the accuracy of clinical measures of non-adherence,4 interventions to improve attendance at appointments for medical services,5 and interventions to enhance medication adherence.6 In the last review some of the included trials were confounded. For example, in one study,7 interventions to increase medication adherence among patients with hypertension were inextricably intertwined with strategies to increase screening for this condition. Our aim in the current review is to summarise all unconfounded randomised control trials (RCTs) of interventions to increase adherence with prescribed medications. Ethical standards for adherence research dictate that attempts to increase adherence must be judged by their clinical benefits, not simply their effects on adherence rates.8 Accordingly, we included only RCTs in which both adherence and treatment effects were measured.
Section snippets
Methods
Unconfounded RCTs of interventions intended to improve adherence with prescribed medications were sought and selected if they reported original data concerning medication adherence, with at least 80% follow-up of participants, and with one or more measures of both medication adherence and treatment outcome. For long-term regimens, studies with initially positive findings were required to have at least 6 months' follow-up from the time of patient entry; negative trials with shorter periods of
Results
Searches of all sources retrieved 1553 citations (including 73 review articles), 252 of which were judged to merit scrutiny of the full article. 13 of the latter articles met all review criteria.9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 Key features of these 13 trials are summarised in the table.* A narrow range of disorders was studied, with five studies in hypertension, three in schizophrenia, one in asthma, one in epilepsy, and only two for short-term conditions (infections in both
Discussion
Most people have difficulty following self-administered medical treatments. The benefits from such treatments are diminished according to the degree of non-adherence and the efficacy of the treatments.1 With the astonishing advances in medical therapeutics during the past two decades, one would think that studies on the nature of non-adherence and on the effectiveness of strategies to help patients overcome it would flourish. On the contrary, little has been published. Compared with the many
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A list of randomised trials of adherence interventions that failed on one or more criteria can be obtained from the authors