Taking medicines safely and effectively

Field: Health Professions (Health Sciences)

David Burton/Science Photo Library When prescribed medicines, about half of us do not use them as prescribed, and many more of us occasionally lapse. A recently updated systematic review focuses on the individuals offered medicines (or their carers), i.e. the people who ultimately decide whether and how to take medicines.[1] What can make how we use medicines safer and more effective? Given the broad range of health conditions that are treated with medicines and the broad range of medicines available, answering such questions is no easy task. Before the first publication of this overview,[2] answers had been sought by addressing specific conditions, interventions, or outcomes separately. The latest update offers general conclusions that can be drawn from a vast literature and a route to finding individual reviews addressing more specific questions.[1] We know from prior reviews that self‐management training improved adherence to antiretroviral therapy,[3] but not adherence for sickle cell therapy.[4] These findings beg the question: how widely applicable are apparently effective approaches? Might similar success (or failure) be expected for other conditions, in other settings or with other types of people? Inconsistencies were also apparent between studies addressing the same health conditions. For instance, education combined with training or personalised care planning improved adherence for glaucoma treatments in some studies but not others.[5, 6] By looking at one study at a time, or even one systematic review at a time, over such a vast area as taking medicines safely, we cannot see the wood for the trees. Ryan and colleagues took on the challenge of navigating this extensive literature – extensive even when other authors have made in‐roads by conducting systematic reviews of different sections of the literature.[1, 2] By systematically reviewing existing systematic reviews the authors were able to build on the work of others to encompass a broad literature. They found 75 unique systematic reviews of medium or low risk of bias. That was a challenge in itself, given the poor indexing of studies addressing interventions aimed at patients. Rather than searching specialist systematic review databases electronically, they inspected all the titles and abstracts in the Cochrane Database of Systematic Reviews and the Database of Abstracts of Reviews of Effects for reviews about prescribing for patients and use of medicines by patients. Having overcome one challenge, they faced the second challenge of making sense of a very diverse set of studies. Identifying which subsets of studies are consistent in their findings, and which are not, required a standardised set of descriptors: a taxonomy of interventions that focused on the aim of interventions (e.g. supporting behaviour change) rather than the type of intervention (e.g. reminders), and a taxonomy of outcomes (consumer outcomes and provider outcomes). These taxonomies provided a framework for comparing findings across the body of literature. This mammoth task of applying the taxonomy to 75 systematic reviews revealed some headline findings. When it comes to taking medicines safely and effectively, self‐monitoring and self‐management programmes seem to help. Making dosing regimens simpler and involving pharmacists in managing medicines both look promising. Other strategies may have some positive effects yet are inconsistent, and some may be ineffective. These headline findings represent important new knowledge for health providers that complements the findings related to specific situations addressed by individual systematic reviews and their included studies. The authors have added value to the specific findings too, by making them accessible in a searchable database, Rx for Change (www.cadth.ca/en/resources/rx‐for‐change). This systematic review of systematic reviews also makes clearer what we still do not know. The authors have made important advances here, too. By carefully constructing a framework they have systematically described the gaps in our knowledge. This is how we know there are no systematic reviews addressing health systems to help patients take their medicines safely; without a taxonomy this gap could well have gone unnoticed. The research literature is clearly incomplete, and some of it flawed. The systematic review itself may benefit from further developments such as more extensive searching or including, where they exist, two or more reviews addressing the same question. This is the nature of science – a cumulative system that, at any moment, offers provisional knowledge. The Rx for Change database, because it is built on a coherent framework of two thoughtfully developed taxonomies, provides a good foundation to build on our current knowledge. It can be used for setting priorities for research to fill gaps, replicate flawed studies with better designs and conduct further analyses across broad areas.[7] The framework may well be refined as our knowledge advances. In the meantime, whether health providers are looking for general approaches for helping patients, or approaches that suit particular circumstances, they have free access to the best available evidence.