Adherence to medication is generally defined as the extent to which people take medications as prescribed by their healthcare providers. It can be assessed in many ways (e.g., by self-reporting, pill counting, direct observation, electronic monitoring, or by pharmacy records). This review reports effects of intervention on adherence to cardiovascular medications however adherence has been measured.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of interventions to improve adherence to long-term medication for cardiovascular disease in adults? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2007 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 39 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: patient health education; prescriber education; prompting mechanisms; reminder packaging (calendar [blister] packs; multi-dose pill boxes); and simplified dosing.
Adherence to medication is generally defined as the extent to which people take medications as prescribed by their healthcare providers.
It can be assessed in many ways (e.g., by self-reporting, pill counting, direct observation, electronic monitoring, or through pharmacy records). In this review, we have reported adherence to cardiovascular medications however it has been measured.
The RCTs we found used a variety of different interventions in different populations, measured adherence differently, and expressed and analysed results differently.
The diversity and complexity of interventions employed in RCTs makes it difficult to separate out any individual components that might be of benefit.
We found evidence that simplified dosing regimens may increase adherence compared with more complex regimens.
While simplifying the frequency of dosage may increase adherence, it is not known whether simplified regimens may increase adherence when someone is taking multiple drugs, as may be the case with cardiovascular medicines.In altering a drug regimen simply to increase adherence, any changes could potentially affect the effectiveness of the treatment, and could also potentially increase adverse effects.
Prompting mechanisms may also increase adherence to medication.
Some prompting mechanisms may be simple and inexpensive (e.g., mailed reminders), while others (e.g., daily telephone calls, installing videophones) seem impracticable for use in routine practice.
Patient health education does not seem effective in increasing adherence.
Adherence behaviour is complex. Traditional education methods may fail to address this.We found some evidence that a combination of strategies, for example, education plus prompting, may be more successful than a single educational strategy.
We found no evidence from one RCT that reminder packaging (a calendar blister pack) was effective, and found insufficient evidence on other types of reminder packaging such as multi-dose pill boxes.
We don't know whether prescriber education is effective, as we found no RCTs.