Medicines adherence

It is estimated that adherence to medicines for chronic conditions stands on average at only about 50%. Health professionals need to be aware of adherence issues and work with patients to address them in an acceptable manner.

As with lifestyle, adherence to medicines is suboptimal for most chronic conditions and chronic disease risk factors. Challenges to improving adherence can vary between conditions. For example, hypertension is generally asymptomatic so the patient doesn't feel ‘sick' and may not see the benefits  of treatment; treatment can be expensive, can cause side effects, and requires them to visit health professionals regularly. Smoking cessation on the other hand is symptomatic, but patients perceive social and personal benefits from continued smoking (e.g. stress relief), and very likely have physical  dependence on tobacco; again treatment can be expensive, and there is often a preference for going ‘cold turkey' when quitting, despite improved likelihood of success with pharmacological treatment.

Overall, only about 50% of patients remain fully adherent to their blood pressure medication 12 months after therapy initiation, many not persisting at all with therapy and others taking ‘drug holidays' or missing occasional doses (Vrijens et al, 2008). Fish et al (2009) and other international  studies suggest that less than one third of patients commenced with nicotine replacement therapy (NRT) will compete the recommended course. Additionally, many patients will not opt to attempt going ‘cold turkey' and will not follow recommendations to start NRT.

The benefits of medicines adherence

Hypertension
Improving adherence to blood pressure medicines is increasingly being considered a cornerstone of achieving blood pressure control (Burnier, 2006). It is now clear that poor compliance with medication regimens and a lack of persistence with medication use are two of  the major reasons for failure to reach target blood pressure. Nelson et al (2006) examined the effect of blood pressure medication adherence on cardiovascular outcomes as part of a large scale clinical trial with over 4000 older Australians. After an average 4.1 years follow up, cardiovascular events  and deaths were both reduced by almost one third. Subjects who stopped their medicines when they felt worse were twice as likely to experience the first occurrence of heart failure.

Smoking cessationRepeated evidence shows that using NRT or other pharmacological aids roughly doubles the likelihood that patients will fully quit tobacco use and remain smoke-free.

How might patients with potential adherence-related problems be identified?

Given the rapid drop-off in persistence with medicines use, it is always worthwhile reinforcing adherence issues with patients early in the course of treatment. A couple of other methods for identifying non-adherence are as follows:

Method 1: Medication possession ratioThe only practical method for screening non-adherence in community pharmacy without involving the patient is to look in patient dispensing records at the medication possession (MP) ratio (compares number of days medication supplied with number of  days elapsed). This indicates if the patient has received enough medicine supplies over a given period to allow them to take the medicines as planned.

A good result does not tell you if the patient actually took the medicine (they may stockpile, or even flush them down the toilet), and it does not tell you if the medicine was used correctly. Likewise, a poor result may arise if the patient gets a free sample from their GP, or was supplied medicine  by a hospital pharmacy as an inpatient. While imperfect, it is a good starting point. Software is available to automatically calculate the medication possession ratio (e.g. MedsIndex).

Method 2: Observed lack of treatment effect
Keep an eye out for non-adherence indicators and proactively approach patient groups at greater risk of non-adherence.

Hypertension
Non-adherence should always be considered if a patient (1) fails to reach their treatment blood pressure target despite active treatment, (2) exhibits resistant hypertension (no response to treatment), or (3) experiences a sudden loss of blood pressure control (Chobanion  et al, 2003). In a pharmacy, this might mean investigating non-adherence as an explanation for the following type of situations: (1) a high blood pressure reading (2) changes to treatment of hypertension due to persistent uncontrolled BP.

Smoking cessation
Many patients will resist commencement of NRT and will also fail to complete the prescribed course of therapy. It is worth discussing adherence to therapy with all smokers who are trying to quit.

How should pharmacists intervene for patients with confirmed non-adherence?

The nature of the counselling/intervention can be educational, practical or motivational. The decision to use one or more of these strategies should be based on your assessment of what is causing non-adherence. To establish the best course of action, you should consider whether the non-adherence is  intentional or unintentional. Certain assistance options may be more logical:

  1. Educational assistance
    For blood pressure management, educational interventions might include counselling, basic written materials (e.g. PSA Self-Care cards, consumer medicines information (CMI) sheets).
  2. Practical assistancePractical assistance may be required where it is believed that patients simply cannot cope unaided with their medicines. Options include dose administration aids; diaries or alarms; engagement with families or carers to help the patient; Home Medicines Review; improved    medicines routines - e.g. store medicines where they will be seen before the morning dose.
    Simplification of regimes is effective in improving adherence. Strive to minimise the number of times during the day when patients are required to take medicines (e.g. use a sustained-release version, change    medicines).(Fahey et al, 2004)
  3. Motivational assistanceRefer to the motivational interviewing page for more details.

The National Heart Foundation of Australia has developed comprehensive resources providing detailed information for management of medicines adherence in cardiovascular disease.
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