The development of combination antiretroviral therapy (ART) for the treatment of HIV infection is one of the major success stories of modern medicine.
Since its introduction in 1996 and increasingly over time, ART has transformed HIV from an inexorably fatal infection into one with a high quality of life and near-normal life expectancy.
ART, if taken properly, also prevents transmission of HIV between sexual partners1-3 and from a mother to her child,4 offering an opportunity for epidemic control at a time when promises of a cure or a vaccine are failing to deliver.
The potential of ART, like many other medicines in chronic illness, is not fully realised.
Suboptimal adherence is a strong independent predictor of immunological progression to AIDS5 and threatens the state of continuous virological suppression necessary to prevent onward transmission.6
This view is supported by data from the UK Health Protection Agency, which reveals that in 2010, one in seven patients who started ART failed to achieve an undetectable HIV viral load within one year.7
Moreover, a significant number of patients disengage from specialist care and are lost to follow-up. A study carried out in London revealed that in 2010, one in five HIV-infected patients were lost to follow-up (and had not transferred their care elsewhere).8 Many of these patients will present or continue to present to primary care.
These data emphasise the importance of the behavioural aspects of living with HIV, in particular, adherence with medication and in a wider sense, engagement with care.
A structured approach to understanding medication adherence can help clinicians to support patients who are living with HIV to achieve and maintain an undetectable viral load.
The perceptions and practicalities approach to non-adherence can help to pinpoint the salient adherence-related matters that may not be immediately apparent to the patient and clinician during a consultation.
|Three steps to improve adherence|
The principle of identifying the specific perceptual and practical barriers to adherence for each individual patient can be summarised in three steps
Critically, this approach emphasises the importance of capacity and motivation, and the need to tailor support to address the patient's specific perceptual and practical concerns.
There are two categories of non-adherence, unintentional and intentional. The term unintentional non-adherence describes a variety of practical barriers concerning capacity and resources, such as misunderstanding instructions, difficulties fitting medication in to the daily schedule, forgetting doses, poor manual dexterity or cognitive impairment (figure 1).
Intentional non-adherence can be understood in terms of the beliefs and preferences influencing the patient's motivation to start and continue with treatment. These are perceptual barriers.
There can be some overlap. For example, the adverse effects of a particular medication may increase the chances of the patient forgetting to take a dose.
However, the distinction helps to maintain a pragmatic perspective of the patient's individual illness experience.
Patients will search for explanations that help them to see their treatment as consistent with their beliefs and perceptions of their illness.
More specifically, a patient's motivation to take a prescribed medication is influenced by the way in which they judge their personal need for that medication (necessity beliefs), relative to their concerns about potential side-effects.
Symptom perceptions relative to expectations are also key - the benefits of HIV treatment are often silent and long-term, which is in stark contrast to the 'no symptoms, no problem' model of an acute condition.9
To arrive at a necessity belief, one asks the question 'How much do I need this treatment?' This aspect of the patient's beliefs can be assessed with a questionnaire, such as the Beliefs about Medicines Questionnaire, a validated research tool.10
Concerns about prescribed medication are often related to a patient's suspicions about the pharmaceutical industry, seeing medicines as intrinsically harmful or addictive and overused by physicians.
Such beliefs might include worry about any long-term effects of the medication. Baseline psychological predictors of adherence to ART at 12 months are shown in figure 2.
Adherence to ART is increasingly recognised as the most important alterable factor in achieving optimal outcomes in HIV, for the individual patient and for public health.
Taking account of a patient's beliefs about ART can improve their involvement in decision-making and promote compliance.
The perceptions and practicalities approach can help the clinician to structure these discussions and can often lead to a more open dialogue. It also enables clinical staff to use a common language, easing some of the frustration of communicating about adherence problems within the multidisciplinary team.
This approach can help to avoid the situation where the patient fails to report non-adherence until it is too late, for example, after virological failure or when onward transmission has already occurred.
- Dr Pao is a clinical lecturer and HIV/GU physician, and Professor Horne is professor of behavioural medicine, UCL School of Pharmacy, London
1. Cohen MS, Chen YQ, McCauley M et al. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med 2011; 365(6): 493-505.
2. Copenhagen HIV Programme (CHIP). Partners of people on ART: a New Evaluation of the Risks (PARTNER). www.cphiv.dk/PARTNER/tabid/406/Default.aspx
3. Fisher M, Pao D, Brown AE et al. Determinants of HIV transmission in men who have sex with men: a combined clinical, epidemiological and phylogenetic approach. AIDS 2010; 24: 1739-47.
4. Townsend CL, Cortina-Borja M, Peckham CS et al. Low rates of mother-to-child transmission of HIV following effective pregnancy interventions in the United Kingdom and Ireland, 2000-2006. AIDS 2008; 22(8): 973-81.
5. Ford N, Darder M, Spelman T et al. Early adherence to antiretroviral medication as a predictor of long-term HIV virological suppression: five-year follow up of an observational cohort. PLoS ONE 2010; 5(5): e10460.
6. Hayes RJ, White RG. Amplified HIV transmission during early-stage infection. J Infect Dis 2006; 193(4): 604-5; author reply 605-6.
7. Health Protection Agency. HIV in the United Kingdom: 2011 report. www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317131685847
8. Gerver S, Chadborn T, Ibrahim F et al. High rate of loss to clinical follow up among African HIV-infected patients attending a London clinic: a retrospective analysis of a clinical cohort. J Int AIDS Soc 2010; 13: 29.
9. Halm EA, Mora P, Leventhal H. No symptoms, no asthma: the acute episodic disease belief is associated with poor self-management among inner-city adults with persistent asthma. Chest 2006; 129(3): 573-80.
10. Horne R, Weinman J, Hankins M. The Beliefs about Medicines Questionnaire: the development and evaluation of a new method for assessing the cognitive representation of medication. Psychol Health 1999; 14: 1-24.