Factors influencing adherence

Many studies have been done on adherence. Some find having a partner helps adherence and others find that it can be a hindrance. In some studies, age and gender matter and yet, in others, they are not consequential. A lack of consistent results across studies tells us that it is very hard to make generalisations about adherence, that every person’s situation and issues are different, and that a person’s situation should be looked at through a much broader lens than improving behavioural coping strategies.

In late 2006, the Canadian Centre for International Health and Human Rights Studies published the results of a meta-analysis of qualitative and quantitative studies looking at barriers to and facilitators of adherence to highly active antiretroviral therapy (HAART). Seventy-two studies were conducted in developed nations, and twelve were done in developing nations.

The results showed that in all economic settings, important barriers to adherence included fear of disclosure, concomitant substance abuse, forgetfulness, doubt about the efficacy of treatment, complicated regimens, number of pills, decreased quality of life, family and work responsibilities, falling asleep, and access to medication.

Barriers to adherence frequently reported in lower-resource areas concerned access to medication and healthcare. This included travelling long distances to receive treatment, running out of medication or having an irregular supply, being away from home, and being too busy or distracted to comply.

In higher-resource settings, barriers in the area of daily schedule included disruptions in routine or a chaotic schedule, finding HAART too inconvenient or difficult to fit into a schedule, and co-ordinating adherence with work, family, and care-giving responsibilities.

The study authors concluded that clinicians should talk openly with their patients to identify the barriers and facilitators to adherence in a particular setting. This is especially necessary in developing world settings, where fewer studies of 'patient-important' factors relating to adherence have been done.¹

Physician and researcher Arachu Castro posits that "The use of a biosocial framework grounded in the lived experience of people diagnosed with AIDS is essential to understanding adherence, the way adherence changes over time, and the reasons for non-adherence."²

Many times, in developed countries, the reasons contributing to non-adherence are personal. In resource-limited settings, barriers to adherence often lie outside the individual’s area of control. When looking at barriers to adherence or planning programmes in resource-limited areas, it may be helpful to use Castro’s framework for analysis.

Social and economic barriers to adherence include lack of social support, homelessness, poverty, and limited or restricted access to care. The last of these can include lack of healthcare insurance or the means to pay for treatment, distance from a clinic or hospital, and social stigma.

Personal barriers to adherence can include lack of belief in one’s ability to successfully stay on treatment; inability to accept one’s health status; decreased quality of life; worry about HIV disclosure to friends, family, neighbours, and colleagues; failure to develop pill-taking skills, illicit drug use, alcoholism, and mental health problems.

Medication-related barriers include a high pill count, overly complicated regimens, the need to stay on treatment long-term, disruption in supply of medications, and adverse drug reactions.

Many barriers can be overcome, once they are identified. Adverse drug reactions are almost universally seen as a barrier to adherence. However, several studies have shown that when patients are fully informed concerning potential side-effects and how to manage them, many of them can stay on therapy at least until they can see their doctor and discuss options. Being prepared for side-effects can lessen some of the anxiety that they engender.

Similarly, reducing the number of pills and/or number of daily doses may not necessarily have a large impact on adherence levels. A comparison of once-a-day, single-pill Atripla (tenofovir/FTC/efavirenz) to the individual medications found a small trend toward better adherence with the single-pill therapy. In 441 patients who switched from efavirenz plus tenofovir plus 3TC or FTC, or efavirenz plus Truvada, to Atripla, the average rate of adherence improved from an already high 93.8% to 96.2% after six months, a difference that was not statistically significant. There was a just-significant improvement in self-reported quality of life, with self-reports of ‘good’ or ‘excellent’ rising from 68.8 to 72.7%.³

As Joia Mukherjee describes the building-up of the HIV Equity Initiative with the Haitian Ministry of Health (MSPP) at seven public clinics, the barrier of poverty was met by housing HIV services within a primary care setting, waiving user fees for clinic attendance, providing free medication and monitoring, reimbursing travel costs, assisting with food costs for the neediest patients, and setting-up local home-based adherence support. The result has been a low rate of treatment failure or need to switch to second-line therapy.⁴

Sometimes, the barriers to treatment involve stigma. Castro mentions that in Senegal, the weight gain that can come with lipodystrophy is seen as a symbol of good health and helps increase adherence. In another social context, weight gain could be a barrier to adherence.

These are just a few examples that illustrate the point that when studying adherence or planning for provision of ARV services, it helps to take a wide perspective on barriers to successful adherence to therapy. Many of these barriers can be overcome, but not until they are identified, explored, and addressed.