The problems of adherence are ubiquitous across medicine. Because adherence is a complex process, attempts to improve it need to be multifaceted. Factors such as the complexity of the treatment regimen, patient-related factors and the relationship between the patient and the provider of care all affect adherence.

Health care providers should work to establish a collaborative treatment relationship with their patients. This can be fostered by involving the patients in selecting regimens with dosing schedules, pill burdens and side-effects that they believe are tolerable and will "fit" into their daily lives. Pharmaceutical companies are currently working diligently to develop once-daily and twice-daily regimens with fewer side-effects and higher tolerability that will better achieve this fit. Providers should openly discuss with patients their readiness to follow treatment, the potential barriers to adherence and possible solutions to problems. While the provider and his or her team can be a source of support, other possible sources (including family, friends and formal support services) should also be discussed with patients.

Clinicians should also be aware of the prevalence of mental health disorders and disorders related to psychoactive substance abuse in certain HIV-infected populations, as inadequate mental health treatment services may jeopardize the ability of affected individuals to adhere to their medical treatment. Appropriate attention to mental illness, as well as to abuse of alcohol and other drugs could greatly enhance adherence to medical treatment of HIV. Social and living conditions, fit of regimen to lifestyle, availability and nature of social support and treatment expectations can also affect adherence.

No patient should be excluded from consideration for antiretroviral therapy simply because he or she exhibits a behaviour, characteristic or risk factor that might be judged as predictive of nonadherence (62). The health care team should make all possible efforts to ensure that patients adhere to therapies. Awareness of patients' risk factors for nonadherence can help to guide clinicians in tailoring regimens to maximize adherence.

Poor adherence to a regimen is only one of several possible reasons for its failure. Others that must be assessed include initial resistance to one or more of the therapeutic agents, altered absorption or metabolism, and multi-drug pharmacokinetics that adversely affect levels of therapeutic drugs. It is therefore important to assess patient adherence carefully before changing antiretroviral therapy. Case managers, social workers and other health care providers involved in the care of the patient may assist in this evaluation.