The guidelines state that low adherence to ARV therapy is associated with detectable viral load, progression to AIDS, and death. Resistance to NNRTIs is more strongly linked to poor adherence than is resistance to unboosted PIs. Information on the effect of low adherence to integrase and entry inhibitors is not yet known.

An assessment of adherence can be made using self-report or a combination of questions answered through recall of pill-taking history over the period of a week or month. In supporting adherence, it helps to know if pills are missed because they are forgotten or avoided, due to side-effects.

Reducing barriers to adherence (e.g. depression, illicit drug use), simpler regimens (pills preferably taken once daily), an emphasis on integrating pill-taking into a daily routine, and an encouraging rather than judgemental attitude when asking about adherence are all seen as useful means of supporting adherence.