Changes in adherence to highly active antiretroviral therapy medications in the Multicenter AIDS Cohort Study.

OBJECTIVES

To characterize the determinants of changes in adherence to antiretroviral therapy and examine whether there are persistent lower adherers.

DESIGN

A cohort study with repeated measurements.

METHODS

Self-reported 100% adherence was defined as taking all doses and numbers of pills over a 4-day period as prescribed for current HIV medications. Independent predictors of changing adherence (< 100% to 100% and 100% to < 100%) were determined by logistic regression, correcting for correlated repeated measures for 597 HIV-positive men reporting the use of highly active antiretroviral therapy (HAART) between October 1998 and October 2000.

RESULTS

Of the 942 visit-pairs with initial 100% adherence, 106 (11.3%) reduced adherence to less than 100%, and 836 (88.7%) remained 100% adherent at the next 6-month visit. No recent outpatient visits, younger age, depression, less than college educated, and later in calendar time predicted decreasing adherence. Among 186 visit-pairs starting with less than 100% adherence, 133 (71.5%) improved adherence to 100% and 53 (28.5%) remained less than 100% adherent at the next visit. The determinants of improving adherence included not being African-American, not using recreational drugs, and having had more than three HAART regimens. Lower adherence was not a random event; it was significantly correlated across visits within the individual.

CONCLUSION

Characteristics associated with improving and lowering adherence differed and should be considered in developing interventions to enhance adherence and optimize effective therapies.