Introduction: Knowledge of adherence to highly active antiretroviral treatment (HAART) and the variables associated with poor compliance is useful for the follow-up of HIV infected patients.
Patients, material and methods: Patients were consecutively recruited from the HIV outpatient clinics of the Hospitals of Leon and El Bierzo from January to June 2000. Patients were considered non-adherent to treatment if they failed to take 10% or more of their prescribed total dose of at least one drug during the 4 days before the interview, or if they had accumulated a delay of more than 9 days over the previous 3 months in picking up their prescribed drugs from the hospital pharmacy. Logistic regression analysis was performed with variables found to be associated with adherence in the univariate analysis.
Results: The methods used to determine adherence had a Kappa index of 12.6%. Among the 206 patients interviewed, 108 were considered non-adherent (52.4%; CI 95% 5 45.6-59.2). Multivariate analysis showed that the following factors were associated with poor treatment adherence: cocaine consumption in the previous six months (adjusted OR 5 5.1); patients unsure about the proper way to take prescribed treatment; (adjusted OR 5 2.5); and patients not prescribed the zidovudine-lamivudine combination (adjusted OR 5 1.9). Over one-third of patients with no variable associated with treatment adherence were considered non-compliant.
Conclusion: Measurement of medication adherence and its predictive factors involved methodological difficulties. With the criteria used in the present study more than half the patients were considered non-compliant. The variables found to be related to poor adherence can be modified by social, psychological or health care interventions.