Impact of a pharmaceutical care program on clinical evolution and antiretroviral treatment adherence: a 5-year study

Background: Antiretroviral treatments (ART) form the basis of adequate clinical control in human immunodeficiency virus-infected patients, and adherence plays a primary role in the grade and duration of the antiviral response. The objectives of this study are: (1) to determine the impact of the implementation of a pharmaceutical care program on improvement of ART adherence and on the immunovirological response of the patients; and (2) to detect possible correlations between different adherence evaluation measurements. Methods: A 60-month long retrospective study was conducted. Adherence measures used were: therapeutic drug monitoring, a simplified medication adherence questionnaire, and antiretroviral dispensation records (DR). The number of interviews and interventions related to adherence made for each patient in yearly periods was related to the changes in the adherence variable (measured with DR) in these same yearly periods. The dates when the laboratory tests were drawn were grouped according to proximity with the study assessment periods (February-May, 2005-2010). Results: A total of 528 patients were included in the study. A significant relationship was observed between the simplified medication adherence questionnaire and DR over the 60-month study period (P < 0.01). Improvement was observed in the mean adherence level (P < 0.001), and there was a considerable decrease in the percentage of patients with CD4+ lymphocytes less than 200 cells/mm(3) (P < 0.001). A relationship was found between the number of patients with optimum adherence levels and the time that plasma viral load remained undetected. The number of interviews and interventions performed in each patient in the first 12 months from the onset of the pharmaceutical care program (month 6), was related to a significant increase in adherence during this same time period. Conclusion: The results suggest that the establishment and permanence of a pharmaceutical care program may increase ART adherence, increase permanence time of the patient with undetectable plasma viral loads, and improve patients' lymphocyte count.