Evolution of adherence to antiretroviral treatment in a spanish hospital during 2001, 2005 and 2008

Abstract

The aim of this study was to analyze the evolution of adherence to highly active antiretroviral therapy (HAART) in the Hospital General Universitario Gregorio Marañón (Madrid, Spain) over the last 8 years and determine the variables associated with the complexity of treatment and suboptimal adherence. An observational, retrospective method was used to measure adherence during the first 6 months of HAART in 3 cohorts: 2001 cohort (n = 90), 2005 cohort (n = 98), and 2008 cohort (n = 110). The adherence rate was determined using 2 methods: Pharmacy Department dispensation records and virologic response data. The evolution of the complexity of treatment and its influence on the adherence rate was analyzed by logistic regression. Adherence to HAART increased progressively from 45.6 % in 2001 to 56.1 % in 2005 and 77.3 % in 2008. Statistically significant differences were only observed between cohorts in 2005 and 2008. The average daily pill burden was 7, 4, and 4.5 tablets, respectively. The percentage of patients on twice-daily regimens decreased from 93.3 % in 2001 to 63.6 % in 2008, with a parallel increase in once-daily regimens. The proportion of patients with dietary restrictions decreased from 24.4 % to 3.6 %. A statistically significant association was found between the number of medication units per day and adherence and between frequency of administration and adherence. Adherence to HAART has improved significantly in the last 8 years. While the complexity of the treatment was significantly reduced in 2005, the largest increase in adherence occurred in the last cohort, which shows the influence of factors other than treatment simplification.