The relationship between characteristics of HIV antiretroviral regimens and treatment adherence was studied in adolescent and adult patients who underwent antiretroviral therapy from January 1998 to September 2000, at the Service for Specialized Assistance in Pelotas. The patients were interviewed on two occasions, and the use of antiretrovirals during the previous 48 hours was investigated by a self-report. Adherence was defined as use of 95% or more of the prescribed medication. Social-demographic variables were collected through direct questionnaires. The antiretroviral regimen and clinical data were copied from the patients' records. Associations between the independent variables and adherence were analyzed by means of logistic regression. The multivariate analysis included characteristics of the antiretroviral regimens, social-demographic variables, as well as perception of negative effects, negative physiological states, and adverse effects of the treatment. Among the 224 selected patients, 194 participated in our study. Their ages varied from 17 to 67 years; most patients were men, with few years of schooling and a low family income. Only 49% adhered to the treatment. Adherence to treatment regimens was reduced when more daily doses were indicated: three to four doses (odds ratio of adherence to treatment (OR)=0.47, 95% confidence interval (CI) 0.22-1.01) and five to six (OR=0.24, 95% CI 0.09-0.62); two or more doses taken in a fasting state (OR=0.59, 95% CI 0.11-0.68), and for patients who reported adverse effects to the treatment (OR=0.39, 95% CI 0.19-0.77). Most of the regimens with more than two daily doses of medication included at least one dose apart from mealtimes. The results suggest that, if possible, regimens with a reduced number of doses should be chosen, with no compulsory fasting, and with few adverse effects. Strategies to minimize these effects should be discussed with the patients.

Factors associated with undetectable viral load (<80 copies/ml) were investigated among non-pregnant adults in antiretroviral treatment in a specialized service for HIV/AIDS in Southern Brazil. Use of antiretrovirals was investigated in two interviews (one month interval). Clinical data were collected from the clinical records; viral load previous to adherence measurement was defined the viral load previous to the first interview; the final viral load, the viral load subsequent to the second interview (interval between measures approximately 6 months). Undetectable final viral load occurred in 48% of the patients and was positively associated with levels of treatment adherence (p<0.001), being 19% for less than 60% of adherence and about 60% for adherence greater than 80%. In the multivariate model, the odds of undetectable final viral load was four times greater for 80-94% and > or = 95% of adherence (CI 95% 1,80-13,28; CI 95% 1,73-9,53), compared with less than 60% adherence; it was greater for less than 6 months in treatment (OR = 3.37; CI 95% 1.09-10.46); and smaller for viral load previous to adherence measurement > or = 5.2 log10 (OR = 0.19; CI95% 0.06-0.58), adjusted for these variables and sex, age, clinical status, current immune status, group of drugs and interval between the two measurements of viral load. The crude odds were lower for age 16-24 years and use of Nucleoside Analog Reverse Transcriptase Inhibitors only, but these effects were not significant in the multivariate model. There was no evidence of effect of sex, clinical status, current immune status, and changes in treatment regimen. Treatment adherence gave the largest effect. Motivational interventions directed at adherence may improve treatment effectiveness.

Uma escala de expectativa de auto-eficácia para seguir prescrição anti-retroviral em situações difíceis (21 itens) foi desenvolvida pela análise do conteúdo de entrevistas com pacientes que estavam em tratamento ou que o abandonaram. A consistência interna e a validade de construto foram examinadas em 60 sujeitos que freqüentaram ambulatório para pacientes em estágios avançados da doença (hospital-dia). Um escore de expectativa de auto-eficácia para adesão ao tratamento foi derivado do primeiro componente da análise de componentes principais. A média do escore foi 0,25 para os sujeitos aderentes e -0,33 para os não-aderentes ao tratamento (teste t, p = 0,046). A chance de adesão duplicou quando o escore de expectativa de auto-eficácia era maior em uma unidade (OR = 2,07; IC95% = 1,002 a 4,26). A consistência interna foi alta (alfa de Cronbach = 0.96). A escala demonstrou validade de construto e confiabilidade para medir auto-eficácia para tratamento anti-retroviral nesses pacientes.

A 21-item scale of efficacy-expectation for adhesion to antiretroviral therapy in high-risk situations was developed by content analysis of interviews with HIV/AIDS patients undergoing and dropouts from therapy. Internal consistency and construct validity were examined in 60 patients attending at an ambulatory for patients in advanced stages of the disease (day-hospital). A score of self-efficacy for treatment adhesion was derived from the first component of the principal component analysis. The mean score was 0.25 among adherent patients and -0.33 among those who were non-adherent (t test, p < 0.046). The odds of treatment adhesion increased 2,07 times when the efficacy-expectation score increased by one unit (OR = 2,07; IC95% = 1,002 a 4,26). The internal consistency was high (Cronbach-alpha = 0.96). The scale demonstrated construct validity and reliability as a measure of self-efficacy for antiretroviral therapy in these patients.