Plasma concentrations of efavirenz are associated with body weight in HIV-positive individuals.

BACKGROUND: Efavirenz is among the most widely used antiretroviral drugs. Increased efavirenz exposure has been associated with CNS side effects and also with the chance of emergence of resistance upon treatment interruptions. The objective of this study was to evaluate factors associated with efavirenz plasma concentrations in a cohort of HIV-infected individuals. METHODS: From July 2009 to March 2010, HIV-infected patients with efavirenz as part of antiretroviral therapy (600 mg at night), undetectable viral load for at least 1 year and CD4 cell count >200 cells/mm(3) were consecutively enrolled at the HIV/AIDS ambulatory care unit in southern Brazil. Plasma samples were taken 18-23 h after efavirenz last dose and analysed by validated ultra-performance liquid chromatography. RESULTS: Forty-one subjects were included (21 females). Mean age and weight were 45.4 years and 70.9 kg, respectively. Mean efavirenz plasma concentration was 2.20 ±â€Š2.17 mg/L. Most plasma concentrations (73%) were within the therapeutic window (1-4 mg/L); 17% were below and 10% above the limits. There were no significant associations between efavirenz concentration and age, CD4 cell count, time on antiretroviral treatment and gender. There was significant and inverse correlation between efavirenz concentrations and body weight (P = 0.013) and body mass index (P = 0.001). CONCLUSIONS: In this cohort of well-controlled HIV-positive individuals, patients with lower weight or body mass index had a higher chance of presenting elevated plasma concentrations of efavirenz. Therapeutic drug monitoring to adjust dose might be a helpful tool to decrease efavirenz dose in order to minimize costs and adverse effects.

Tobacco smoking and body composition in persons living with HIV/AIDS.

This study aimed to assess the association between tobacco smoking and body composition in patients with HIV/AIDS in combination antiretroviral therapy (cART). This is a cross-sectional study with people of HIV followed in specialized care service for HIV patients located in the South of Brazil. The Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) was used to assess smoking and other psychoactive substance use. Body mass index (BMI) was calculated as the ratio of body weight (in kilograms) to squared height (in meters). Patients also had their body composition evaluated with a multi-frequency bioelectrical impedance (Bodystat® Quadscan 4000, RU) to estimate skeletal muscle index (SMI). In total, 320 subjects were included in the study. The prevalence of smoking was 54.7%. Tobacco smoking was associated with malnutrition, lower body mass index scores, and lower skeletal muscle mass index. It is concluded that there is a high prevalence of smoking among patients with HIV/AIDS and that this behavior is associated with worse body composition. Thus, it is suggested to implement strategies to support smoking cessation among people with HIV/AIDS.

Prevalence and risk factors associated to chronic kidney disease in HIV-infected patients on HAART and undetectable viral load in Brazil.

BACKGROUND: To determine the prevalence and associated factors with chronic kidney disease (CKD) in a cohort of HIV-positive individuals with undetectable viral load on HAART. METHODS: From March, 2009 to September 2009, 213 individuals between 18-70 years, period on HAART ≥12 months, viral load < 50 copies/mm(3), and CD4 ≥ 200 cells/mm(3), were consecutively enrolled at the outpatient clinic of Hospital de Clínicas, Porto Alegre, Brazil. Exclusion criteria were obesity, malnourishment, amputee, paraplegic, previous history of renal disease, pregnancy and hepatic insufficiency. Renal function was determined by estimated glomerular filtration rate (eGFR) assessed by the modification of diet in renal disease. CKD was defined as an eGFR less or equal than 60 ml/min/1.73 m(2), for a period of at least 3 months. Poisson regression was used to determine factors associated with CKD. RESULTS: CKD was diagnosed in 8.4% of the population, and after adjustment, the risk factors were hypertension (RR = 3.88, 95%CI, 1.84-8.16), time on HAART (RR = 1.15, 95%CI,1.03-1.27) and tenofovir exposure (RR = 2.25, 95%CI, 1.04-4.95). Higher weight (RR = 0.88 95%CI, 0.82-0.96) was associated to normal function. CONCLUSIONS: CKD was a common finding in this cohort of patients and was related to hypertension, time on HAART and tenofovir exposure. We suggest a more frequent monitoring of renal function, especially for those with risk factors to early identify renal impairment.