Pathophysiology of body composition and metabolic abnormalities in HIV-infection: therapeutic implications

Fasting Triglyceride Concentrations are Associated with Early Mortality Following Antiretroviral Therapy in Zambia

BACKGROUND: In developing countries, 8 to 71% of patients initiating highly active antiretroviral therapy (HAART) die within the first year of treatment. Apart from baseline CD4 count, viral load, hemoglobin, BMI and stage of the disease, there may be other variables that contribute to AIDS-related mortality. We investigated the potential role of nutrition, lipids and insulin resistance-related phenotypes in predicting early mortality. METHODS: We recruited 210 HAART-naïve HIV/AIDS patients in Lusaka, Zambia. Dietary intake, anthropometric measurements, fasting serum insulin, glucose, and lipid profiles were assessed at baseline. Mortality was assessed after 90 days of follow-up. We used logistic regression models to identify variables associated with mortality. RESULTS: The mean±SD for age, BMI and CD4 count at baseline were 34±7.4 y, 20±3 kg/m(2) and 138±52 cells/μL, respectively. Sixteen patients (7.6%) died during follow-up. Triglyceride concentrations were associated with increased mortality [odds ratio (OR) for 1 mmol/L increase in triglyceride concentration=2.51; 95% CI: 1.34-4.71]. This association remained significant (OR=3.24; 95% CI: 1.51-6.95) after adjusting for age, gender, smoking, alcohol use, total cholesterol, BMI, CD4 count and n3 fatty acid intake. Apart from higher n3 fat intake which was inversely associated with mortality (survivors: 1.81±0.99% total energy/day vs. non-survivors 1.28±0.66% energy/day, P=0.04), there were no other macronutrients associated with mortality. CONCLUSION: Triglyceride concentrations at the time of initiating HAART are independently associated with increased risk for early mortality. If this association is confirmed in larger studies, assessment of triglycerides could become part of routine care of HIV patients initiating HAART in developing countries.

Pharmacokinetics of enfuvirtide in patients treated in typical routine clinical settings

Therapeutic drug monitoring (TDM) is gaining importance for improving the success of antiretroviral treatment in human immunodeficiency virus-infected patients. However, enfuvirtide (ENF) concentrations are not regularly determined. The objective of this work was to study the pharmacokinetics (PK) of ENF in patients treated in routine clinical settings, to develop a population PK model describing the concentration-time profile, and to establish PK reference values. A liquid chromatography-tandem mass spectrometry method was developed and applied to serum samples submitted for TDM. A two-compartment model with linear absorption and elimination was fitted to 329 concentrations from 131 patients. The PK model was used for simulations resulting in percentile curves for ENF levels for the full dosing interval. The model predicted that a median concentration of 1,968 ng/ml would be reached 12 h after administration of 90 mg of ENF, and 23% and 58% of patients are expected to have concentrations below 1,000 ng/ml and 2,200 ng/ml, respectively. Both values have been proposed as cutoffs for virological efficacy. The median maximum concentration of drug in serum (Cmax) of 3,943 ng/ml, predicted for 3 h after drug administration, is lower than the Cmax reported previously. We found an enormous interpatient variability at every time point, with concentration spectrums covering >1 log and 52% and 123% interindividual variabilities in the typical clearance and volume of distribution, respectively, in contrast to preexisting PK data. In summary, ENF levels are lower and more variable than expected. Many patients may achieve insufficient concentrations. Further covariate analysis in the population PK model might help to identify factors influencing the variability in ENF concentrations.

Low-dose growth hormone and human immunodeficiency virus-associated lipodystrophy syndrome: a pilot study

BACKGROUND

Treatment with high doses (2-6 mg day(-1)) of human growth hormone (hGH) in patients with human immunodeficiency virus (HIV)-associated lipodystrophy syndrome (HALS) has been shown to increase concentrations of total insulin-like growth-factor-I (IGF-I) more than twofold greater than the normal upper range and is accompanied by adverse effects such as joint pain and glucose intolerance.

MATERIALS AND METHODS

We performed a 16-week open-labelled prospective pilot study in six male HALS patients using a s.c. low-dose hGH, 0.7 mg day(-1), aiming to examine the impact on total and free IGF-I and fat distribution. Glucose metabolism was examined by oral glucose tolerance tests and hyperinsulinaemic euglycaemic clamps.

RESULTS

Total IGF-I increased twofold (P < 0.01) and free IGF-I increased 2.5-fold (P < 0.01) to the level of the normal upper range. HDL-cholesterol increased (P = 0.01). Patients reported improvements of lipodystrophy, which was supported by a decreased waist-to-thigh ratio (P = 0.01), and waist-to-hip ratio (P = 0.06). Ratio of peripheral to trunk soft tissue mass increased (P = 0.01, measured by dual-energy X-ray absorptiometry scans) and a trend towards reduction in percentage of trunk fat was suggested (P = 0.12). Total fat mass, exercise capacity, glucose tolerance, glucose disposal rate and immune status, respectively, did not change (all P > 0.5). The patients did not complain of arthralgia or other known GH-related side-effects.

CONCLUSIONS

Sixteen weeks' treatment of lipodystrophic HIV-infected patients with hGH, 0.7 mg day(-1), increased total and free IGF-I twofold and appeared safe and tolerable. The potential of low-dose hGH in the treatment of HIV-lipodystrophy awaits examination by placebo-controlled, randomized trials.