Changes in metabolic parameters and body shape after replacement of protease inhibitor With efavirenz in virologically controlled HIV-1-positive persons: single-arm observational cohort

Patterns and Predictors of First-Line Antiretroviral Therapy Modification in HIV-1-Infected Adults in a Large Urban Outpatient Cohort in Nigeria

OBJECTIVE

We described the magnitude, type, and factors associated with first-line antiretroviral therapy (ART) modification in HIV-1-infected adults on ART in Jos, Nigeria.

METHOD

Data on 6309 patients initiated on first-line ART between January 2004 and December 2006 were analyzed retrospectively. Factors predictive of modification to initial ART were assessed by chi-square and multivariable logistic regression analysis.

RESULTS

Overall, 5212 (83%) included patients incurred a modification (73.3% drug substitution and 9.7% drug switch) to their initial first-line ARV regimen during a median (interquartile range) follow-up period of 7 (3-8) years. Drug substitutions of zidovudine (ZDV) were less likely than of tenofovir (TDF; adjusted odd ratio [AOR] 0.6; 95% confidence interval [CI]: 0.51-0.71), and Drug substitutions of efavirenz (EFV) were more likely than of nevirapine (NVP)-containing (AOR 1.82; 95% CI: 1.42-2.33) regimens. Predictors of switch to second-line regimen include older age (AOR 2.05; 95% CI: 1.68-2.51), CD4 count≤100 cells/mm3 (AOR 1.89; 95% CI: 1.49-2.37), EFV compared to NVP (AOR 1.38; 95% CI: 1.02-1.88), and drug toxicity (AOR 1.90; 95% CI: 1.48-2.43).

CONCLUSION

Modification to initial ART was common in this study. Further evaluation of the contribution of guideline changes on regimen modification and treatment outcomes is recommended.

Current treatment methods for combination antiretroviral therapy-induced lipoatrophy of the face

Summary

Combination antiretroviral therapy (CART) reduces the mortality and morbidity in HIV-infected patients. However, facial lipoatrophy (FLA) is one of the well-known side-effects of this treatment and subsequently imposes major problems for HIV-infected patients. In the last decade, ample experience has been obtained with both local therapeutic options as well as possible systemic treatment options. Soft tissue fillers are a relatively simple and efficient treatment option for FLA. Especially, the biodegradable semi-permanent fillers combine a good effect with durability and an acceptable safety profile. The best way to prevent or restrict the development of FLA remains the exclusion of thymidine analogue nucleoside reverse-transcriptase inhibitors from the CART schedule.

A randomized comparative 96-week trial of boosted atazanavir versus continued boosted protease inhibitor in HIV-1 patients with abdominal adiposity

BACKGROUND

Abdominal adiposity in HIV-1 patients initiating antiretroviral therapy may be part of a restoration-to-health phenomenon. Lipoatrophy is associated with long-term thymidine analogue therapy. Individual protease inhibitors (PIs) differ in their effects on lipids and insulin resistance.

METHODS

A randomized open-label multicentre 96-week trial compared changes in fat distribution in patients with suppressed HIV-1 RNA and abdominal adiposity, who either continued on their current twice-daily ritonavir-boosted PI (PI/r) or switched to once-daily boosted atazanavir (ATV/r). Treatment with two nucleoside reverse transcriptase inhibitors was unchanged. Body composition was assessed by dual-energy x-ray absorptiometry (DEXA) and abdominal computerized tomography (CT) scanning.

RESULTS

In total, 201 patients were randomized; 131 switched to ATV/r. Viral suppression (<50 copies/ml) was similarly maintained (93% ATV/r versus 89% PI/r). Mean changes from baseline in trunk-to-limb fat ratio were similar; difference estimates 0.03 (95% CI -0.06, 0.12; P=0.48 at week 48) and 0.02 (95% CI -0.10, 0.14; P=0.73 at week 96). More patients in the PI/r arm had a decrease of ≥20% in limb fat from baseline at week 96. Significantly greater reductions in proatherogenic lipids occurred following switch to ATV/r. Both treatment regimens were generally well-tolerated; the incidence of grade 3-4 treatment-related clinical adverse events was 34% among ATV/r recipients versus 4% of PI/r-treated patients.

CONCLUSIONS

Switching to ATV/r had no demonstrable benefit on abdominal adiposity. Maintenance of efficacy, less limb fat loss and marked reduction in proatherogenic lipids was observed with ATV/r compared with continuing a PI/r regimen.

Impact of switching antiretroviral therapy on lipodystrophy and other metabolic complications: a review

Following the introduction of highly active antiretroviral therapy (HAART), metabolic and morphological complications known as HIV associated lipodystrophy syndrome (HALS) have been increasingly common. The approaches to target these complications span from resistance exercise, diet and use of the antidiabetics metformin or glitazones to high dose recombinant human growth hormone therapy or switching antiretroviral regimen. When looking at the effect of switching therapy, focus has been addressed to protease inhibitor (PI) based regimens, as PI was the first component of HAART recognized to be correlated with the disfiguring body-alterations known as HALS. More recently, however, regimens containing nucleoside reverse-transcriptase inhibitors (NRTI) have attracted attention. Reviewing switch studies regarding metabolic parameters and body shape changes, certain trends emerge. Switching from PI, the metabolic complications such as dyslipidaemia and insulin resistance seem to be partly reversible, whereas the morphologic alterations appear to be unchanged. In studies in which NRTI's are switched, dyslipidaemia appears unaffected, but a modest improvement in peripheral lipoatrophy has been reported. However the results are often inconsistent and difficult to interpret, mostly because of limitations in study design, patient number and duration of follow-up. The need for larger, controlled, randomized, long-term studies is evident.

Therapy insight: Body-shape changes and metabolic complications associated with HIV and highly active antiretroviral therapy

Increasingly effective therapies for HIV infection are now available. These treatments, referred to collectively as highly active antiretroviral therapy, comprise various combinations of anti-HIV drugs from different drug classes. Recently, a range of metabolic complications have emerged as important toxicities in treated patients. Complications present as abnormalities of body-fat mass distribution in association with an often significant dyslipidemia and glucose homeostasis dysregulation. The body-shape changes, manifesting as peripheral lipoatrophy or central lipohypertrophy, can have a negative impact on quality of life and consequently on adherence to treatment. The combination of central lipohypertrophy, dyslipidemia and insulin resistance is associated with accelerated rates of atherosclerosis and other potentially significant long-term effects. The pathogenesis of these effects is complex and is still being actively investigated. Possible contributing factors relate to host characteristics, HIV viral parameters and specific effects of anti-HIV drugs on adipose-tissue biology and on intermediary metabolism. Management of these complications involves manipulation of the anti-HIV drugs using an understanding of their particular effects on lipid and glucose metabolism, in association with standard therapeutic interventions. Individualized approaches, taking into consideration quality-of-life issues, and assessment of potential cardiovascular risks, are now an important component of effective care of HIV-infected patients.

Insulin resistance, glucose intolerance and diabetes mellitus in HIV-infected patients

An increased prevalence of insulin resistance, glucose intolerance and diabetes has been reported in HIV infection in the highly active antiretroviral therapy (HAART) era. This development might be clinically significant because of its association with cardiovascular morbidity and mortality as well as the therapeutic challenges of managing polypharmacy. The development of insulin resistance, glucose intolerance and diabetes could be related to the underlying HIV infection, the contribution of different antiretroviral agents, treatment-associated weight gain, immune restoration, as well as the non-HIV related factors. Dissecting these factors in clinical practice might be difficult. Clinical studies include short-term treatments in healthy, non-HIV-infected individuals; randomized, controlled trials; comparative studies of different HAART regimens; and randomized studies of switching regimens in patients with viral suppression and stable immune function. This article reviews the latest knowledge regarding the epidemiology, pathogenesis, prevention and treatment of insulin resistance, glucose intolerance and diabetes mellitus in HIV-infected individuals.

Protease inhibitor-induced diabetic complications : incidence, management and prevention

Protease inhibitors (PIs) have become a crucial element in the treatment of patients infected with HIV. However, the widespread use of PI therapy has also been associated with a number of metabolic adverse effects, including fat redistribution and hyperglycaemia. The objective of this review is a discussion of the incidence, pathophysiology, management and prevention of PI-associated hyperglycaemia. Initial case reports have been followed by large cross-sectional and cohort studies, which demonstrate that the incidence of PI-induced impaired glucose tolerance, as well as frank diabetes mellitus, is significant and demands attention. Investigations into the pathophysiology behind PI-associated hyperglycaemia have identified an underlying problem of insulin resistance that is presumably caused by both direct PI-induced mechanisms and lipotoxicity. Given this, clinical trials have explored the use of various classes of oral hypoglycaemic agents in the management of PI-induced diabetic complications, and the use of insulin therapy must be considered as well. Newer PI agents are also under development, with the hope of reducing metabolic adverse effects. In the meantime, prevention, in the form of dietary modification, regular physical activity and periodic screening for impaired glucose tolerance, must receive heightened attention in the care plan of patients receiving long-term PI therapy.

Metabolic benefits 24 months after replacing a protease inhibitor with abacavir, efavirenz or nevirapine

OBJECTIVE

To evaluate the 24-month metabolic and morphological benefits obtained from replacing the protease inhibitor (PI) in a regimen with nevirapine, efavirenz or abacavir.

DESIGN AND METHODS

NEFA was a randomized study designed to compare the efficacy of nevirapine, efavirenz or abacavir as substitutes for PI. A subset of 90 patients [abacavir (n = 29), efavirenz (n = 32), nevirapine (n = 29)] formed the metabolic study. Fasting total cholesterol (TC), high density lipoprotein cholesterol (HDL-c) and triglycerides levels were determined. Glucose homeostasis parameters were also collected. Lipodystrophy was evaluated by clinical examination and morphological measurements.

RESULTS

Treatment simplification led to overall lipid profile improvements. At 24 months, the two non-nucleoside reverse transcriptase inhibitors produced similar lipid benefits: HDL-c levels increased [efavirenz, 15% (P = 0.001); nevirapine, 21% (P < 0.001)] and TC to HDL-c ratios decreased [efavirenz, 14% (P < 0.001); nevirapine, 19% (P < 0.01)], an effect not observed in the abacavir arm. Non-HDL-c levels decreased by 10% in both the abacavir (P = 0.001) and efavirenz (P < 0.05) arms. Significant decreases in the levels of triglycerides occurred for the first year in all treatments; however, at 24 months most of the initial loss had been regained. Patients with baseline moderate or severe lipodystrophy obtained less-pronounced lipid benefits. Several insulin resistance markers showed a trend towards improvement. Conversely, no improvements in morphological abnormalities were observed.

CONCLUSIONS

Replacing PI with efavirenz, nevirapine or abacavir improved the lipid profile, with more marked results in non-lipodystrophic patients. In contrast, this strategy does not seem to be effective for reversing body fat abnormalities.

Overcoming obstacles to the success of protease inhibitors in highly active antiretroviral therapy regimens

Success with current protease inhibitors (PIs) is limited by substantial variability in pharmacokinetics, onset of adverse metabolic effects that include sustained lipid elevations and insulin resistance, and increased risk of lipodystrophy. Additionally, poor adherence to the often complex regimens can lead to emergence of PI-resistant human immunodeficiency virus (HIV) variants and treatment failure. Boosting blood levels of current PIs through coadministration of ritonavir can improve the pharmacokinetic characteristics of these agents, increasing the chances of success, but often at the price of additional adverse effects. New PIs in development have the potential to overcome at least some of these obstacles. Tipranavir, mozenavir, and atazanavir have favorable and unique resistance profiles, making them potentially effective in new treatment strategies in both PI-naïve and PI-experienced patients. Atazanavir does not cause the lipid elevations seen with current PIs, and it may improve adherence through once-daily dosing.

Switching effective antiretroviral therapy: a review

One approach to target the long-term metabolic toxicity and disfiguring body-shape changes associated with antiretroviral therapy is to switch one component of a regimen to an alternative drug, usually from a different class of antiretrovirals. Most commonly, substitutions have involved protease inhibitors, but the thymidine analogue nucleosides, especially stavudine, have been investigated more recently. Certain trends from these studies have emerged. First, if the patient has had sustained viral suppression, switching therapy is generally virologically safe. Second, metabolic disturbances, such as insulin resistance and dyslipidemia, appear to be at least partially reversible. Substitution of other agents for protease inhibitors has not been associated with reversal or improvement in fat redistribution. Studies in which thymidine analogue reverse-transcriptase inhibitors have been switched have reported modest improvements in peripheral lipoatrophy. Larger, controlled, long-term studies and a more standardized approach to definition of metabolic and morphological abnormalities are needed.