Zidovudine/lamivudine contributes to insulin resistance within 3 months of starting combination antiretroviral therapy

Antiretroviral therapy with or without protease inhibitors impairs postprandial TAG hydrolysis in HIV-infected men

Mechanisms underlying the lipodystrophy syndrome associated with antiretroviral therapy (ART) for HIV infection are not completely understood. We investigated the effect of ART on blood lipid concentrations in the fasting state and after consumption of a meal containing [1-13C]palmitic acid in HIV-positive men receiving nucleoside reverse transcriptase inhibitors (NRTI,n7), NRTI combined with protease inhibitors (PI; NRTIPI,n6), in HIV-positive but therapy-naïve men (noART,n5) and in HIV-seronegative men (controls,n6). HIV-positive subjects had higher fasting TAG concentrations and resting energy expenditure than controls. Subjects receiving NRTIPI therapy had higher fasting NEFA concentrations than the other groups. There were no significant differences in postprandial lipid metabolism between noART subjects and controls. NRTI therapy impaired hydrolysis of meal-derived TAG, most evidently when combined with PI (the NRTIPI group). Accumulation of13C-label in the NEFA fraction was not different between groups. In the NRTIPI group, fasting and postprandial NEFA concentrations were significantly higher than other groups. Postprandial glucose and insulin responses in HIV-positive subjects did not differ from controls. These findings suggest that ART dyslipidaemia is associated with impaired postprandial TAG clearance, which is exacerbated by NRTIPI therapy. If dyslipidaemia is to be minimised in ART, the specific adverse effects of particular combinations during the fed state should be considered.

Zidovudine/lamivudine for HIV-1 infection contributes to limb fat loss

Background

Lipoatrophy is known to be associated with stavudine as part of the treatment for HIV infection, but it is less clear if this serious side effect is also related to other nucleoside reverse transcriptase inhibitors like zidovudine. We aimed to determine whether zidovudine-sparing first-line antiretroviral therapy would lead to less lipoatrophy and other metabolic changes than zidovudine-containing therapy.

Methodology/Principal Findings

Fifty antiretroviral therapy-naïve HIV-1 infected men with an indication to start antiretroviral therapy were included in a randomized single blinded clinical trial. Randomisation was between zidovudine-containing therapy (zidovudine/lamivudine+lopinavir/ritonavir) and zidovudine-sparing therapy (nevirapine+lopinavir/ritonavir). Main outcome measures were body composition assessed by computed tomography and dual-energy X-ray absorptiometry scan and lipid profile before and after 3, 12, 24 months of antiretroviral therapy. In the zidovudine/lamivudine+lopinavir/ritonavir group, from 3 months onward limb fat decreased progressively by 684±293 grams (estimated mean±standard error of the mean)(p = 0.02) up to 24 months whereas abdominal fat increased, but exclusively in the visceral compartment (+21.9±8.1 cm², p = 0.008)). In contrast, in the nevirapine+lopinavir/ritonavir group, a generalized increase in fat mass was observed. After 24 months no significant differences in high density lipoprotein and total/high density lipoprotein cholesterol ratio were found between both treatment groups, but total and low density lipoprotein cholesterol levels were higher in the nevirapine+lopinavir/ritonavir group (6.1±0.2 versus 5.3±0.2 and 3.6±0.1 versus 2.8±0.1 mmol/l respectively, p<0.05). Virologic response and safety were comparable in both groups.

Conclusions/Significance

Zidovudine/lamivudine+lopinavir/ritonavir, but not nevirapine+lopinavir/ritonavir in antiretroviral therapy-naïve patients, is associated with lipoatrophy and greater relative intraabdominal lipohypertrophy, suggesting that zidovudine/lamivudine contributes to both these features of lipodystrophy. These findings support to no longer consider zidovudine/lamivudine as one of the preferred possible components of first-line antiretroviral therapy where alternative treatments are available.

Trial Registration

ClinicalTrials.gov NCT 00122226

Prevalence and pathogenesis of diabetes mellitus in HIV-1 infection treated with combined antiretroviral therapy

Combined antiretroviral therapy (cART) in the treatment of HIV-1 infection confers significant survival benefit and, by immunoreconstitution, has altered the natural history of this life-threatening disease. Metabolic complications of cART include hyperlipidemia, insulin resistance, and lipodystrophy, with resultant increases in risk for type 2 diabetes and cardiovascular disease. These diseases will present new challenges in the management of HIV infection. This article reviews the prevalence of diabetes mellitus and its antecedents in HIV-infected patients treated with cART. It also reviews the current understanding of mechanisms involved in the pathogenesis of type 2 diabetes in cART considering insulin resistance and insulin secretion, both requisites for the development of type 2 diabetes mellitus.

Risk factors for incident diabetes mellitus among HIV-infected patients receiving combination antiretroviral therapy in Taiwan: a case-control study

OBJECTIVES

Recent studies suggest that patients with HIV infection are at increased risk for incident diabetes mellitus (DM). We investigated the incidence and risk factors of DM among HIV-infected patients receiving combination antiretroviral therapy (CART) in Taiwan.

METHODS

Incident cases of DM were identified among HIV-infected patients at the National Taiwan University Hospital between 1993 and 2006. A retrospective case-control study was conducted after matching cases with controls for sex, age at HIV diagnosis, year of HIV diagnosis, mode of HIV transmission and baseline CD4 lymphocyte count. A multivariate analysis was performed to identify risk factors for incident DM among HIV-infected patients.

RESULTS

In 824 HIV-infected patients eligible for analysis, 50 cases of incident DM were diagnosed, resulting in an incidence of 13.1 cases per 1000 person-years of follow-up. In total, 100 matched controls were identified. Risk factors for incident DM were a family history of DM [odds ratio (OR) 2.656; 95% confidence interval (CI) 1.209-5.834], exposure to zidovudine (OR 3.168; 95% CI 1.159-8.661) and current use of protease inhibitors (OR 2.528; 95% CI 1.186-5.389).

CONCLUSIONS

Incident DM was associated with a family history of DM, exposure to zidovudine and current use of protease inhibitors in HIV-infected patients receiving CART in Taiwan.

Diabetes mellitus, preexisting coronary heart disease, and the risk of subsequent coronary heart disease events in patients infected with human immunodeficiency virus: the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D Study)

BACKGROUND

Although guidelines in individuals not infected with the human immunodeficiency virus (HIV) consider diabetes mellitus (DM) to be a coronary heart disease (CHD) equivalent, there is little information on its association with CHD in those infected with HIV. We investigated the impact of DM and preexisting CHD on the development of a new CHD episode among 33,347 HIV-infected individuals in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D Study).

METHODS AND RESULTS

Over 159,971 person-years, 698 CHD events occurred. After adjustment for gender, age, cohort, HIV transmission, ethnicity, family history of CHD, smoking, and calendar year, the rate of a CHD episode was 7.52 times higher (Poisson regression, 95% CI 6.02 to 9.39, P=0.0001) in those with preexisting CHD than in those without preexisting CHD, but it was only 2.41 times higher (95% CI 1.91 to 3.05, P=0.0001) in those with preexisting DM compared with those without DM. No statistical interactions were apparent between either diagnosis and sex; although older people with DM had an increased CHD rate compared with younger people, older people with preexisting CHD had a lower event rate. A statistically significant interaction between preexisting DM and CHD (P=0.003) suggested that the CHD rate in those with preexisting CHD and DM is lower than expected on the basis of the main effects alone.

CONCLUSIONS

DM and preexisting CHD are both important risk factors for CHD events in HIV-infected individuals. There is a need for targeted interventions to reduce the risk of CHD in both high-risk groups of HIV-infected individuals.

Predictors of insulin resistance among Hispanic adults infected with or at risk of infection with the human immunodeficiency virus and hepatitis C virus

Both the human immunodeficiency (HIV) and hepatitis C (HCV) viruses have been associated with insulin resistance (IR). However, our understanding of the prevalence of IR, the underlying mechanisms and predisposing factors is limited, particularly among minority populations. We conducted a study of 333 Hispanic adults including: 76 HIV monoinfected, 62 HCV monoinfected, 97 HIV/HCV co-infected and 98 uninfected controls with a specific focus on HCV infection and liver injury as possible predictors of IR. IR was measured using the Quantitative Insulin Sensitivity Check Index (QUICKI). The majority (55-69%) of participants in all groups had QUICKI values <0.350. Body mass index was associated with IR in all groups. Triglycerides were associated with IR in the uninfected control group only (-1.83, SE = 0.58, P = 0.0022). HCV was associated with IR in participants infected with HIV (-0.012, SE = 0.0046, P = 0.010). Liver injury, as measured by score to assess liver injury (FIB-4) score, was significantly associated with IR independently of HCV infection (-0.0035, SE = 0.0016, P = 0.027). In the HIV/HCV co-infected group, treatment with nucleoside reverse-transcriptase (RT) inhibitors plus non-nucleoside RT inhibitors (-0.021, SE = 0.080, P = 0.048), but not protease inhibitors (-0.000042, SE = 0.0082, P = 0.96) was associated with IR. HCV infection and antiretroviral agents, including nucleoside RT inhibitor plus non-nucleoside RT inhibitor treatment are contributors to IR in HIV infection. Liver injury, as measured by the FIB-4 score, is a predictor of IR independently of HCV infection.

Hyperglycemia prevents the suppressive effect of hyperinsulinemia on plasma adiponectin levels in healthy humans

Adiponectin is a fat-derived hormone with insulin-sensitizing properties. In patients with type 2 diabetes plasma adiponectin levels are decreased. Since these patients are characterized by high plasma insulin and glucose concentrations, hyperinsulinemia and hyperglycemia could be responsible for the downregulation of adiponectin. Insulin decreases adiponectin levels in humans. The effect of hyperglycemia is unknown. To determine the selective effects of insulin, glucose, or their combination on plasma adiponectin, clamps were performed in six healthy males on four occasions in a crossover design: 1) lower insulinemic-euglycemic clamp (100 pmol/l insulin, 5 mmol/l glucose) (reference clamp); 2) hyperinsulinemic-euglycemic clamp (400 pmol/l insulin, 5 mmol/l glucose); 3) lower insulinemic-hyperglycemic clamp (100 pmol/l insulin, 12 mmol/l glucose); and 4) hyperinsulinemic-hyperglycemic clamp (400 pmol/l insulin, 12 mmol/l glucose). Adiponectin concentrations and high-molecular-weight (HMW)-to-total adiponectin ratio were measured at the start and end of the 6-h clamps. After the 6-h study period, total plasma adiponectin levels were significantly (P = 0.045) decreased by 0.63 microg/ml in the lower insulinemic-euglycemic clamp (clamp 1). In both euglycemic groups (clamps 1 and 2) adiponectin concentrations significantly declined (P = 0.016) over time by 0.56 microg/ml, whereas there was no change in both hyperglycemic groups (clamps 3 and 4) (P = 0.420). In none of the clamps did the ratio of HMW to total adiponectin change. We conclude that insulin suppresses plasma adiponectin levels already at a plasma insulin concentration of 100 pmol/l. Hyperglycemia prevents the suppressive effect of insulin. This suggests that, in contrast to glucose, insulin could be involved in the downregulation of plasma adiponectin in insulin-resistant patients.

Approach to the human immunodeficiency virus-infected patient with lipodystrophy

Subcutaneous atrophy and central fat accumulation are common among HIV-infected patients receiving highly active antiretroviral therapy, and may be accompanied by dyslipidemia and insulin resistance. These fat changes, although commonly referred to together as lipodystrophy, are best considered as separate disorders, with distinct pathogeneses and treatment approaches. These morphological and metabolic abnormalities first appeared after introduction of protease inhibitors more than 10 yr ago, but research has demonstrated that their pathogenesis is multifactorial, with contributions from other antiretroviral medications, patient-related factors, and HIV itself. Switching to a less toxic highly active antiretroviral therapy regimen has shown partial effectiveness for the management of fat atrophy and lipid abnormalities. Lifestyle modification or surgical approaches are the treatment of choice for lipohypertrophy, although novel therapies targeting the GH axis show promise. HIV-related dyslipidemia may be difficult to treat, and can be complicated by drug-drug interactions between some lipid-lowering medications and antiretroviral medications. Treatment of diabetes in HIV-infected patients should generally follow established guidelines, but thiazolidinediones, rather than metformin, may be considered first-line treatment in a patient with lipoatrophy, given their potential to increase sc fat. The contribution of body fat changes and metabolic abnormalities to cardiovascular risk and the changing risk profiles of newer antiretroviral regimens are under intense investigation.