Changes in Body Fat Measured by DEXA in Patients Taking Different Formulations of Stavudine

Changes in Facial Fat in HIV-Related Lipoatrophy, Wasting, and Weight Gain Measured by Magnetic Resonance Imaging

BACKGROUND

Changes in facial fat occurring over time in patients with HIV-related lipoatrophy have not been properly quantified. We aimed to define the longitudinal changes in facial fat compartments in patients with lipoatrophy and to compare these with changes accompanying wasting or weight gain.

METHOD

Facial MRI scans were performed at baseline and repeated after a median of 10 months in 24 patients, of whom 12 had moderate to severe lipodystrophy continuing antiretroviral therapy, 5 lost weight, and 7 gained weight (more than 10% weight change).

RESULTS

Superficial facial fat decreased by a median of 5.2 mL (p = .03) in patients with lipoatrophy, and 8 of 12 individuals showed more than 15% decrease (all of whom were taking stavudine). The decrease was mainly cheek fat. Superficial facial fat decreased by 6.0 mL in patients with weight loss (p = .04) and increased by 20.2 mL (p = .02) in patients with weight gain, and changes occurred in cheek fat, temporal fat, and masseter muscle and temporalis muscle compartments.

CONCLUSION

MRI can detect substantial ongoing changes in facial fat in patients with facial lipoatrophy. A characteristic pattern of compartmental change distinguishes lipoatrophy from wasting and weight recovery. MRI should be considered for use in clinical trials of interventions to prevent or treat lipoatrophy and may be useful for documenting changes in individual patients during clinical follow-up.

The Official Positions of the International Society for Clinical Densitometry: Indications of Use and Reporting of DXA for Body Composition

The technique of body composition by dual-energy X-ray absorptiometry (DXA) has been used for several years in the research environment. Its ability to accurately and precisely measure lean, fat, and mineral composition in various body compartments has been well validated. Furthermore, the technique is widely available to clinical patients on existing DXA instruments throughout the world through the use of specific software packages and scanning algorithms. There have been few clear statements regarding the clinical indications for body composition measurement in patients outside the research setting. This is in part because of the lack of specific documented interventions that would be affected by body composition test results, beyond usual clinical advice. We have examined a few of the most common, specific scenarios (HIV therapy, sarcopenia, bariatric surgery, obesity) and proposed indications for body composition assessment. We have also discussed contraindications to body composition testing.

Stavudine extended release (once-daily, Bristol-Myers Squibb) for the treatment of HIV/AIDS

INTRODUCTION

Stavudine extended release (d4T XR) was a formulation which tried to solve the two main problems associated with the use of stavudine immediate release (d4T IR). These were twice daily dosing schema at a time when most formulations were long-life allowing once daily dosing; and that the use of d4T IR was associated with long-term toxicity through mitochondrial toxicity clinically expressed as peripheral neuropathy, pancreatitis and above all, lipodystrophy. The link between stavudine exposure and lipodystrophy had a great negative impact on its use in clinical practice.

AREAS COVERED

The authors cover the most relevant papers related to the efficacy and safety of d4T XR-based antiretroviral therapy.

EXPERT OPINION

The development of d4T XR has only been partially successful with regard to its objectives. Improved pharmacokinetic properties allow its once daily dosing, and although it exhibits less mitochondrial toxicity it is still hampered by its development in a significant proportion of patients. This has caused its use to be almost residual in industrialised countries. As of now, d4T XR has not been made available in developing countries, despite the extended use of the immediate-release formulation. Currently, if there is no other chance of starting combination antiretroviral therapy, d4T XR could play a role in the treatment of HIV infection.

Ethnicity and gender differences in lipodystrophy of HIV-positive individuals taking antiretroviral therapy in Ontario, Canada

PURPOSE

This study assessed ethnicity and gender differences in prevalence, type, and severity of antiretroviral-associated lipodystrophy in HIV-positive individuals in Ontario.

METHODS

This was a cross-sectional analysis of the Ontario Cohort Study (OCS), a prospective study of HIV-positive patients in Ontario. Lipodystrophy was defined as at least 1 major or 2 minor self-reported changes of peripheral lipoatrophy and/or central lipohypertrophy. Prevalence, type, and severity were compared by ethnicity (Black, White, or Other) and gender. Univariate and multivariate logistic regression analyses identified predictors of lipodystrophy.

RESULTS

Data were available for 778 participants (659 men, 119 women). There were 517 Whites, 121 Blacks, and 140 patients of Other ethnicities. In univariate analyses, Whites reported more peripheral lipoatrophy (P = .004) and abdominal lipohypertrophy (P = .04); these ethnic differences were observed in males (P = .05 and P = .03, respectively) but not females. Males reported more peripheral lipoatrophy (P = .01), whereas females had more central lipohypertrophy (P < .0001) and mixed fat redistribution (P < .0001). Multivariable regression analyses revealed Black women to be most vulnerable to lipodystrophy (P = .02), particularly lipohypertrophy (P < .0001).

CONCLUSIONS

Ethnicity and gender are important factors influencing lipodystrophy. Combining lipoatrophy and lipohypertrophy into a single entity is not appropriate. Black women were most vulnerable to lipohypertrophy, which has important implications for antiretroviral therapy roll-out in Africa.