RESUMO
Body composition tools vary in reliability, portability, and accessibility. The purpose of this study was to evaluate test-retest reliability of MuscleSound® (MS) and dual-energy x-ray absorptiometry (DXA) for both two compartment (region) and three compartment (tissue) models. A secondary aim was to compare body composition values produced by both devices. Fifty participants (n = 25 male, n = 25 female) aged 18-39 years completed two body composition assessments, twice in a single session. Participants arrived at the lab after a 12-hour fast. DXA required participants to lay supine for 10-15 minutes during the scanning process. Thereafter, MS was utilized to measure subcutaneous adipose tissue thickness at seven sites: chest, subscapula, triceps, axilla, suprailium, abdomen, and mid-thigh. MS automatically estimated body composition utilizing a modified Jackson-Pollock equation and the Siri equation within the software. The sequence of assessments was then repeated. Statistical analysis included paired T-tests with Pearson correlations, intraclass correlation coefficients (ICC), and least significant change (LSC). Both methods were strongly reliable (ICCMS = .997, ICCDXA-region = .999, ICCDXA-tissue = .999). MS and DXA-region body fat percentages were significantly different (mean difference (%): 2.60 ± 1.32, p < .001) but highly correlated (r = .928, p < .001). Notably, the mean difference was within DXA-region's calculated least significant change of 3.24%. MS is reliable for assessing body fat percentage in young and middle-aged adults and operators can utilize MS to collect body composition data in the field.
RESUMO
BACKGROUND: Stavudine continues to be used in antiretroviral treatment (ART) regimens in many resource-limited settings. The use of zidovudine instead of stavudine in higher-risk patients to reduce the likelihood of lactic acidosis and hyperlactatemia (LAHL) has not been examined. METHODS: Antiretroviral-naïve, HIV-infected adults initiating ART between 2004 and 2007 were divided into cohorts of those initiated on stavudine- or zidovudine-containing therapy. We evaluated stavudine or zidovudine use, age, sex, body mass index (BMI), baseline CD4 cell count, creatinine, hemoglobin, alanine aminotransferase, and albumin as predictors of time to LAHL with Cox Proportional Hazards (PH) regression models. RESULTS: Among 2062 patients contributing 2747 patient years (PY), the combined incidence of LAHL was 3.2/100 PY in those initiating stavudine- and 0.34/100 PY in those initiating zidovudine-containing ART (RR 9.26, 95% CI: 1.28-66.93). In multivariable Cox PH analysis, stavudine exposure (HR 14.31, 95% CI: 5.79-35.30), female sex (HR 3.41, 95% CI: 1.89-6.19), higher BMI (HR 3.21, 95% CI: 2.16-4.77), higher creatinine (1.63, 95% CI: 1.12-2.36), higher albumin (HR 1.04, 95% CI: 1.01-1.07), and lower CD4 cell count (HR 0.96, 95% CI: 0.92-1.0) at baseline were associated with higher LAHL rates. Among participants who started on stavudine, switching to zidovudine was associated with lower LAHL rates (HR 0.15, 95% CI: 0.06-0.35). Subgroup analysis limited to women with higher BMI≥25 kg/m2 initiated on stavudine also showed that switch to zidovudine was protective when controlling for other risk factors (HR 0.21, 95% CI .07-0.64). CONCLUSIONS: Stavudine exposure, female sex, and higher BMI are strong, independent predictors for developing LAHL. Patients with risk factors for lactic acidosis have less LAHL while on zidovudine- rather than stavudine-containing ART. Switching patients from stavudine to zidovudine is protective. Countries continuing to use stavudine should avoid this drug in women and patients with higher BMI.
