Publications

OBJECTIVES

The purpose of this study was to investigate the associations of traditional risk factors and longitudinal measures of human immunodeficiency virus (HIV) disease severity with risk of incident atrial fibrillation (AF) in a contemporary cohort of HIV-infected individuals.

BACKGROUND

Cardiovascular disease is common in HIV-infected persons; however, the most common cardiac arrhythmia, AF, has not been adequately studied in this population.

METHODS

We studied a national sample of 30,533 HIV-infected veterans followed in the Veterans Affairs HIV Clinical Case Registry from 1996 to 2011. We examined the independent associations of demographic characteristics, time-updated comorbidities, and time-updated clinical measurements including CD4(+) cell count and viral load with the outcome of incident AF using proportional hazards regression for multivariable analysis.

RESULTS

Over a median follow-up of 6.8 years, 780 (2.6%) patients developed AF. After multivariable adjustment for traditional risk factors, a lower CD4(+) cell count (<200 compared with >350 cells/mm(3); hazard ratio [HR]: 1.4; 95% confidence interval [CI]: 1.1 to 1.8; p = 0.018) and higher viral load (>100,000 compared with <500 copies/ml; HR: 1.7; 95% CI: 1.2 to 2.4; p = 0.002) were independently associated with increased risk of incident AF. Additional risk factors independently associated with risk of AF included older age, White race, coronary artery disease, congestive heart failure, alcoholism, proteinuria, reduced kidney function, and hypothyroidism.

CONCLUSIONS

In a large HIV-infected cohort, markers of HIV disease severity represented by low CD4(+) cell count and high viral load, assessed by multiple time-updated measures, were independently associated with development of AF.

Access to sputum smear microscopy in high-tuberculosis (TB)-burden regions is limited by a scarcity of microscopes and experienced technicians. We evaluated the accuracy of CellScope, a novel digital fluorescence microscope that may expand access to microscopy. The study utilized smear microscopy slides prepared from sputum specimens submitted by consecutive adults with ≥ 2 weeks of cough who were admitted to Mulago Hospital (Kampala, Uganda). Conventional light-emitting diode (LED) fluorescence microscopy (FM) and mycobacterial culture were performed by experienced technicians. Two U.S.-based postgraduate researchers without prior microscopy experience restained, imaged, and interpreted the slides using CellScope. We assessed whether sensitivity and specificity of CellScope-based LED FM was noninferior to conventional LED FM by using a preselected margin of inferiority of 15%. Of 525 patients included, 72% were HIV seropositive and 39% had culture-confirmed TB. The proportions of positive results were similar with CellScope and conventional LED FM (34% versus 32%, respectively; P = 0.32), and agreement was substantial. CellScope accuracy was within the noninferiority margin for both sensitivity (63% versus 70%; difference, -7%; 95% confidence interval [CI], -13% to -1%) and specificity (85% versus 92%; difference, -7%; 95% CI, -12% to -3%). A subanalysis of 43 slides evaluated by each CellScope reader found substantial interreader reliability (custom-weighted kappa, 0.65) and variable intrareader reliability (custom-weighted kappa, 0.11 versus 0.48). CellScope offers promise for expanding microscopy services. Future studies should evaluate the device when operated by health workers in low-resource settings, the feasibility of image transmission and analysis by experienced microscopists, and the accuracy of automated image analysis algorithms.

The purpose of this study was to describe application and machine accuracy for a new computed tomography (CT) guided, frameless, stereotactic brain biopsy system in dogs. Heads from ten canine cadavers were secured to a bite-plate with six attached fiducial markers and imaged using CT. Fiducialized CT images were imported into stereotactic software and spherical phantom lesions between 3.9 and 5.5 mm in diameter were created in six locations. Infrared cameras and reflective markers were used to register fiducials to the reconstructed image set. Coordinates in the X, Y, and Z planes were identified for each lesion center. Iohexol (1.5 μl of 240 mgI/ml) was injected into the center of each lesion and CT scans were repeated. Pre- and postinjection CT images for each cadaver were fused using the system software. Application accuracy was calculated using the center of each phantom lesion and the center of each injected contrast material location. Machine accuracy was calculated using a phantom with known distances between four fixed points in the X, Y, and Z planes. Mean application accuracy in the first 5 cadavers was 4.3 mm (95% confidence interval [CI] 2.9-4.3 mm) and in the second 5 cadavers was 2.9 mm (95% CI 2-3.9 mm). The more superficial lesions were targeted significantly less accurately than the deeper lesions (P = 0.0183). Median machine accuracy was 0.1 mm and the range was 0.1-0.2 mm. Findings supported use of the new biopsy system for canine brain lesions >3.9 mm in diameter.

Although increasing adiposity is usually associated with adipose tissue infiltration by inflammatory cells and systemic insulin resistance, Stolarczyk et al. (2013) report in this issue that mice deficient in the T-box transcription factor, T-bet, display a dissociated phenotype with enhanced perigonadal adipose but enhanced insulin sensitivity.

Atrial fibrillation (AF) is the most common arrhythmia worldwide, and it has a significant effect on morbidity and mortality. It is a significant risk factor for stroke and peripheral embolization, and it has an effect on cardiac function. Despite widespread interest and extensive research on this topic, our understanding of the etiology and pathogenesis of this disease process is still incomplete. As a result, there are no set primary preventive strategies in place apart from general cardiology risk factor prevention goals. It seems intuitive that a better understanding of the risk factors for AF would better prepare medical professionals to initially prevent or subsequently treat these patients. In this article, we discuss widely established risk factors for AF and explore newer risk factors currently being investigated that may have implications in the primary prevention of AF. For this review, we conducted a search of PubMed and used the following search terms (or a combination of terms): atrial fibrillation, metabolic syndrome, obesity, dyslipidemia, hypertension, type 2 diabetes mellitus, omega-3 fatty acids, vitamin D, exercise toxicity, alcohol abuse, and treatment. We also used additional articles that were identified from the bibliographies of the retrieved articles to examine the published evidence for the risk factors of AF.

GOALS AND BACKGROUND

Besides United States population born between 1945 and 1965, screening for hepatitis C virus (HCV) is not recommended for the general US population. However, HCV may be more prevalent in certain subgroups and screening may be warranted. The goal of this study was to examine the proportion of HCV in a large sample of community Asian American patients presenting for non-liver-related complaints.

STUDY

We conducted a cross-sectional study of 1246 patients tested for hepatitis C virus antibodies (anti-HCV) referred to 2 gastroenterology clinics for non-liver-related gastrointestinal reasons between January 2001 and February 2011. We determined HCV status and patient history via electronic medical record review.

RESULTS

Of the 1246 study patients tested for anti-HCV, the majority were Asian (81.4%) and 29 Asian patients (2.9%) had positive anti-HCV. HCV proportion in the remaining 232 non-Asians (non-Hispanic whites and Hispanics) was 1.7%. Asians with positive anti-HCV were more likely to have had blood transfusions (31.0% vs. 6.6%, P<0.0001) or acupuncture (10.3% vs. 1.5%, P<0.0001). Of the 976 Asian patients with hepatitis B surface antigen testing, 38 (3.9%) also had detectable hepatitis B surface antigen.

CONCLUSIONS

Among patients seen at community gastroenterology clinics for non-liver-related reasons, HCV proportion was 1.7% for non-Asians and 2.9% for Asians. Screening for HCV should be offered to high-risk patients presenting to gastroenterology clinics with unrelated gastrointestinal complaints.