Performance of Methods to Estimate Low-Density Lipoprotein Cholesterol in Women With and Without HIV Infection.

BACKGROUND: Low-density lipoprotein cholesterol (LDL-C) is estimated from total cholesterol, high-density lipoprotein cholesterol and triglycerides using predefined equations which assume fixed or varying relationships between these parameters and may underestimate or overestimate LDL-C. Data on the performance of these equations in persons with HIV are limited. We sought to investigate the utility of the 3 most widely used methods (Friedewald, Hopkins, and the recently proposed NIH equation) to predict LDL-C in persons with HIV. METHODS: We identified 7397 direct LDL-C (5219 HIV, 2127 uninfected controls, 51 seroconvertors) measurements in the Women's Interagency HIV Study, and used the 3 equations (Friedewald, Hopkins, and NIH) to calculate LDL-C. We compared the performance of the 3 equations using root mean square error and coefficient of determination (R2). RESULTS: Overall, the Friedewald equation had the best performance characteristics, outperforming Hopkins and NIH methods with lower root mean square error and higher R2 at lower triglyceride levels. However, this association did not hold true at higher triglyceride levels (quartiles 3 and 4), whereas the Hopkins equation had better performance characteristics in quartile 3, none of the 3 equations were optimal in quartile 4. After adjusting for fasting status and triglycerides levels, HIV+ had larger mean difference compared with directly measured LDL using all 3 methods. CONCLUSIONS: All 3 methods have lower accuracy in HIV+ vs HIV- women, even after adjusting for triglyceride levels and fasting status. Further research should focus on identifying methods to estimate LDL-C in HIV.

The effects of HIV and smoking on aortic and splenic inflammation.

OBJECTIVE: To determine the association of smoking and HIV status with tissue-specific inflammation measured by flurodeoxyglucose positron emission tomography (PET). DESIGN: A cross-sectional study. METHODS: We prospectively enrolled 55 HIV study participants on stable antiretroviral therapy and 19 age-matched HIV-uninfected controls without known cardiovascular disease. We measured aortic target-to-background ratio (TBR) and spleen standardized uptake values (SUV) 3-h post-FDG, and used regression models to examine the independent association of HIV and smoking status with PET variables. RESULTS: Overall, median (interquartile range) age was 50 (42-55) years; 81% were men and 54% were current smokers (median 0.5 packs/day, 25 pack-years]. Median CD4 of HIV study participants was 690 cells/ml and 88% had HIV-1 RNA less than 20 c/ml; 43% were on a protease inhibitor. In fully adjusted models, HIV was associated with 0.16 (95% confidence interval 0.04-0.27; P = 0.009) higher aortic TBR, whereas current smoking was marginally associated with a lower TBR [-0.11 (95% confidence interval -0.23 to 0.01); P = 0.07]. Spleen SUVmean was not associated with HIV or smoking, and there was no evidence for an HIVsmoking interaction for aortic or spleen models (all P > 0.1). Spleen SUVmean was positively associated with biomarkers of inflammation and coronary artery calcium, but adjustment for traditional cardiovascular disease risk factors attenuated these relationships. CONCLUSION: The FDG-PET study of HIV study participants suggests that HIV is associated with increased aortic inflammation independent of traditional risk factors, but smoking is not. Future studies should continue to explore the mechanistic roles of smoking and inflammation at various stages of clinical and subclinical atherosclerotic vascular disease in HIV.

Cybersupport: empowering asthma caregivers.

In the United States, an estimated 6.5 million children have asthma (Akinbami, 2005). Due to the chronic and unpredictable nature of asthma, the condition places excessive demands on the primary caregiver. The complexity of asthma management has required parents to take increased responsibility for the assessment and treatment of their child's asthma (Dickinson & Dignam, 2002). Many families are turning to the Internet for information and support. The purpose of this study was to gain insight into the "lived" experiences of an online asthma caregivers support group. Archived messages posted to an online discussion list were analyzed using phenomenological thematic analysis. Five themes emerged providing insight into the meaning of caregiving and the provision of social support. Online support narratives provide a unique way to gain insight and understanding of the experiences of mother's enacting the caregiver role. Understanding the everyday lives of asthma caregivers can help nurses and other health care providers better meet caregiver needs.