The impact of neurobehavioral features on medication adherence in HIV: evidence from longitudinal models.

Effective antiretroviral therapy has led to substantial improvements in health-related outcomes among individuals with HIV. Despite advances in HIV pharmacotherapy, suboptimal medication adherence remains a significant barrier to successful treatment. Although several factors have been associated with medication adherence in the extant literature, study assessing the effects of some of the neurobehavioral features specific to HIV has been limited. Moreover, although there is a growing body of literature measuring medication adherence in HIV prospectively, few employ advanced statistical methodologies suited to handle advanced models with multiple predictors that would strengthen our understanding of medication adherence trajectories in HIV. This study sought to integrate traditionally assessed predictors of medication adherence with neurobehavioral features of HIV in a longitudinal study of medication adherence to combined antiretroviral therapy (cART). The current study used multilevel modeling to examine a wide arrangement of categories of factors - demographic, medication related, psychosocial, and neurobehavioral - on medication adherence. The sample consisted of 235 HIV+ individuals whose medication adherence was monitored over the course of six months using electronic monitoring devices. After controlling for the effects of demographic, medication, and psychosocial factors, neurobehavioral features added predictive validity to the model. In the final model, simultaneously controlling for the effects of each of the predictors within all the categories, age, self-efficacy, executive functioning, apathy, and frequency of stimulant use emerged as unique individual predictors of average medication adherence across the 6-month study. Self-efficacy and irritability predicted changes in medication adherence over time. Adherence behavior is multidetermined. Adequate assessment of these factors, combined with timely intervention, appears to be warranted in order to boost adherence rates.

The role of HIV infection, cognition, and depression in risky decision-making.

The authors examined the impact of HIV, cognitive dysfunction, and depression on decision-making. HIV+ (N=100) and HIV- (N=26) participants were administered a comprehensive neuropsychological battery, a modified version of the Iowa Gambling Task, and a measure of depressive symptoms. HIV+ participants demonstrated more difficulties in learning the gambling task than did HIV- participants. Executive functioning and depression emerged as strong predictors of gambling task performance. Depression partially mediated the relationship between executive functioning and gambling performance. Our findings suggest that HIV infection, executive dysfunction, and depression place individuals at risk for poor decision-making.

Pomegranate Supplementation Protects against Memory Dysfunction after Heart Surgery: A Pilot Study.

Memory dysfunction is a common complaint following heart surgery and may be related to a diffuse ischemic state induced by microemboli dislodged during the procedure. Ischemia can induce damage by a number of mechanisms, including oxidative stress. Because pomegranates contain a variety of polyphenols with antioxidant and other potentially beneficial effects, we tested whether supplementation with a pomegranate extract before and after heart surgery could protect against postoperative cognitive dysfunction. Patients undergoing elective coronary artery bypass graft and/or valve surgery were given either 2 g of pomegranate extract (in 2 POMx pills) or placebo (pills containing no pomegranate ingredients) per day from one week before surgery to 6 weeks after surgery. The patients were also administered a battery of neuropsychological tests to assess memory function at 1 week before surgery (baseline), 2 weeks after surgery, and 6 weeks after surgery. The placebo group had significant deficits in postsurgery memory retention, and the pomegranate treatment not only protected against this effect, but also actually improved memory retention performance for up to 6 weeks after surgery as compared to presurgery baseline performance.

The aggregate effects of multiple comorbid risk factors on cognition among HIV-infected individuals.

This study developed and then cross-validated a novel weighting algorithm based on multiple comorbid risk factors (stimulant use, vascular disease, hepatitis C, HIV disease severity, cognitive reserve) to predict cognitive functioning among 366 HIV+ adults. The resultant "risk severity score" was used to differentially weight, as a function of age, the impact and magnitude of multiple risk factors on cognition. Among older adults (≥50 years) the risk severity index was differentially predictive of learning/memory and verbal fluency, whereas among younger adults it was linked to working memory and executive function. Cognitive reserve was found to be the most robust predictor of neurocognition.

Apolipoprotein-E genotype and human immunodeficiency virus-associated neurocognitive disorder: the modulating effects of older age and disease severity.

BACKGROUND: The apolipoprotein-E (APOE) ε4 allele is a risk factor for vascular dementia and Alzheimer's disease. Recent studies are equivocal with regards to whether or not the ε4 allele confers increased risk for the development of human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND), but suggest that age and/or disease severity may be modulating factors. The aim of this study was to assess the interactions and contributions of APOE genotype, age, and HIV disease severity as risk factors for HAND in HIV-infected adults. METHODS: Participants were 259 HIV-positive individuals who underwent APOE genotyping, a standardized neurological evaluation, a comprehensive neuropsychological evaluation, and laboratory testing. RESULTS: Older ε4 carriers showed a higher frequency of HAND compared with age-matched non-ε4 carriers. Analysis by discrete neurocognitive domain revealed that advanced age modulated the effect of the ε4 allele, such that older ε4 allele carriers showed reduced executive functioning and information processing speed. Exploratory analyses assessing the relationship between ε4 and disease severity in the overall sample revealed that disease severity modulated the effect of the ε4 allele on cognition. Lower absolute CD4+ cell count among ε4 allele carriers was associated with poorer working memory ability. CONCLUSION: Advancing age and degree of immunosuppression may influence the association between APOE ε4 allele status and HAND. These two factors need to be taken into account in future research.

Differential predictors of medication adherence in HIV: findings from a sample of African American and Caucasian HIV-positive drug-using adults.

Modest or even occasional nonadherence to combined antiretroviral therapy (cART) can result in adverse clinical outcomes. African Americans demonstrate lower rates of adherence than Caucasians or Latinos. Identifying factors that influence medication adherence among African Americans is a critical step toward reducing HIV/AIDS disease progression and mortality. In a sample of 181 African American (n=144) and Caucasian (n=37) HIV-positive drug-using individuals [age (M=42.31; SD=6.6) education (M=13.41; SD=2.1)], we examined the influence of baseline drug use, literacy, neurocognition, depression, treatment-specific social support, and patient satisfaction with health care provider on medication adherence averaged over the course of 6 months (study dates 2002-2006). Our findings suggest differential baseline predictors of medication adherence for African Americans and Caucasians, such that patient satisfaction with provider was the strongest predictor of follow-up medication adherence for African Americans whereas for Caucasians depressive symptoms and treatment-specific social support were predictive of medication adherence (after controlling for duration of drug use).