<p>Inter-individual variability in efavirenz (EFV) pharmacokinetics and dynamics is dominantly driven by the polymorphism in cytochrome P450 (CYP) isoenzyme 2B6 516G&gt;T. We hypothesized that additional CYP polymorphisms mediate the relationship between CYP2B6 516G&gt;T, EFV metabolism, and clinical events. We investigated 21 SNPs in 814 HIV-infected adults initiating EFV-based therapy in Botswana for population pharmacokinetics, CNS toxicities, and treatment outcomes. Two SNPs (rs28399499 and rs28399433) showed reduced apparent oral EFV clearance. Four SNPs (rs2279345, rs4803417, rs4802101, and rs61663607) showed extensive clearance. Composite CYP2B-mediated EFV metabolism was significantly associated with CNS toxicity (p = 0.04), with extensive metabolizers reporting more and slow and very slow metabolizers reporting less toxicity after 1 month compared to intermediate metabolizers. Composite CYP2B6 metabolism was not associated with composite early treatment failure. In conclusion, our data suggest that CNS-related toxicities might not be solely the result of super-therapeutic parent EFV concentrations in HIV-infected individuals in patients of African ancestry.</p>

<p><strong>OBJECTIVES: </strong>To determine the association between cytochrome p450 2B6 genotypes and efavirenz-based HIV treatment outcomes.</p>

<p><strong>DESIGN: </strong>Observational cohort study of HIV infected adults initiating efavirenz-based regimens in Botswana.</p>

<p><strong>METHODS: </strong>The primary endpoint was a composite of death or loss to care or HIV RNA&gt;25 copies/ml at 6 months. CYP2B6 516G&gt;T and 983T&gt;C genotyping was done with Taqman Open Array platform. Adverse experiences were measured using the Subject Experience Questionnaire. Metabolism alleles were included in logistic regression models of the composite endpoint.</p>

<p><strong>RESULTS: </strong>801 individuals included 406 (51%) males, median age 37 years, median baseline CD4 count 195 cells/mm and plasma HIV RNA 4·9 log10 copies/ml. 277 (35%) reached the endpoint including 34 (4%) deaths, 151 (19%) lost to care, and 92 (11%) with plasma HIV RNA&gt;25 copies/ml. Metabolism variant alleles were common with 396 (49%) intermediate and 192 (24%) slow metabolizers. There were no statistically significant associations between metabolism and treatment endpoints. However, slower metabolism was associated with fewer adverse experiences.</p>

<p><strong>CONCLUSIONS: </strong>Slow metabolism alleles were associated with lower efavirenz clearance but not any of the treatment endpoints. Slow efavirenz metabolism did not exacerbate CNS toxicity. These results should allay concern that slow efavirenz metabolism adversely impacts individuals in sub-Saharan African settings in which these alleles are common.</p>

<p><strong>BACKGROUND: </strong>CYPB2B6 polymorphisms that affect efavirenz (EFV) concentrations are common, but the effect of this polymorphism on HIV virologic failure in clinical practice settings has not fully been elucidated. Our objective was to investigate the relationship between the CYPB2B6 516G&gt;T genotype and late virologic failure in patients treated with EFV in Gaborone, Botswana.</p>

<p><strong>SETTING: </strong>We performed a case-control study that included 1,338 HIV-infected black Batswana on EFV-based antiretroviral therapy (ART). Patients were approached for enrollment during regular visits at one of the outpatient HIV clinics between 7/2013-4/2014.</p>

<p><strong>METHODS: </strong>Cases experienced late HIV failure, defined as plasma HIV RNA &gt;1000 copies/mL after maintaining viral suppression (&lt;400 copies/mL) for at least 6 months. For each case, a total of 4 control patients were randomly sampled from the same population. Controls had plasma HIV RNA &lt;400 copies/mL on ART for at least 6 months. Logistic regression was used to determine the adjusted odds of late HIV failure by 516G&gt;T genotype.</p>

<p><strong>RESULTS: </strong>After adjustment for the confounding variables age and CD4 count, the CYPB2B6 516 T-allele was protective against late HIV virologic breakthrough, adjusted OR 0.70; 95%CI 0.50-0.97.</p>

<p><strong>CONCLUSION: </strong>The CYPB2B6 516 T-allele was protective against late virologic breakthrough in patients with initial (6 month) HIV RNA suppression on EFV-based ART. Future studies are needed to assess long-term viral benefits of identifying and offering EFV containing ART to black African HIV-infected patients with CYPB2B6 T-alleles, especially given the wider availability of a single pill EFV in this setting.</p>

<p><strong>BACKGROUND: </strong>Pneumonia is the leading cause of death in children under age of 5 years worldwide. The role of vitamin D in respiratory infections including pneumonia is unclear; therefore, we aimed to determine if children with lower respiratory tract infections had low serum 25-hydroxyvitamin D3 .</p>

<p><strong>METHODS: </strong>We performed a case-control study of children ages 3-60 months from the Guatemala City metropolitan area, hospitalized with community-acquired pneumonia between September and December 2012. Controls were selected from the well-baby/care immunization clinics serving the population from which cases emerged. We analyzed serum 25-hydroxyvitamin D3 levels and conducted parental interviews to assess subject age, sex, race, feeding type, vitamin D supplementation, frequency of sun exposure, and maternal education. Height and weight were ascertained from medical records. Complete information was available for 70 (83%) of 84 eligible cases and 68 (60%) of 113 eligible controls.</p>

<p><strong>RESULTS: </strong>The median (IQR) serum 25-hydroxyvitamin D3 concentration for cases was 23.2 ng/ml (14.4-29.9) compared to 27.5 ng/ml (21.4-32.3) in controls (P = 0.006). Multiple regression analysis using an a priori cut-point for vitamin D of &lt;20 ng/ml showed that children with lower respiratory tract infections were more likely to have low 25-hydroxyvitamin D3 levels than controls (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.2, P = 0.02).</p>

<p><strong>CONCLUSIONS: </strong>Children with lower respiratory tract infections in Guatemala had low 25-hydroxyvitamin D3 levels. Pediatr Pulmonol. © 2016 Wiley Periodicals, Inc.</p>

<p><strong>OBJECTIVE: </strong>The authors sought to determine whether use of methylphenidate in adults is associated with elevated rates of serious cardiovascular events compared with rates in nonusers.</p>

<p><strong>METHOD: </strong>This was a cohort study of new users of methylphenidate based on administrative data from a five-state Medicaid database and a 14-state commercial insurance database. All new methylphenidate users with at least 180 days of prior enrollment were identified. Users were matched on data source, state, sex, and age to as many as four comparison subjects who did not use methylphenidate, amphetamines, or atomoxetine. A total of 43,999 new methylphenidate users were identified and matched to 175,955 nonusers. Events of primary interest were 1) sudden death or ventricular arrhythmia, 2) stroke, 3) myocardial infarction, and 4) a composite endpoint of stroke or myocardial infarction.</p>

<p><strong>RESULTS: </strong>The age-standardized incidence rate per 1,000 person-years of sudden death or ventricular arrhythmia was 2.17 (95% CI=1.63-2.83) in methylphenidate users and 0.98 (95% CI=0.89-1.08) in nonusers, for an adjusted hazard ratio of 1.84 (95% CI=1.33-2.55). Dosage was inversely associated with risk. Adjusted hazard ratios for stroke, myocardial infarction, and the composite endpoint of stroke or myocardial infarction did not differ statistically from 1.</p>

<p><strong>CONCLUSIONS: </strong>Although initiation of methylphenidate was associated with a 1.8-fold increase in risk of sudden death or ventricular arrhythmia, the lack of a dose-response relationship suggests that this association may not be a causal one.</p>

<p><strong>MAIN OBJECTIVE: </strong>To compare the incidence rates of serious cardiovascular events in adult initiators of amphetamines or atomoxetine to rates in non-users.</p>

<p><strong>METHODS: </strong>This was a retrospective cohort study of new amphetamines (n=38,586) or atomoxetine (n=20,995) users. Each medication user was matched to up to four non-users on age, gender, data source, and state (n=238,183). The following events were primary outcomes of interest 1) sudden death or ventricular arrhythmia, 2) stroke, 3) myocardial infarction, 4) a composite endpoint of stroke or myocardial infarction. Cox proportional hazard regression was used to calculate propensity-adjusted hazard ratios for amphetamines versus matched non-users and atomoxetine versus matched non-users, with intracluster dependence within matched sets accounted for using a robust sandwich estimator.</p>

<p><strong>RESULTS: </strong>The propensity-score adjusted hazard ratio for amphetamines use versus non-use was 1.18 (95% CI: 0.55-2.54) for sudden death/ventricular arrhythmia, 0.80 (95% CI: 0.44-1.47) for stroke, 0.75 (95% CI: 0.42-1.35) for myocardial infarction, and 0.78 (95% CI: 0.51-1.19) for stroke/myocardial infarction. The propensity-score adjusted hazard ratio for atomoxetine use versus non-use was 0.41 (95% CI: 0.10-1.75) for sudden death/ventricular arrhythmia, 1.30 (95% CI: 0.52-3.29) for stroke, 0.56 (95% CI: 0.16-2.00) for myocardial infarction, and 0.92 (95% CI: 0.44-1.92) for stroke/myocardial infarction.</p>

<p><strong>CONCLUSIONS: </strong>Initiation of amphetamines or atomoxetine was not associated with an elevated risk of serious cardiovascular events. However, some of the confidence intervals do not exclude modest elevated risks, e.g. for sudden death/ventricular arrhythmia.</p>