Percolation model for structural phase transitions in Li1−x_{1-x}Hx_xIO3_3 mixed crystals

A percolation model is proposed to explain the structural phase transitions found in Li$_{1-x}$H$_x$IO$_3$ mixed crystals as a function of the concentration parameter $x$. The percolation thresholds are obtained from Monte Carlo simulations on the specific lattices occupied by lithium atoms and hydrogen bonds. The theoretical results strongly suggest that percolating lithium vacancies and hydrogen bonds are indeed responsible for the solid solution observed in the experimental range $0.22 < x < 0.36$.Comment: 4 pages, 2 figure

Mind the Gap: Hospitalizations from Multiple Sources in a Longitudinal Study

Background Medicare claims and prospective studies with self-reported utilization are important sources of hospitalization data for epidemiologic and outcomes research. Objectives To assess the concordance of Medicare claims merged with interview-based surveillance data to determine factors associated with source completeness. Methods The Atherosclerosis Risk in Communities (ARIC) study recruited 15,792 cohort participants aged 45 to 64 years in the period 1987 to 1989 from four communities. Hospitalization records obtained through cohort report and hospital record abstraction were matched to Medicare inpatient records (MedPAR) from 2006 to 2011. Factors associated with concordance were assessed graphically and using multinomial logit regression. Results Among fee-for-service enrollees, MedPAR and ARIC hospitalizations matched approximately 67% of the time. For Medicare Advantage enrollees, completeness increased after initiation of hospital financial incentives in 2008 to submit shadow bills for Medicare Advantage enrollees. Concordance varied by geographic site, age, veteran status, proximity to death, study attrition, and whether hospitalizations were within ARIC catchment areas. Conclusions ARIC and MedPAR records had good concordance among fee-for-service enrollees, but many hospitalizations were available from only one source. MedPAR hospital records may be missing for veterans or observation stays. Maintaining study participation increases stay completeness, but new sources such as electronic health records may be more efficient than surveillance for mobile elderly populations

Position matters: Validation of medicare hospital claims for myocardial infarction against medical record review in the atherosclerosis risk in communities study

Purpose: The objectives of this study were to investigate sensitivity and specificity of myocardial infarction (MI) case definitions using multiple discharge code positions and multiple diagnosis codes when comparing administrative data to hospital surveillance data. Methods: Hospital surveillance data for ARIC Study cohort participants with matching participant ID and service dates to Centers for Medicare and Medicaid Services (CMS) hospitalization records for hospitalizations occurring between 2001 and 2013 were included in this study. Classification of Definite or Probable MI from ARIC medical record review defined “gold standard” comparison for validation measures. In primary analyses, an MI was defined with ICD9 code 410 from CMS records. Secondary analyses defined MI using code 410 in combination with additional codes. Results: A total of 25 549 hospitalization records met study criteria. In primary analysis, specificity was at least 0.98 for all CMS definitions by discharge code position. Sensitivity ranged from 0.48 for primary position only to 0.63 when definition included any discharge code position. The sensitivity of definitions including codes 410 and 411.1 were higher than sensitivity observed when using code 410 alone. Specificity of these alternate definitions was higher for women (0.98) than for men (0.96). Conclusion: Algorithms that rely exclusively on primary discharge code position will miss approximately 50% of all MI cases due to low sensitivity of this definition. We recommend defining MI by code 410 in any of first 5 discharge code positions overall and by codes 410 and 411.1 in any of first 3 positions for sensitivity analyses of women

Predictors of Medication Adherence in the Elderly: The Role of Mental Health

The aging population routinely has comorbid conditions requiring complicated medication regimens, yet nonadherence can preclude optimal outcomes. This study explored the association of adherence in the elderly with demographic, socioeconomic, and disease burden measures. Data were from the fifth visit (2011-2013) for 6,538 participants in the Atherosclerosis Risk in Communities Study, conducted in four communities. The Morisky–Green–Levine Scale measured self-reported adherence. Forty percent of respondents indicated some nonadherence, primarily due to poor memory. Logit regression showed, surprisingly, that persons with low reading ability were more likely to report being adherent. Better self-reported physical or mental health both predicted better adherence, but the magnitude of the association was greater for mental than for physical health. Compared with persons with normal or severely impaired cognition, mild cognitive impairment was associated with lower adherence. Attention to mental health measures in clinical settings could provide opportunities for improving medication adherence

Antihypertensive adherence and outcomes among community-dwelling Medicare beneficiaries: the Atherosclerosis Risk in Communities Study

Rationale, aims, and objectives: Despite proven benefits for reducing incidence of major cardiac events, antihypertensive drug therapy remains underutilized in the United States. This analysis assesses antihypertensive drug adherence, utilization predictors, and associations between adherence and outcomes (a composite of cardiovascular events, Medicare inpatient payments, and inpatient days). Methods: The sample consisted of Atherosclerosis Risk in Communities Study cohort participants reporting hypertension without prevalent cardiovascular disease during 2006 to 2007 annual follow-up calls. Atherosclerosis Risk in Communities records were linked to Medicare claims through 2012. Antihypertensive medication adherence was measured as more than 80% proportion days covered by using Medicare Part D claims. Standard and hierarchical regression models were used to evaluate adjusted associations between person characteristics and adherence and between adherence and outcomes. Results: Among 1826 hypertensive participants with Part D coverage, 31.5% had no antihypertensive class with more than 80% proportion days covered in the 3 months preceding the report of hypertension in 2006 to 2007. After adjustment for confounders, positive predictors of use included female gender and diabetes; negative predictors were African-American race and current smoking. Adjusted association between receiving no therapy and a composite endpoint of cardiovascular outcomes through 2012 was not statistically significant (hazard ratio: 0.93; 95% confidence interval: 0.72, 1.22) nor was the adjusted association with Medicare inpatient days or payments (incremental difference at 48 months in payments: $1217; 95$2030, $4463). Conclusions: Despite having medical and prescription coverage, nearly a third of hypertensive participants were not adherent to antihypertensive drug therapy. Differences in clinical outcomes associated with nonadherence, though not statistically significant, were consistent with results from randomized trials. The approach provides a model framework for rigorous assessment of detailed data that are increasingly available through emerging sources

Heart Failure and Cognitive Impairment in the Atherosclerosis Risk in Communities (ARIC) Study

Background: Previous studies suggest that heart failure (HF) is an independent risk factor for cognitive decline. A better understanding of the relationship between HF, cognitive status, and cognitive decline in a community-based sample may help clinicians understand disease risk. Objective: To examine whether persons with HF have a higher prevalence of cognitive impairment and whether persons developing HF have more rapid cognitive decline. Design: This observational cohort study of American adults in the Atherosclerosis Risk in Communities (ARIC) study has two components: cross-sectional analysis examining the association between prevalent HF and cognition using multinomial logistic regression, and change over time analysis detailing the association between incident HF and change in cognition over 15 years. Participants: Among visit 5 (2011–2013) participants (median age 75 years), 6495 had neurocognitive information available for cross-sectional analysis. Change over time analysis examined the 5414 participants who had cognitive scores and no prevalent HF at visit 4 (1996–1998). Measurements: The primary outcome was cognitive status, classified as normal, mild cognitive impairment [MCI], and dementia on the basis of standardized cognitive tests (delayed word recall, word fluency, and digit symbol substitution). Cognitive change was examined over a 15-year period. Control variables included socio-demographic, vascular, and smoking/drinking measures. Results: At visit 5, participants with HF had a higher prevalence of dementia (adjusted relative risk ratio [RRR] = 1.60 [95% CI 1.13, 2.25]) and MCI (RRR = 1.36 [1.12, 1.64]) than those without HF. A decline in cognition between visits 4 and 5 was − 0.07 standard deviation units [− 0.13, − 0.01] greater among persons who developed HF compared to those who did not. Results did not differ by ejection fraction. Conclusion: HF is associated with neurocognitive dysfunction and decline independent of other co-morbid conditions. Further study is needed to determine the underlying pathophysiology

Contribution of medications and risk factors to QTc interval lengthening in the atherosclerosis risk in communities (ARIC) study

Rationale, aims, and objectives: Prolongation of the corrected QT (QTc) interval is associated with increased morbidity and mortality. The association between QTc interval–prolonging medications (QTPMs) and risk factors with magnitude of QTc interval lengthening is unknown. We examined the contribution of risk factors alone and in combination with QTPMs to QTc interval lengthening. Method: The Atherosclerosis Risk in Communities study assessed 15 792 participants with a resting, standard 12-lead electrocardiogram and ≥1 measure of QTc interval over 4 examinations at 3-year intervals (1987-1998). From 54 638 person-visits, we excluded participants with QRS ≥ 120 milliseconds (n = 2333 person-visits). We corrected the QT interval using the Bazett and Framingham formulas. We examined QTc lengthening using linear regression for 36 602 person-visit observations for 14 160 cohort members controlling for age ≥ 65 years, female sex, left ventricular hypertrophy, QTc > 500 milliseconds at the prior visit, and CredibleMeds categorized QTPMs (Known, Possible, or Conditional risk). We corrected standard errors for repeat observations per person. Results: Eighty percent of person-visits had at least one risk factor for QTc lengthening. Use of QTPMs increased over the 4 visits from 8% to 17%. Among persons not using QTPMs, history of prolonged QTc interval and female sex were associated with the greatest QTc lengthening, 39 and 12 milliseconds, respectively. In the absence of risk factors, Known QTPMs and ≥2 QTPMs were associated with modest but greater QTc lengthening than Possible or Conditional QTPMs. In the presence of risk factors, ≥2 QTPM further increased QTc lengthening. In combination with risk factors, the association of all QTPM categories with QTc lengthening was greater than QTPMs alone. Conclusion: Risk factors, particularly female sex and history of prolonged QTc interval, have stronger associations with QTc interval lengthening than any QTPM category alone. All QTPM categories augmented QTc interval lengthening associated with risk factors

Calotropis procera: um levantamento preliminar sobre as suas capacidades de fitoextração no Brasil

Calotropis procera (Apocynaceae) is a non-native species that has its origin in Africa and Asia, but was introduced into the northeastern region of Brazil in the beginning of last century. In some areas, the dry biomass of C. procera is used as animal feed. However, previous studies indicated that the species is capable of accumulating many chemical elements. On the other hand, it could also mean that this species may be used for phytoremediation. Hence, we used neutron activation analysis, k0-method, to test the capability of the leaves of C. procera to accumulate trace elements. The study was carried out in two distinct areas (polluted and non-polluted) in the State of Pernambuco, Brazil. Our results indicate that new elements can be added to the list of elements taken up by C. procera, thus contributing to the understanding of the biology of this plant species as an accumulator of trace elements. Some elements, such as Ba and Sr, have higher concentrations in the non-polluted areas than in polluted areas. Thus, the presence of many trace elements in C. procera indicates that its use as animal feed should be viewed with extreme caution. However low levels of these trace elements in C. procera do not indicate that this species is a hyper-accumulator plant.Key words: phytoremediation, biological invasion, invasive species, Pernambuco.Calotropis procera (Apocynaceae) é uma espécie exótica originária da África e Ásia tropical, introduzida na região nordeste do Brasil no início do século passado. Em algumas regiões do Brasil e do mundo, a biomassa seca de C. procera é utilizada como alimento forrageiro para animais. Entretanto, muitos estudos indicam que essa espécie é capaz de acumular diversos elementos químicos. Isso pode significar que a espécie também pode ser utilizada em processos de fitorremediação. Dessa forma, foi realizada uma análise de ativação neutrônica, método k0, para testar a capacidade das folhas de C. procera acumularem elementos-traço. O estudo foi realizado em duas áreas distintas (poluídas e não poluídas) no estado de Pernambuco, Brasil. Nossos resultados indicam que novos elementos podem ser adicionados à lista de elementos-traço absorvidos por C. procera, contribuindo para o entendimento da biologia dessa espécie como acumuladora de elementos-traço. Alguns destes, tais como Ba e Sr, ocorreram em maiores concentrações em áreas não-poluídas em comparação com áreas poluídas. Dessa forma, o uso de C. procera como ração animal deve ser vista com extrema cautela. Entretanto, as baixas concentrações desses elementos-traço não sugerem que C. procera seja uma hiperacumuladora.Palavras-chave: fitorremediação, invasão biológica, espécie invasora, Pernambuco

Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies