Akaike's information criterion in generalized estimating equations

The first-order Markov conditional linear expectation approach for analysis of longitudinal data

We consider longitudinal discrete data that may be unequally spaced in time and may exhibit overdispersion, so that the variance of the outcome variable is inflated relative to its assumed distribution. We implement an approach that extends generalized linear models for analysis of longitudinal data and is likelihood based, in contrast to generalized estimating equations (GEE) that are semiparametric. The method assumes independence between subjects; first-order antedependence within subjects; exponential family distributions for the first outcome on each subject and for the subsequent conditional distributions; and linearity of the expectations of the conditional distributions. We demonstrate application of the method in an analysis of seizure counts and in a study to evaluate the performance of transplant centers. Simulations for both studies demonstrate the benefits of the proposed likelihood based approach; however, they also demonstrate better than anticipated performance for GEE.

Comparison of Radiomic Models Based on Low-Dose and Standard-Dose CT for Prediction of Adenocarcinomas and Benign Lesions in Solid Pulmonary Nodules

Objectives

This study aimed to develop radiomic models based on low-dose CT (LDCT) and standard-dose CT to distinguish adenocarcinomas from benign lesions in patients with solid solitary pulmonary nodules and compare the performance among these radiomic models and Lung CT Screening Reporting and Data System (Lung-RADS). The reproducibility of radiomic features between LDCT and standard-dose CT were also evaluated.

Methods

A total of 141 consecutive pathologically confirmed solid solitary pulmonary nodules were enrolled including 50 adenocarcinomas and 48 benign nodules in primary cohort and 22 adenocarcinomas and 21 benign nodules in validation cohort. LDCT and standard-dose CT scans were conducted using same acquisition parameters and reconstruction method except for radiation dose. All nodules were automatically segmented and 104 original radiomic features were extracted. The concordance correlation coefficient was used to quantify reproducibility of radiomic features between LDCT and standard-dose CT. Radiomic features were selected to build radiomic signature, and clinical characteristics and radiomic signature were combined to develop radiomic nomogram for LDCT and standard-dose CT, respectively. The performance of radiomic models and Lung-RADS was assessed by area under curve (AUC) of receiver operating characteristic curve, sensitivity, and specificity.

Results

Shape and first order features, and neighboring gray tone difference matrix features were highly reproducible between LDCT and standard-dose CT. No significant differences of AUCs were found among radiomic signature and nomogram of LDCT and standard-dose CT in both primary and validation cohort (0.915 vs. 0.919 vs. 0.898 vs. 0.909 and 0.976 vs. 0.976 vs. 0.985 vs. 0.987, respectively). These radiomic models had higher specificity than Lung-RADS (all correct P < 0.05), while there were no significant differences of sensitivity between Lung-RADS and radiomic models.

Conclusions

The diagnostic performance of LDCT-based radiomic models to differentiate adenocarcinomas from benign lesions in solid pulmonary nodules were equivalent to that of standard-dose CT. The LDCT-based radiomic model with higher specificity and lower false-positive rate than Lung-RADS might help reduce overdiagnosis and overtreatment of solid pulmonary nodules in lung cancer screening.

Age-dependent Interactions Among Clinical Characteristics, Viral Loads and Disease Severity in Young Children With Respiratory Syncytial Virus Infection

BACKGROUND

Age-dependent differences in clinical presentation and viral loads in infants and young children with respiratory syncytial virus (RSV) infection, and their correlation with disease severity are poorly defined.

METHODS

Previously healthy children <2 years old with mild (outpatients) and severe (inpatients) RSV infection were enrolled and viral loads measured by polymerase chain reaction in nasopharyngeal swabs. Patients were stratified by age in 0-<3, 3-6 and >6-24 months, and multivariable analyses were performed to identify clinical and viral factors associated with severe disease.

RESULTS

From 2014 to 2018, we enrolled 534 children with RSV infection, 130 outpatients with mild RSV infection and 404 inpatients with severe RSV disease. Median duration of illness was 4 days for both groups, yet viral loads were higher in outpatients than in inpatients (P < 0.001). In bivariate analyses, wheezing was more frequent in outpatients of older age (>3 months) than in inpatients (P < 0.01), while fever was more common in inpatients than outpatients (P < 0.01) and its frequency increased with age. Adjusted analyses confirmed that increased work of breathing and fever were consistently associated with hospitalization irrespective of age, while wheezing in infants >3 months, and higher RSV loads in children >6-24 months were independently associated with reduced disease severity.

CONCLUSIONS

Age had a significant impact defining the interactions among viral loads, specific clinical manifestations and disease severity in children with RSV infection. These observations highlight the importance of patient stratification when evaluating interventions against RSV.

Estimating health state utilities in hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocyti.c lymphohistiocytosis (HLH) is a rare and severe disorder characterized by abnormal activation of the immune system. Primary HLH causes prolonged fever, spleen and liver enlargement, and organ dysfunction, usually in infancy and early childhood and is fatal if left untreated. As effective treatment options emerge, such as emapalumab-lzsg, Health Technology Assessment bodies around the world will assess them in terms of cost-effectiveness. This study was designed to estimate quality of life weights (utilities) for such analyses.

METHODS

Vignettes were developed describing HLH treatment related health states. Health states included active HLH, HLH plus neurological symptoms, receiving chemotherapy, undergoing stem cell transplant (SCT), graft versus host disease (GVHD), cure and end of life care. The vignettes were based on information from in depth interviews with clinical specialists; and qualitative research with four parents of children with primary HLH aged between 1 and 18 years old. The vignettes were then assessed in time trade off (TTO) interviews with members of the UK general public in one on one face to face interviews with trained, experienced interviewers. Preference data were analysed using the generalised estimating equations framework.

RESULTS

Detailed qualitative data captured the substantial burden of this disease for young children. One hundred participants completed the TTO interviews. The utility score for Active HLH was estimated as 0.32 (95% CI, 0.24 to 0.39). Values for other states were HLH plus neurological symptoms (0.27, 95%CI 0.18-0.35), receiving chemotherapy (0.26, 95%CI 0.17-0.34), undergoing SCT (0.18, 95%CI 0.07-0.28), GVHD (0.07, 95%CI -0.04-0.17), cure (0.72, 95%CI 0.67-0.77) and end of life care (- 0.17, 95%CI -0.27- -0.07).

CONCLUSIONS

This study has estimated utility weights for seven different HLH related states which are based on detailed input from carers and physicians and have good face validity. There are few other options for collecting these data in an ultra-rare setting.

The impact of structural changes to community nursing services on the rate of emergency hospital use of older people: a longitudinal ecological study of based on 140 primary care trusts in England

Purpose

In 2011, community nursing services were reorganised in England in response to a national policy initiative, but little is known about the impact of these changes. A total of three dominant approaches emerged: (1) integration of community nursing services with an acute hospital provider, (2) integration with a mental health provider and (3) the establishment of a stand-alone organisation, i.e. without structural integration. The authors explored how these approaches influenced the trends in emergency hospital admissions and bed day use for older people.

Design/methodology/approach

The methodology was a longitudinal ecological study using panel data over a ten-year period from April 2006 to March 2016. This study’s outcome measures were (1) emergency hospital admissions and (2) emergency hospital bed use, for people aged 65+ years in 140 primary care trusts (PCTs) in England.

Findings

The authors found no statistically significant difference in the post-intervention trend in emergency hospital admissions between those PCTS that integrated community nursing services with an acute care provider and those integrated with a mental health provider (IRR 0.999, 95% CI 0.986–1.013) or those that did not structurally integrate services (IRR 0.996, 95% CI 0.982–1.010). The authors similarly found no difference in the trends for emergency hospital bed use.

Research limitations/implications

PCTs were abolished in 2011 and replaced by clinical commissioning groups in 2013, but the functions remain.

Practical implications

The authors found no evidence that any one structural approach to the integration of community nursing services was superior in terms of reducing emergency hospital use in older people.

Originality/value

As far as the authors are aware, previous studies have not examined the impact of alternative approaches to integrating community nursing services on healthcare use.

Continuity in general practice and hospitalization patterns: an observational study

BACKGROUND

High continuity of care is a key feature of strong general practice. This study aimed to assess the effect of a programme for enhancing strong general practice care on the continuity of care in Germany. The second aim was to assess the effect of continuity of care on hospitalization patterns.

METHODS

We performed an observational study in Germany, involving patients who received a strong general practice care programme (n=1.037.075) and patients who did not receive this programme (n=723.127) in the year 2017. We extracted data from a health insurance database. The cohorts were compared with respect to three measures of continuity of care (Usual Provider Index, Herfindahl Index, and the Sequential Continuity Index), adjusted for patient characteristics. The effects of continuity in general practice on the rates of hospitalization, rehospitalization, and avoidable hospitalization were examined in multiple regression analyses.

RESULTS

Compared to the control cohort, continuity in general practice was higher in patients who received the programme (continuity measures were 12.47 to 23.76% higher, P< 0.0001). Higher continuity of care was independently associated with lowered risk of hospitalization, rehospitalization, and avoidable hospitalization (relative risk reductions between 2.45 and 9.74%, P< 0.0001). Higher age, female sex, higher morbidity (Charlson-index), and home-dwelling status (not nursing home) were associated with higher rates of hospitalization.

CONCLUSION

Higher continuity of care may be one of the mechanisms underlying lower hospitalization rates in patients who received strong general practice care, but further research is needed to examine the causality underlying the associations.

PEMCRC anaphylaxis study protocol: a multicentre cohort study to derive and validate clinical decision models for the emergency department management of children with anaphylaxis

INTRODUCTION

There remain significant knowledge gaps about the management and outcomes of children with anaphylaxis. These gaps have led to practice variation regarding decisions to hospitalise children and length of observation periods following treatment with epinephrine. The objectives of this multicentre study are to (1) determine the prevalence of and risk factors for severe, persistent, refractory and biphasic anaphylaxis, as well as persistent and biphasic non-anaphylactic reactions; (2) derive and validate prediction models for emergency department (ED) discharge; and (3) determine data-driven lengths of ED and inpatient observation prior to discharge to home based on initial reaction severity.

METHODS AND ANALYSIS

The study is being conducted through the Pediatric Emergency Medicine Collaborative Research Committee (PEMCRC). Children 6 months to less than 18 years of age presenting to 30 participating EDs for anaphylaxis from October 2015 to December 2019 will be eligible. The primary outcomes for each objective are (1) severe, persistent, refractory or biphasic anaphylaxis, as well as persistent or biphasic non-anaphylactic reactions; (2) safe ED discharge, defined as no receipt of acute anaphylaxis medications or hypotension beyond 4 hours from first administered dose of epinephrine; and (3) time from first to last administered dose of epinephrine and vasopressor cessation. Analyses for each objective include (1) descriptive statistics to estimate prevalence and generalised estimating equations that will be used to investigate risk factors for anaphylaxis outcomes, (2) least absolute shrinkage and selection operator regression and binary recursive partitioning to derive and validate prediction models of children who may be candidates for safe ED discharge, and (3) Kaplan-Meier analyses to assess timing from first to last epinephrine doses and vasopressor cessation based on initial reaction severity.

ETHICS AND DISSEMINATION

All sites will obtain institutional review board approval; results will be published in peer-reviewed journals and disseminated via traditional and social media, blogs and online education platforms.

Association between Age, Weight, and Dose and Clinical Response to Probiotics in Children with Acute Gastroenteritis

BACKGROUND

Gastroenteritis is a common and impactful disease in childhood. Probiotics are often used to treat acute gastroenteritis (AGE); however, in a large multicenter randomized controlled trial (RCT) in 971 children, Lactobacillus rhamnosus GG (LGG) was no better than placebo in improving patient outcomes.

OBJECTIVES

We sought to determine whether the effect of LGG is associated with age, weight z score and weight percentile adjusted for age and sex, or dose per kilogram administered.

METHODS

This was a preplanned secondary analysis of a multicenter double-blind RCT of LGG 1 × 1010 CFU twice daily for 5 d or placebo in children 3-48 mo of age with AGE. Our primary outcome was moderate to severe gastroenteritis. Secondary outcomes included diarrhea and vomiting frequency and duration, chronic diarrhea, and side effects. We used multivariable linear and nonlinear models testing for interaction effects to assess outcomes by age, weight z score and weight percentile adjusted for age and sex, and dose per kilogram of LGG received.

RESULTS

A total of 813 children (84%) were included in the analysis; 413 received placebo and 400 LGG. Baseline characteristics were similar between treatment groups. There were no differential interaction effects across ranges of age (P-interaction = 0.32), adjusted weight z score (P-interaction = 0.43), adjusted weight percentile (P-interaction = 0.45), or dose per kilogram of LGG received (P-interaction = 0.28) for the primary outcome. Whereas we found a statistical association favoring placebo at the extremes of adjusted weight z scores for the number of vomiting episodes (P-interaction = 0.02) and vomiting duration (P-interaction = 0.0475), there were no statistically significant differences in other secondary outcome measures (all P-interactions > 0.05).

CONCLUSIONS

LGG does not improve outcomes in children with AGE regardless of the age, adjusted weight z score, and adjusted weight percentile of participants, or the probiotic dose per kilogram received. These results further strengthen the conclusions of low risk of bias clinical trials which demonstrate that LGG provides no clinical benefit in children with AGE.This trial was registered at clinicaltrials.gov as NCT01773967.

The Disaggregated Repeated Measures Design: A Novel Approach to Assess Sexual Risk Behaviors

Although numerous studies have examined sexual and substance use behaviors that put people at risk for sexually transmitted infections including HIV, most focus on an overall measure of aggregate risk or a few simple and particular subtypes of sexual acts assessed in separate analyses. In this article, we introduce a more sensitive approach to assess how the relative characteristics of sex acts may determine the level of risk in which an individual chooses to engage. Project AWARE, a randomized clinical trial conducted among 5012 patients in nine STD clinics across the U.S., is used to illustrate the approach. Our study was guided by two aims: (1) describe a new approach to examine the count of sexual acts using a disaggregated repeated measures design and (2) show how this new approach can be used to evaluate interactions among different categories of sexual risk behaviors and other predictors of interest (such as gender/sexual orientation). Profiles of different subtypes of sexual acts in the past 6 months were assessed. Potential interactions of the characteristics associated with each subtype which resulted in up to 48 distinct subtypes of sexual risk behaviors-sex with a primary/non-primary partner; partner's HIV status; vaginal/anal sex; condom use; and substance use before or during sex act-can be examined. Specifically, we chose condom use and primary and non-primary status of partner as an application in this paper to illustrate our method. There were significantly more condomless sex acts (M = 23, SE = 0.9) and sex acts with primary partners (M = 27.1, SE = 0.9) compared to sex acts with condoms (M = 10.9, SE = 0.4, IRR = 2.10, 95% CI 1.91-2.32, p < .001) and sex acts with non-primary partner (M = 10.9, SE = 0.5, IRR = 2.5, 95% CI 2.33-2.78, p < .001). In addition, there were significant differences for the count of sexual risk behaviors among women who have sex with men (WSM), men who have sex with women (MSW) and men who have sex with men (MSM) for sex acts with and without condom use, primary and non-primary partner, and their interaction (ps = .03, < .0001, and .001, respectively). This approach extends our understanding of how people make choices among sexual behaviors and may be useful in future research on disaggregated characteristics of sex acts.

Modeling Individual Patient Count/Rate Data over Time with Applications to Cancer Pain Flares and Cancer Pain Medication Usage

The purpose of this article is to investigate approaches for modeling individual patient count/rate data over time accounting for temporal correlation and non-constant dispersions while requiring reasonable amounts of time to search over alternative models for those data. This research addresses formulations for two approaches for extending generalized estimating equations (GEE) modeling. These approaches use a likelihood-like function based on the multivariate normal density. The first approach augments standard GEE equations to include equations for estimation of dispersion parameters. The second approach is based on estimating equations determined by partial derivatives of the likelihood-like function with respect to all model parameters and so extends linear mixed modeling. Three correlation structures are considered including independent, exchangeable, and spatial autoregressive of order 1 correlations. The likelihood-like function is used to formulate a likelihood-like cross-validation (LCV) score for use in evaluating models. Example analyses are presented using these two modeling approaches applied to three data sets of counts/rates over time for individual cancer patients including pain flares per day, as needed pain medications taken per day, and around the clock pain medications taken per day per dose. Means and dispersions are modeled as possibly nonlinear functions of time using adaptive regression modeling methods to search through alternative models compared using LCV scores. The results of these analyses demonstrate that extended linear mixed modeling is preferable for modeling individual patient count/rate data over time, because in example analyses, it either generates better LCV scores or more parsimonious models and requires substantially less time.

Association of Malnutrition with Subsequent Malaria Parasitemia among Children Younger than Three years in Kenya: A Secondary Data Analysis of the Asembo Bay Cohort Study

Malaria and malnutrition remain primary causes of morbidity and mortality among children younger than 5 years in Africa. Studies investigating the association between malnutrition and subsequent malaria outcomes are inconsistent. We studied the effects of malnutrition on incidence and prevalence of malaria parasitemia in data from a cohort studied in the 1990s. Data came from the Asembo Bay cohort study, which collected malaria and health information on children from 1992 to 1996 in western Kenya. Infants were enrolled at birth and followed up until loss to follow-up, death, end of study, or 5 years old. Anthropometric measures and blood specimens were obtained monthly. Nutritional exposures included categorized Z-scores for height-for-age, weight-for-age, and weight-for-height. Febrile parasitemia and afebrile parasitemia were assessed with thick and thin blood films. Multiply imputed and weighted multinomial generalized estimating equation models estimated odds ratios (OR) for the association between exposures and outcomes. The sample included 1,182 children aged 0-30 months who contributed 18,028 follow-up visits. There was no significant association between malnutrition and either incident febrile parasitemia or prevalent febrile parasitemia. Prevalence ORs for afebrile parasitemia increased from 1.07 (95% CI: 0.89, 1.29) to 1.35 (1.03, 1.76) as stunting severity increased from mild to severe, and from 1.16 (1.02, 1.33) to 1.35 (1.09, 1.66) as underweight increased from mild to moderate. Stunting and underweight did not show a significant association with subsequent febrile parasitemia infections, but they did show a modest association with subsequent afebrile parasitemia. Consideration should be given to testing malnourished children for malaria, even if they present without fever.

Seasonal productivity drives aggregations of killer whales and other cetaceans over submarine canyons of the Bremer Sub-Basin, south-western Australia

Cetaceans are iconic predators that serve as important indicators of marine ecosystem health. The Bremer Sub-Basin, south-western Australia, supports a diverse cetacean community including the largest documented aggregation of killer whales (Orcinus orca) in Australian waters. Knowledge of cetacean distributions is critical for managing the area’s thriving ecotourism industry, yet is largely sporadic. Here we combined aerial with opportunistic ship-borne surveys during 2015–2017 to describe the occurrence of multiple cetacean species on a regional scale. We used generalised estimating equations to model variation in killer whale relative density as a function of both static and dynamic covariates, including seabed depth, slope, and chlorophyll a concentration, while accounting for autocorrelation. Encountered cetacean groups included: killer (n=177), sperm (n=69), long-finned pilot (n=29), false killer (n=2), and strap-toothed beaked (n=1) whales, as well as bottlenose (n=12) and common (n=5) dolphins. Killer whale numbers peaked in areas of low temperatures and high primary productivity, likely due to seasonal upwelling of nutrient-rich waters supporting high prey biomass. The best predictive model highlighted potential killer whale ‘hotspots’ in the Henry, Hood, Pallinup and Bremer Canyons. This study demonstrates the value of abundance data from platforms of opportunity for marine planning and wildlife management in the open ocean.

Static internal representation of dynamic situations reveals time compaction in human cognition

Introduction

The human brain has evolved under the constraint of survival in complex dynamic situations. It makes fast and reliable decisions based on internal representations of the environment. Whereas neural mechanisms involved in the internal representation of space are becoming known, entire spatiotemporal cognition remains a challenge. Growing experimental evidence suggests that brain mechanisms devoted to spatial cognition may also participate in spatiotemporal information processing.

Objectives

The time compaction hypothesis postulates that the brain represents both static and dynamic situations as purely static maps. Such an internal reduction of the external complexity allows humans to process time-changing situations in real-time efficiently. According to time compaction, there may be a deep inner similarity between the representation of conventional static and dynamic visual stimuli. Here, we test the hypothesis and report the first experimental evidence of time compaction in humans.

Methods

We engaged human subjects in a discrimination-learning task consisting in the classification of static and dynamic visual stimuli. When there was a hidden correspondence between static and dynamic stimuli due to time compaction, the learning performance was expected to be modulated. We studied such a modulation experimentally and by a computational model.

Results

The collected data validated the predicted learning modulation and confirmed that time compaction is a salient cognitive strategy adopted by the human brain to process time-changing situations. Mathematical modelling supported the finding. We also revealed that men are more prone to exploit time compaction in accordance with the context of the hypothesis as a cognitive basis for survival.

Conclusions

The static internal representation of dynamic situations is a human cognitive mechanism involved in decision-making and strategy planning to cope with time-changing environments. The finding opens a new venue to understand how humans efficiently interact with our dynamic world and thrive in nature.

Monitoring udder health on routinely collected census data: Evaluating the short- to mid-term consequences of implementing selective dry cow treatment

In 2013, the preventive use of antimicrobials in Dutch livestock was prohibited, including a ban on the blanket application of antimicrobial dry cow treatment (BDCT). Since then, selective dry cow treatment (SDCT) has become the standard approach. In this study, we aimed to determine the effect of the ban on BDCT and the extent of the subsequent adoption of SDCT on antimicrobial usage (AMU) and udder health on Dutch dairy farms. In the Dutch cattle health surveillance system, AMU for dry cow treatment (AMU_DCT), AMU for intramammary treatment at any point in time (AMU_IMM), and udder health indicators are routinely and continuously monitored. This provided the opportunity to study associations among SDCT, udder health, and AMU on census data of approximately 17,000 dairy herds, with about 1.67 million cows in total (>2 yr old) at one moment in time in the period from 2013 until 2017. Six udder health parameters were evaluated using multivariable population-averaged generalized estimating equation models. The year in which the ban on BDCT was introduced (2013) was compared with the period thereafter (2014-2017). Additionally, AMU_IMM and AMU_DCT were included as independent variables to evaluate whether the extent to which SDCT was implemented on the herd level was associated with udder health. Demographic parameters were included as potential confounders. Since the ban on BDCT, overall declines of 63% in AMU_DCT and 15% in AMU_IMM were observed. The raw data show an improvement in 5 out of 6 evaluated udder health parameters between 2013 and 2017. Nevertheless, the multivariable model results showed that the period since the ban on BDCT was associated with a small but significant increase in the percentage of cows with high somatic cell count (HSCC) and new HSCC (+0.41% and +0.06%, respectively). Additionally, the probability of belonging to the group of herds with more than 25% of primiparous cows having HSCC during the start of lactation increased slightly, associated with the period after which BDCT was banned (odds ratio = 1.08). The probability of belonging to the group of herds with more than 25% cows having a persistent HSCC during the dry period was not affected and bulk milk somatic cell count showed a slight but significant reduction. The only udder health parameter that notably worsened during the study period was the probability of belonging to the group of herds with more than 25% of multiparous cows with a new HSCC after the dry period, during the start of lactation (odds ratio = 1.23). In herds where the farmer decided not to apply any dry cow therapy (≈20% of all herds), all udder health parameters were poorer compared with herds in which dry cow therapy was applied to some extent. The ban on BDCT and implementation of SDCT in the Netherlands was associated with a considerable reduction in AMU without a major impairment in udder health at the national level. Although negative effects of changed dry cow management were observed in some herds, we conclude that SDCT can be introduced without substantial negative effects on udder health.

Assessment of Weight Loss and Gastrointestinal Symptoms Suggestive of Exocrine Pancreatic Dysfunction After Acute Pancreatitis

INTRODUCTION

Studies evaluating the natural history of exocrine pancreatic dysfunction (EPD) after acute pancreatitis (AP) are sparse. This study aims to assess incidence and predictors of weight loss and gastrointestinal (GI) symptoms suggestive of EPD 12 months after an AP episode.

METHODS

Patients enrolled in the Pancreatitis-associated Risk of Organ Failure Study at the time of an AP episode were included. Weight and GI symptom data were prospectively collected by self-report at enrollment and at 3- and 12-month (windows 2-7 and 8-20) telephone follow-ups. Multivariable logistic regression was used to assess factors associated with ≥10% total body weight loss (EPD surrogate) at 12 months. A generalized estimating equation was used to measure each factor's population effect (in pounds) over 12 months after AP.

RESULTS

Follow-up at 12 months in 186 patients (median age = 54 years, 46% men, 45% biliary, 65% first AP attack) revealed weight loss ≥10% from baseline, occurring in 44 patients (24%). Risk of weight loss increased with higher baseline body mass index, previous diagnosis of diabetes mellitus, and worsening AP severity (all P < 0.010). GI symptoms were reported in 13/31 (42%) patients at 12 months. AP severity was independently associated with ≥10% weight loss at 12 months. Over 12 months, men lost more weight than women (average 9.5 lbs); patients with severe AP lost, on average, 14 lbs.

DISCUSSION

Weight loss after AP occurs in one-quarter of patients and is associated with AP severity. EPD incidence after AP is likely underappreciated. Further work is needed to assess EPD and potential for pancreatic enzyme supplementation.

Factors Associated With Human Immunodeficiency Virus Infections Linked in Genetic Clusters But Disconnected in Partner Tracing

BACKGROUND

Successful partner notification can improve community-level outcomes by increasing the proportion of persons living with human immunodeficiency virus (HIV) who are linked to HIV care and virally suppressed, but it is resource intensive. Understanding where HIV transmission pathways may be undetected by routine partner notification may help improve case finding strategies.

METHODS

We combined partner notification interview and HIV sequence data for persons diagnosed with HIV in Wake County, NC in 2012 to 2013 to evaluate partner contact networks among persons with HIV pol gene sequences 2% or less pairwise genetic distance. We applied a set of multivariable generalized estimating equations to identify correlates of disparate membership in genetic versus partner contact networks.

RESULTS

In the multivariable model, being in a male-male pair (adjusted odds ratio [AOR], 16.7; P = 0.01), chronic HIV infection status (AOR, 4.5; P < 0.01), and increasing percent genetic distance between each dyad member's HIV pol gene sequence (AOR, 8.3 per each 1% increase, P < 0.01) were all associated with persons with HIV clustering but not being identified in the partner notification network component. Having anonymous partners or other factors typically associated with risk behavior were not associated.

CONCLUSIONS

Based on genetic networks, partnerships which may be stigmatized, may have occurred farther back in time or may have an intervening partner were more likely to be unobserved in the partner contact network. The HIV genetic cluster information contributes to public health understanding of HIV transmission networks in these settings where partner identifying information is not available.

Socioeconomic and behavioral determinants of cardiovascular diseases among older adults in Belgium and France: A longitudinal analysis from the SHARE study

Despite advances in the healthcare system, cardiovascular diseases (CVDs) are still an important public health problem with disparities in the burden within and between countries. Studies among the adult population documented that socioeconomic and environmental factors play a role in the incidence and progression of CVDs. However, evidence is scarce on the socioeconomic determinants and the interplay with behavioral risks among older adults. Therefore, we identified socioeconomic and behavioral determinants of CVDs among older adults. Our sample consisted of 14,322 people aged 50 years and above from Belgium and France who responded to the waves 4, 5, 6 and/or 7 of the Survey of Health Ageing and Retirement in Europe. The effect of determinants on the occurrence of CVD was examined using a Generalized Estimating Equation (GEE) approach for binary longitudinal data. The overall rate of heart attack was 8.3%, which is 7.6% in Belgium and 9.1% in France. Whereas, 2.6% and 2.3% in Belgium and France, respectively, had experienced stroke. In the multivariable GEE model, older age [AOR: 1.057, 95%CI: 1.055-1.060], living in large cities [AOR: 1.14, 95%CI: 1.07-1.18], and retirement [AOR: 1.21, 95%CI: 1.16-1.31] were associated with higher risk of CVD. Furthermore, higher level of education [AOR: 0.82, 95%CI: 0.79-0.90], upper wealth quantile [AOR: 0.82, 95%CI: 0.76-0.86] and having social support [AOR: 0.81, 95%CI: 0.77-0.84] significantly lowers the odds of having CVD. A higher hand grip strength was also significantly associated with lower risk of CVD [AOR: 0.987, 95%CI: 0.984-0.990]. This study demonstrated that older adults who do not have social support, live in big cities, belong to the lowest wealth quantile, and have a low level of education have a higher likelihood of CVD. Therefore, community-based interventions aimed at reducing cardiovascular risks need to give more emphasis to high-risk retired older adults with lower education, no social support and those who live in large cities.

Generalized estimating equations approach for spatial lattice data: A case study in adoption of improved maize varieties in Mozambique

Generalized estimating equations (GEE) are extension of generalized linear models (GLM) widely applied in longitudinal data analysis. GEE are also applied in spatial data analysis using geostatistics methods. In this paper, we advocate application of GEE for spatial lattice data by modeling the spatial working correlation matrix using the Moran's index and the spatial weight matrix. We present theoretical developments and results for simulated and actual data as well. For the former case, 1,000 samples of a random variable (response variable) defined in (0, 1) interval were generated using different values of the Moran's index. In addition, 1,000 samples of a binary and a continuous variable were also randomly generated as covariates. In each sample, three structures of spatial working correlation matrices were used while modeling: The independent, autoregressive, and the Toeplitz structure. Two measures were used to evaluate the performance of each of the spatial working correlation structures: the asymptotic relative efficiency and the working correlation selection criterions. The results showed that both measures indicated that the autoregressive spatial working correlation matrix proposed in this paper presents the best performance in general. For the actual data case, the proportion of small farmers who used improved maize varieties was considered as the response variable and a set of nine variables were used as covariates. Two structures of spatial working correlation matrices were used and the results showed consistence with those obtained in the simulation study.

A robust and unified framework for estimating heritability in twin studies using generalized estimating equations

The 'heritability' of a phenotype measures the proportion of trait variance due to genetic factors in a population. In the past 50 years, studies with monozygotic and dizygotic twins have estimated heritability for 17,804 traits;¹ thus twin studies are popular for estimating heritability. Researchers are often interested in estimating heritability for non-normally distributed outcomes such as binary, counts, skewed or heavy-tailed continuous traits. In these settings, the traditional normal ACE model (NACE) and Falconer's method can produce poor coverage of the true heritability. Therefore, we propose a robust generalized estimating equations (GEE2) framework for estimating the heritability of non-normally distributed outcomes. The traditional NACE and Falconer's method are derived within this unified GEE2 framework, which additionally provides robust standard errors. Although the traditional Falconer's method cannot adjust for covariates, the corresponding 'GEE2-Falconer' can incorporate mean and variance-level covariate effects (e.g. let heritability vary by sex or age). Given a non-normally distributed outcome, the GEE2 models are shown to attain better coverage of the true heritability compared to traditional methods. Finally, a scenario is demonstrated where NACE produces biased estimates of heritability while Falconer remains unbiased. Therefore, we recommend GEE2-Falconer for estimating the heritability of non-normally distributed outcomes in twin studies.

Serological study of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Tarassovi and Ballum in beef cattle, sheep and deer in New Zealand

AIMS

To estimate animal-level seroprevalence of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Ballum and Tarassovi, in beef cattle, sheep and deer on New Zealand farms, and herd/flock-level seroprevalence of any serovar when existing same-sera data for serovars Hardjobovis and Pomona were included, and to determine associations between risk factors and animal-level seroprevalence.

METHODS

Banked sera from sheep (n = 82), beef (n = 54) and deer (n = 62) herds/flocks (n = 3,878 animals) from seven regions were analysed using the microscopic agglutination test. Titres of ≥48 were designated positive. Herds/flocks were considered positive if either ≥1, ≥2 or ≥3 animals were positive. Existing same-sera data for serovars Hardjobovis and Pomona were included to establish farm-level any-serovar seropositivity. Factors associated with serological status were analysed using generalised estimating equations.

RESULTS

Animal-level seroprevalence for serovars Ballum, Copenhageni, and Tarassovi, respectively, was 13.7 (95% CI = 11.7-16.0)%, 12.6 (95% CI = 10.6-14.7)% and 18.0 (95% CI = 15.7-20.5)% for beef cattle, 10.5 (95% CI = 9.0-12.1)%, 16.7 (95% CI = 14.9-18.6)% and 14.0 (95% CI = 12.4-15.8)% for sheep and 6.6 (95% CI = 5.3-8.2)%, 15.5 (95% CI = 13.5-17.7)% and 3.6 (95% CI = 2.7-4.8)% for deer, respectively. Herd/flock-level seroprevalence for Ballum was 86.6, 52.4 and 39.0% for sheep, 85.2, 52.7 and 33.3% for beef cattle and 50.8, 27.9 and 21.3% for deer at definitions ≥1, ≥2 and ≥3 seropositive animals per species, respectively. For Copenhageni, corresponding data were 95.1, 73.2 and 56.1% for sheep, 68.5, 48.2 and 29.6% for beef cattle and 73.8, 57.4 and 41.0% for deer, and for Tarassovi, 80.5, 59.7 and 45.1% for sheep, 83.3, 68.5 and 61.1% for beef cattle, and 42.6, 16.4 and 4.9% for deer. Seropositivity to all serovars was observed from all regions, with some differences in seroprevalence observed between species and regions, but not between islands. Combining with Hardjobovis and Pomona data, herd/flock-level seropositivity for all animal species and all five Leptospira serovars was 100% at definition ≥1 animal positive, and 97.5 and 96.3% for sheep flocks, 87.8 and 97.8% for beef cattle herds, and 89.3 and 75% for deer herds at ≥2 and ≥3 animals positive, respectively.

CONCLUSIONS

Seropositivity to serovars Ballum, Copenhageni and Tarassovi is common in sheep, beef cattle and deer New Zealand and most, or all farms have ≥1 livestock species seropositive to ≥1 serovar.

CLINICAL RELEVANCE

Serovars Ballum, Tarassovi and Copenhageni should be considered when clinical or subclinical signs of leptospirosis are observed in sheep, beef cattle or deer. Livestock sector workers are potentially at risk of exposure.

Patient descriptions of loss of control and eating episode size interact to influence expert diagnosis of ICD-11 binge-eating disorder

BACKGROUND

Although data suggest that the sense of "loss of control" (LOC) is the most salient aspect of binge eating, the definition of LOC varies widely across eating disorder assessments. The WHO ICD-11 diagnostic guidelines for binge eating do not require an objectively large amount of food, which makes accurate LOC diagnosis even more critical. However, it can be especially challenging to assess LOC in the context of elevated weight status and in the absence of compensatory behaviors. This ICD-11 field sub-study examined how descriptions of subjective experience during distressing eating episodes, in combination with different eating episode sizes, influence diagnoses of binge-eating disorder (BED).

METHOD

Mental health professionals with eating disorder expertise from WHO's Global Clinical Practice Network (N = 192) participated in English, Japanese, and Spanish. Participants were asked to select the correct diagnosis for two randomly assigned case vignettes and to rate the clinical importance and ease of use of each BED diagnostic guideline.

RESULTS

The presence of LOC interacted with episode size to predict whether a correct diagnostic conclusion was reached. If the amount consumed during a typical distressing eating episode was only subjectively large compared to objectively large, clinicians were 23.1 times more likely to miss BED than to correctly diagnose it, and they were 9.7 times more likely to incorrectly diagnose something else than to correctly diagnose BED. In addition, clinicians were 10.8 times more likely to make a false positive diagnosis of BED when no LOC was described if the episode was objectively large. Descriptions of LOC that were reliably associated with correct diagnoses across episodes sizes included two that are similar to those already included in proposed ICD-11 guidelines and a third that is not. This third description of LOC focuses on giving up attempts to control eating because perceived overeating feels inevitable.

CONCLUSIONS

Results highlight the importance of detailed clarification of the LOC construct in future guidelines. Explicitly distinguishing LOC from distressing and mindless overeating could help promote consistent and accurate diagnosis of BED versus another or no eating disorder.

Motion-Dependent Effects of Functional Magnetic Resonance Imaging Preprocessing Methodology on Global Functional Connectivity

Background: While functional magnetic resonance imaging (fMRI) has become an established noninvasive tool for studying brain activity in both healthy and diseased states, no broad consensus has been reached regarding preprocessing methodology. Furthermore, the relationship between variations in preprocessing and functional connectivity (FC) networks remains incompletely understood. Purpose: The aim of this study was to relate FC to (1) choices in preprocessing methodology and (2) subject motion. Methods: Clinical and MRI data were analyzed from healthy subjects acquired as part of the Autism Brain Imaging Data Exchange (ABIDE). Data were obtained from 508 healthy subjects. Data from subjects in the highest and lowest quartiles for motion were used to calculate the interaction between motion and preprocessing. Data were analyzed across four domains of fMRI preprocessing: (1) pipeline, (2) global signal regression (GSR), (3) bandpass filtering, and (4) anatomic atlas. For the FC network calculated from each preprocessing scheme, overall FC using Pearson correlation, as well as leaf fraction and diameter, was calculated for each subject, and statistical comparison was made across schemes using generalized estimating equations. Results: FC and global network properties were significantly affected by each preprocessing step, and each preprocessing step significantly interacted with subject motion to differentially affect global functional network properties, with GSR having the strongest effect. Conclusion: Preprocessing choices in fMRI studies influence overall FC and global network properties and can have motion-dependent effects. Impact statement Different parameter choices across the four domains of functional magnetic resonance imaging (fMRI) preprocessing analyzed in this study (global signal regression, bandpass filtering, anatomic atlas, and pipeline) were associated with differences in functional connectivity (FC) as well as global network properties in healthy subjects. Some fMRI preprocessing parameter choices resulted in motion-dependent effects on FC and global network properties.

Seasonal weather and climate prediction over area burned in grasslands of northeast China

Grassland fire dynamics are subject to myriad climatic, biological, and anthropogenic drivers, thresholds, and feedbacks and therefore do not conform to assumptions of statistical stationarity. The presence of non-stationarity in time series data leads to ambiguous results that can misinform regional-level fire management strategies. This study employs non-stationarity in time series data among multiple variables and multiple intensities using dynamic simulations of autoregressive distributed lag models to elucidate key drivers of climate and ecological change on burned grasslands in Xilingol, China. We used unit root methods to select appropriate estimation methods for further analysis. Using the model estimations, we developed scenarios emulating the effects of instantaneous changes (i.e., shocks) of some significant variables on climate and ecological change. Changes in mean monthly wind speed and maximum temperature produce complex responses on area burned, directly, and through feedback relationships. Our framework addresses interactions among multiple drivers to explain fire and ecosystem responses in grasslands, and how these may be understood and prioritized in different empirical contexts needed to formulate effective fire management policies.

Kinetic profile of N,N-dimethyltryptamine and β-carbolines in saliva and serum after oral administration of ayahuasca in a religious context

Ayahuasca is a beverage obtained from Banisteriopsis caapi plus Psychotria viridis. B. caapi contains the β-carbolines harmine, harmaline, and tetrahydroharmine that are monoamine oxidase inhibitors and P. viridis contains N,N-dimethyltryptamine (DMT) that is responsible for the visionary effects of the beverage. Ayahuasca use is becoming a global phenomenon, and the recreational use of DMT and similar alkaloids has also increased in recent years; such uncontrolled use can lead to severe intoxications. In this investigation, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to study the kinetics of alkaloids over a 24 h period in saliva and serum of 14 volunteers who consumed ayahuasca twice a month in a religious context. We compared the area under the curve (AUC), maximum concentration (C_max ), time to reach C_max (T_max ), mean residence time (MRT), and half-life (t_1/2 ), as well as the serum/saliva ratios of these parameters. DMT and β-carboline concentrations (C_max ) and AUC were higher in saliva than in serum and the MRT was 1.5-3.0 times higher in serum. A generalized estimation equations (GEEs) model suggested that serum concentrations could be predicted by saliva concentrations, despite large individual variability in the saliva and serum alkaloid concentrations. The possibility of using saliva as a biological matrix to detect DMT, β-carbolines, and their derivatives is very interesting because it allows fast noninvasive sample collection and could be useful for detecting similar alkaloids used recreationally that have considerable potential for intoxication.

Comparing bowel and urinary domains of patient-reported quality of life at the end of and 3 months post radiotherapy between intensity-modulated radiotherapy and proton beam therapy for clinically localized prostate cancer

PURPOSE

To prospectively assess acute differences in patient-reported outcomes in bowel and urinary domains between intensity-modulated radiotherapy (IMRT) and proton beam therapy (PBT) for prostate cancer.

METHODS AND MATERIALS

Bowel function (BF), urinary irritative/obstructive symptoms (UO), and urinary incontinence (UI) domains of EPIC-26 were collected in patients with T1-T2 prostate cancer receiving IMRT or PBT at a tertiary cancer center (2015-2018). Mean changes in domain scores were analyzed from pretreatment to the end of and 3 months post-radiotherapy for each modality. A clinically meaningful change was defined as a score change >50% of the baseline standard deviation.

RESULTS

A total of 157 patients receiving IMRT and 105 receiving PBT were included. There were no baseline differences in domain scores between cohorts. At the end of radiotherapy, there was significant and clinically meaningful worsening of BF and UO scores for patients receiving either modality. In the BF domain, the IMRT cohort experienced greater decrement (-13.0 vs -6.7, P < .01), and had a higher proportion of patients with clinically meaningful reduction (58.4% vs 39.5%, P = .01), compared to PBT. At 3 months post-radiotherapy, the IMRT group had significant and clinically meaningful worsening of BF (-9.3, P < .001), whereas the change in BF score of the PBT cohort was no longer significant or clinically meaningful (-1.2, P = .25). There were no significant or clinically meaningful changes in UO or UI 3 months post-radiotherapy.

CONCLUSIONS

PBT had less acute decrement in BF than IMRT following radiotherapy. There was no difference between the two modalities in UO and UI.

Clusters of pain trajectories among patients with sickle cell disease hospitalized for vaso-occlusive crisis: a data-driven approach

BACKGROUND

Vaso-occlusive crises (VOC) are the hallmark of sickle cell disease (SCD), with higher severity among hospitalized patients. Clustering hospitalizations with similar pain trajectories could identify vulnerable patient subgroups. Aims were to (1) identify clusters of hospitalizations based on pain trajectories; (2) identify factors associated with these clusters; and (3) determine the association between these clusters and 30-day readmissions.

METHODS

We retrospectively included 350 VOC hospitalizations from 2013-2016 among 59 patients. Finite mixture modeling identified clusters of hospitalizations from intercepts and slopes of pain trajectories during the hospitalization. Generalized estimating equations for multinomial and logistic models were used to identify factors associated with clusters of hospitalizations based on pain trajectories and 30-day readmissions, respectively, while accounting for multiple hospitalizations per patient.

RESULTS

Three clusters of hospitalizations based on pain trajectories were identified: slow (n=99), moderate (n=207), and rapid (n=44) decrease in pain scores. In multivariable analysis, SCD complications, female gender, and affective disorders were associated with clusters with slow or moderate decrease in pain scores (compared to rapid decrease). Although univariate analysis found that the cluster with moderate decrease in pain scores was associated with lower odds of 30-day readmissions compared to the cluster with slow decrease, it was non-significant in multivariable analysis. SCD complications were associated with higher odds of 30-day readmissions and older age was associated with lower odds of 30-day readmissions.

CONCLUSIONS

Our results highlight variability in pain trajectories among patients with SCD experiencing VOC and provide a novel approach for identifying subgroups of patients that could benefit from more intensive follow-up.

Association between Co-Morbidities and the Prevalence of Excessive Daytime Sleepiness over a Four-Year Period

Excessive daytime sleepiness (EDS) is a common problem in general the Canadian population. It can effect day-to-day activities and is also associated with several health issues. This study aimed to investigate the association between co-morbidities and the prevalence of EDS over a four-year period in adults living in two First Nation communities. Data collected during the First Nations Lung Health Project (FNLHP) conducted in two Cree First Nation communities in Saskatchewan in 2012–2013 (Cycle 1) and 2016 (Cycle 2) were used for this analysis. There were 859 participants aged 18 years and older at baseline (Cycle 1) and 821 participants aged 18 years and older at follow-up (Cycle 2) who completed the interviewer-administered questionnaire. An Epworth Sleepiness Scale (ESS) score > 10 was considered to be abnormal and identified as a case of EDS at both time points. A multilevel logistic regression model using a generalized estimating equations approach was used to analyze the data. The prevalence of EDS at baseline (Cycle 1) was 11.2% (91/815) and 10.0% (80/803) at follow-up (Cycle 2). Based on the predicted model, longitudinal change in the prevalence of EDS was −0.11% for 358 individuals who participated in both cycles. There were 49% males at baseline and 48% males at follow-up. Multivariate regression model results revealed that crowding, shortness of breath, loud snoring, chronic lung disease, depression and gastric reflux were the main significant predictors of EDS. In addition, the interaction between sex and age was significant. Some of the co-morbid conditions were associated with EDS. Therefore, managing such conditions requires considerations in strategies to decrease the prevalence of daytime sleepiness.

Self-reported driving after marijuana use in association with medical and recreational marijuana policies

BACKGROUND

A common concern surrounding increasingly permissive marijuana policies in the US is that they will lead to more dangerous behavior, including driving after marijuana use. Although there is considerable research on the effects of marijuana policies on behaviours, few studies have examined self-reported driving after marijuana use. In this study, we use data from the Traffic Safety Culture Index (TSCI) to model self-reported past-year driving after marijuana use in association with medical and recreational marijuana policies.

METHODS

We analysed individual responses to annual administrations of TSCI from years 2013-2017 using a multiple logistic regression model. Our outcome variable was self-reported past-year driving after marijuana use (at least once vs. never), and our primary explanatory variable was the respondents' state medical marijuana (MM) and recreational marijuana (RM) policy. Additional explanatory variables include policies that specify thresholds for marijuana-intoxicated driving, year, and demographic factors.

RESULTS

Drivers in states that legalized MM but not RM had marginally higher odds of self-reporting driving after marijuana use compared to drivers in states where both RM and MM were illegal (adjusted OR 1.29; 95% CI 0.98, 1.70; p = 0.075). However, we found little evidence that drivers in states that legalized both RM and MM had higher odds of driving after marijuana use compared to drivers in states where both RM and MM were illegal (adjusted OR 1.06; 95% CI 0.71, 1.56; p = 0.784). Per-se or THC threshold laws were associated with lower self-reported driving after marijuana use (adjusted OR 0.74; 95% CI 0.57, 0.95; p = 0.018).

CONCLUSION

Although we found some evidence of an association between MM legalization and self-reported driving after marijuana use, our results provide only mixed support for the hypothesis that permissive marijuana policies are associated with higher odds of self-reported driving after marijuana use.

Validation of galectin-1 as potential diagnostic biomarker of early rheumatoid arthritis

Galectin 1 (Gal1) is a lectin with a wide cellular expression that functions as a negative regulator of the immune system in several animal models of autoimmune diseases. Identification of patients with rheumatoid arthritis (RA) has improved during the last decade, although there is still a need for biomarkers allowing an early diagnosis. In this regard, it has been recently proposed that Gal1 serum levels are increased in patients with RA compared to the general population. However, this topic is controversial in the literature. In this work, we provide additional information about the potential usefulness of Gal1 serum levels as a biomarker for RA diagnosis. We studied Gal1 serum and synovial fluid levels and clinical parameters in samples from 62 patients with early arthritis belonging to the PEARL study. In addition, 24 healthy donors were studied. We found that both patients fulfilling RA criteria and patients with undifferentiated arthritis showed higher Gal1 levels than healthy donors. Similar findings were observed in synovial fluid, which showed even higher levels than serum. However, we did not find correlation between Gal1 levels and disease activity or disability. Therefore, our results suggest that Gal1 could be a diagnostic but not a severity biomarker.

Behavioral modifications by a large-northern herbivore to mitigate warming conditions

BACKGROUND

Temperatures in arctic-boreal regions are increasing rapidly and pose significant challenges to moose (Alces alces), a heat-sensitive large-bodied mammal. Moose act as ecosystem engineers, by regulating forest carbon and structure, below ground nitrogen cycling processes, and predator-prey dynamics. Previous studies showed that during hotter periods, moose displayed stronger selection for wetland habitats, taller and denser forest canopies, and minimized exposure to solar radiation. However, previous studies regarding moose behavioral thermoregulation occurred in Europe or southern moose range in North America. Understanding whether ambient temperature elicits a behavioral response in high-northern latitude moose populations in North America may be increasingly important as these arctic-boreal systems have been warming at a rate two to three times the global mean.

METHODS

We assessed how Alaska moose habitat selection changed as a function of ambient temperature using a step-selection function approach to identify habitat features important for behavioral thermoregulation in summer (June-August). We used Global Positioning System telemetry locations from four populations of Alaska moose (n = 169) from 2008 to 2016. We assessed model fit using the quasi-likelihood under independence criterion and conduction a leave-one-out cross validation.

RESULTS

Both male and female moose in all populations increasingly, and nonlinearly, selected for denser canopy cover as ambient temperature increased during summer, where initial increases in the conditional probability of selection were initially sharper then leveled out as canopy density increased above ~ 50%. However, the magnitude of selection response varied by population and sex. In two of the three populations containing both sexes, females demonstrated a stronger selection response for denser canopy at higher temperatures than males. We also observed a stronger selection response in the most southerly and northerly populations compared to populations in the west and central Alaska.

CONCLUSIONS

The impacts of climate change in arctic-boreal regions increase landscape heterogeneity through processes such as increased wildfire intensity and annual area burned, which may significantly alter the thermal environment available to an animal. Understanding habitat selection related to behavioral thermoregulation is a first step toward identifying areas capable of providing thermal relief for moose and other species impacted by climate change in arctic-boreal regions.

Patterns of Cardiovascular Risk Factors in Old Age and Survival and Health Status at 90

BACKGROUND

The population age 90 years and older is the fastest growing segment of the U.S. population. Only recently is it possible to study the factors that portend survival to this age.

METHODS

Among participants of the Cardiovascular Health Study, we studied the association of repeated measures of cardiovascular risk factors measured over 15-23 years of follow-up and not only survival to 90 years of age, but also healthy aging outcomes among the population who reached age 90. We included participants aged 67-75 years at baseline (n = 3,613/5,888) to control for birth cohort effects, and followed participants until death or age 90 (median follow-up = 14.7 years).

RESULTS

Higher systolic blood pressure was associated with a lower likelihood of survival to age 90, although this association was attenuated at older ages (p-value for interaction <.001) and crossed the null for measurements taken in participants' 80's. Higher levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and body mass index (BMI) were associated with greater longevity. Among the survivors to age 90, those with worse cardiovascular profile (high blood pressure, LDL cholesterol, glucose, and BMI; low HDL cholesterol) had lower likelihood of remaining free of cardiovascular disease, cognitive impairment, and disability.

CONCLUSION

In summary, we observed paradoxical associations between some cardiovascular risk factors and survival to old age; whereas, among those who survive to very old age, these risk factors were associated with higher risk of adverse health outcomes.

Emergency physicians' active patient queues over the course of a shift

OBJECTIVES

When emergency physicians see new patients in an ad libitum system, they see fewer patients as the shift progresses. However, it is unclear if this reflects a decreasing workload, as patient assessments often span many hours. We sought to investigate whether the size of a physician's queue of active patients similarly declines over a shift.

METHODS

Retrospective cohort study, conducted over two years in three community hospitals in the Northeastern United States, with 8 and 9-h shifts. Timestamps of all encounters were recorded electronically. Generalized estimating equations were constructed to predict the number of active patients a physician concurrently managed per hour.

RESULTS

We evaluated 64 physicians over a two-year period, with 9822 physician-shifts. Across all sites, physicians managed an increasing queue of active patients in the first several hours. This queue plateaued in the middle of the shift, declining in the final hours, independently of other factors. Physicians' queues of active patients increased slightly with greater volume and acuity, but did not affect the overall pattern of work. Similarly, working alone or with colleagues had little effect on the number of active patients managed.

CONCLUSIONS

Emergency physicians in an ad libitum system tend to see new patients until reaching a stable roster of active patients. This pattern may help explain why physicians see fewer new patients over the course of a shift, should be factored into models of throughput, and suggests new avenues for evaluating relationships between physician workload, patient safety, physicians' well-being, and the quality of care.

Sleep and sleepiness in shift-working tram drivers

Driver sleepiness contributes to traffic accidents. However, sleepiness in urban public transport remains an understudied subject. To fill this gap, we examined the sleepiness, sleep, and on-duty sleepiness countermeasures (SCMs) in 23 tram drivers working morning, day, and evening shifts for three weeks. Sleepiness was measured using Karolinska Sleepiness Scale (KSS). Nocturnal total sleep time (TST) was measured with wrist actigraphy. SCMs and naps were self-reported with a smartphone application. Caffeine and napping were considered effective SCMs. Severe sleepiness (KSS ≥ 7) was observed in 22% of shifts with no differences between shift types. Rest breaks were associated with slight reductions in sleepiness. TST between days off averaged 7 h but was 1 h 33 min and 38 min shorter prior to morning and day shifts, respectively. The use of effective SCMs showed little variance between shift types. These results highlight the need for fatigue management in non-night-working tram drivers.

Residential green is associated with reduced annoyance to road traffic and railway noise but increased annoyance to aircraft noise exposure

BACKGROUND

In recent years, residential green and availability of neighbourhood green spaces came into focus as a potential means to reduce transportation noise annoyance. Literature suggests that various characteristics of residential green may play a role, namely, greenness of the residential areas as quantified by the normalized difference vegetation index (NDVI), visible vegetation from home, and the presence of public green spaces as identified by land use classification data (LU-green), as well as their accessibility and noise pollution (i.e., transportation noise exposure within green areas, how loud/quiet they are). So far, studies mostly focused on road traffic noise in urban areas.

OBJECTIVE

We investigated the effects of residential green on noise annoyance, accounting for different transportation noise sources as well as for the degree of urbanisation.

METHODS

We complemented the data set of the recent Swiss SiRENE survey on road traffic, railway and aircraft noise annoyance with a wide range of "green" metrics, and investigated their association with annoyance by means of logistic regression analysis (generalized estimating equations).

RESULTS

Increasing residential green was found to be associated with reduced road traffic and railway noise annoyance, but increased aircraft noise annoyance. The overall effect corresponded to equivalent level reductions of about 6 dB for road traffic and 3 dB for railway noise, but to an increase of about 10 dB for aircraft noise, when residential green increased from "not much green" (5th percentile of the study sample distribution) to "a lot of green" (95th percentile). Overall, NDVI and LU-green were particularly strongly linked to annoyance. The effects of visible vegetation from home and accessibility and/or quietness of green spaces were, overall, less strong, but depended on the degree of urbanisation. For road traffic noise, visible vegetation and accessibility of green spaces seem to particularly strongly reduce annoyance in cities, while quiet green spaces are more effective in rural areas.

CONCLUSIONS

Our study emphasizes that residential green should be fostered by city planners, particularly in densely populated areas.

Structural barriers to condom access in a community-based cohort of sex workers in Vancouver, Canada: influence of policing, violence and end-demand criminalisation

OBJECTIVES

Sex workers (SWs) face a disproportionate burden of HIV/sexually transmitted infections (STIs), violence and other human rights violations. While recent HIV prevention research has largely focused on the HIV cascade, condoms remain a cornerstone of HIV prevention, requiring further research attention. Given serious concerns regarding barriers to condom use, including policing, violence and 'end-demand' sex work criminalisation, we evaluated structural correlates of difficulty accessing condoms among SWs in Vancouver over an 8-year period.

METHODS

Baseline and prospective data were drawn from a community-based cohort of women SWs (2010-2018). SWs completed semi-annual questionnaires administered by a team that included lived experience (SWs). Multivariable logistic regression using generalised estimating equations (GEE) modelled correlates of difficulty accessing condoms over time.

RESULTS

Among 884 participants, 19.1% reported difficulty accessing condoms during the study. In multivariable GEE analysis, exposure to end-demand legislation was not associated with improved condom access; identifying as a sexual/gender minority (adjusted odds ratio (aOR) 1.62, 95% CI 1.16 to 2.27), servicing outdoors (aOR 1.52, 95% CI 1.17 to 1.97), physical/sexual workplace violence (aOR 1.98, 95% CI 1.44 to 2.72), community violence (aOR 1.79, 95% CI 1.27 to 2.52) and police harassment (aOR 1.66, 95% CI 1.24 to 2.24) were associated with enhanced difficulty accessing condoms.

CONCLUSIONS

One-fifth of SWs faced challenges accessing condoms, suggesting the need to scale-up SW-tailored HIV/STI prevention. Despite the purported goal of 'protecting communities', end-demand criminalisation did not mitigate barriers to condom access, while sexual/gender minorities and those facing workplace violence, harassment or those who worked outdoors experienced poorest condom accessibility. Decriminalisation of sex work is needed to support SWs' labour rights, including access to HIV/STI prevention supplies.

Fractures in patients with rheumatoid arthritis and end-stage renal disease

Having rheumatoid arthritis (RA) or end-stage renal disease (ESRD) can lead to fractures. RA independently increases the risk of hip or other femur fracture in dialysis patients. Use of corticosteroids is a potentially modifiable risk factor for fractures among persons with RA and ESRD on dialysis.

PURPOSE

Rheumatoid arthritis (RA) and end-stage renal disease (ESRD) both independently increase fracture risk; however, how RA and ESRD interplay to affect fracture risk is unknown. We aim to determine the association of RA with fracture in ESRD and identify risk factors for fracture in patients with RA and ESRD.

METHODS

A retrospective cohort study was conducted using the United States Renal Data System (USRDS) to identify ESRD adults with and without a history of RA who initiated dialysis in 2005-2008. International Classification of Diseases, 9th Revision (ICD-9) codes were used to identify fractures following start of dialysis. Risk for incident fracture was compared between those with and without RA. Potential risk factors for fracture among persons with RA and ESRD were analyzed.

RESULTS

There were 754 persons with ESRD and RA, of whom 126 (17%) had any incident fracture. In multivariable adjusted final models, among ESRD patients, RA was an independent risk factor for hip/femur fracture (RR 1.28, 95% CI 1.01-1.64). Among persons with RA and ESRD, in final models, only corticosteroid use was a significant risk factor for both any incident (RR 2.00, 95% CI 1.40-2.87) and hip/femur (RR 1.97, 95% CI 1.24-3.11) fracture. Those with higher body mass index had a lower relative risk of hip/femur fracture (RR 0.95, 95% CI 0.91-0.99).

CONCLUSION

Among ESRD patients, those with RA have a 28% increased risk for hip or other femur fracture. Use of corticosteroids is a potentially modifiable risk factor for fractures among persons with RA and ESRD.

The combined use of salivary biomarkers and clinical parameters to predict the outcome of scaling and root planing: A cohort study

AIM

To explore the application of the combined use of baseline salivary biomarkers and clinical parameters in predicting the outcome of scaling and root planing (SRP).

MATERIALS AND METHODS

Forty patients with advanced periodontitis were included. Baseline saliva samples were analysed for interleukin-1β (IL-1β), matrix metalloproteinase-8 and the loads of Porphyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans and Tannerella forsythia. After SRP, pocket closure and further attachment loss at 6 months post-treatment were chosen as outcome variables. Models to predict the outcomes were established by generalized estimating equations.

RESULTS

The combined use of baseline clinical attachment level (CAL), site location and IL-1β (area under the curve [AUC] = 0.764) better predicted pocket closure than probing depth (AUC = 0.672), CAL (AUC = 0.679), site location (AUC = 0.654) or IL-1β (AUC = 0.579) alone. The combination of site location, tooth loss, percentage of deep pockets, detection of A. actinomycetemcomitans and T. forsythia load (AUC = 0.842) better predicted further clinical attachment loss than site location (AUC = 0.715), tooth loss (AUC = 0.530), percentage of deep pockets (AUC = 0.659) or T. forsythia load (AUC = 0.647) alone.

CONCLUSION

The combination of baseline salivary biomarkers and clinical parameters better predicted SRP outcomes than each alone. The current study indicates the possible usefulness of salivary biomarkers in addition to tooth-related parameters in predicting SRP outcomes.

Effects of disease activity on lipoprotein levels in patients with early arthritis: can oxidized LDL cholesterol explain the lipid paradox theory?

Background

An increased risk of cardiovascular (CV) complications has been described in patients with rheumatoid arthritis (RA). It is the result of the combined effect of classic CV risk factors and others that are specific to the disease.

Methods

We assessed data from 448 early arthritis (EA) patients: 79% women, age (median [p25-p75]) at onset: 55 [44–67] years and disease duration at study entry 5 [3–8] months; and 72% fulfilled the 1987 RA criteria at 2 years of follow-up. Rheumatoid factor was positive in 54% of patients and anti-citrullinated peptide antibodies in 50%. The follow-up of patients ranged from 2 to 5 years with more than 1400 visits with lipoprotein measurements available (mean 2.5 visits/patient). Demographic- and disease-related variables were systematically recorded. Total cholesterol (TC), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) levels were obtained from routine laboratory tests. Oxidized-LDL (oxLDL-C) levels were assessed using a commercial ELISA kit. We fitted population-averaged models nested by patient and visit to determine the effect of independent variables on serum levels of TC, its fractions, and oxLDL-C.

Results

After adjustment for several confounders, high-disease activity was significantly associated with decreased TC, HDL-C, and LDL-C levels and increased oxLDL-C levels. Standardized coefficients showed that the effect of disease activity was greater on oxLDL-C and HDL-C. Interestingly, we observed that those patients with lower levels of LDL-C showed higher oxLDL-C/LDL-C ratios.

Conclusions

High-disease activity in EA patients results in changes in the HDL-C and oxLDL-C levels, which in turn may contribute to the increased risk of CV disease observed in these patients.

Impact of Area Deprivation Index on the Performance of Claims-Based Risk-Adjustment Models in Predicting Health Care Costs and Utilization

Traditionally, risk-adjustment models do not address the characteristics of minority populations, such as race or socioeconomic status. This study aimed to evaluate the added value of place-based social determinants on risk-adjustment models in explaining health care costs and utilization. Statewide commercial claims from the Maryland Medical Care Database were used, including 1,150,984 Maryland residents aged 18 to 63 with ≥6 months enrollment in 2013 and 2014. Area Deprivation Index (ADI) was assigned to individuals through zip code. The authors examined the addition of ADI to predictive models of concurrent and prospective costs and utilization; linear regression was adopted for costs and logistic regression for utilization markers. Performance measures included R² for costs (total, pharmacy, and medical costs) and the area under the curve (AUC) for utilization (being top 5% top users, having any hospitalization, having any emergency room [ER] visit, having any avoidable ER visit, and having any readmission). All performance measures were derived from the bootstrapping analysis with 200 iterations. Study subjects were ∼48% male with a mean age of ∼41 years. Adding ADI to the demographics or claims-based models generally did not improve performance except in predicting the probability of having any ER or any avoidable ER visit; for example, AUC of avoidable ER visits increased significantly from .610 to .613 when using ADI rank deciles in claims-based models. Future research should focus on patients with a higher need for social services, assess more granular place-based determinants (eg, Census block group), and evaluate the added value of individual social variables.

Meteorological conditions and nonpharmaceutical interventions jointly determined local transmissibility of COVID-19 in 41 Chinese cities: A retrospective observational study

Background

Before effective vaccines become widely available, sufficient understanding of the impacts of climate, human movement and non-pharmaceutical interventions on the transmissibility of COVID-19 is needed but still lacking.

Methods

We collected by crowdsourcing a database of 11 003 COVID-19 cases from 305 cities outside Hubei Province from December 31, 2019 to April 27, 2020. We estimated the daily effective reproduction numbers (R_t) of COVID-19 in 41 cities where the crowdsourced case data are comparable to the official surveillance data. The impacts of meteorological variables, human movement indices and nonpharmaceutical emergency responses on R_t were evaluated with generalized estimation equation models.

Findings

The median R_t was 0•46 (IQR: 0•37–0•87) in the northern cities, higher than 0•20 (IQR: 0•09–0•52) in the southern cities (p=0•004). A higher local transmissibility of COVID-19 was associated with a low temperature, a relative humidity near 70–75%, and higher intracity and intercity human movement. An increase in temperature from 0℃ to 20℃ would reduce R_t by 30% (95 CI 10–46%). A further increase to 30℃ would result in another 17% (95% CI 5–27%) reduction. An increase in relative humidity from 40% to 75% would raise the transmissibility by 47% (95% CI 9–97%), but a further increase to 90% would reduce the transmissibility by 12% (95% CI 4–19%). The decrease in intracity human movement as a part of the highest-level emergency response in China reduced the transmissibility by 36% (95% CI 27–44%), compared to 5% (95% CI 1–9%) for restricting intercity transport. Other nonpharmaceutical interventions further reduced R_t by 39% (95% CI 31–47%).

Interpretation

Climate can affect the transmission of COVID-19 where effective interventions are implemented. Restrictions on intracity human movement may be needed in places where other nonpharmaceutical interventions are unable to mitigate local transmission.

Funding

China Mega-Project on Infectious Disease Prevention; U.S. National Institutes of Health and National Science Foundation.

Racial Disparities in Incidence and Outcomes Among Patients With COVID-19

IMPORTANCE

Initial public health data show that Black race may be a risk factor for worse outcomes of coronavirus disease 2019 (COVID-19).

OBJECTIVE

To characterize the association of race with incidence and outcomes of COVID-19, while controlling for age, sex, socioeconomic status, and comorbidities.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 2595 consecutive adults tested for COVID-19 from March 12 to March 31, 2020, at Froedtert Health and Medical College of Wisconsin (Milwaukee), the largest academic system in Wisconsin, with 879 inpatient beds (of which 128 are intensive care unit beds).

EXPOSURES

Race (Black vs White, Native Hawaiian or Pacific Islander, Native American or Alaska Native, Asian, or unknown).

MAIN OUTCOMES AND MEASURES

Main outcomes included COVID-19 positivity, hospitalization, intensive care unit admission, mechanical ventilation, and death. Additional independent variables measured and tested included socioeconomic status, sex, and comorbidities. Reverse transcription polymerase chain reaction assay was used to test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

RESULTS

A total of 2595 patients were included. The mean (SD) age was 53.8 (17.5) years, 978 (37.7%) were men, and 785 (30.2%) were African American patients. Of the 369 patients (14.2%) who tested positive for COVID-19, 170 (46.1%) were men, 148 (40.1%) were aged 60 years or older, and 218 (59.1%) were African American individuals. Positive tests were associated with Black race (odds ratio [OR], 5.37; 95% CI, 3.94-7.29; P = .001), male sex (OR, 1.55; 95% CI, 1.21-2.00; P = .001), and age 60 years or older (OR, 2.04; 95% CI, 1.53-2.73; P = .001). Zip code of residence explained 79% of the overall variance in COVID-19 positivity in the cohort (ρ = 0.79; 95% CI, 0.58-0.91). Adjusting for zip code of residence, Black race (OR, 1.85; 95% CI, 1.00-3.65; P = .04) and poverty (OR, 3.84; 95% CI, 1.20-12.30; P = .02) were associated with hospitalization. Poverty (OR, 3.58; 95% CI, 1.08-11.80; P = .04) but not Black race (OR, 1.52; 95% CI, 0.75-3.07; P = .24) was associated with intensive care unit admission. Overall, 20 (17.2%) deaths associated with COVID-19 were reported. Shortness of breath at presentation (OR, 10.67; 95% CI, 1.52-25.54; P = .02), higher body mass index (OR per unit of body mass index, 1.19; 95% CI, 1.05-1.35; P = .006), and age 60 years or older (OR, 22.79; 95% CI, 3.38-53.81; P = .001) were associated with an increased likelihood of death.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study of adults tested for COVID-19 in a large midwestern academic health system, COVID-19 positivity was associated with Black race. Among patients with COVID-19, both race and poverty were associated with higher risk of hospitalization, but only poverty was associated with higher risk of intensive care unit admission. These findings can be helpful in targeting mitigation strategies for racial disparities in the incidence and outcomes of COVID-19.

Comparing fast thinking and slow thinking: The relative benefits of interventions, individual differences, and inferential rules

Research on judgment and decision making has suggested that the System 2 process of slow thinking can help people to improve their decision making by reducing well-established statistical decision biases (including base rate neglect, probability matching, and the conjunction fallacy). In a large pre-registered study with 1,706 participants and 23,292 unique observations, we compare the effects of individual differences and behavioral interventions to test the relative benefits of slow thinking on performance in canonical judgment and decision-making problems, compared to a control condition, a fast thinking condition, an incentive condition, and a condition that combines fast and slow thinking. We also draw on the rule-based reasoning literature to examine the benefits of having access to a simple form of the rule needed to solve a specific focal problem. Overall, we find equivocal evidence of a small benefit from slow thinking, evidence for a small benefit to accuracy incentives, and clear evidence of a larger cost from fast thinking. The difference in performance between fast-thinking and slow-thinking interventions is comparable to a one-scale point difference on the 4-point Cognitive Reflection Test (CRT). Inferential rules contribute unique explanatory power and interact with individual differences to support the idea that System 2 benefits from a combination of slower processes and knowledge appropriate to the problem.

Efficacy, safety and cost-effectiveness of a web-based platform delivering the results of a biomarker-based predictive model of biotherapy response for rheumatoid arthritis patients: a protocol for a randomized multicenter single-blind active controlled clinical trial (PREDIRA)

BACKGROUND

Rheumatoid arthritis (RA) is one of the leading chronic inflammatory rheumatism. First-line therapy with synthetic disease-modifying antirheumatic drugs (sDMARD) is insufficiently effective in 40% of cases and these patients are treated with biotherapies. The increased use of these drugs each year is becoming a public health issue with considerable economic burden. This cost is 20 times higher than that of sDMARD. However, among patients treated with biotherapies, clinical practice shows that about one third will not respond to the selected drug. In nonresponse cases, practitioners currently have no choice but to perform an empirical switching between different treatments, because no tool capable of predicting the response or nonresponse to these molecules is currently available.

METHODS

The study is a prospective, phase III, controlled, multicenter, and randomized, single-blind (patient) clinical trial, including RA patients with a previous failure to anti-TNF therapies. The main objective is the analysis of the clinical and pharmacoeconomic impact after 6 months of treatment. Intervention arm: prescription of biotherapy (rituximab, adalimumab, abatacept) using SinnoTest® software, a prediction software based on proteomic biomarkers. Control arm: prescription of biotherapy based on current practice, without the SinnoTest® software (any biotherapy). In addition, a substudy will be carried out within this trial to generate a biobank and further analyze the proteomic profile of the patients and their modification throughout the study.

DISCUSSION

This clinical trial study will be the first validation study of a biotherapy response prediction software, bringing personalized medicine into the management of RA. We expect that the findings from this study will bring several benefits for the patient and the Health Care System.

TRIAL REGISTRATION

ClincalTrials.gov NCT04147026 . Registered on 31 October, 2019.

The effects of incidental findings from whole-body MRI on the frequency of biopsies and detected malignancies or benign conditions in a general population cohort study

Magnetic resonance imaging (MRI) yields numerous tumor-related incidental findings (IFs) which may trigger diagnostics such as biopsies. To clarify these effects, we studied how whole-body MRI IF disclosure in a population-based cohort affected biopsy frequency and the detection of malignancies. Laboratory disclosures were also assessed. Data from 6753 participants in the Study of Health in Pomerania (SHIP) examined between 2008 and 2012 were utilized. All underwent laboratory examinations and 3371 (49.9%) a whole-body MRI. Electronic biopsy reports from 2002 to 2017 were linked to participants and assigned to outcome categories. Biopsy frequency 2 years pre- and post-SHIP was investigated using generalized estimating equations with a negative-binomial distribution. Overall 8208 IFs (laboratory findings outside reference limits: 6839; MRI: 1369) were disclosed to 4707 participants; 2271 biopsy reports belonged to 1200 participants (17.8%). Of these, 938 biopsies occurred pre-SHIP; 1333 post-SHIP (event rate/100 observation years = 6.9 [95% CI 6.5; 7.4]; 9.9 [9.3; 10.4]). Age, cancer history, recent hospitalization, female sex, and IF disclosure were associated with higher biopsy rates. Nonmalignant biopsy results increased more in participants with disclosures (post-/pre-SHIP rate ratio 1.39 [95% CI 1.22; 1.58]) than without (1.09 [95% CI 0.85; 1.38]). Malignant biopsy results were more frequent post-SHIP (rate ratio 1.74 [95% CI 1.27; 2.42]). Biopsies increased after participation in a population-based cohort study with MRI and laboratory IF disclosure. Most biopsies resulted in no findings and few malignancies were diagnosed, indicating potential overtesting and overdiagnosis. A more restrictive policy regarding IF disclosure from research findings is required.