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1.
Proc Natl Acad Sci U S A ; 121(18): e2321494121, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38648491

RESUMO

In the absence of universal healthcare in the United States, federal programs of Medicaid and Medicare are vital to providing healthcare coverage for low-income households and elderly individuals, respectively. However, both programs are under threat, with either enacted or proposed retractions. Specifically, raising Medicare age eligibility and the addition of work requirements for Medicaid qualification have been proposed, while termination of continuous enrollment for Medicaid was recently effectuated. Here, we assess the potential impact on mortality and morbidity resulting from these policy changes. Our findings indicate that the policy change to Medicare would lead to over 17,000 additional deaths among individuals aged 65 to 67 and those to Medicaid would lead to more than 8,000 deaths among those under the age of 65. To illustrate the implications for morbidity, we further consider a case study among those people with diabetes who would be likely to lose their health insurance under the policy changes. We project that these insurance retractions would lead to the loss of coverage for over 700,000 individuals with diabetes, including more than 200,000 who rely on insulin.

3.
PNAS Nexus ; 3(3): pgae080, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38505694

RESUMO

The ongoing Russian aggression against Ukraine has forced over eight million people to migrate out of Ukraine. Understanding the dynamics of forced migration is essential for policy-making and for delivering humanitarian assistance. Existing work is hindered by a reliance on observational data which is only available well after the fact. In this work, we study the efficacy of a data-driven agent-based framework motivated by social and behavioral theory in predicting outflow of migrants as a result of conflict events during the initial phase of the Ukraine war. We discuss policy use cases for the proposed framework by demonstrating how it can leverage refugee demographic details to answer pressing policy questions. We also show how to incorporate conflict forecast scenarios to predict future conflict-induced migration flows. Detailed future migration estimates across various conflict scenarios can both help to reduce policymaker uncertainty and improve allocation and staging of limited humanitarian resources in crisis settings.

4.
Ann Intern Med ; 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38527289

RESUMO

BACKGROUND: The U.S. Food and Drug Administration has proposed administering annual SARS-CoV-2 vaccines. OBJECTIVE: To evaluate the effectiveness of an annual SARS-CoV-2 vaccination campaign, quantify the health and economic benefits of a second dose provided to children younger than 2 years and adults aged 50 years or older, and optimize the timing of a second dose. DESIGN: An age-structured dynamic transmission model. SETTING: United States. PARTICIPANTS: A synthetic population reflecting demographics and contact patterns in the United States. INTERVENTION: Vaccination against SARS-CoV-2 with age-specific uptake similar to that of influenza vaccination. MEASUREMENTS: Incidence, hospitalizations, deaths, and direct health care cost. RESULTS: The optimal timing between the first and second dose delivered to children younger than 2 years and adults aged 50 years or older in an annual vaccination campaign was estimated to be 5 months. In direct comparison with a single-dose campaign, a second booster dose results in 123 869 fewer hospitalizations (95% uncertainty interval [UI], 121 994 to 125 742 fewer hospitalizations) and 5524 fewer deaths (95% UI, 5434 to 5613 fewer deaths), averting $3.63 billion (95% UI, $3.57 billion to $3.69 billion) in costs over a single year. LIMITATIONS: Population immunity is subject to degrees of immune evasion for emerging SARS-CoV-2 variants. The model was implemented in the absence of nonpharmaceutical interventions and preexisting vaccine-acquired immunity. CONCLUSION: The direct health care costs of SARS-CoV-2, particularly among adults aged 50 years or older, would be substantially reduced by administering a second dose 5 months after the initial dose. PRIMARY FUNDING SOURCE: Natural Sciences and Engineering Research Council of Canada, Notsew Orm Sands Foundation, National Institutes of Health, Centers for Disease Control and Prevention, and National Science Foundation.

5.
Clin Infect Dis ; 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38035791

RESUMO

BACKGROUND: Two prefusion F protein-based vaccines, Arexvy and Abrysvo, have been authorized by the US Food and Drug Administration for protecting older adults against respiratory syncytial virus (RSV)-associated lower respiratory tract illness. We evaluated the health benefits and cost-effectiveness of these vaccines. METHODS: We developed a discrete-event simulation model, parameterized with the burden of RSV disease including outpatient care, hospitalization, and death for adults aged 60 years or older in the United States. Taking into account the costs associated with these RSV-related outcomes, we calculated the net monetary benefit using quality-adjusted life-year (QALY) gained as a measure of effectiveness and determined the range of price-per-dose (PPD) for Arexvy and Abrysvo vaccination programs to be cost-effective from a societal perspective. RESULTS: Using a willingness-to-pay of $95 000 per QALY gained, we found that vaccination programs could be cost-effective for a PPD up to $127 with Arexvy and $118 with Abrysvo over the first RSV season. Achieving an influenza-like vaccination coverage of 66% for the population of older adults in the United States, the budget impact of these programs at the maximum PPD ranged from $6.48 to $6.78 billion. If the benefits of vaccination extend to a second RSV season as reported in clinical trials, we estimated a maximum PPD of $235 for Arexvy and $245 for Abrysvo, with 2-year budget impacts of $11.78 and $12.25 billion, respectively. CONCLUSIONS: Vaccination of older adults would provide substantial direct health benefits by reducing outcomes associated with RSV-related illness in this population.

6.
Psychother Psychosom ; 92(5): 283-286, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37883947
7.
medRxiv ; 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37645896

RESUMO

Background: Two prefusion F protein-based vaccines, Arexvy and Abrysvo, have been authorized by the US Food and Drug Administration for protecting older adults against Respiratory Syncytial Virus (RSV)-associated lower respiratory tract illness. We evaluated the health benefits and cost-effectiveness of these vaccines. Methods: We developed a discrete-event simulation model, parameterized with the burden of RSV disease including outpatient care, hospitalization, and death for adults aged 60 years or older in the US. Taking into account the costs associated with these RSV-related outcomes, we calculated the net monetary benefit using quality-adjusted life-years (QALY) gained as a measure of effectiveness, and determined the range of price-per-dose (PPD) for Arexvy and Abrysvo vaccination programs to be cost-effective from a societal perspective. Results: Using a willingness-to-pay of $95,000 per QALY gained, we found that vaccination programs could be cost-effective for a PPD under $120 with Arexvy and $111 with Abrysvo over the first RSV season. Achieving an influenza-like vaccination coverage of 66% for the population of older adults in the US, the budget impact of these programs at the maximum PPD ranged from $5.74 to $6.10 billion. If the benefits of vaccination extend to a second RSV season as reported in clinical trials, we estimated a maximum PPD of $250 for Arexvy and $233 for Abrysvo, with two-year budget impacts of $11.59 and $10.89 billion, respectively. Conclusions: Vaccination of older adults would provide substantial direct health benefits by reducing outcomes associated with RSV-related illness in this population.

8.
Proc Natl Acad Sci U S A ; 120(8): e2215424120, 2023 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-36780515

RESUMO

The Russian invasion of Ukraine on February 24, 2022, has displaced more than a quarter of the population. Assessing disease burdens among displaced people is instrumental in informing global public health and humanitarian aid efforts. We estimated the disease burden in Ukrainians displaced both within Ukraine and to other countries by combining a spatiotemporal model of forcible displacement with age- and gender-specific estimates of cardiovascular disease (CVD), diabetes, cancer, HIV, and tuberculosis (TB) in each of Ukraine's 629 raions (i.e., districts). Among displaced Ukrainians as of May 13, we estimated that more than 2.63 million have CVDs, at least 615,000 have diabetes, and over 98,500 have cancer. In addition, more than 86,000 forcibly displaced individuals are living with HIV, and approximately 13,500 have TB. We estimated that the disease prevalence among refugees was lower than the national disease prevalence before the invasion. Accounting for internal displacement and healthcare facilities impacted by the conflict, we estimated that the number of people per hospital has increased by more than two-fold in some areas. As regional healthcare systems come under increasing strain, these estimates can inform the allocation of critical resources under shifting disease burdens.


Assuntos
Doenças Cardiovasculares , Infecções por HIV , Refugiados , Tuberculose , Humanos , Saúde Pública , Atenção à Saúde , Tuberculose/epidemiologia , Efeitos Psicossociais da Doença , Infecções por HIV/epidemiologia
9.
J Clin Sleep Med ; 19(4): 673-683, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36661100

RESUMO

STUDY OBJECTIVES: Sleep deficiency can adversely affect the performance of resident physicians, resulting in greater medical errors. However, the impact of sleep deficiency on surgical outcomes, particularly among attending surgeons, is less clear. METHODS: Sixty attending surgeons from academic and community departments of surgery or obstetrics and gynecology were studied prospectively using direct observation and self-report to explore the effect of sleep deprivation on patient safety, operating room communication, medical errors, and adverse events while operating under 2 conditions, post-call (defined as > 2 hours of nighttime clinical duties) and non-post-call. RESULTS: Each surgeon contributed up to 5 surgical procedures post-call and non-post-call, yielding 362 cases total (150 post-call and 210 non-post-call). Most common were caesarian section and herniorrhaphy. Hours of sleep on the night before the operative procedure were significantly less post-call (4.98 ± 1.41) vs non-post-call (6.68 ± 0.88, P < .01). Errors were infrequent and not related to hours of sleep or post-call status. However, Non-Technical Skills for Surgeons ratings demonstrated poorer performance while post-call for situational awareness, decision-making, and communication/teamwork. Fewer hours of sleep also were related to lower ratings for situational awareness and decision-making. Decreased self-reported alertness was observed to be associated with increased procedure time. CONCLUSIONS: Sleep deficiency in attending surgeons was not associated with greater errors during procedures performed during the next day. However, procedure time was increased, suggesting that surgeons were able to compensate for sleep loss by working more slowly. Ratings on nontechnical surgical skills were adversely affected by sleep deficiency. CITATION: Quan SF, Landrigan CP, Barger LK, et al. Impact of sleep deficiency on surgical performance: a prospective assessment. J Clin Sleep Med. 2023;19(4):673-683.


Assuntos
Internato e Residência , Sono , Humanos , Estudos Prospectivos , Privação do Sono/complicações , Conscientização , Atenção , Competência Clínica
10.
Mar Environ Res ; 185: 105884, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36701826

RESUMO

Macroalgae canopies are common in tropical coastlines, and can be feeding grounds for coral reef fishes. We investigated whether fish transfer algal material from Sargassum-dominated macroalgae habitats to coral reefs by collecting gut contents of two herbivorous fish species (Naso elegans and N. unicornis) from coral reefs in the central Red Sea. On inshore reefs close to macroalgae canopies, Sargassum accounted for up to 41% of these species' gut contents while almost no Sargassum was found in the stomachs of fish on offshore reefs farther from macroalgae canopies. Using consumption and excretion rates from literature, we estimate that these fish consume up to 6.0 mmol C/m2 reef/day and excrete up to 10.8 µmol N/m2 reef/day and 1.0 µmol P/m2 reef/day across inshore reefs as a result of Sargassum consumption. Examining fish-mediated connections between habitats illuminates the role of fish as a vector of nutrition to nutrient-poor coral reefs.


Assuntos
Antozoários , Alga Marinha , Animais , Recifes de Corais , Oceano Índico , Ecossistema , Peixes , Herbivoria , Nutrientes
11.
J Asthma ; 60(1): 57-62, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-34978948

RESUMO

INTRODUCTION: In children admitted for asthma exacerbation, multiple evidence-based, clinical practice guidelines exist to identify readiness for discharge. At many institutions, weaning of albuterol is part of the discharge process, though presently there is limited evidence to guide best practice. We sought to determine how many children required escalation of care once placed on every 4-h dosing of albuterol. METHODS: We performed a consecutive case series of pediatric patients between 5 and 18 years of age admitted to a single tertiary care center's pediatric hospitalist service between April 2015 and April 2018 with a discharge diagnosis of asthma. Patients admitted to the intensive care unit (PICU) or a subspecialty service were excluded, as has been done previously. Time between albuterol administrations was tracked. "Treatment escalation" was defined as when a patient required more frequent albuterol more dosing after previously tolerating albuterol doses separated by more than 3.5 h. RESULTS: A total of 331 patients met inclusion criteria; 136 were female (41.1%), and the average age was 8.8 years. Twenty-six of the 331 patients (7.8%) required escalation of albuterol therapy. Eleven patients returned to the emergency department (ED) following discharge, 2 of which had experienced treatment escalation while admitted. CONCLUSIONS: Our case series showed that most patients were safe to discharge after spacing albuterol treatments to 4 h, with few returns to the ED and readmissions. Albuterol spacing to every 4 h once appears to be a reasonable discharge criterion, but future studies are needed to determine if this is a safe and efficient.


Assuntos
Albuterol , Asma , Criança , Humanos , Feminino , Masculino , Albuterol/uso terapêutico , Asma/diagnóstico , Alta do Paciente , Pacientes Internados , Hospitalização , Serviço Hospitalar de Emergência , Broncodilatadores/uso terapêutico
12.
J Neural Eng ; 19(6)2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-36317300

RESUMO

Objective.Peripheral nerve interfaces seek to restore nervous system function through electrical stimulation of peripheral nerves. In clinical use, these devices should function reliably for years or decades. In this study, we assessed evoked sensations from multi-channel cuff electrode stimulation in macaque monkeys up to 711 d post-implantation.Approach.Three trained macaque monkeys received multi-channel cuff electrode implants at the median or ulnar nerves in the upper arm. Electrical stimuli from the cuff interfaces evoked sensations, which we measured via standard psychophysical tasks. We adjusted pulse amplitude or pulse width for each block with various electrode channel configurations to examine the effects of stimulus parameterization on sensation. We measured detection thresholds and just-noticeable differences (JNDs) at irregular, near-daily intervals for several months using Bayesian inferencing from trial data. We examined data trends using classical models such as Weber's Law and the strength-duration relationship using linear regression.Main results.Detection thresholds were similar between blocks with pulse width modulation and blocks with pulse amplitude modulation when represented as charge per pulse, the product of the amplitude and the pulse width. Conversely, Weber fractions-calculated as the slope of the regression between JND charge values and reference stimulus charge-were significantly different between pulse width and pulse amplitude modulation blocks for the discrimination task.Significance.Weber fractions were lower in blocks with amplitude modulation than in blocks with pulse width modulation, suggesting that pulse amplitude modulation allows finer resolution of sensory encoding above threshold. Consequently, amplitude modulation may enable a greater dynamic range for sensory perception with neuroprosthetic devices.


Assuntos
Macaca , Extremidade Superior , Animais , Teorema de Bayes , Limiar Diferencial , Estimulação Elétrica/métodos , Eletrodos
13.
Mar Pollut Bull ; 185(Pt B): 114352, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36395713

RESUMO

Anthropogenic stressors increasingly cause ecosystem-level changes to sensitive marine habitats such as coral reefs. Intensification of coastal development and shipping traffic can increase nutrient and oil pollution on coral reefs, yet these two stressors have not been studied in conjunction. Here, we simulate a disturbance scenario exposing carbonate settlement tiles to nutrient and oil pollution in a full-factorial design with four treatments: control, nutrients, oil, and combination to examine community structure and net primary productivity (NPP) of pioneer communities throughout 28 weeks. Compared to the control treatment oil pollution decreased overall settlement and NPP, while nutrients increased turf algae and NPP. However, the combination of these two stressors resulted in similar community composition and NPP as the control. These results indicate that pioneer communities may experience shifts due to nutrient enrichment, and/or oil pollution. However, the timing and duration of an event will influence recovery trajectories requiring further study.


Assuntos
Poluição por Petróleo , Petróleo , Recifes de Corais , Ecossistema , Nutrientes
14.
PLoS One ; 17(10): e0276556, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36301851

RESUMO

Aspergillus flavus is an agriculturally important fungus that causes ear rot of maize and produces aflatoxins, of which B1 is the most carcinogenic naturally-produced compound. In the US, the management of aflatoxins includes the deployment of biological control agents that comprise two nonaflatoxigenic A. flavus strains, either Afla-Guard (member of lineage IB) or AF36 (lineage IC). We used genotyping-by-sequencing to examine the influence of both biocontrol agents on native populations of A. flavus in cornfields in Texas, North Carolina, Arkansas, and Indiana. This study examined up to 27,529 single-nucleotide polymorphisms (SNPs) in a total of 815 A. flavus isolates, and 353 genome-wide haplotypes sampled before biocontrol application, three months after biocontrol application, and up to three years after initial application. Here, we report that the two distinct A. flavus evolutionary lineages IB and IC differ significantly in their frequency distributions across states. We provide evidence of increased unidirectional gene flow from lineage IB into IC, inferred to be due to the applied Afla-Guard biocontrol strain. Genetic exchange and recombination of biocontrol strains with native strains was detected in as little as three months after biocontrol application and up to one and three years later. There was limited inter-lineage migration in the untreated fields. These findings suggest that biocontrol products that include strains from lineage IB offer the greatest potential for sustained reductions in aflatoxin levels over several years. This knowledge has important implications for developing new biocontrol strategies.


Assuntos
Aflatoxinas , Aspergillus flavus , Aspergillus flavus/genética , Aflatoxinas/genética , Agentes de Controle Biológico , Zea mays/genética , Zea mays/microbiologia , Recombinação Genética
16.
PNAS Nexus ; 1(3): pgac100, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35909795

RESUMO

Quarantine and serial testing strategies for a disease depend principally on its incubation period and infectiousness profile. In the context of COVID-19, these primary public health tools must be modulated with successive SARS CoV-2 variants of concern that dominate transmission. Our analysis shows that (1) vaccination status of an individual makes little difference to the determination of the appropriate quarantine duration of an infected case, whereas vaccination coverage of the population can have a substantial effect on this duration, (2) successive variants can challenge disease control efforts by their earlier and increased transmission in the disease time course relative to prior variants, and (3) sufficient vaccine boosting of a population substantially aids the suppression of local transmission through frequent serial testing. For instance, with Omicron, increasing immunity through vaccination and boosters-for instance with 100% of the population is fully immunized and at least 24% having received a third dose-can reduce quarantine durations by up to 2 d, as well as substantially aid in the repression of outbreaks through serial testing. Our analysis highlights the paramount importance of maintaining high population immunity, preferably by booster uptake, and the role of quarantine and testing to control the spread of SARS CoV-2.

17.
Commun Med (Lond) ; 2: 84, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35822105

RESUMO

Background: Rapid antigen (RA) tests are being increasingly employed to detect SARS-CoV-2 infections in quarantine and surveillance. Prior research has focused on RT-PCR testing, a single RA test, or generic diagnostic characteristics of RA tests in assessing testing strategies. Methods: We have conducted a comparative analysis of the post-quarantine transmission, the effective reproduction number during serial testing, and the false-positive rates for 18 RA tests with emergency use authorization from The United States Food and Drug Administration and an RT-PCR test. To quantify the extent of transmission, we developed an analytical mathematical framework informed by COVID-19 infectiousness, test specificity, and temporal diagnostic sensitivity data. Results: We demonstrate that the relative effectiveness of RA tests and RT-PCR testing in reducing post-quarantine transmission depends on the quarantine duration and the turnaround time of testing results. For quarantines of two days or shorter, conducting a RA test on exit from quarantine reduces onward transmission more than a single RT-PCR test (with a 24-h delay) conducted upon exit. Applied to a complementary approach of performing serial testing at a specified frequency paired with isolation of positives, we have shown that RA tests outperform RT-PCR with a 24-h delay. The results from our modeling framework are consistent with quarantine and serial testing data collected from a remote industry setting. Conclusions: These RA test-specific results are an important component of the tool set for policy decision-making, and demonstrate that judicious selection of an appropriate RA test can supply a viable alternative to RT-PCR in efforts to control the spread of disease.


Previous research on SARS-CoV-2 infection has determined optimal timing for testing in quarantine and the utility of different frequencies of testing for infection surveillance using RT-PCR and generalized rapid antigen tests. However, these strategies can depend on the specific rapid antigen test used. By examining 18 rapid antigen tests, we demonstrate that a single rapid antigen test performs better than RT-PCR when quarantines are two days or less in duration. In the context of infection surveillance, the ability of a rapid antigen test to provide results quickly counteracts its lower sensitivity with potentially more false positives. Our findings indicate that rapid antigen tests can be a suitable alternative to RT-PCR for application in quarantine and infection surveillance.

18.
PLoS One ; 17(7): e0264245, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35802673

RESUMO

BACKGROUND: Use of PICCs has been rising since 2001. They are used when long-term intravenous access is needed and for blood draws in patients with difficult venous access. OBJECTIVE: To determine which risk factors contribute to inappropriate PICC line insertion defined as removal of a PICC within five days of insertion for reasons other than a PICC complication. DESIGN: Retrospective, observational study. SETTING: Tertiary-care, Level 1 trauma center. PATIENTS: Adult patients with a PICC removed 1/1/2017 to 5/4/2020. MEASUREMENTS: Frequency of PICC removal within five days of insertion and associated risk factors for early removal. RESULTS: Between 1/1/2017 and 5/4/2020, 995 of 5348 PICCs inserted by the IV nursing team were removed within five days (19%). In 2017, 5 of 429 PICCs developed a central line-associated infection (1.2%) and 29 of 429 PICCs developed symptomatic venous thromboembolism (6.7%). Patients with PICCs whose primary service was in an ICU were independently at higher risk of early removal (OR 1.44, 95% CI 1.14, 1.83); weekday insertion was independently associated with a lower likelihood of early removal compared to weekend insertion (OR 0.60; 95% CI 0.49, 0.75). LIMITATION: PICC removal after discharge was not assessed and paper records were likely incomplete and biased. CONCLUSION: Nearly one in five PICCs were removed within five days. Patients whose primary team was in an ICU and PICCs ordered on weekends were at independently higher risk of early removal.


Assuntos
Infecções Relacionadas a Cateter , Cateterismo Venoso Central , Cateterismo Periférico , Centros Médicos Acadêmicos , Adulto , Infecções Relacionadas a Cateter/etiologia , Cateterismo Venoso Central/efeitos adversos , Cateterismo Periférico/efeitos adversos , Humanos , Pacientes Internados , Estudos Retrospectivos , Fatores de Risco
19.
Proc Natl Acad Sci U S A ; 119(25): e2200536119, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35696578

RESUMO

The fragmented and inefficient healthcare system in the United States leads to many preventable deaths and unnecessary costs every year. During a pandemic, the lives saved and economic benefits of a single-payer universal healthcare system relative to the status quo would be even greater. For Americans who are uninsured and underinsured, financial barriers to COVID-19 care delayed diagnosis and exacerbated transmission. Concurrently, deaths beyond COVID-19 accrued from the background rate of uninsurance. Universal healthcare would alleviate the mortality caused by the confluence of these factors. To evaluate the repercussions of incomplete insurance coverage in 2020, we calculated the elevated mortality attributable to the loss of employer-sponsored insurance and to background rates of uninsurance, summing with the increased COVID-19 mortality due to low insurance coverage. Incorporating the demography of the uninsured with age-specific COVID-19 and nonpandemic mortality, we estimated that a single-payer universal healthcare system would have saved about 212,000 lives in 2020 alone. We also calculated that US$105.6 billion of medical expenses associated with COVID-19 hospitalization could have been averted by a single-payer universal healthcare system over the course of the pandemic. These economic benefits are in addition to US$438 billion expected to be saved by single-payer universal healthcare during a nonpandemic year.


Assuntos
COVID-19 , Pandemias , Assistência de Saúde Universal , COVID-19/prevenção & controle , Humanos , Cobertura do Seguro , Pessoas sem Cobertura de Seguro de Saúde , Pandemias/prevenção & controle , Estados Unidos/epidemiologia
20.
Ann Appl Stat ; 16(1): 391-413, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35757598

RESUMO

Characterizing the shared memberships of individuals in a classification scheme poses severe interpretability issues, even when using a moderate number of classes (say 4). Mixed membership models quantify this phenomenon, but they typically focus on goodness-of-fit more than on interpretable inference. To achieve a good numerical fit, these models may in fact require many extreme profiles, making the results difficult to interpret. We introduce a new class of multivariate mixed membership models that, when variables can be partitioned into subject-matter based domains, can provide a good fit to the data using fewer profiles than standard formulations. The proposed model explicitly accounts for the blocks of variables corresponding to the distinct domains along with a cross-domain correlation structure, which provides new information about shared membership of individuals in a complex classification scheme. We specify a multivariate logistic normal distribution for the membership vectors, which allows easy introduction of auxiliary information leveraging a latent multivariate logistic regression. A Bayesian approach to inference, relying on Pólya gamma data augmentation, facilitates efficient posterior computation via Markov Chain Monte Carlo. We apply this methodology to a spatially explicit study of malaria risk over time on the Brazilian Amazon frontier.

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