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1.
Medicine (Baltimore) ; 99(37): e22108, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32925754

RESUMO

BACKGROUND: The incidence rate of prediabetes is increasing year by year. Prediabetes is a continuous ever fount of diabetes. Diabetes is closely related to intestinal flora imbalance and insulin resistance (IR). Previous studies have proved that Baduanjin can effectively improve the blood glucose and blood lipid of patients, but there is no relevant research on intestinal flora and IR. Therefore, this study focuses on the influence of Baduanjin on intestinal flora of patients with prediabetes, so as to improve the effect of IR, and finally delay or prevent the occurrence of to diabetes mellitus 2 type (T2DM). METHODS: This study will recruit 80 patients who meet the diagnostic criteria of prediabetes from Hospital of Chengdu University of traditional Chinese Medicine. Eighty patients will be randomly divided into experimental group and control group, 40 cases in each group. The control group received routine lifestyle intervention, and the experimental group received Baduanjin at least 3 to 5 times a week for a total of 6 months. The researchers monitored the intestinal flora, insulin resistance index, blood glucose, blood lipid, body mass index, and other indicators after 3 months of intervention and 6 months of intervention DISCUSSION:: Based on previous studies, intestinal flora is closely related to the occurrence and development of T2DM-IR. Baduanjin can significantly improve the blood glucose and blood lipid of patients with prediabetes, and has a positive effect on the intestinal flora of the elderly and significantly improve the intestinal microecological balance. This study used randomized controlled trial to explore the control method between Baduanjin and conventional lifestyle, in order to further establish the application of Baduanjin in patients with prediabetes. TRIAL REGISTRATION: This trial protocol has been approved by the research hospital and registered in China clinical trial registration center on July 6, 2020 (ChiCTR2000034490).


Assuntos
Microbioma Gastrointestinal , Resistência à Insulina , Estado Pré-Diabético/microbiologia , Estado Pré-Diabético/terapia , Qigong/métodos , Adulto , Idoso , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Tamanho da Amostra
2.
Medicine (Baltimore) ; 99(37): e22134, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32925765

RESUMO

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is an illness characterized by progressive aggravation of airflow limitation, which seriously affects patients' quality of life, and even life-threatening. The lung function of COPD patients is chronically and progressively deteriorated. Among them, the lung function of early COPD patients deteriorates rapidly, and forced expiratory volume in 1 second (FEV1) declines faster than other stages. If diagnosed early and effectively treated in time, it can greatly affect the prognosis. As a traditional exercise regimen, Baduanjin can improve lung function, exercise capacity, and quality of life of COPD patients. However, high-quality evidence-based medical evidence is so far be lacking to confirm the effectiveness of Baduanjin in reducing or preventing mild COPD lung function decline. METHODS: This study is a randomized controlled trial, 192 patients with mild COPD were randomly divided into experimental group and control group. Both of them will receive basic treatment (health education and Tiotropium bromide), the experimental group will receive Baduanjin exercise training, and the control group will be told to maintain the original lifestyle and control the exercise. The Baduanjin exercise will last for 24 weeks and will be followed up for 72 weeks. The primary outcome is the change in lung function, including FEV1, FEV1/forced vital capacity (FVC), and FEV1/predicted. The secondary results included COPD assessment test, 6-minute walk test, St. George Respiratory Questionnaire, and Dyspnea Scale. Safety will also serve as assessing during the test. DISCUSSION: The results of this trial will provide that traditional Baduanjin exercises can prevent COPD lung function deterioration, and provide a simple, inexpensive, and daily pulmonary rehabilitation measure for the patients with mild COPD.


Assuntos
Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/terapia , Qigong/métodos , Tolerância ao Exercício , Humanos , Seleção de Pacientes , Qualidade de Vida , Testes de Função Respiratória , Tamanho da Amostra
4.
Nan Fang Yi Ke Da Xue Xue Bao ; 40(4): 475-482, 2020 Apr 30.
Artigo em Chinês | MEDLINE | ID: mdl-32895141

RESUMO

OBJECTIVE: To explore the application and advantages of conditional inference forest in survival analysis. METHODS: We used simulated experiment and actual data to compare the predictive performance of 4 models, including Coxproportional hazards model, accelerated failure time model, random survival forest model and conditional inference forest model based on their Brier scores. RESULTS: Simulation experiment suggested that both of the two forest models had more accurate and robust predictive performance than the other two regression models. Conditional inference forest model was superior to the other models in analyzing time-to-event data with polytomous covariates, collinearity or interaction, especially for a large sample size and a high censoring rate. The results of actual data analysis demonstrated that conditional inference forest model had the best predictive performance among the 4 models. CONCLUSIONS: Compared with the commonly used survival analysis methods, conditional inference forest model performs better especially when the data contain polytomous covariates with collinearity and interaction.


Assuntos
Análise de Dados , Modelos de Riscos Proporcionais , Tamanho da Amostra , Análise de Sobrevida
5.
Nan Fang Yi Ke Da Xue Xue Bao ; 40(5): 713-717, 2020 May 30.
Artigo em Chinês | MEDLINE | ID: mdl-32897205

RESUMO

OBJECTIVE: To explore the relationship between sample size in the groups and statistical power of ANOVA and Kruskal-Wallis H test with an imbalanced design. METHODS: The sample sizes of the two tests were estimated by SAS program with given parameter settings, and Monte Carlo simulation was used to examine the changes in power when the total sample size varied or remained fixed. RESULTS: In ANOVA, when the total sample size was fixed, increasing the sample size in the group with a larger mean square error improved the statistical power, but an excessively large difference in the sample sizes between groups led to reduced power. When the total sample size was not fixed, a larger mean square error in the group with increased sample size was associated with a greater increase of the statistical power. In Kruskal-wallis H test, when the total sample size was fixed, increasing the sample size in groups with large mean square errors increased the statistical power irrespective of the sample size difference between the groups; when total sample size was not fixed, a larger mean square error in the group with increased sample size resulted in an increased statistical power, and the increment was similar to that for a fixed total sample size. CONCLUSIONS: The relationship between statistical power and sample size in groups is affected by the mean square error, and increasing the sample size in a group with a large mean square error increases the statistical power. In Kruskal-Wallis H test, increasing the sample size in a group with a large mean square error is more cost- effective than increasing the total sample size to improve the statistical power.


Assuntos
Modelos Estatísticos , Simulação por Computador , Método de Monte Carlo , Tamanho da Amostra
6.
PLoS One ; 15(9): e0237925, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32911496

RESUMO

BACKGROUND: Invasive Breast Cancer (IBC) risk estimates continue to be based on data collated from cancer registries, i.e., retrospective research that excludes disease-free women. For women without a prior diagnosis, these estimates inflate both risk and screening frequency recommendations and inadvertently increase recently recognized harms from overdiagnosis and overtreatment. OBJECTIVE: To estimate the likelihood that pre or postmenopausal women with no prior diagnosis will remain free of IBC in order to enable evidence-based screening recommendations. METHODS: Prospective data from 21 studies of 2,402,672 women were analyzed, updating our previously published systematic search of 19 studies. This second systematic search included PubMed and The Cochrane Library from 2012 through April 2019. Inclusion criteria: only studies reporting the number of women enrolled, length of follow-up, and number of women diagnosed with IBC. Linear regression was used to estimate the percentage of women expected to remain free from an IBC diagnosis based on follow-up duration. To minimize non-response bias and selective outcome bias, only studies reporting outcomes for all enrolled women followed for similar, specific lengths of time were included. Sensitivity analyses confirm that the overall findings were unchanged by age at enrollment, menopausal status, screened women, variation in sample size, duration of follow-up, and heteroskedasticity. RESULTS: The calculated percentage of women remaining IBC-free after follow-ups of 5, 10, 15, 20 and 25 years decreases uniformly by about one-fourth of one percent per year, i.e., 0.255% (95% CI: -0.29, -0.22; p < .0001). At 25 years, the expected percentage of women with no invasive breast cancer is 93.41% (95% CI: 92.75, 94.07). CONCLUSIONS: Over 99.7% of pre/postmenopausal women with no prior diagnosis continued with no IBC each year, with 93.41% still free after 25 years. Our study supports the medical justification for reducing the frequency of mammograms for menopausal women with no prior IBC diagnosis.


Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/patologia , Pós-Menopausa/fisiologia , Viés , Detecção Precoce de Câncer , Feminino , Seguimentos , Humanos , Invasividade Neoplásica , Probabilidade , Fatores de Risco , Tamanho da Amostra , Reino Unido
7.
Pediatrics ; 146(4)2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32917847

RESUMO

BACKGROUND: International guidelines for resuscitation recommend using positive end-expiratory pressure (PEEP) during ventilation of preterm newborns. Reliable PEEP-valves for self-inflating bags have been lacking, and effects of PEEP during resuscitation of term newborns are insufficiently studied. The objective was to determine if adding a new PEEP valve to the bag-mask during resuscitation of term and near-term newborns could improve heart rate response. METHODS: This randomized controlled trial was performed at Haydom Lutheran Hospital in Tanzania (September 2016 to June 2018). Helping Babies Breathe-trained midwives performed newborn resuscitation using self-inflating bags with or without a new, integrated PEEP valve. All live-born newborns who received bag-mask ventilation at birth were eligible. Heart rate response measured by ECG was the primary outcome, and clinical outcome and ventilation data were recorded. RESULTS: Among 417 included newborns (median birth weight 3200 g), 206 were ventilated without and 211 with PEEP. We found no difference in heart rate response. Median (interquartile range) measured PEEP in the PEEP group was 4.7 (2.0-5.6) millibar. The PEEP group received lower tidal volumes (4.9 [1.9-8.2] vs 6.3 [3.9-10.5] mL/kg; P = .02) and had borderline lower expired CO2 (2.9 [1.5-4.3] vs 3.3 [1.9-5.0] %; P = .05). Twenty four-hour mortality was 9% in both groups. CONCLUSIONS: We found no evidence for improved heart rate response during bag-mask ventilation with PEEP compared with no PEEP. The PEEP valve delivered a median PEEP within the intended range. The findings do not support routine use of PEEP during resuscitation of newborns around term.


Assuntos
Frequência Cardíaca/fisiologia , Respiração com Pressão Positiva/instrumentação , Respiração Artificial/métodos , Ressuscitação/instrumentação , Eletrocardiografia , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Tocologia , Respiração com Pressão Positiva/estatística & dados numéricos , Ressuscitação/métodos , Ressuscitação/estatística & dados numéricos , Tamanho da Amostra , Nascimento a Termo
8.
Pediatrics ; 146(4)2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32938778

RESUMO

BACKGROUND: Involvement with Child Protective Services (CPS) provides an opportunity to recognize those children at risk for ongoing adverse childhood experiences (ACEs). The relationship between ACEs and child health among CPS-involved children and the role of primary care providers (PCPs) in moderating this relationship is unknown. METHODS: We conducted a convergent mixed-methods study of caregivers of children age 2 to 12 years with a CPS finding of physical abuse, modeling the association between cumulative ACEs and child health-related quality of life (HRQoL) using the PedsQL4.0, a validated 23-item survey of multidimensional health, with and without the moderator of a patient-centered medical home. Interviews elicited descriptions of a child's experience with ACEs, the impact of ACEs on child health, and the role of a PCP in this context. RESULTS: One hundred seventy-eight surveyed caregivers reported a mean of 5.5 (±3.3) ACE exposures per child. In a fully adjusted model, each ACE resulted in a 1.3-point (95% confidence interval: 0.7-2.0) reduction in HRQoL, a clinically important difference in HRQoL associated with ACE exposures. This association was explained by reduced psychosocial HRQoL and was not moderated by a patient-centered medical home. Twenty-seven interviewed caregivers described the influence of ACEs on a child's health. Many felt that a trusted PCP could support a child's well-being after such experiences. CONCLUSIONS: Children with CPS involvement have ACE exposures that are associated with reduced HRQoL. Although PCPs are often unaware of CPS involvement or other ACEs, many caregivers welcome the support of a child's PCP in improving child well-being after adversity.


Assuntos
Experiências Adversas da Infância/estatística & dados numéricos , Cuidadores/psicologia , Maus-Tratos Infantis/psicologia , Saúde da Criança , Serviços de Proteção Infantil , Qualidade de Vida/psicologia , Adulto , Cuidadores/estatística & dados numéricos , Criança , Pré-Escolar , Intervalos de Confiança , Feminino , Humanos , Masculino , Assistência Centrada no Paciente , Pesquisa Qualitativa , Tamanho da Amostra
9.
BMC Bioinformatics ; 21(1): 357, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32795265

RESUMO

BACKGROUND: Previous studies have reported that labeling errors are not uncommon in omics data. Potential outliers may severely undermine the correct classification of patients and the identification of reliable biomarkers for a particular disease. Three methods have been proposed to address the problem: sparse label-noise-robust logistic regression (Rlogreg), robust elastic net based on the least trimmed square (enetLTS), and Ensemble. Ensemble is an ensembled classification based on distinct feature selection and modeling strategies. The accuracy of biomarker selection and outlier detection of these methods needs to be evaluated and compared so that the appropriate method can be chosen. RESULTS: The accuracy of variable selection, outlier identification, and prediction of three methods (Ensemble, enetLTS, Rlogreg) were compared for simulated and an RNA-seq dataset. On simulated datasets, Ensemble had the highest variable selection accuracy, as measured by a comprehensive index, and lowest false discovery rate among the three methods. When the sample size was large and the proportion of outliers was ≤5%, the positive selection rate of Ensemble was similar to that of enetLTS. However, when the proportion of outliers was 10% or 15%, Ensemble missed some variables that affected the response variables. Overall, enetLTS had the best outlier detection accuracy with false positive rates < 0.05 and high sensitivity, and enetLTS still performed well when the proportion of outliers was relatively large. With 1% or 2% outliers, Ensemble showed high outlier detection accuracy, but with higher proportions of outliers Ensemble missed many mislabeled samples. Rlogreg and Ensemble were less accurate in identifying outliers than enetLTS. The prediction accuracy of enetLTS was better than that of Rlogreg. Running Ensemble on a subset of data after removing the outliers identified by enetLTS improved the variable selection accuracy of Ensemble. CONCLUSIONS: When the proportion of outliers is ≤5%, Ensemble can be used for variable selection. When the proportion of outliers is > 5%, Ensemble can be used for variable selection on a subset after removing outliers identified by enetLTS. For outlier identification, enetLTS is the recommended method. In practice, the proportion of outliers can be estimated according to the inaccuracy of the diagnostic methods used.


Assuntos
Biomarcadores/metabolismo , Biologia Computacional/métodos , Teorema de Bayes , Bases de Dados Factuais , Análise Discriminante , Feminino , Humanos , Análise dos Mínimos Quadrados , Modelos Logísticos , Tamanho da Amostra , Neoplasias de Mama Triplo Negativas/diagnóstico , Neoplasias de Mama Triplo Negativas/genética
10.
Trials ; 21(1): 717, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32799933

RESUMO

BACKGROUND: There are no specific generally accepted therapies for the coronavirus disease 2019 (COVID-19). The full spectrum of COVID-19 ranges from asymptomatic disease to mild respiratory tract illness to severe pneumonia, acute respiratory distress syndrome (ARDS), multisystem organ failure, and death. The efficacy of corticosteroids in viral ARDS remains unknown. We postulated that adjunctive treatment of established ARDS caused by COVID-19 with intravenous dexamethasone might change the pulmonary and systemic inflammatory response and thereby reduce morbidity, leading to a decrease in duration of mechanical ventilation and in mortality. METHODS/DESIGN: This is a multicenter, randomized, controlled, parallel, open-label, superiority trial testing dexamethasone in 200 mechanically ventilated adult patients with established moderate-to-severe ARDS caused by confirmed SARS-CoV-2 infection. Established ARDS is defined as maintaining a PaO2/FiO2 ≤ 200 mmHg on PEEP ≥ 10 cmH2O and FiO2 ≥ 0.5 after 12 ± 3 h of routine intensive care. Eligible patients will be randomly assigned to receive either dexamethasone plus standard intensive care or standard intensive care alone. Patients in the dexamethasone group will receive an intravenous dose of 20 mg once daily from day 1 to day 5, followed by 10 mg once daily from day 6 to day 10. The primary outcome is 60-day mortality. The secondary outcome is the number of ventilator-free days, defined as days alive and free from mechanical ventilation at day 28 after randomization. All analyses will be done according to the intention-to-treat principle. DISCUSSION: This study will assess the role of dexamethasone in patients with established moderate-to-severe ARDS caused by SARS-CoV-2. TRIAL REGISTRATION: ClinicalTrials.gov NCT04325061 . Registered on 25 March 2020 as DEXA-COVID19.


Assuntos
Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , Dexametasona/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto , Adulto , Dexametasona/efeitos adversos , Humanos , Avaliação de Resultados em Cuidados de Saúde , Pandemias , Síndrome do Desconforto Respiratório do Adulto/tratamento farmacológico , Tamanho da Amostra
11.
Nat Commun ; 11(1): 4238, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843633

RESUMO

Recently, deep learning has unlocked unprecedented success in various domains, especially using images, text, and speech. However, deep learning is only beneficial if the data have nonlinear relationships and if they are exploitable at available sample sizes. We systematically profiled the performance of deep, kernel, and linear models as a function of sample size on UKBiobank brain images against established machine learning references. On MNIST and Zalando Fashion, prediction accuracy consistently improves when escalating from linear models to shallow-nonlinear models, and further improves with deep-nonlinear models. In contrast, using structural or functional brain scans, simple linear models perform on par with more complex, highly parameterized models in age/sex prediction across increasing sample sizes. In sum, linear models keep improving as the sample size approaches ~10,000 subjects. Yet, nonlinearities for predicting common phenotypes from typical brain scans remain largely inaccessible to the examined kernel and deep learning methods.


Assuntos
Encéfalo/diagnóstico por imagem , Neuroimagem/métodos , Bancos de Espécimes Biológicos , Aprendizado Profundo , Humanos , Modelos Lineares , Aprendizado de Máquina , Fenótipo , Tamanho da Amostra , Reino Unido
13.
Transfus Med Rev ; 34(3): 158-164, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32771272

RESUMO

Many parallel studies of convalescent plasma with modest enrolment projections have been launched for the treatment of COVID-19. By pooling data from multiple parallel studies that are similar, we can increase the effective sample size and achieve enough statistical power to determine effectiveness more quickly through meta-analysis. A scoping review of registered clinical trials of convalescent plasma for COVID-19 was conducted to assess the feasibility of performing a rapid and timely meta-analysis that will support accelerated review for approval and implementation. ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform were searched April 23, 2020. Trials were included if they utilized convalescent plasma to treat or prevent COVID-19. Forty-eight registered trials (projected to enroll more than 5000 subjects) of convalescent plasma were identified and included for analysis. The majority of studies (33 studies with 4440 projected enrolment) will address the treatment of severe and/or critical cases of COVID-19. Twenty-nine studies are controlled and 17 of these are reported as actively recruiting. The combined enrolment of patients from similar studies should be sufficient to determine meaningful improvements in mortality, rates of admission to intensive care and need for mechanical ventilation by the end of 2020-sooner than any individual study could determine effectiveness. Accessing supplemental outcome data from investigators may be needed; however, to align reporting of some outcomes from these studies. Heterogeneity in product potency due to different antibody titers is anticipated and studies using conventional treatment as controls instead of placebo may complicate our understanding of efficacy. Convalescent plasma is being tested in ongoing controlled studies, largely to treat severe and/or critical cases of COVID-19. Sufficient combined power to detect clinically important reductions in multiple outcomes, including mortality, is expected by September 2020. Regulatory approval, funding and implementation by blood operators could be accelerated by planned meta-analysis as study results become available.


Assuntos
Infecções por Coronavirus/terapia , Pneumonia Viral/terapia , Betacoronavirus , Ensaios Clínicos como Assunto , Cuidados Críticos , Saúde Global , Humanos , Imunização Passiva , Pandemias , Sistema de Registros , Reprodutibilidade dos Testes , Projetos de Pesquisa , Respiração Artificial , Tamanho da Amostra , Resultado do Tratamento
14.
PLoS One ; 15(8): e0235469, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845880

RESUMO

Random sampling is an important approach to field vegetation surveys. However, sampling surveys in desert areas are difficult because determining an appropriate quadrat size that represent the sparse and unevenly distributed vegetation is challenging. In this study, we present a methodology for quadrat size optimization based on low-altitude high-precision unmanned aerial vehicle (UAV) images. Using the Daliyaboyi Oasis as our study area, we simulated random sampling and analyzed the frequency distribution and variation in the fractional vegetation cover (FVC) index of the samples. Our results show that quadrats of 50 m × 50 m size are the most representative for sampling surveys in this location. The method exploits UAV technology to rapidly acquire vegetation information and overcomes the shortcomings of traditional methods that rely on labor-intensive fieldwork to collect species-area relationship (SAR) data. Our method presents two major advantages: (1) speed and efficiency stemming from the application of UAV, which also effectively overcomes the difficulties posed in vegetation surveys by the challenging desert climate and terrain; (2) the large sample size enabled by the use of a sampling simulation. Our methodology is thus highly suitable for selecting the optimal quadrat size and making accurate estimates, and can improve the efficiency and accuracy of field vegetation sampling surveys.


Assuntos
Clima Desértico , Monitorização de Parâmetros Ecológicos/métodos , Fenômenos Fisiológicos Vegetais , Biodiversidade , Biomassa , Monitorização de Parâmetros Ecológicos/instrumentação , Monitorização de Parâmetros Ecológicos/normas , Tecnologia de Sensoriamento Remoto/instrumentação , Tamanho da Amostra
15.
Ecotoxicol Environ Saf ; 203: 110992, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32771767

RESUMO

In 2011, the U.S. EPA Office of Research and Development released a field-based method for deriving aquatic life benchmarks for conductivity. Since its release, it has been verified, validated, and corroborated by the authors, reviewers, and independent researchers. However, the method and published results have been recently challenged as being artifacts of small sample sizes, prompting this re-evaluation. This paper supplements prior causal analyses by weighing evidence that specifically addresses the hypothesis that the benchmark is a statistical artifact. Four types of evidence are presented: (1) Permutation analyses show that the data sets are able to reliably estimate the extirpation of 5% of genera. (2) Analyses show that 25 occurrences of a genus are sufficient to estimate extirpation. (3) Coherent ecological explanations show that the claimed influence of sample size is actually a result of community ecology. (4) A review of relevant independent studies supports the benchmark. The permutation test is a useful test of the adequacy of field data sets. Furthermore, this weight-of-evidence approach and the individual types of evidence can be a model for analysis of other field-based benchmark values.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Monitoramento Ambiental/métodos , Benchmarking , Tamanho da Amostra , West Virginia
16.
PLoS One ; 15(7): e0236079, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735597

RESUMO

In this preregistered study, we investigated whether the statistical power of a study is higher when researchers are asked to make a formal power analysis before collecting data. We compared the sample size descriptions from two sources: (i) a sample of pre-registrations created according to the guidelines for the Center for Open Science Preregistration Challenge (PCRs) and a sample of institutional review board (IRB) proposals from Tilburg School of Behavior and Social Sciences, which both include a recommendation to do a formal power analysis, and (ii) a sample of pre-registrations created according to the guidelines for Open Science Framework Standard Pre-Data Collection Registrations (SPRs) in which no guidance on sample size planning is given. We found that PCRs and IRBs (72%) more often included sample size decisions based on power analyses than the SPRs (45%). However, this did not result in larger planned sample sizes. The determined sample size of the PCRs and IRB proposals (Md = 90.50) was not higher than the determined sample size of the SPRs (Md = 126.00; W = 3389.5, p = 0.936). Typically, power analyses in the registrations were conducted with G*power, assuming a medium effect size, α = .05 and a power of .80. Only 20% of the power analyses contained enough information to fully reproduce the results and only 62% of these power analyses pertained to the main hypothesis test in the pre-registration. Therefore, we see ample room for improvements in the quality of the registrations and we offer several recommendations to do so.


Assuntos
Comitês de Ética em Pesquisa , Tamanho da Amostra , Estatística como Assunto/métodos
17.
PLoS One ; 15(8): e0237879, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810192

RESUMO

OBJECTIVES: To perform fragility index (FI) analysis on the evidence that forms the basis of the guidelines for the management of severe traumatic brain injury (TBI), and develop a deeper understanding of the pitfalls associated with FI. DESIGN: Meta-epidemiological analysis and numerical simulations. METHODS: The Brain Trauma Foundation guidelines (4th edition) for management of severe TBI were used to identify relevant randomised controlled trials (RCTs). FI based on Fisher's exact test and relative risk was performed on eligible RCTs. The relationship between FI, event counts and P values was explored by exhaustively considering different combinations of outcomes for studies of total size ranging from 80 to 10000. Sample size calculations were also performed for a range of power, baseline risk and relative risk, to determine the influence of study design on FI. RESULTS: FI analysis of the severe TBI management guidelines revealed that most studies were associated with a low FI. In the majority of studies, FI was of a similar magnitude to the number lost to follow-up. The simulations revealed that while FI was inversely related to P value, a wide range of FI may be associated with a given P value. FI is also affected by sample size, baseline risk and effect size. Sample size calculations suggest that aside from very high-powered studies, most are likely to yield low FI values in the range typically encountered in the literature. CONCLUSIONS: Many studies are underpowered and are expected to be associated with a small FI. Furthermore, FI over-simplifies the complex, non-linear relationships between sample size, effect size and P value, which hinder comparisons of FI between studies. FI places undue importance on the "significance" of P values and accordingly should only be used sparingly.


Assuntos
Lesões Encefálicas Traumáticas/epidemiologia , Lesões Encefálicas Traumáticas/terapia , Simulação por Computador , Guias de Prática Clínica como Assunto , Ensaios Clínicos como Assunto , Humanos , Tamanho da Amostra
18.
JAMA ; 324(6): 571-580, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32780139

RESUMO

Importance: Slowing myopia progression could decrease the risk of sight-threatening complications. Objective: To determine whether soft multifocal contact lenses slow myopia progression in children, and whether high add power (+2.50 D) slows myopia progression more than medium (+1.50 D) add power lenses. Design, Setting, and Participants: A double-masked randomized clinical trial that took place at 2 optometry schools located in Columbus, Ohio, and Houston, Texas. A total of 294 consecutive eligible children aged 7 to 11 years with -0.75 D to -5.00 D of spherical component myopia and less than 1.00 D astigmatism were enrolled between September 22, 2014, and June 20, 2016. Follow-up was completed June 24, 2019. Interventions: Participants were randomly assigned to wear high add power (n = 98), medium add power (n = 98), or single-vision (n = 98) contact lenses. Main Outcomes and Measures: The primary outcome was the 3-year change in cycloplegic spherical equivalent autorefraction, as measured by the mean of 10 autorefraction readings. There were 11 secondary end points, 4 of which were analyzed for this study, including 3-year eye growth. Results: Among 294 randomized participants, 292 (99%) were included in the analyses (mean [SD] age, 10.3 [1.2] years; 177 [60.2%] were female; mean [SD] spherical equivalent refractive error, -2.39 [1.00] D). Adjusted 3-year myopia progression was -0.60 D for high add power, -0.89 D for medium add power, and -1.05 D for single-vision contact lenses. The difference in progression was 0.46 D (95% CI, 0.29-0.63) for high add power vs single vision, 0.30 D (95% CI, 0.13-0.47) for high add vs medium add power, and 0.16 D (95% CI, -0.01 to 0.33) for medium add power vs single vision. Of the 4 secondary end points, there were no statistically significant differences between the groups for 3 of the end points. Adjusted mean eye growth was 0.42 mm for high add power, 0.58 mm for medium add power, and 0.66 mm for single vision. The difference in eye growth was -0.23 mm (95% CI, -0.30 to -0.17) for high add power vs single vision, -0.16 mm (95% CI, -0.23 to -0.09) for high add vs medium add power, and -0.07 mm (95% CI, -0.14 to -0.01) for medium add power vs single vision. Conclusions and Relevance: Among children with myopia, treatment with high add power multifocal contact lenses significantly reduced the rate of myopia progression over 3 years compared with medium add power multifocal and single-vision contact lenses. However, further research is needed to understand the clinical importance of the observed differences. Trial Registration: ClinicalTrials.gov Identifier: NCT02255474.


Assuntos
Lentes de Contato Hidrofílicas , Miopia/reabilitação , Criança , Lentes de Contato Hidrofílicas/efeitos adversos , Progressão da Doença , Método Duplo-Cego , Feminino , Humanos , Modelos Lineares , Masculino , Ohio , Refração Ocular , Tamanho da Amostra , Texas , Fatores de Tempo , Resultado do Tratamento
19.
Pediatrics ; 146(3)2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32843440

RESUMO

BACKGROUND: New biomarkers like procalcitonin and C-reactive protein may help design an accurate decision support tool used to identify children with pleocytosis at low or high risk of bacterial meningitis. Our objective was to develop and validate a score (that we call the meningitis score for emergencies [MSE]) to distinguish bacterial meningitis from aseptic meningitis in children with pleocytosis when initially evaluated at the emergency department. METHODS: We included children between 29 days and 14 years old with meningitis admitted to 25 Spanish emergency departments. A retrospective cohort from between 2011 and 2016 was used as the derivation set and a prospective cohort recruited during 2017 and 2018 was used as the validation set. RESULTS: Among the 1009 patients included, there were 917 cases of aseptic meningitis and 92 of bacterial meningitis. Using multivariable logistic regression analysis, we identified the following predictors of bacterial meningitis from the derivation set: procalcitonin >1.2 ng/mL, cerebrospinal fluid (CSF) protein >80 mg/dL, CSF absolute neutrophil count >1000 cells per mm3, and C-reactive protein >40 mg/L. Using the derivation set, we developed the MSE, assigning 3 points for procalcitonin, 2 points for CSF protein, and 1 point for each of the other variables. An MSE ≥1 predicted bacterial meningitis with a sensitivity of 100% (95% confidence interval [CI]: 95.0%-100%), a specificity of 83.2 (95% CI: 80.6-85.5), and a negative predictive value of 100% (95% CI 99.4-100.) CONCLUSIONS: The MSE accurately distinguishes bacterial from aseptic meningitis in children with CSF pleocytosis.


Assuntos
Regras de Decisão Clínica , Meningite Asséptica/diagnóstico , Meningites Bacterianas/diagnóstico , Adolescente , Biomarcadores/sangue , Proteína C-Reativa/análise , Proteínas do Líquido Cefalorraquidiano/análise , Criança , Pré-Escolar , Intervalos de Confiança , Diagnóstico Diferencial , Serviço Hospitalar de Emergência , Feminino , Humanos , Lactente , Contagem de Leucócitos , Leucocitose/diagnóstico , Modelos Logísticos , Masculino , Meningite Asséptica/sangue , Meningite Asséptica/epidemiologia , Meningites Bacterianas/sangue , Meningites Bacterianas/epidemiologia , Meningites Bacterianas/microbiologia , Neutrófilos/citologia , Pró-Calcitonina/sangue , Estudos Prospectivos , Curva ROC , Estudos Retrospectivos , Tamanho da Amostra , Sensibilidade e Especificidade , Espanha
20.
PLoS One ; 15(8): e0237254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853204

RESUMO

Although many novel phase I designs have been developed in recent years, few studies have discussed how to incorporate external information into dose-finding designs. In this paper, we first propose a new method for developing a phase I design, Bayesian optimal interval design (BOIN)[Liu S et al. (2015), Yuan Y et al. (2016)], for formally incorporating historical information. An algorithm to automatically generate parameters for prior set-up is introduced. Second, we propose a method to relax the fixed boundaries of the BOIN design to be adaptive, such that the accumulative information can be used more appropriately. This modified design is called adaptive BOIN (aBOIN). Simulation studies to examine performances of the aBOIN design in small and large sample sizes revealed comparable performances for the aBOIN and original BOIN designs for small sample sizes. However, aBOIN outperformed BOIN in moderate sample sizes. Simulation results also showed that when historical trials are conducted in settings similar to those for the current trial, their performance can be significantly improved. This approach can be applied directly to pediatric cancer trials, since all phase I trials in children are followed by similar efficient adult trials in the current drug development paradigm. However, when information is weak, operating characteristics are compromised.


Assuntos
Ensaios Clínicos Fase I como Assunto , Desenvolvimento de Medicamentos , Adulto , Algoritmos , Antineoplásicos/uso terapêutico , Teorema de Bayes , Criança , Ensaios Clínicos Fase I como Assunto/métodos , Simulação por Computador , Desenvolvimento de Medicamentos/métodos , Humanos , Neoplasias/tratamento farmacológico , Projetos de Pesquisa , Tamanho da Amostra , Fenômenos Toxicológicos/efeitos dos fármacos
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