Comparison of 7 methods for sample size determination based on confidence interval estimation for a single proportion / 南方医科大学学报

OBJECTIVE@#To compare different methods for calculating sample size based on confidence interval estimation for a single proportion with different event incidences and precisions.@*METHODS@#We compared 7 methods, namely Wald, AgrestiCoull add z2, Agresti-Coull add 4, Wilson Score, Clopper-Pearson, Mid-p, and Jefferys, for confidence interval estimation for a single proportion. The sample size was calculated using the search method with different parameter settings (proportion of specified events and half width of the confidence interval [ω=0.05, 0.1]). With Monte Carlo simulation, the estimated sample size was used to simulate and compare the width of the confidence interval, the coverage of the confidence interval and the ratio of the noncoverage probability.@*RESULTS@#For a high accuracy requirement (ω =0.05), the Mid-p method and Clopper Pearson method performed better when the incidence of events was low (P < 0.15). In other settings, the performance of the 7 methods did not differ significantly except for a poor symmetry of the Wald method. In the setting of ω=0.1 with a very low p (0.01-0.05), failure of iteration occurred with nearly all the methods except for the Clopper-Pearson method.@*CONCLUSION@#Different sample size determination methods based on confidence interval estimation should be selected for single proportions with different parameter settings.

Sesgos en investigación quirúrgica / Biases in surgical research

Resumen Los resultados de diversos hallazgos de investigación han sido objeto de crítica, en especial en los últimos años, debido a presencia de errores sistemáticos (sesgos), los que ponen en duda la validez interna de los resultados obtenidos. Estos sesgos pueden ocurrir en cualquier etapa del curso de una investigación, es decir, desde la planificación del estudio hasta la presentación y publicación de sus resultados. Los sesgos se han clasificado de diferentes formas, intentado agruparlos bajo dimensiones conceptuales, objeto de organizar de mejor forma la información existente, que además es considerable. Los sesgos pueden ocurrir por diversos motivos, pero en general, los más frecuentes son aquellos originados por el observador (él o los que miden), por lo que es observado (sujeto en estudio); y aquello con lo que se observa (instrumento de medición). Por otra parte, varios de los múltiples sesgos existentes, se pueden agrupar en: sesgos de selección, de medición o información, y de confusión. El objetivo de este manuscrito fue comentar la importancia de los sesgos más comunes en la investigación quirúrgica, y su relación con algunos diseños de investigación; así como, conocer las estrategias existentes para minimizar su ocurrencia.

The results of many research findings have come under scrutiny in recent years due to the introduction of systematic errors (biases), which can occur at any stage during an investigation, from planning to presentation of results and their presentation and further publication. Biases have been classified in different ways, trying to group them under conceptual dimensions to better organize the existing information, which is considerable. Biases can occur for various reasons, but in general, the most frequent are those originated by the observer, what is observed; and what is observed with. I.e., the subject that is measured, who measures it and with what it measures it. On the other hand, several of the multiple biases can be grouped into selection, measurement or information, and confounding biases. The aim of this manuscript was to comment on the importance of the most common biases in surgical research, and their relationship with some research designs; as well as know the existing strategies to reduce its occurrence.

Resultados funcionales de un programa de prehabilitación en cirugía electiva de cáncer colorrectal / Functional results of a prehabilitation program in elective colorectal cancer surgery

Resumen Introducción: El cáncer colorrectal (CCR) es el segundo tipo más frecuente de cáncer en el mundo. La cirugía es la intervención terapéutica más común y se asocia con la reducción de 20-40% en la capacidad fisiológica y funcional. Un programa de prehabilitación podría mejorar la condición funcional basal de los pacientes previo a la cirugía. Objetivo: Describir los resultados funcionales de un programa de prehabilitación en personas adultas candidatos a cirugía electiva de CCR. Materiales y Método: Estudio descriptivo, longitudinal y retrospectivo. Se registraron los antecedentes sociodemográficos, clínicos y las variables funcionales como capacidad cardiorrespiratoria, fuerza de presión manual, fatiga, independencia en actividades de la vida diaria (AVDs) y equilibrio dinámico de 50 personas que ingresaron a un programa de prehabilitación entre mayo 2019 y febrero de 2020. Los datos fueron analizados con estadística descriptiva y pruebas de diferencia entre tiempo de evaluación, previo y posterior a la prehabilitación. Resultados: Posterior al programa de prehabilitación, los pacientes mejoraron la capacidad cardiorrespiratoria, fatiga, equilibrio dinámico y fuerza prensil (p 0,05; tamaño de efecto: 0,01). Conclusión: Un programa estructurado de prehabilitación para pacientes candidatos a cirugía electiva de CCR basado en ejercicios y educación, logró cambios significativos en los resultados funcionales en un período de 3 a 4 semanas previo a la cirugía.

Introduction: Colorectal cancer (CRC) is the second most frequent type of cancer in the world. Surgery is the most common therapeutic intervention and is associated with a 20-40% reduction in physiological and functional capacity. A prehabilitation program could improve the baseline functional condition of patients prior to surgery. Aim: To describe the functional results of a prehabilitation program in adults who will undergo elective surgery CCR. Materials and Method: Descriptive, longitudinal and retrospective study. The sociodemographic, clinical and functional variables such as cardiorespiratory capacity, manual pressure force, fatigue, independence in activities of daily living and dynamic balance of 50 people who entered a pre-rehabilitation program between may 2019 and february 2020 were compiled. Data were analyzed with descriptive statistics and difference tests between evaluation time, before and after prehabilitation. Results: After the prehabilitation program, the patients improved cardiorespiratory capacity, fatigue, dynamic balance and grip strength (p 0.05; effect size: 0.01). Conclusión: A structured prehabilitation program for patients who are candidates for elective colorectal cancer surgery based on exercises and education, achieved significant changes in functional results in a period of 3 to 4 weeks prior to surgery.

Surgical Management of Infected Pancreatic Necrosis. Case Series in a Quaternary Care Hospital in Bogotá, Colombia, 2014-2021 / Manejo quirúrgico de la necrosis pancreática infectada. Serie de casos en un hospital de cuarto nivel en Bogotá, Colombia, 2014-2021

Abstract Introduction: Pancreatitis is a frequent pathology in our environment, mostly related to benign biliary pathology. It can progress to severe forms in 10-15 % of cases, where the pancreatic tissue becomes necrotic and forms large collections with risk of infection. We do not have epidemiological data about the incidence or management of this complication in Colombia. Aim: This study aims to study the prevalence of infected pancreatic necrosis and describe the cases identified in a quaternary care hospital between 2014 and 2021. Materials and methods: A cross-sectional observational study. We analyzed records of patients diagnosed with stage 2 pancreatitis. Those cases with infected pancreatic necrosis that underwent debridement plus laparoscopic and open surgical drainage at Hospital Universitario Mayor Méderi in Bogotá, Colombia, between January 2014 and January 2021 were studied. A convenience sampling was carried out without calculating the sample size. We collected the patients' demographic and clinical variables, performing a descriptive statistical analysis in Excel. Qualitative variables were described through absolute and relative frequencies, while quantitative ones were expressed through measures of central tendency and dispersion based on their distribution. Results: We analyzed 1020 episodes of pancreatitis, finding pancreatic necrosis in 30 patients, i.e., a period prevalence of 2.9 %. Of the patients, 83 % (n = 25) underwent open drainage, with 48 % (n = 12) mortality. About laparoscopic management, the reduction in postoperative organ failure was 40 % (n = 2), with a 30 % shorter hospital stay than the open drainage approach. Those patients with a level of procalcitonin (PCT) lower than 1.8 ng/mL had less mortality. Conclusions: The laparoscopic approach shows promising results regarding final morbidity and mortality.

Resumen Introducción: la pancreatitis es una patología frecuente en nuestro medio, mayormente relacionada con la patología biliar benigna. Esta puede progresar a formas severas en 10 %-15 % de los casos, en donde el tejido pancreático se necrosa y forma grandes colecciones, con riesgo de infección. En Colombia no conocemos los datos epidemiológicos acerca de la incidencia de este tipo de complicaciones, ni del manejo de las mismas. Objetivo: este estudio tiene como objetivo estudiar la prevalencia de la necrosis pancreática infectada y describir los casos identificados en un hospital de alto nivel de complejidad entre 2014 y 2021. Métodos: estudio observacional de corte transversal. Se analizaron los registros de pacientes diagnosticados con pancreatitis en segunda etapa. Se estudiaron aquellos casos que presentaron necrosis pancreática infectada y se sometieron a desbridamiento más drenaje quirúrgico por vía laparoscópica y abierta en el Hospital Universitario Mayor Méderi de Bogotá, Colombia, entre enero de 2014 y enero de 2021. Se realizó un muestreo por conveniencia, sin cálculo de tamaño de muestra. Se recolectaron variables demográficas y clínicas de los pacientes. Se realizó un análisis estadístico descriptivo de las variables obtenidas en Excel. Las variables cualitativas se describieron a través de frecuencias absolutas y relativas; mientras que las cuantitativas se expresaron mediante medidas de tendencia central y de dispersión en función de su distribución. Resultados: se analizaron 1020 episodios de pancreatitis y se evidenció necrosis pancreática en 30 pacientes, es decir, una prevalencia de período de 2,9 %. De los pacientes, 83 % (n = 25) se llevó a drenajes por vía abierta, con un 48 % (n = 12) de mortalidad. En relación con el manejo por vía laparoscópica, la reducción en la falla orgánica posoperatoria fue de 40 % (n = 2), con un 30 % menos de duración en la estancia hospitalaria, comparado con la vía abierta. Aquellos pacientes que presentaron un nivel de procalcitonina (PCT) menor de 1,8 ng/mL tuvieron menos mortalidad. Conclusiones: el abordaje laparoscópico muestra resultados prometedores en cuanto a la morbilidad y mortalidad final observada.

Sample size calculations in health research: Contemporary issues and practices

@#Sample size computations, which should be done at the planning stage of the study, are necessary for research to estimate a population parameter or test a hypothesis. For causal analysis of observational databases, sample size computations are generally not needed. Post-hoc power analyses, which are typically done with non-significant findings, should not be performed since reporting post-hoc power is nothing more than reporting p values differently. While sample size calculations are typically based on the tradition of significance testing, sample size calculations based on precision are feasible – if not preferred – alternatives. Sample size calculations depend on several factors such as the study objective, scale of measurement of the outcome variable, study design, and sampling design. Computing for sample size is not as straightforward as presented in textbooks but specific strategies may be resorted to in the face of challenges and constraints.

PSS Health: como calcular tamanho de amostra para testes de comparação de médias de dois grupos / PSS Health: how to calculate sample sizes for mean comparison tests between two groups

Dando continuidade à série de artigos que pretendem orientar o usuário na utilização da ferramenta PSS Health para o planejamento de uma pesquisa, esta edição apresenta um passo a passo de como realizar o cálculo e de quais informações são necessárias para comparar médias: de dois grupos dependentes ou independentes, de dois grupos independentes com duas medidas repetidas (deltas), e com duas ou mais medidas repetidas. Todos os exemplos também são ilustrados e disponibilizados em vídeos no canal da Unidade de Bioestatística.

Following the series of articles aiming to guide users in using the PSS Health tool for research planning, this issue presents a step-by-step guide on how to calculate and what information is needed to compare means between 2 dependent or independent groups, 2 independent groups with 2 repeated measures (deltas), and 2 independent groups with 2 or more repeated measures. All examples are accompanied by figures and available in video on the Biostatistics Unit's channel.

Comparison of sampling designs from the two editions of the Brazilian National Health Survey, 2013 and 2019 / Comparação de desenhos amostrais das duas edições da Pesquisa Nacional de Saúde, 2013 e 2019 / Comparación entre diseños muestrales de las dos ediciones de la Encuesta Nacional de Salud Brasil, 2013 y 2019

Our objective is to describe the differences in the sampling plans of the two editions of the Brazilian National Health Survey (PNS 2013 and 2019) and to evaluate how the changes affected the coefficient of variation (CV) and the design effect (Deff) of some estimated indicators. Variables from different parts of the questionnaire were analyzed to cover proportions with different magnitudes. The prevalence of obesity was included in the analysis since anthropometry measurement in the 2019 survey was performed in a subsample. The value of the point estimate, CV, and the Deff were calculated for each indicator, considering the stratification of the primary sampling units, the weighting of the sampling units, and the clustering effect. The CV and the Deff were lower in the 2019 estimates for most indicators. Concerning the questionnaire indicators of all household members, the Deffs were high and reached values greater than 18 for having a health insurance plan. Regarding the indicators of the individual questionnaire, for the prevalence of obesity, the Deff ranged from 2.7 to 4.2, in 2013, and from 2.7 to 10.2, in 2019. The prevalence of hypertension and diabetes per Federative Unit had a higher CV and lower Deff. Expanding the sample size to meet the diverse health objectives and the high Deff are significant challenges for developing probabilistic household-based national survey. New probabilistic sampling strategies should be considered to reduce costs and clustering effects.

Nosso objetivo é descrever as diferenças nos desenhos amostrais das duas edições da Pesquisa Nacional de Saúde (PNS 2013 e 2019) e avaliar como suas mudanças afetaram o coeficiente de variação (CV) e o efeito do desenho (Deff) de alguns dos indicadores avaliados. Variáveis de diferentes partes do questionário foram analisadas para avaliar proporções com diferentes magnitudes. A prevalência de obesidade foi incluída na análise uma vez que a medição de antropometria na pesquisa de 2019 foi realizada em uma subamostra. Os valores do estimador pontual, CV e Deff foram calculados para cada indicador considerando a estratificação das unidades amostrais primárias, a ponderação das unidades amostrais, e o efeito do agrupamento. Para a maioria dos indicadores, CV e Deff foram menores nas estimativas de 2019. Em relação aos indicadores para todos os membros familiares, Deffs foram elevados e atingiram valores superiores a 18 para a posse de um plano de saúde. Quanto aos indicadores no questionário individual, Deff variou de 2,7 a 4,2 em 2013 e de 2,7 a 10,2 em 2019 para a prevalência de obesidade. A prevalência de hipertensão arterial e diabetes por Unidade Federativa apresentou CV maior e Deff menor. A expansão do tamanho da amostra para atender aos diversos objetivos de saúde e Deff altos são desafios expressivos para o desenvolvimento de uma pesquisa nacional domiciliar probabilística. Novas estratégias de amostragem probabilística devem ser consideradas para reduzir custos e efeitos do agrupamento.

Nuestro objetivo es describir las diferencias en los diseños muestrales de las dos ediciones de la Encuesta Nacional de Salud (PNS 2013 y 2019) y evaluar cómo sus cambios afectaron el coeficiente de variación (CV) y el efecto de diseño (Deff) de algunos de los indicadores evaluados. Se analizaron variables de diferentes partes del cuestionario para evaluar proporciones con diferentes magnitudes. La prevalencia de obesidad se incluyó en el análisis, ya que la medición de la antropometría en la encuesta de 2019 se realizó en una submuestra. Los valores del estimador puntual, CV y Deff se calcularon para cada indicador considerando la estratificación de las unidades de muestreo primarias, la ponderación de las unidades de muestreo y el efecto de agrupamiento. Para la mayoría de los indicadores, CV y Deff fueron más bajos en las estimaciones de 2019. En cuanto a los indicadores para todos los miembros de la familia, los Deff fueron altos y alcanzaron valores superiores a 18 por tener un plan de salud. En cuanto a los indicadores del cuestionario individual, Deff osciló entre 2,7 y 4,2 en 2013, y entre 2,7 y 10,2 en 2019 para la prevalencia de obesidad. La prevalencia de hipertensión arterial y diabetes por Unidad Federativa tuvo mayor CV y menor Deff. Un mayor tamaño de la muestra para cumplir con los diversos objetivos de salud y un alto valor de Deff son desafíos importantes para el desarrollo de una encuesta nacional domiciliar probabilística. Se deben considerar nuevas estrategias de muestreo probabilístico para reducir los costos y efectos de agrupamiento.

PSS Health: como calcular tamanho de amostra para testar relações de variáveis com um desfecho binário / PSS Health: how to calculate the sample size to test variables relationships with a binary outcome

Dando continuidade à série de artigos que pretendem orientar o usuário na utilização da ferramenta PSS Health para o planejamento de uma pesquisa, esta edição apresenta um passo a passo de como realizar o cálculo para tamanho de amostra e de quais informações são necessárias para testar relações estatísticas entre variáveis e um desfecho binário: comparação de proporções entre grupos independentes (dois ou mais), comparação de duas proporções dependentes e regressão logística. Todos os exemplos também são ilustrados e disponibilizados em vídeos no canal da Unidade de Bioestatística.

Following the series of articles that aim to guide the user in using the PSS Health tool for planning research, this issue presents a step-by-step guide on how to perform the sample size calculation and what information is needed to test statistical relationships between variables and a binary outcome: comparison of proportions between independent groups (two or more), comparison of two dependent proportions, and logistic regression. All examples are also illustrated and available in videos on the Biostatistics Unit's channel.

Statistical methods for relative risk estimation and applications in case-cohort study / 中华流行病学杂志

Objective: To systematically introduce the design of case-cohort study and the statistical methods of relative risk estimation and their application in the design. Methods: First, we introduced the basic principles of case-cohort study design. Secondly, Prentice's method, Self-Prentice method and Barlow method were described in the weighted Cox proportional hazard regression models in detail, finally, the data from the Shanghai Women's Health Study were used as an example to analyze the association between obesity and liver cancer incidence in the full cohort and case-cohort sample, and the results of parameters from each method were compared. Results: Significant association was observed between obesity and risk for liver cancer incidence in women in both the full cohort and the case-cohort sample. In the Cox proportional hazard regression model, the partial regression coefficients of the full cohort and the case-cohort sample fluctuated with the adjustment of confounding factors, but the hazard ratio estimates of them were close. There was a difference in the standard error of the partial regression coefficient between the full cohort and the case-cohort sample. The standard error of the partial regression coefficient of the case-cohort sample was larger than that of the full cohort, resulting in a wider 95% confidence interval of the relative risk. In the weighted Cox proportional hazard regression model, the standard error of the partial regression coefficient of Prentice's method was closer to the parameter estimates from full cohort than Self-Prentice method and Barlow method, and the 95% confidence interval of hazard ratio was closer to that of the full cohort. Conclusions: Case-cohort design could yield parameter results closer to the full cohort by collecting and analyzing data from sub-cohort members and patients with the disease, and reduce sample size and improve research efficiency. The results suggested that Prentice's method would be preferred in case-cohort design.

Spatial distribution and sample size to estimate Lycosa erythrognatha (Araneae: Lycosidae) population density overwintering / Distribuição espacial e tamanho de amostra para estimar a densidade populacional de Lycosa erythrognatha (Araneae: Lycosidae) durante o inverno

Abstract Lycosa erythrognatha Lucas, 1833 (Araneae: Lycosidae) is a predatory arthropod with potential for conservation biological control. In addition to being considered a bioindicator of environmental quality, this arthropod provides an important service for agriculture by reducing insect-pest populations. In this work we seek to understand how the plants Andropogon bicornis L., Saccharum angustifolium Nees and Eustachys retusa Lag (Poales: Poaceae) and their different clump sizes affect the population density, spatial distribution and determination of the minimum number of samples to estimate its population density during the winter. Among the evaluated host plants, S. angustifolium and A. bicornis presented higher population density than E. retusa, but we observed that the clump diameter significantly influences the population density and the minimum number of samples. We observed a gregarious behavior in plants of A. bicornis and E. retusa. For S. angustifolium, a uniform distribution was observed.

Resumo Lycosa erythrognatha Lucas, 1833 (Araneae: Lycosidae) é um artrópode predador com potencial para controle biológico de conservação. Além de ser considerado um bioindicador da qualidade ambiental, esse artrópode fornece um importante serviço para a agricultura, reduzindo as populações de insetos-praga. Neste trabalho buscamos entender como as plantas Andropogon bicornis L., Saccharum angustifolium Nees e Eustachys retusa Lag (Poales: Poaceae) e seus diferentes tamanhos de touceira afetam a densidade populacional, distribuição espacial e a determinação do número mínimo de amostras para estimar sua densidade populacional durante o inverno. Entre as plantas hospedeiras avaliadas, S. angustifolium e A. bicornis apresentaram maior densidade populacional que E. retusa, observamos que o diâmetro da touceira influencia significativamente a densidade populacional e o número mínimo de amostras. Observamos um comportamento gregário nas plantas de A. bicornis e E. retusa. Para S. angustifolium, uma distribuição uniforme foi observada.

Decreased circulatory levels of Vitamin D in Vitiligo (ViViD Study): a meta-analysis

Abstract Background: The serum Vitamin D status in patients with vitiligo is ambiguous when compared to controls. A systematic review and updated meta-analysis were conducted to evaluate the association between Vitamin D and vitiligo. Methods: Relevant studies were identified by searching PubMed and other databases. The random effects model was used to obtain standardized mean differences and pooled correlation coefficients. Meta-regression and sub-group analyses were conducted to explore heterogeneity. The presence of publication bias and the study robustness were tested using funnel plot and sensitivity analyses, respectively. Results: This meta-analysis finally included 31 studies. Compared with controls, vitiligo patients showed significantly decreased serum Vitamin D levels (standardized mean difference = −1.03; p < 0.0001). The sub-group analysis showed that vitiligo patients with indoor/urban work had a significantly lower Vitamin D level when compared to their outdoor/rural counterparts (standardized mean differences = −0.45; p = 0.03). The sensitivity analysis indicated that no single study had a significant influence on the overall outcome, suggesting the robustness of this meta-analysis. Study limitations: Varied sample sizes and heterogeneous study populations from different countries are the limitations of this study. However, the between-study heterogeneity has been addressed by the random-effects model with meta-regression and sensitivity analyses. Conclusions: This meta-analysis showed significantly decreased Vitamin D level in vitiligo, and its association with indoor/outdoor type of work of vitiligo patients. This study highlights the need to assess Vitamin D status for improving its level in vitiligo.

Decreased circulatory levels of Vitamin D in Vitiligo: a meta-analysis

Abstract Background: The serum Vitamin D status in patients with vitiligo is ambiguous when compared to controls. A systematic review and updated meta-analysis were conducted to evaluate the association between Vitamin D and vitiligo. Methods: Relevant studies were identified by searching PubMed and other databases. The random effects model was used to obtain standardized mean differences and pooled correlation coefficients. Meta-regression and sub-group analyses were conducted to explore heterogeneity. The presence of publication bias and the study robustness were tested using funnel plot and sensitivity analyses, respectively. Results: This meta-analysis finally included 31 studies. Compared with controls, vitiligo patients showed significantly decreased serum Vitamin D levels (standardized mean difference = −1.03; p < 0.0001). The sub-group analysis showed that vitiligo patients with indoor/urban work had a significantly lower Vitamin D level when compared to their outdoor/rural counterparts (standardized mean differences = −0.45; p = 0.03). The sensitivity analysis indicated that no single study had a significant influence on the overall outcome, suggesting the robustness of this meta-analysis. Study limitations: Varied sample sizes and heterogeneous study populations from different countries are the limitations of this study. However, the between-study heterogeneity has been addressed by the random-effects model with meta-regression and sensitivity analyses. Conclusions: This meta-analysis showed significantly decreased Vitamin D level in vitiligo, and its association with indoor/outdoor type of work of vitiligo patients. This study highlights the need to assess Vitamin D status for improving its level in vitiligo.

Comparación entre trazados cefalométricos manual y digital en radiografías laterales del cráneo / Comparison between Manual and Digital Cephalometric Tracing in Side Radiographies of the Skull

Resumen Objetivo: Evaluar la diferencia del trazado cefalométrico manual con el digital en radiografías laterales de cráneo. Materiales y métodos: Inicialmente se realizó un piloto para calibrar al investigador principal, en donde se analizaron 10 radiografías pertenecientes a cinco pacientes del Servicio de Radiología del Centro Odontológico de nuestra institución para evaluar la concordancia entre los dos evaluadores y establecer el tamaño de la muestra. Finalmente, se analizaron 78 radiografías cefalométricas de 39 pacientes, en las que se realizó el trazado cefalométrico de Steiner manual y digital. Esas radiografías se analizaron en una escala 1:1 y posteriormente se evaluó la diferencia de las mediciones mediante el análisis univariado, se determinó en mediana e intervalo intercuartil por separado. En el análisis bivariado, se aplicó la prueba de signo de rangos de Wilcoxon y muestras pareadas para determinar la diferencia de las mediciones cefalométricas de Steiner entre el tipo del análisis cefalométrico. El nivel de significancia se fijó en p < 0,05 y confiabilidad al 95%, respectivamente. Resultados: No hubo diferencia significativa en la mayoría de las mediciones hechas de manera manual y digital, siendo el ángulo interincisal la única medición angular en la cual hubo diferencia significativa al obtener un resultado de p = 0,002. Mientras tanto, en las mediciones lineales, la única medición en la que hubo diferencia significativa fue en el segmento incisivo inferior - NB con p = 0,005. Conclusión: No se encuentran diferencias significativas entre el trazado cefalométrico manual y el digital. No obstante, es importante tener en cuenta que la muestra o población evaluada es reducida para definir conclusiones.

Abstract Objective: To evaluate the difference of the manual cephalometric tracing with the digital tracing on lateral cranial radiographs. Materials and Methods: Initially, a pilot study was carried out to calibrate the principal investigator, where 10 radiographs belonging to 5 patients of the Radiology Service of the Dental Center, were analyzed to evaluate the intraclass concordance between the two evaluators. To establish the size of the sample, finally, 78 cephalometric radiographs of 39 patients were analyzed, in which the manual and digital Steiner cephalometric tracing was performed. These radiographs were analyzed on a 1: 1 scale and then the difference of the measurements was evaluated using the univariate analysis, which was determined in the median and interquartile range, separately. In the bivariate analysis, the Wilcoxon rank sign test and paired samples were applied to determine the difference of Steiner's cephalometric measurements between the cephalometric analysis type. The level of significance was set at p < 0.05 and 95% reliability, respectively. Results: There was no significant difference in most of the measurements made manually and digitally. The interincisal angle the only angular measurement in which there was a significant difference when obtaining a result of p = 0.002, while, in the linear measurements, the only measurement in which there was significant difference was in the lower incisor segment - NB with p = 0.005. Conclusion: There is no significant difference between manual and digital cephalometric tracing, nevertheless it is important to keep in mind that the simple or population evaluated is reduced to define conclusions.

Qualidade de vida e desfechos em longo prazo após hospitalização por COVID-19: Protocolo para um estudo de coorte prospectivo (Coalizão VII) / Quality of life and long-term outcomes after hospitalization for COVID-19: Protocol for a prospective cohort study (Coalition VII)

RESUMO Introdução: Os efeitos provocados pela COVID-19 em longo prazo são desconhecidos. O presente estudo tem como objetivo avaliar os fatores associados com a qualidade de vida relacionada à saúde e os desfechos em longo prazo em sobreviventes à hospitalização por COVID-19 no Brasil. Métodos: Este será um estudo multicêntrico de coorte prospectivo, aninhado em cinco ensaios clínicos randomizados desenhados para avaliar os efeitos dos tratamentos específicos para COVID-19 em mais de 50 centros no Brasil. Pacientes adultos sobreviventes à hospitalização por infecção por SARS-CoV-2 comprovada ou suspeita serão seguidos por um período de 1 ano, por meio de entrevistas telefônicas estruturadas. O desfecho primário é o escore de utilidade para qualidade de vida relacionada à saúde após 1 ano, avaliado segundo o questionário EuroQol-5D3L. Os desfechos secundários incluirão mortalidade por todas as causas, eventos cardiovasculares graves, reospitalizações, retorno ao trabalho ou estudo, condição funcional física avaliada pelo instrumento Lawton-Brody Instrumental Activities of Daily Living, dispneia avaliada segundo a escala de dispneia modificada do Medical Research Council, necessidade de suporte ventilatório em longo prazo, sintomas de ansiedade e depressão avaliados segundo a Hospital Anxiety and Depression Scale, sintomas de transtorno de estresse pós-traumático avaliados pela ferramenta Impact of Event Scale-Revised e autoavaliação da condição de saúde, conforme a Escala Visual Analógica do EuroQol-5D3L. Serão utilizadas equações de estimativas generalizada para testar a associação entre cinco conjuntos de variáveis (1 - características demográficas, 2 - condição de saúde pré-morbidade, 3 - características da doença aguda, 4 - terapias específicas para COVID-19 recebidas e 5 - variáveis pós-alta atualizadas) e desfechos. Ética e disseminação: O protocolo do estudo foi aprovado pelos Comitês de Ética em Pesquisa de todas as instituições participantes. Os resultados serão disseminados por meio de conferências e periódicos revisados por pares.

Abstract Introduction: The long-term effects caused by COVID-19 are unknown. The present study aims to assess factors associated with health-related quality of life and long-term outcomes among survivors of hospitalization for COVID-19 in Brazil. Methods: This is a multicenter prospective cohort study nested in five randomized clinical trials designed to assess the effects of specific COVID-19 treatments in over 50 centers in Brazil. Adult survivors of hospitalization due to proven or suspected SARS-CoV-2 infection will be followed-up for a period of 1 year by means of structured telephone interviews. The primary outcome is the 1-year utility score of health-related quality of life assessed by the EuroQol-5D3L. Secondary outcomes include all-cause mortality, major cardiovascular events, rehospitalizations, return to work or study, physical functional status assessed by the Lawton-Brody Instrumental Activities of Daily Living, dyspnea assessed by the modified Medical Research Council dyspnea scale, need for long-term ventilatory support, symptoms of anxiety and depression assessed by the Hospital Anxiety and Depression Scale, symptoms of posttraumatic stress disorder assessed by the Impact of Event Scale-Revised, and self-rated health assessed by the EuroQol-5D3L Visual Analog Scale. Generalized estimated equations will be performed to test the association between five sets of variables (1- demographic characteristics, 2- premorbid state of health, 3- characteristics of acute illness, 4- specific COVID-19 treatments received, and 5- time-updated postdischarge variables) and outcomes. Ethics and dissemination: The study protocol was approved by the Research Ethics Committee of all participant institutions. The results will be disseminated through conferences and peer-reviewed journals.

PSS Health: como calcular tamanho de amostra para estimar média, proporção e correlação / PSS Health: how to calculate a sample size to estimate means, proportions, and correlations

A ferramenta PSS Health (Power and Sample Size for Health Researchers) foi desenvolvida com o propósito de facilitar o cálculo do tamanho amostral e do poder de testes de hipóteses para diferentes objetivos de estudo, usando interface amigável e terminologia comum à área da saúde. Este é o primeiro de uma série de artigos que pretendem orientar o usuário na utilização da ferramenta PSS Health para o planejamento de uma pesquisa. Neste artigo, se ensina como utilizar o PSS Health quando o objetivo principal do estudo é estimar uma média, estimar uma proporção (prevalência ou incidência) ou estimar uma correlação. São disponibilizados vídeos demonstrando o uso da ferramenta em cada um dos contextos citados. (AU)

The PSS Health (Power and Sample Size for Health Researchers) tool was developed with the purpose of facilitating the calculation of sample size and power of hypothesis tests for different study objectives, based on a user-friendly interface and common health care terminology. This is the first in a series of articles intending to guide the user in how to use the PSS Health tool for planning a research project. This article teaches how to use PSS Health when the main objective of the study is to estimate means, proportions (prevalence or incidence), or correlations. Videos showing how to use the tool in each of the mentioned contexts are available. (AU)

Sample size estimation in acupuncture and moxibustion clinical trials / 中国针灸

The appropriate sample size estimation is very important in the design of clinical trials. However, insufficient or inappropriate sample size estimation is still a prominent problem in the currently published acupuncture and moxibustion clinical trials. At present, the superiority test, non-inferiority test and equivalence test have been widely used in acupuncture and moxibustion clinical trials. This article focuses on the application, calculation methods and PASS11 software using of these three hypothesis test types. In view of the problems in the estimation of sample size in acupuncture and moxibustion clinical trials, the particularity of sample size estimation in acupuncture and moxibustion is summarized from the aspects of parameter setting, ratio of intervention group and control group, and multi-group comparison, in order to guide acupuncture clinical researchers to correctly estimate sample size when conducting clinical trials.

Estrés Académico en Alumnos Ingresantes a la Carrera de Odontología en la Universidad Nacional de Córdoba, Argentina / Academic Stress of Freshmen Students at the Faculty of Dentistry Universidad Nacional de Cordoba, Argentina

RESUMEN: El estrés es un estado de inestabilidad y angustia emocional que dificulta la capacidad para concentrarse y funcionar eficazmente de forma rutinaria. En el ámbito de la educación, el estrés académico cuenta con tres dimensiones: estresores, reacciones sobre la salud en general y los reguladores del estrés. Varios estudios han señalado que los estudiantes de carreras de la salud pueden estar expuestos a niveles de estrés más elevados que la población en general. El propósito de este estudio fue evaluar el estrés académico autopercibido en alumnos ingresantes a la Carrera de Odontología de la Universidad Nacional de Córdoba (Córdoba, Argentina). Se realizó un estudio descriptivo, donde la muestra estuvo conformada por 291 estudiantes. La información se recolectó a través del cuestionario autoadministrado Inventario Sisco del Estrés Académico (Barraza Macías, 2007a,b). El análisis de los datos se llevó a cabo empleando baremos específicos, y para la asociación entre variables se utilizaron las pruebas de Pearson y Anova, fijando el nivel de significación estadística en p<0,05. Una mayoría significativa de los alumnos (98,3 %) presentó estrés académico, con un 88,81 % de los participantes inclinándose por las categorías de intensidad más altas de estrés. Se identificó una muy significativa correlación entre las dimensiones Estresores y Reacciones (p<0,001) y entre Estresores y Estrategias (p= 0,034). La identificación de estrés académico, su caracterización y la prevención respecto a la potencial instalación de hábitos o empleo de medicamentos en muchos casos insalubres, permitirá desarrollar estrategias que favorezcan a los estudiantes el poder hacer frente a las situaciones que el nuevo entorno demanda.

ABSTRACT: Stress is a state of instability and emotional anguish that complicates the ability to focus and function effectively on a routine basis. In educational science, it is called academic stress encompassing three dimensions: stressors, general health reactions, and stress regulators. Several studies have indicated that health career students may be exposed to higher stress levels than the general population. The aim of this study was to evaluate the self-perceived academic stress in freshmen students at the Faculty of Dentistry, Universidad Nacional de Cordoba (Cordoba, Argentina). A descriptive study was carried out, where the sample consisted of 291 students. The information was collected through the self-administered questionnaire Sisco Inventory of Academic Stress (Barraza Macias, 2007). Data analysis was carried out using specific scales, and for the association between variables, Pearson and Anova tests were used, setting the level of a statistical significance at p<0.05. A significant majority of the students (98.3 %) presented academic stress, with 88.81 % of participants leaning towards the highest intensity categories of stress. A very significant correlation was identified between the Stressors and Reactions dimensions (p<0.001) and between Stressors and Strategies (p=0.034). The identification of academic stress, its characterization and prevention of potential habits or use of medication often considered unhealthy, will promote the development of strategies for students, in order to better face situations encountered in the new environment.

Valoración del riesgo de caries dental en niños de 6 a 11 años de edad de la unidad educativa Jorge Escudero de la ciudad de Quito mediante el instrumento CAT / Assessment of dental caries risk in children from 6 to 11 years of age of the Jorge Escudero educational unit of the city of Quito through the CAT instrument

RESUMEN Objetivo: Valorar el riesgo de caries dental en niños de 6 a 11 años de edad de la Unidad Educativa Jorge Escudero de la ciudad de Quito mediante el instrumento CAT. Materiales y métodos: Estudio transversal realizado en 283 niños de 6 a 11 años de edad. Se evaluó el riesgo de caries mediante el instrumento validado CAT (Caries-risk Assessment Tool), el cual consta de 14 ítems, dividido en dos partes: un cuestionario dirigido a los padres de familia, complementándose con una exploración clínica oral al niño, previa estandarización de criterios con el fin de minimizar la variabilidad inter-examinador. Se realizó una prueba piloto en 20 personas adultas que no pertenezcan al tamaño de la muestra. Resultados: Se obtuvo un 98,2% de riesgo alto de caries y un 1,8% de riesgo moderado. No hubo diferencias significativas en la edad del niño donde (p=0,057) fue superior a 0,05, sin embargo en el sexo femenino frente al masculino hubo diferencia significativa de (p = 0,024). El nivel socioeconómico está directamente relacionado con el riesgo alto de caries, donde (p = 0,002). Conclusión: Se evidenció que los principales factores de riesgo de caries dental son la presencia de placa bacteriana visible y la presencia de zonas de esmalte desmineralizadas. Además existe una correlación pequeña o casi nula en lo que refiere a lo indicado por parte de los padres de familia en la encuesta y lo observado durante el examen clínico del niño con respecto al riego de caries

ABSTRACT Objective: To assess the dental caries risk in children from 6 to 11 years of age of the Jorge Escudero Educational Unit of the city of Quito through the CAT instrument. Materials and methods: Cross-sectional study conducted on 283 children aged 6 to 11 years old. The caries risk was assessed using the validated CAT (Caries-risk Assessment Tool), which consists of 14 items, divided into two parts: a questionnaire addressed to the parents, complemented by an oral clinical examination of the child, prior standardization of criteria in order to minimize inter-examiner variability. A pilot test was performed on 20 adults who do not belong to the sample size. Results: There was a 98.2% high risk of caries and a 1.8% moderate risk. There were no significant differ-ences in the age of the child where (p = 0.057) was greater than 0.05; however, in female versus male there was a significant difference of (p = 0.024). The socioeconomic level is directly related to the high risk of caries, where (p = 0.002). Conclusion: It was evidenced that the main risk factors for dental caries are the presence of visible bacterial plaque and the presence of demineralized enamel areas. In addition, there is a small or almost zero correla-tion regarding what is indicated by the parents in the survey and what was observed during the clinical examination of the child regarding the caries risk.