Estudios de corte transversal: un diseño de investigación a considerar en ciencias morfológicas / Cross section studies: a research design to consider in morphological sciences

Los estudios de corte transversal (ECT) inician en la década de los 40 en países Europeos. Los ECT corresponden a investigaciones de tipo observacional que permiten estudiar prevalencia de enfermedad, determinar asociación entre variables y el desarrollo de un efecto de interés, conocer propiedades de una prueba diagnóstica, y censar poblaciones; describiendo las características de una población en un momento y lugar determinado. Esto implica, que no se requieren periodos de seguimiento, que no son prospectivos ni retrospectivos; características que permiten que sean más baratos y fáciles de realizar en relación a los estudios longitudinales. Por otro lado, al ser de carácter descriptivo sirven como insumo y evidencia preliminar para estudios de mayor complejidad metodológica, como estudios de cohortes. Sin embargo, tienen limitantes y sesgos que deben ser considerados por los investigadores. El objetivo de este manuscrito fue generar un documento de estudio para revisar características esenciales, fortalezas y debilidades; discutir cuestiones metodológicas de los ECT en ciencias de la salud; y proporcionar algunos ejemplos obtenidos de la literatura, para mejor comprensión del diseño.

SUMMARY: Cross-sectional studies (CSS) began European countries in the 1940s in. The CSSs correspond to observational-type investigations that allow studying the prevalence of disease, determining the association between variables and the development of an effect of interest, discovering the properties of a diagnostic test, and censusing populations, describing the characteristics of a population at a given time and place. This implies that follow-up periods are not required, and that they are neither prospective nor retrospective. These characteristics allow them to be cheaper and easier to perform in relation to longitudinal studies. On the other hand, being descriptive in nature, they serve as input and preliminary evidence for studies of greater methodological complexity, such as cohort studies. However, they have limitations and biases that must be considered by researchers. The aim of this manuscript was to generate a study document to review essential characteristics, strengths and weaknesses; discuss methodological issues of ECT in health sciences; and provide some examples obtained from the literature, for a better understanding of the design.

Principales sesgos en la investigación epidemiológica en salud ocupacional / Main biases in epidemiological research in occupational health

El objetivo de este documento es mostrar una síntesis de los principales sesgos que pueden aparecer en el estudio de la salud del trabajo, sus orígenes y consecuencias. Para ello, se realizó una revisión documental de libros y artículos publicados en los últimos 10 años en inglés y español. Se dejó fuera aquellos documentos que no estuvieran publicados en revistas con comité editorial y en caso de los libros, que no tuvieran registro ISBN. Se incluyeron 7 libros y 14 artículos. Un sesgo es un error sistemático, que sucede en el proceso de investigación y que pueden darse durante la planeación, recolección y procesamiento de datos. Se revisarán dos tipos principales de sesgos: 1) Selección y 2) Información y/o medición, en cada caso se describe la definición, potencial impacto en los resultados y se plantean una serie de ejemplos que ayudan a su compresión. Uno de los efectos principales de la presencia de sesgos en investigación es que ocasiona un error de clasificación en los participantes, que puede ser diferencial o no, esto impacta los resultados al sobre o subestimarlos, en otras palabras, se encuentran efectos mayores a los reales o peor, no los encontramos cuando si existen. Para ilustrar el impacto de los sesgos, se revisan distintos escenarios que ejemplifican los casos de sobreestimación y subestimación que originan resultados poco confiables(AU)

This document aims to show a synthesis of the main biases that can be present in occupational health studies, their origins and their consequences. For this purpose, a documentary review was conducted of books and articles published in the last 10 years in English and Spanish. Excluding those documents that were not published in journals with an editorial board and, in the case of books, that did not have an ISBN registry. A total of 7 books and 14 articles were included. A bias is a systematic error that occurs in the research process and can occur during the data planning, collection, and processing. Two main types of biases will be reviewed: 1) Selection and 2) Information and/or measurement biases, in each case their definition and, their possible impact on the results are described, a series of examples that may help to understand them are provided. One of the main effects of the presence of biases in research is that they cause an error in the classification of participants, which can be differential or not, and this has an impact on the results by overestimating or underestimating them, i.e., finding stronger effects than the real ones, or worse, not finding them when they exist. To illustrate the impact of biases, different scenarios were reviewed that provide examples of cases of overestimation and underestimation that lead to unreliable results(AU)

Transtorno de Estresse Pós-traumático e funções executivas em adultos: uma revisão sistemática / Posttraumatic Stress Disorder and executive functions in adults: a systematic review / Trastorno de Estrés Postraumático y funciones ejecutivas en adultos: una revisión sistemática

O Transtorno do Estresse Pós-traumático (TEPT) é caracterizado por apresentar sintomas de desconforto e medo diante de situações diretas e/ou imaginadas em relação a experiências que ameaçam a integridade pessoal. As Funções Executivas (FE) são processos responsáveis pela análise de uma situação, tomada de decisão e ações voltadas à resolução de problemas. Sabe-se que o TEPT está associado a prejuízos em diferentes dimensões das FE. Deste modo, o presente estudo investigou a produção científica sobre o tema feita nos últimos 12 anos. Duzentos e três registros foram identificados e 18 deles cumpriram os critérios de inclusão. A avaliação das pesquisas incluídas nesta revisão apontou o comprometimento das funções executivas e a reabilitação neuropsicológica mostrou-se eficiente como estratégia de intervenção para adultos diagnosticados com TEPT. A ausência de informações sobre a intensidade dos sintomas presentes no TEPT foi uma limitação comum aos estudos encontrados nesta pesquisa.(AU)

Posttraumatic Stress Disorder (PTSD) is characterized by symptoms of uneasiness and fear when faced with direct and/or imagined situations related to experiences that threaten personal integrity. Executive Functions (EF) are processes defined by situational analysis, making decisions and taking actions to solve problems. It is known that PTSD is associated with dysfunctions in different dimensions of EF. Accordingly, the present study investigated the scientific production on the subject considering the last 12 years. A total of203 records were identified, with 18 of them meeting the inclusion criteria. The evaluation of the studies included in this review showed the impairment of EF and that neuropsychological rehabilitation has proven to be an efficient intervention strategy for adults diagnosed with PTSD. The absence of information about the intensity of symptoms present in PTSD was a common limitation of the studies found in this review.(AU)

El Trastorno de Estrés Postraumático (TEPT) se caracteriza por presentar síntomas de malestar y miedo ante situaciones directas y/o imaginadas en relación con experiencias que amenazan la integridad personal. Las Funciones Ejecutivas (FE) son procesos definidos por el análisis de una situación, toma de decisiones y acciones encaminadas a la resolución de problemas. Se sabe que el TEPT está asociado con disfunciones en diferentes dimensiones de la FE. De esta manera, el presente estudio investigó la producción científica sobre el tema en los últimos 12 años. Se identificaron 203 registros y 18 de ellos cumplieron los criterios de inclusión. La evaluación de los estudios incluidos en esta revisión mostró que el compromiso de las funciones ejecutivas, y la rehabilitación neuropsicológica, demostró ser eficiente como estrategia de intervención para adultos diagnosticados con TEPT. La ausencia de información sobre la intensidad de los síntomas presentes en el TEPT fue una limitación común de los estudios encontrados en esta investigación.(AU)

Who really counts in Iran's National Food Assistance Program? Lessons from multi-stakeholder processes in the wicked policy area of food security / Quem importa realmente no Programa Nacional de Assistência Alimentar do Irã? Lições dos processos com múltiplos atores na área política complexa de segurança alimentar / ¿A quién se tiene en cuenta realmente en el Programa Nacional de Asistencia Alimentaria en Irán? Lecciones sobre procesos con participación múltiple en la complicada área de política de seguridad alimentaria

Abstract: Multi-stakeholder processes - as a necessary part in the development of public policies - can provide diverse perspectives to inform and to improve food security policy-making. Iran's National Food Assistance Program (NFAP) is one of the major welfare programs in Iran that reduces food insecutiry to low-income households. This study aimed to identify and to categorize actual and potential stakeholders in NFAP using the stakeholder salience model. According to Mitchell's theory, stakeholders' attributes (power, legitimacy, and urgency) were assessed based on the nature of their interactions, roles, and level of engagement. Results revealed a number of significant but marginalized stakeholders, including Iranian Ministry of Health (office of community nutrition improvement), academia, center for food and nutrition research, target group, charities, and international organizations, who have not received any targeted organizational attention and priority to their claims. The unbalanced attention provided to some stakeholder groups characterized as "definitive" and "dominant" and ignoring some important ones will jeopardize long-term viability and undermine support for the program with inevitable declines in legitimacy. Understanding the change in the stakeholders' characteristics is the main variable to determine the allocation of organizational resources in response to different and rising stakeholders' demands and possibly the projects outcomes. This will facilitate and enhance the possibility of knowledge exchange and learning, and greater trust among stakeholders during the food and nutrition policy-making process.

Resumo: Os processos com múltiplos atores (multi-stakeholder), como parte necessária do desenvolvimento de políticas públicas, podem ajudar a reunir perspectivas diversas para informar e melhorar as políticas de segurança alimentar. O Programa Nacional de Assistência Alimentar do Irã (NFAP) é um dos maiores programas de bem-estar social no Irã, e que fornece apoio a famílias de baixa renda para reduzir a insegurança alimentar. O estudo teve como objetivo identificar e categorizar os atores atuais e potenciais envolvidos no NFAP, usando o modelo de stakeholder salience). De acordo com a teoria de Mitchell, os atributos (poder, legitimidade e urgência) foram avaliados com base na natureza de suas interações, papeis e níveis de engajamento. Os resultados revelaram uma série de atores importantes, porém marginalizados, incluindo o Ministério da Saúde do Irã (Divisão de Melhoria Nutricional Comunitária), academia, centros de pesquisas em alimentação e nutrição, grupo-alvo, filantropias e organizações internacionais, que não receberam nenhuma atenção institucional dirigida ou prioritária quanto às suas demandas. O desequilíbrio da atenção prestada a alguns dos grupos interessados, caracterizados como "definitivos" e "dominantes", ignorando outros atores importantes, irá prejudicar a viabilidade no longo prazo e reduzir o apoio para o programa, com um declínio inevitável na legitimidade. A compreensão da mudança nas características dos atores é a principal variável na determinação da alocação dos recursos institucionais na resposta às diversas e crescentes demandas dos atores, e possivelmente dos resultados dos projetos. Tal compreensão facilitará e fortalecerá a troca de conhecimentos e lições, além de maior confiança mútua entre os atores durante o processo de políticas de alimentação e nutrição.

Resumen: Los procesos de participación múltiple, constituyen una parte necesaria en el desarrollo de políticas públicas, puesto que pueden ayudar a presentar diversas perspectivas, así como informar y mejorar la creación de políticas públicas en seguridad alimentaria. El Programa Nacional de Asistencia Alimentaria de Irán (NFAP) es uno de los principales programas de bienestar social en Irán, que proporciona ayuda a los hogares con bajos ingresos, a fin de reducir la inseguridad alimentaria. El objetivo del estudio fue identificar y categorizar a los actuales y potenciales participantes múltiples en el NFAP, utilizando un modelo de copartícipes relevantes. Los atributos de las partes interesadas (poder, legitimidad y urgencia), según la teoría de Mitchell, fueron evaluados basados en la naturaleza de sus interacciones, roles, y nivel de implicación. Los resultados revelaron un número de copartícipes importantes, pero marginalizados, incluyendo el Ministerio de Salud de Irán (Departamento de Mejora de la Nutrición en la Población), instituciones académicas, centros de investigación de alimentación y nutrición, así como grupos objetivo, organizaciones de beneficencia, y organizaciones internacionales, que no habían recibido ninguna atención específica institucional, ni ninguna prioridad en sus reclamaciones. La atención desequilibrada, otorgada a alguno de los grupos partícipes, caracterizada como "definitiva" y "dominante", e ignorando algunas otras importantes, pondrá en peligro a largo plazo la viabilidad y socavará el apoyo para el programa con su inevitable declive en términos de legitimidad. Entender el cambio en las características de los participantes es la variable principal para determinar la asignación de los recursos organizativos, en respuesta a las diferentes y crecientes demandas de los participantes, así como posiblemente a los resultados de los proyectos. Esto facilitará y acrecentará la posibilidad de intercambio de conocimiento y aprendizaje, así como una mayor confianza entre los partícipes durante los procesos de políticas alimentarias y nutricionales.

Sampling bias in Brazilian studies on transgender and gender diverse populations: the two-step measure for assessing gender identity in surveys / Viés amostral em estudos brasileiros sobre populações transgênero e não binárias: a medida de dois passos para avaliar a identidade de gênero / Muestras con sesgo en estudios brasileños sobre poblaciones transgénero o de género diverso: modelo de dos etapas para evaluar la identidad de género

Abstract: Correctly recognizing gender identity in population-based surveys is essential to develop effective public health strategies to improve the living conditions of transgender and gender-diverse populations, as well as to adequately collect data on cisgender individuals. This study aims to present the two-step measure as the best strategy for assessing gender identity in Brazilian surveys, thus we performed two separate analyses. Firstly, we conducted a systematic review concerning HIV-related care among Brazilian transgender and gender-diverse populations to assess the strategy used to identify participants' gender identity. Secondly, we re-analyzed data from a recent survey that included Brazilian transgender populations, comparing characteristics and health outcomes from the sample identified by single-item and by the two-step measure. Concerning the systematic review, from 6,585 references, Brazilian research teams published seven articles, and only one study used the two-step measure. Regarding this survey, the two-step measure recognized 567 cisgender and 773 transgender and gender diverse participants among the 1,340 participants who answered the questionnaire, whereas the single-item measure was able to recognize only 540 transgender and gender diverse people. Furthermore, 31 transgender women self-identified as "transgender men" on the single-item measure. Therefore, although scarcely used in Brazil, the two-step measure is a more accurate strategy to recognize gender identity.

Resumo: O reconhecimento correto da identidade de género em inquéritos populacionais é essencial para desenvolver estratégias eficazes de saúde pública para melhorar as duras condições de vida das populações transgênero e não binárias, além de coletar dados adequados sobre pessoas cisgênero. O estudo tem como objetivo apresentar a medida de dois passos como a melhor estratégia para avaliar a identidade de gênero em inquéritos brasileiros. Para tanto, fizemos duas análises separadas. Primeiro, realizamos uma revisão sistemática sobre a assistência relacionada ao HIV em populações transgênero e não binárias brasileiras para avaliar a estratégia aplicada ao reconhecimento da identidade de gênero dos participantes. Depois, reanalisamos os dados de um inquérito recente que incluiu populações transgênero brasileiras, comparando as características e os desfechos de saúde na amostra identificada com as medidas de item único e de dois passos, respectivamente. Quanto à revisão sistemática, entre 6.585 referências, sete artigos foram publicados por pesquisadores brasileiros, e apenas um estudo aplicou a medida de dois passos. Com relação ao inquérito, a medida de dois passos reconheceu 567 pessoas cisgênero e 773 pessoas transgênero e não binárias entre os 1.340 participantes que iniciaram o questionário, enquanto a medida de item único reconheceu somente 540 pessoas transgênero e não binárias. Além disso, 31 mulheres transgênero se identificaram como "homens transgênero", quando foi usada a medida de item único. Portanto, embora a medida de dois passos seja pouco aplicada no Brasil, é uma estratégia mais precisa para reconhecer a identidade de gênero.

Resumen: Reconocer correctamente la identidad de género en las encuestas basadas en población es esencial para desarrollar estrategias públicas de salud efectivas, con el objeto de mejorar las duras condiciones de vida de las poblaciones transgénero y de género diverso, así como recabar adecuadamente datos sobre personas cisgénero. El objetivo de este estudio es presentar un modelo de dos etapas como la mejor estrategia para evaluar la identidad de género en encuestas brasileñas. Para tal fin, se realizaron dos análisis separados. En primer lugar, se llevó a cabo una revisión sistemática relacionada con los cuidados recibidos por la población transgénero brasileña con VIH y poblaciones de género diverso, con el fin de evaluar la estrategia aplicada para reconocer la identidad de género de los participantes. En segundo lugar, volvimos a analizar los datos de una encuesta reciente, que incluyó a poblaciones transgénero brasileñas, comparando características y resultados de salud de la muestra identificada por un modelo de ítem único y por el modelo de dos etapas. Respecto a la revisión sistemática, de las 6.585 referencias se publicaron siete artículos por parte de equipos de investigación brasileños, y solamente un estudio donde se aplicó el modelo de dos etapas. Respecto a esta encuesta, el modelo de dos etapas reconoció a 567 cisgénero y 773 transgénero, así como a participantes de género diverso, entre los 1.340 participantes que realizaron el cuestionario, aunque el modelo de un único ítem fue capaz de reconocer solo a 540 personas transgénero y de género diverso. Además, 31 mujeres transgénero se autoidentificaron como "hombres transgéneros" en el modelo de un único ítem. Por consiguiente, a pesar de que se aplicó escasamente en Brasil, el modelo de dos etapas es una estrategia más precisa para reconocer la identidad de género.

Subarachnoid opioids for cesarean section. Letter to the Editor / Opioides subaracnoideos en cesárea. Carta al editor

After reading the article entitled "Comparison of subarachnoid opioid mix for cesarean section" published by Isabel Osorio et al., in January 2020; I would like to make the following observations and comments. The number of patients studied (n =71) is surprising considering that the hospital where the research was conducted is a third-level institution and a referral center for high complexity obstetric care. During the duration of the trial (one year, from June 2028 through May 2019) most likely many patients underwent this type of surgical intervention. Is it then possible to consider a potential selection bias? Moreover, the group distribution is not clearly defined, and certainly it was not random: A (29), B (16), C (26)

Después de leer el artículo titulado "Comparación de mezcla de opioides subaracnoides para cesárea" publicado por Isabel Osorio et al., En enero de 2020; Me gustaría hacer las siguientes observaciones y comentarios. Sorprende el número de pacientes estudiadas ( n = 71) si se considera que el hospital donde se realizó la investigación es una institución de tercer nivel y un centro de referencia de atención obstétrica de alta complejidad. Durante la duración del ensayo (un año, desde junio de 2028 hasta mayo de 2019), lo más probable es que muchos pacientes se hayan sometido a este tipo de intervención quirúrgica. ¿Es posible entonces considerar un posible sesgo de selección? Además, la distribución de los grupos no está claramente definida, y ciertamente no fue aleatoria: A (29), B (16), C (26)

Reply to the letter to the Editor / Respuesta a la carta al Editor

The SES-Hospital Universitario de Caldas takes care of approximately 210 deliveries per month, with an overall cesarean section rate of 32 %, of which 72 % were conducted with, or had an epidural catheter, as an extension of the analgesia delivered during labor and were therefore excluded from the trial. This may address some of the concerns expressed by Sotelo 1 It is important to consider the observational character of the study discussed; in the discussion paragraph, mention is made of a potential selection bias, based on the convenience sampling and the non-randomized approach which are typical of the design used

el SES-Hospital Universitario de Caldas atiende aproximadamente 210 partos por mes, con una tasa global de cesáreas del 32%, de las cuales el 72% se realizaron con o tenían un catéter epidural, como una extensión de la analgesia administrada durante el trabajo de parto y por lo tanto, fueron excluidos del ensayo. Esto puede abordar algunas de las preocupaciones expresadas por Sotelo 1 Es importante considerar el carácter observacional del estudio discutido; En el párrafo de discusión, se menciona un posible sesgo de selección, basado en el muestreo de conveniencia y el enfoque no aleatorio que son típicos del diseño utilizado.

Paladar o Tuberosidad, ¿Cuál es la Mejor Zona Donadora para un Injerto de Tejido Blando?: Una Revisión Sistemática / Palate or Tuberosity, Which is the Best Donor Site for a Soft tissue graft? A Systematic Review

RESUMEN: Comparar mediante una revisión sistemática los resultados clínicos de los procedimientos de cirugía plástica periodontal/periimplantar (CP) con injerto de tejido blando autógeno (ITB) obtenido del área lateral del paladar (ALP) versus del área de la tuberosidad (AT). Se realizó una búsqueda electrónica de ensayos clínicos en la base de datos Medline/Pubmed, Cochrane y las revistas de Periodoncia e Implantes de mayor impacto según la Web of Science, para hallar artículos publicados hasta abril del 2020. Se valoró el riesgo de sesgo de los artículos añadidos según el manual Cochrane Versión 5.1.0 para ensayos clínicos aleatorizados y la escala Newcastle-Ottawa para ensayos clínicos controlados. De una muestra inicial de 930 artículos, cuatro ensayos clínicos (tres aleatorizados) fueron incluidos en el presente estudio, donde se realizaron un total de 87 CP alrededor de piezas e implantes dentales, de las cuales 42 cirugías fueron realizadas con ITB del ALP y 45 cirugías con ITB del AT, se evaluó los resultados desde las 8 semanas hasta los 12 meses. No se hallaron diferencias estadísticamente significativas en los resultados clínicos entre ambos grupos, se mejoró el fenotipo gingival en la zona receptora para el grupo que obtuvo el ITB del AT y el nivel del dolor del sitio donador del AT fue menor en las dos primeras semanas que el sitio donante del ALP. Los estudios incluidos manifestaron un bajo riesgo de sesgo en promedio. Ambas áreas donantes de injerto de tejido blando proporcionan resultados clínicos similares, el injerto del área de la tuberosidad mejora el fenotipo gingival de la zona receptora y reduce el dolor post operatorio en las primeras semanas del sitio donador.

ABSTRACT: The objective of the study was to compare, through a systematic review, the clinical results of periodontal / peri-implant plastic surgery (CP) procedures with autogenous soft tissue graft (ITB) obtained from the lateral palate area (ALP) versus the tuberosity area (AT). We conducted an electronic search of clinical trials in the Medline/Pubmed, Cochrane database and the journals of Periodontics and Implants with the greatest impact according to the Web of Science, to find articles published until April 2020. The risk of bias of the articles added was assessed according to the Cochrane Manual Version 5.1.0 for randomized clinical trials and the Newcastle-Ottawa scale for controlled clinical trials. From the initial sample of 930 articles, four clinical trials were included (three randomized) in the present study, where a total of 87 PC were performed around dental pieces and implants, of which 42 surgeries were performed with ITB of the ALP and 45 surgeries with ITB of the AT, the results were evaluated from the 8 weeks to 12 months. No statistically significant differences were found in the clinical results between the two groups, the gingival phenotype in the receiving area was improved for the group that obtained the ITB of the AT and the level of pain at the donor site was lower in the first two weeks than the ALP donor site. The studies showed a lowrisk of bias on average. Both soft tissue graft donor areas provide similar clinical results, grafting the tuberosity area improves the gingival phenotype of the recipient area and reduces post-operative pain of the donor site in the first few weeks.

Detecting the extent of control over selection bias relating to oral health and otorhinolaryngology: cross-sectional study

ABSTRACT BACKGROUND: The authors of randomized controlled trials will usually claim that they have met the randomization process criterion. However, sequence generation schemes differ and some schemes that are claimed to be randomized are not genuinely randomized. Even less well understood, and often more difficult to ascertain, is whether the allocation was really concealed. OBJECTIVE: To detect the extent of control over selection bias, in a comparison between two Cochrane groups: oral health and otorhinolaryngology; and to describe the methods used to control for this bias. DESIGN AND SETTING: Cross-sectional study conducted in a public university in São Paulo, Brazil. METHODS: The risk of selection bias in 1,714 records indexed in Medline database up to 2018 was assessed, independent of language and access. Two dimensions implicated in the allocation were considered: generation of the allocation sequence; and allocation concealment. RESULTS: We included 420 randomized controlled trials and all of them were evaluated to detect selection bias. In the sample studied, only 28 properly controlled the selection bias. Lack of control over selection bias was present in 80% of the studies evaluated in both groups. CONCLUSION: The two groups were similar regarding control over selection bias. They are also similar to the methods used. The dimension of allocation concealment appears to be a limiting factor with regard to production of randomized controlled trials with low risk of selection bias. The quality of reporting in studies on oral health and otorhinolaryngology is suboptimal and needs to be improved, in line with other fields of healthcare.

Comparing the predictive power of the CART and CTREE algorithms / Comparando o poder preditivo dos Algoritmos CART e CTREE / Comparando el poder predictivo de los algoritmos CART y CTREE

The CART algorithm has been extensively applied in predictive studies, however, researchers argue that CART produces variable selection bias. This bias is reflected in the preference of CART in selecting predictors with large numbers of cutpoints. Considering this problem, this article compares the CART algorithm to an unbiased algorithm (CTREE), in relation to their predictive power. Both algorithms were applied to the 2011 National Exam of High School Education, which includes many categorical predictors with a large number of categories, which could produce a variable selection bias. A CTREE tree and a CART tree were generated, both with 16 leaves, from a predictive model with 53 predictors and the students' writing essay achievement as the outcome. The CART algorithm yielded a tree with a better outcome prediction. This result suggests that for large data sets, called big data, the CART algorithm might give better results than the CTREE algorithm.(AU)

O algoritmo CART tem sido aplicado de forma extensiva em estudos preditivos. Porém, pesquisadores argumentam que o CART apresenta sério viés seletivo. Esse viés aparece na preferência do CART pelos preditores com grande número de categorias. Este artigo considera esse problema e compara os algoritmos CART e CTREE, este considerado não enviesado, tomando como resultado seu poder preditivo. Os algoritmos foram aplicados no Exame Nacional do Ensino Médio de 2011, no qual estão incluídos vários preditores nominais e ordinais com muitas categorias, o que pode produzir um viés seletivo. Foram geradas uma árvore do CTREE e outra do CART, ambas com 16 folhas, provenientes de um modelo com 53 variáveis preditoras e a nota da redação, como desfecho. A árvore do algoritmo CART apresentou uma melhor predição. Para grandes bancos de dados, possivelmente o algoritmo CART é mais indicado do que o algoritmo CTREE.(AU)

El algoritmo CART es ampliamente utilizado en análisis predictivos. Sin embargo, los investigadores argumentan que el CART presenta un fuerte sesgo de selección. Este sesgo se refleja en el CART en la preferencia de seleccionar predictores con elevado número de categorías. Teniendo en cuenta este problema, el presente artículo compara el algoritmo CART y un algoritmo imparcial (CTREE) con relación a su poder predictivo. Ambos algoritmos se aplicaron en el Examen Nacional de la Enseñanza Secundaria de 2011, incluyendo predictores nominales y ordinales con diversas categorías, un escenario susceptible de producir el sesgo de selección de variables mencionado. Fueron generados un árbol CTREE y un árbol CART, ambos con 16 hojas, provenientes de un modelo predictivo con 53 variables y la nota del comentario de texto. El árbol del algoritmo CART presentó mejor predicción. Para grandes bases de datos el algoritmo CART puede proporcionar mejores resultados que el CTREE.(AU)

Postoperative Radiotherapy Improves Survival in Gastric Signet-Ring Cell Carcinoma: a SEER Database Analysis

PURPOSE: To identify the potential therapeutic role of postoperative radiotherapy (RT) in patients with locally advanced (stage II and stage III) gastric signet ring cell carcinoma (SRC).MATERIALS AND METHODS: Patients with locally advanced gastric SRC from the Surveillance, Epidemiology, and End Results program database between 2004 and 2012 were included in our study. Univariate and multivariate Cox proportional models were performed, and survival curves were generated to evaluate the prognostic effect of postoperative RT and surgery alone on SRC patients. Propensity score matching (PSM) was used to avoid selection bias among the study cohorts.RESULTS: We found that patients with postoperative RT had better probability of survival compared with those who did not receive RT (overall survival [OS], P<0.001; cancer-specific survival [CSS], P<0.001). After PSM, analysis of both overall and CSS showed that patients who underwent postoperative RT had better prognosis than those receiving surgery alone in the matched cohort (OS, P=0.00079; CSS, P=0.0036). Multivariate Cox proportional model indicated that postoperative RT had better effect on prognosis compared with surgery alone with respect to both overall (hazard ratio [HR], 0.716; 95% confidence interval [95% CI], 0.590–0.87; P=0.001) and CSS (HR, 0.713; 95% CI, 0.570–0.890; P=0.003).CONCLUSIONS: Postoperative RT had better prognosis compared with surgery alone for both overall and CSS for patients with locally advanced gastric SRC.

Feasibility of Linear-Shaped Gastroduodenostomy during the Performance of Totally Robotic Distal Gastrectomy

PURPOSE: Although linear-shaped gastroduodenostomy (LSGD) was reported to be a feasible and reliable method of Billroth I anastomosis in patients undergoing totally laparoscopic distal gastrectomy (TLDG), the feasibility of LSGD for patients undergoing totally robotic distal gastrectomy (TRDG) has not been determined. This study compared the feasibility of LSGD in patients undergoing TRDG and TLDG.MATERIALS AND METHODS: ALL C: onsecutive patients who underwent LSGD after distal gastrectomy for gastric cancer between January 2009 and December 2017 were analyzed retrospectively. Propensity score matching (PSM) analysis was performed to reduce the selection bias between TRDG and TLDG. Short-term outcomes, functional outcomes, learning curve, and risk factors for postoperative complications were analyzed.RESULTS: This analysis included 414 patients, of whom 275 underwent laparoscopy and 139 underwent robotic surgery. PSM analysis showed that operation time was significantly longer (163.5 vs. 132.1 minutes, P<0.001) and postoperative hospital stay significantly shorter (6.2 vs. 7.5 days, P<0.003) in patients who underwent TRDG than in patients who underwent TLDG. Operation time was the independent risk factor for LSGD after intracorporeal gastroduodenostomy. Cumulative sum analysis showed no definitive turning point in the TRDG learning curve. Long-term endoscopic findings revealed similar results in the two groups, but bile reflux at 5 years showed significantly better improvement in the TLDG group than in the TRDG group (P=0.016).CONCLUSIONS: LSGD is feasible in TRDG, with short-term and long-term outcomes comparable to that in TLDG. LSGD may be a good option for intracorporeal Billroth I anastomosis in patients undergoing TRDG.

Validation of the Japanese Version of the Quality of Life after Brain Injury (QOLIBRI) Scale

The goal of the present study was to test the reliability and validity of the Japanese version of the Quality of Life after Brain Injury (QOLIBRI) scale. Correlations between the QOLIBRI and Glasgow Coma Scale scores, anxiety, depression, general quality of life (QOL), and demographic characteristics were examined to assess scale validity. The structure of the QOLIBRI was investigated with exploratory and confirmatory factor analyses, as well as the Partial Credit Model. Test–retest reliability was assessed over a 2-week interval. Participants were 129 patients with traumatic brain injury (TBI) recruited from rehabilitation centers in Japan. The QOLIBRI showed good-to-excellent internal consistency (Cronbach's α: 0.82–0.96), test–retest reliability, and validity (r = 0.77–0.90). Factor analyses revealed a 6-factor structure. Compared to an international sample (IS), Japanese patients had lower QOLIBRI scores and lower satisfaction in several domains. There were positive correlations between the QOLIBRI scales and the Short Form 36 Health Survey (r = 0.22–0.41). The Japanese version of the QOLIBRI showed good-to-excellent psychometric properties. Differences between JS and IS may reflect sampling bias and cultural norms regarding self-evaluation. The QOLIBRI could be a useful tool for assessing health-related QOL in individuals with TBI.

Oncologic Outcomes of Postoperative Chemoradiotherapy Versus Chemotherapy Alone in Stage II and III Upper Rectal Cancer

PURPOSE: The aim of this study was to assess oncological outcomes of postoperative radiotherapy plus chemotherapy (CRT) versus chemotherapy alone (CTx) in stage II or III upper rectal cancer patients who underwent curative surgery. METHODS: We retrospectively reviewed 263 consecutive patients with pathologic stage II or III upper rectal cancer who underwent primary curative resection with postoperative CRT or CTx from January 2008 to December 2014 at Chonnam National University Hwasun Hospital. Multivariate and propensity score matching analyses were used to reduce selection bias. RESULTS: Median follow-up was 48.1 months for the entire cohort and 53.5 months for the matched cohort. In subgroup analysis of the propensity score matched cohort, the 3-year local recurrence-free survival was 94.1% (95% confidence interval [CI], 87.8%–100%) in the CRT group and 90.1% (95% CI, 82.8%–97.9%) in the CTx group (P = 0.370). No significant difference in disease-free survival was observed according to treatment type. On multivariate analysis, circumferential resection margin involvement (hazard ratio [HR], 2.386; 95% CI, 1.190–7.599; P = 0.032), N stage (HR, 6.262; 95% CI, 1.843–21.278, P = 0.003), and T stage (HR, 5.896, 95% CI, 1.298–6.780, P = 0.021) were identified as independent risk factors for local recurrence of tumors of the upper rectum. CONCLUSION: Omission of radiotherapy in an adjuvant treatment setting may not jeopardize oncologic outcomes in stages II and III upper rectal cancer.

The effect of early extubation on postoperative delirium in patients with liver transplantation: a propensity score matching analysis

BACKGROUND: Maintenance of tracheal intubation is associated with use of sedatives, stress due to mechanical ventilation, or respiratory complications. The aim of this study is to compare the incidence of delirium between early and late extubation groups after liver transplantation (LT). METHODS: Medical records from 247 patients who received LT from January 2010 to July 2017 in a single university hospital were retrospectively reviewed. Patients were divided with 2 groups: Those who underwent early extubation after LT (E group, n = 52) and those who underwent extubation within few hours of intensive care unit (ICU) admission after surgery (C group, n = 195). The patients’ demographic data, perioperative managements and postoperative complications were collected. Early extubation was defined as performing extubation in the operating room after LT. A propensity score matching analysis was performed to reduce the effects of selection bias. RESULTS: Among them, 4/52 (7.69%) in E group and 30/195 (15.38%) in C group occurred postoperative delirium after LT, respectively (P = 0.180). After propensity score matching, there was no difference of the period of hospitalization in ICU (P = 0.961), time to discharge after surgery (P = 0.117) and incidence of delirium between groups (P = 1.000). CONCLUSIONS: Although this study is a retrospective study and limited by the small number of subjects, early extubation does not affect the incidence of delirium after LT. Therefore, further prospective studies on this were needed.

Randomization in clinical studies / 대한마취과학회지

Randomized controlled trial is widely accepted as the best design for evaluating the efficacy of a new treatment because of the advantages of randomization (random allocation). Randomization eliminates accidental bias, including selection bias, and provides a base for allowing the use of probability theory. Despite its importance, randomization has not been properly understood. This article introduces the different randomization methods with examples: simple randomization; block randomization; adaptive randomization, including minimization; and response-adaptive randomization. Ethics related to randomization are also discussed. The study is helpful in understanding the basic concepts of randomization and how to use R software.

Effects of Atomoxetine on Height and Weight in Korean Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: A Retrospective Chart Review

OBJECTIVE: We aimed to investigate the long-term effects of atomoxetine on growth in Korean children and adolescents with attention-deficit/hyperactivity disorder (ADHD). METHODS: The medical records of 82 subjects (mean age, 9.0±2.0 years; 64 boys) with ADHD treated with atomoxetine for at least 1 year at the Department of Psychiatry at Asan Medical Center were retrospectively reviewed. Height and weight data were prospectively obtained and retrospectively gathered and converted to age- and gender-corrected z scores using norms from Korean youths. Growth changes were analyzed using random coefficients models with changes in height or weight z scores as the dependent variables. RESULTS: Height z scores significantly decreased during the treatment period (β=-0.054, p=0.024). Height z scores decreased during the 1st year of treatment (β=-0.086, p=0.003), but did not change after the 1st year. Weight z scores did not change significantly during treatment (β=0.004, p=0.925). CONCLUSION: Our results suggest that long-term atomoxetine treatment may be associated with deficits in height growth in Korean youths, although this effect was minor and tended to be attenuated over the first year. Because of the limitations of this study such as retrospective design and selection bias, further prospective studies are needed.

Who Can Perform Adjuvant Chemotherapy Treatment for Gastric Cancer? A Multicenter Retrospective Overview of the Current Status in Korea

PURPOSE: To investigate the current status of adjuvant chemotherapy (AC) regimens in Korea and the difference in efficacy of AC administered by surgical and medical oncologists in patients with stage II or III gastric cancers. MATERIALS AND METHODS: We performed a retrospective observational study among 1,049 patients who underwent curative resection and received AC for stage II and III gastric cancers between February 2012 and December 2013 at 29 tertiary referral university hospitals in Korea. To minimize the influence of potential confounders on selection bias, propensity score matching (PSM) was used based on binary logistic regression analysis. The 3-year disease-free survival (DFS) rates were compared between patients who received AC administered by medical oncologists or surgical oncologists. RESULTS: Between February 2012 and December 2013 in Korea, the most commonly prescribed AC by medical oncologists was tegafur/gimeracil/oteracil (S-1, 47.72%), followed by capecitabine with oxaliplatin (XELOX, 16.33%). After performing PSM, surgical oncologists (82.74%) completed AC as planned more often than medical oncologists (75.9%), with statistical significance (P=0.036). No difference in the 3-year DFS rates of stage II (P=0.567) or stage III (P=0.545) gastric cancer was found between the medical and surgical oncologist groups. CONCLUSIONS: S-1 monotherapy and XELOX are a main stay of AC, regardless of whether the prescribing physician is a medical or surgical oncologist. The better compliance with AC by surgical oncologists is a valid reason to advocate that surgical oncologists perform the treatment of AC for stage II or III gastric cancers.

Avaliação das taxas de adequabilidade dos laudos citopatológicos de mulheres atendidas pelo SUS no município de Anápolis-GO / Evaluation of suitability rates of the women's cytopathology reports attended by the SUS on the Anapolis-GO

O exame citopatológico é o método mais difundido mundialmente para o rastreamento do câncer do colo do útero e suas lesões precursoras, sua vulnerabilidade aos erros de coleta e de preparação da lâmina. A subjetividade na interpretação dos resultados pode comprometer sua sensibilidade e especificidade. Este trabalho teve como objetivo avaliar as taxas de adequabilidade dos laudos citopatológicos de cérvice uterina em exames realizados pelo Sistema Único de Saúde (SUS) na cidade de Anápolis-GO em dois anos, bem como especificar os principais fatores obscurecedores de amostra. A amostra foi composta pelo levantamento de laudos citopatológicos de cérvice uterina em pacientes atendidas pelo SUS no município de Anápolis-GO nos anos de 2012 e 2013 nas bases de dados do Data-SUS e do Programa Siscolo. A taxa de laudos insatisfatórios foi de 3,4/1000 laudos (IC 95% 2,4 - 4,6) e 4,9/1000 laudos (IC 95% 3,9 - 6,1) para os anos de 2012 e 2013, respectivamente. A taxa geral do estudo para laudos insatisfatórios foi de 4,3/1000 laudos (IC 95% 3,5 - 5,1). O principal fator responsável pelos laudos insatisfatórios foi a presença de artefatos de dessecamento tanto na taxa geral, com 2,1/1000 laudos (IC 95% 1,7 ­ 2,8), quanto na estratificação anual, com 1,8/1000 laudos (IC 95% 1,2 ­ 2,7) em 2012 e 2,4/1000 laudos (IC 95% 1,7 ­ 3,3) em 2013. Estes achados indicam que as ações de educação continuada com os profissionais que realizam a coleta do exame preventivo são de fundamental importância, já que os fatores mais visualizados são passíveis de correção.(AU)

The cytopathological exam is the most used method around the globe in screening for cancer of the cervix and its precursor lesions. The vulnerability to collection errors, preparation of the glass and the subjectivity in the interpretation of the results can impact the sensibility and specificity of the exam. This article aims to avaliate the adequacy rates of cytopathological reports in uterine cervix by the Health Unic System (HUS) in Anapolis-GO in two years, as well as specify the main obscuring factors of the sample. The sample was taken by the cytopathological reports in uterine cervix treated by HUS in the city of Anapolis-GO between 2012 and 2013 on HUS database and Siscolo Program. The rate on unsatisfying reports was 3,4/1000 reports (IC 95% 2,4 ­ 4,6) and 4,9/1000 reports (IC 95% 3,9 ­ 6,1) between 2012 e 2013. The general rate on unsatisfying reports was 4,3/1000 reports (IC 95% 3,5 ­ 5,1). The main factor responsible for inadequate reports was the presence of artifacts from desiccation on the general rate at 2,1/1000 reports (IC 95% 1,7 ­ 2,8), as well on the annual stratification at 1,8/1000 reports (IC 95% 1,2 ­ 2,7) in 2012 and 2,4/1000 reports (IC 95% 1,7 ­ 3,3) in 2013. These findings reveal that continuing education activities with the professionals who perform the collection of the screening test are highly important, once that the findings are likely to correct.(AU)