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.

High frequency of spin bias in controlled trials of cannabis derivatives and their synthetic analogues: A meta-epidemiologic study.

OBJECTIVE: To investigate the frequency and perform a qualitative analysis of spin bias in publications of controlled trials assessing the therapeutic use of cannabis derivatives and their synthetic analogues. STUDY DESIGN AND SETTING: Meta-epidemiologic study carried out at the Universidade Federal de São Paulo, Brazil. RESULTS: A total of 65 publications with at least one efficacy primary outcome were considered. The results analysis for the primary outcome indicated statistically significant effects in 44.6% (29/65) of the publications, and 70.7% (45/65) of the conclusions were considered favorable to the intervention. Among the 36 publications that found statistically nonsignificant results for the primary outcome, 44.4% (16/36) presented conclusions favorable to or recommending the intervention, which represents spin bias according to the definition adopted in this study. Qualitative analysis of the 16 studies with spin bias showed selective outcomes reporting (elevating secondary outcomes that had positive results or reporting only subgroup results), deviations from the planned statistical analysis, and failure to consider or report uncertainty in the estimates of treatment effects. CONCLUSION: The frequency of spin bias among publications of controlled trials with statistically nonsignificant results assessing the therapeutic use of cannabis derivatives and their synthetic analogues reached 44.4%. When not observed by readers, such deviation can lead to misconduct in clinical practice through the adoption of interventions that are not effective or whose effectiveness is uncertain.

Precision clinical trials: a framework for getting to precision medicine for neurobehavioural disorders.

The goal of precision medicine (individually tailored treatments) is not being achieved for neurobehavioural conditions such as psychiatric disorders. Traditional randomized clinical trial methods are insufficient for advancing precision medicine because of the dynamic complexity of these conditions. We present a pragmatic solution: the precision clinical trial framework, encompassing methods for individually tailored treatments. This framework includes the following: (1) treatment-targeted enrichment, which involves measuring patients' response after a brief bout of an intervention, and then randomizing patients to a full course of treatment, using the acute response to predict long-term outcomes; (2) adaptive treatments, which involve adjusting treatment parameters during the trial to individually optimize the treatment; and (3) precise measurement, which involves measuring predictor and outcome variables with high accuracy and reliability using techniques such as ecological momentary assessment. This review summarizes precision clinical trials and provides a research agenda, including new biomarkers such as precision neuroimaging, transcranial magnetic stimulation-electroencephalogram digital phenotyping and advances in statistical and machine-learning models. Validation of these approaches - and then widespread incorporation of the precision clinical trial framework - could help achieve the vision of precision medicine for neurobehavioural conditions.

Diretrizes metodológicas: elaboração de revisão sistemática e meta-análise de ensaios clínicos randomizados [recurso eletrônico] / Methodological guidelines: elaboration of systematic review and meta-analysis of randomized clinical trials [electronic resource]

DEFINIÇÃO DE REVISÃO SISTEMÁTICA: A RS sintetiza os resultados de estudos primários que se enquadram nos critérios de elegibilidade para responder uma pergunta de pesquisa3. A busca por estudos é realizada de forma sistemática, por meio de várias fontes de dados, com o uso de uma estratégia de busca ampla e sensível7 . A pergunta da pesquisa nas RS de ECR é estruturada no formato PICO (População, Intervenção, Comparador e Desfecho ­ em inglês, outcome). Esse tipo de revisão se baseia em métodos rigorosos, explícitos e reprodutíveis, para minimizar o risco de viés, entender as inconsistências dos resultados e então fornecer resultados confiáveis para a tomada de decisão. DEFINIÇÃO DE META-ANÁLISE META-ANÁLISE: é um método estatístico que pode ser realizado em RS para combinar os resultados de dois ou mais estudos independentes, que podem testar ou não a mesma pergunta/hipótese, gerando uma única estimativa de efeito8. A meta-análise pode ser em pares/ direta ou as meta-análises em rede, ou meta-análises de comparações múltiplas. Na presente diretriz, serão apresentados apenas os conceitos de meta-análise em pares. A vantagem da meta-análise é que esta pode apresentar uma estimativa mais precisa do tamanho do efeito, com considerável aumento do poder estatístico, o que é importante quando o poder do estudo primário é limitado devido ao pequeno tamanho da amostra9. Uma meta-análise pode, em alguns casos, produzir resultados conclusivos quando estudos individuais primários são inconclusivos. Uma RS não necessariamente precisa apresentar uma meta-análise para sintetizar seus resultados. Ao contrário, em alguns casos não é apropriado que elas sejam realizadas, podendo até mesmo gerar conclusões errôneas. Nesse caso, sínteses qualitativas devem ser utilizadas. IMPORTÂNCIA DAS REVISÕES SISTEMÁTICAS: A RS sintetiza os estudos primários da literatura sobre uma questão específica de pesquisa, auxiliando a tomada de decisão na saúde em torno da melhor conduta terapêutica ou profilática. Além disso, esse tipo de estudo ajuda a evitar desperdícios de pesquisa, garantindo que novas pesquisas primárias sejam realizadas com pleno conhecimento da evidência existente11. Um único estudo primário frequentemente não consegue detectar diferenças clinicamente relevantes de efeitos entre dois tratamentos, pois elaborar um ECR, com estimativas corretas para o cálculo do tamanho de amostra e poder estatístico adequados, exige, na maioria das vezes, um tamanho de amostra bastante significativo. Finalizar um ECR com um tamanho de amostra grande necessita de infraestrutura, recursos humanos especializados e recursos financeiros importantes, não disponíveis na maioria das vezes. De qualquer forma, RS com ou sem meta-análise são complementares aos estudos randomizados, por fornecerem ao profissional de saúde uma síntese do conhecimento atual disponível11. As RS também podem contribuir para aumentar a validade externa dos estudos, ou seja, contribuir para a generalização dos resultados. Em algumas situações, os achados de um estudo particular podem ser válidos apenas para uma população com as mesmas características das investigadas no estudo 10. LIMITAÇÕES E DESAFIOS DA ELABORAÇÃO DE REVISÕES SISTEMÁTICAS: As RS possuem alguns desafios, como a gestão de grande volume de informações e extração de dados, o tempo para a realização do estudo e as possíveis limitações de recursos humanos e materiais disponíveis12. As principais limitações que podem afetar a confiabilidade dos resultados de uma RS são o viés de publicação, além de dificuldades em combinar estudos que possam ter diferenças nas populações, nas intervenções, nos comparadores e na definição dos desfechos (diversidade clínica). Assim, é necessário explorar criticamente a evidência apresentada pela RS. Interpretações enganosas podem ser evitadas se princípios básicos forem observados. Nessa diretriz, serão discutidas as etapas para realização de RS de ECR, com ênfase em princípios básicos para garantir a validade dos resultados. RECURSOS NECESSÁRIOS: O conjunto de recursos, conhecimentos e habilidades da equipe envolvida é decisivo para a realização de uma RS de forma otimizada. O tempo é fator predominante e vai depender do tema e do escopo da revisão, assim como das habilidades e dos conhecimentos técnicos dos revisores. É preciso estimar o tempo que será necessário para a condução da RS e a disponibilidade que cada membro da equipe terá para trabalhar na revisão. A elaboração de um cronograma é importante, e este deve incluir todas as etapas, como treinamentos, reuniões, desenvolvimento do protocolo, busca e seleção dos estudos, extração e análise de dados etc. É importante prever gastos, como a necessidade de contratar um tradutor, para tradução de estudos em idioma não dominado pela equipe, ou comprar estudos em texto completo, não disponíveis para os revisores. Assim, sugere-se a elaboração de um orçamento, contemplando todos os itens com seus respectivos valores. Os recursos financeiros podem ser próprios ou podem ser financiados por entidades de agências de fomento à pesquisa (ex.: Conselho Nacional de Desenvolvimento Científico e Tecnológico [CNPq], Fundação de Amparo à Pesquisa do Estado de São Paulo [Fapesp] etc.), instituições responsáveis pela avaliação tecnológica (Ministério da Saúde) ou envolvidas na elaboração de diretrizes para prática clínica (sociedades brasileiras de especialidades clínicas). Recursos humanos: é importante estimar o número de pessoas que irão compor a equipe da revisão, em quais etapas, quem será o coordenador principal da revisão, a necessidade de consultoria de especialistas no assunto, além de apoio estatístico e bibliotecário (se necessário). É importante ter pelo menos três pesquisadores envolvidos para que seja possível minimizar os vieses e os erros em todos os estágios da RS7 . A equipe de pesquisa pode conter outros membros da sociedade envolvidos com o tema, os quais podem ser consultados em vários estágios da RS, como profissionais de saúde especialistas no tema pesquisado, representantes de pacientes, usuários de serviços e especialistas em métodos estatísticos7 . As habilidades e os conhecimentos são fundamentais para a garantia da qualidade metodológica da RS. Assim, conhecimentos aprofundados sobre métodos de pesquisa, epidemiologia, conhecimento clínico da questão de pesquisa, informática e domínio de língua inglesa são necessários. Além disso, a equipe deve saber utilizar as ferramentas necessárias à condução da revisão, como os gerenciadores de referência, bases de dados bibliográficas, softwares que auxiliem na condução ou no relato da revisão sistemática, programas estatísticos para meta-análise. Recursos materiais: é importante estimar todos os recursos necessários para elaboração da RS, como computadores, acesso à internet, softwares de gerenciamento de referências (por exemplo, Mendeley, Endnote, Zotero), e softwares estatísticos (RevMan, R, Stata, Comprehensive Meta-Analysis, por exemplo), além de eventual aquisição de textos completos de publicações com acesso restrito.

SEOM clinical guidelines for the treatment of small-cell lung cancer (SCLC) (2019).

Small-cell lung cancer (SCLC) accounts for 15% of lung cancers. Only one-third of patients are diagnosed at limited stage. The median survival remains to be around 15-20 months without significative changes in the strategies of treatment for many years. In stage I and IIA, the standard treatment is the surgery followed by adjuvant therapy with platinum-etoposide. In stage IIB-IIIC, the recommended treatment is early concurrent chemotherapy with platinum-etoposide plus thoracic radiotherapy followed by prophylactic cranial irradiation in patients without progression. However, in the extensive stage, significant advances have been observed adding immunotherapy to platinum-etoposide chemotherapy to obtain a significant increase in overall survival, constituting the new recommended standard of care. In the second-line treatment, topotecan remains as the standard treatment. Reinduction with platinum-etoposide is the recommended regimen in patients with sensitive relapse (≥ 3 months) and new drugs such as lurbinectedin and immunotherapy are new treatment options. New biomarkers and new clinical trials designed according to the new classification of SCLC subtypes defined by distinct gene expression profiles are necessary.

SEOM clinical guideline for secondary prevention (2019).

Cancer is one of the major public health problems in our society. It is estimated that more than 18 million new cases are diagnosed worldwide every year; 280,000 in Spain. Incidence in following a growing trend. This epidemic could be controlled with research into new treatments and, above all, with adequate prevention. Primary prevention could prevent avoid up to half of all cases. For many others, secondary prevention is essential, as it make diagnosis possible in the stages of the disease when it is easily curable. These guidelines present the scientific evidence regarding secondary prevention in tumors in which its use is well-accepted: breast, cervical, colorectal, prostate, lung, ovarian, melanoma, and gastric cancer.

SEOM clinical guideline thyroid cancer (2019).

Thyroid carcinoma is the most frequent endocrine malignancy and accounts for around 3% of global cancer incidence. Different histologies and clinical scenarios make necessary a multidisciplinary approach that includes new diagnostic methods and surgical, radiopharmaceutical and systemic therapies. This guideline updates several aspects of management of thyroid cancer.

SEOM clinical guidelines in hereditary breast and ovarian cancer (2019).

Mutations in BRCA1 and BRCA2 high penetrance genes account for most hereditary breast and ovarian cancer, although other new high-moderate penetrance genes included in multigene panels have increased the genetic diagnosis of hereditary breast and ovarian cancer families by 50%. Multigene cancer panels provide new challenges related to increased frequency of variants of uncertain significance, new gene-specific cancer risk assessments, and clinical recommendations for carriers of mutations of new genes. Although clinical criteria for genetic testing continue to be largely based on personal and family history with around a 10% detection rate, broader criteria are being applied with a lower threshold for detecting mutations when there are therapeutic implications for patients with breast or ovarian cancer. In this regard, new models of genetic counselling and testing are being implemented following the registration of PARP inhibitors for individuals who display BRCA mutations. Massive sequencing techniques in tumor tissue is also driving a paradigm shift in genetic testing and potential identification of germline mutations. In this paper, we review the current clinical criteria for genetic testing, as well as surveillance recommendations in healthy carriers, risk reduction surgical options, and new treatment strategies in breast cancer gene-mutated carriers.

SEOM clinical guideline for the management of immune-related adverse events in patients treated with immune checkpoint inhibitors (2019).

The use of immune checkpoint inhibitors has emerged as an effective treatment option for patients with several tumor types. By increasing the activity of the immune system, they can induce inflammatory side effects, which are often termed immune-related adverse events. These are pathophysiologically unique toxicities, compared with those from other anticancer therapies. In addition, the spectrum of the target organs is very broad. Immune-inflammatory adverse events can be life threatening. Prompt diagnosis and pharmacological intervention are instrumental to avoid progression to severe manifestations. Consequently, clinicians require new skills to successfully diagnose and manage these events. These SEOM guidelines have been developed with the consensus of ten medical oncologists. Relevant studies published in peer-review journals were used for the guideline elaboration. The Infectious Diseases Society of America grading system was used to assign levels of evidence and grades of recommendation.

SEOM clinical guideline for treatment of kidney cancer (2019).

In this article, we review de state of the art on the management of renal cell carcinoma (RCC) and provide recommendations on diagnosis and treatment. Recent advances in molecular biology have allowed the subclassification of renal tumours into different histologic variants and may help to identify future prognostic and predictive factors. For patients with localized disease, surgery is the treatment of choice with nephron-sparing surgery recommended when feasible. No adjuvant therapy has demonstrated a clear benefit in overall survival. Considering the whole population of patients with advanced disease, the combination of axitinib with either pembrolizumab or avelumab increase response rate and progression-free survival, compared to sunitinib, but a longer overall survival has only been demonstrated so far with the pembrolizumab combo. For patients with IMDC intermediate and poor prognosis, nephrectomy should not be considered mandatory. In this subpopulation, the combination of ipilimumab and nivolumab has also demonstrated a superior response rate and overall survival vs. sunitinib. In patients progressing to one or two antiangiogenic tyrosine-kinase inhibitors, both nivolumab and cabozantinib in monotherapy have shown benefit in overall survival compared to everolimus. Although no clear sequence can be recommended, medical oncologists and patients should be aware of the recent advances and new strategies that improve survival and quality of life in patients with metastatic RCC.

SEOM clinical guideline for the diagnosis and treatment of gastric cancer (GC) and gastroesophageal junction adenocarcinoma (GEJA) (2019).

Gastric cancer (GC) is the fifth most common cancer worldwide with a varied geographic distribution and an aggressive behavior. In Spain, it represents the sixth cause of cancer death. In Western countries, the incidence is decreasing slightly, with an increase in gastroesophageal junction adenocarcinoma (GEJA), a different entity that we separate specifically in the guideline. Molecular biology advances have been done recently, but do not yet lead to the choice in treatment approach except in advanced disease with overexpression of HER2. Endoscopic resection in very early stage, perioperative chemotherapy in locally advanced tumors and preliminary immune therapy resulting in advanced disease are the main treatment innovations in the GC/GEJA treatment. We describe the different evidences and recommendations following the statements of the American College of Physicians.

SEOM clinical guidelines for cervical cancer (2019).

Cervical cancer (CC) is the fourth most common cancer in women worldwide, strongly linked to high-risk human papilloma virus infection. In high-income countries, the screening programs have dramatically decreased the incidence of CC; however, the lack of accessibility to them in developing countries makes CC an important cause of mortality. Clinical stage is the most relevant prognostic factor in CC. The new FIGO staging system published in 2018 is more accurate than the previous one since it takes into account the lymph node status. In early stages, the primary treatment is surgery-with some concerns recently raised regarding minimally invasive surgery because it might decrease survival-or radiotherapy, whereas concomitant chemo-radiotherapy is the conventional approach in locally advanced stages. For recurrent or metastatic CC, the combination of chemotherapy plus bevacizumab is the preferred therapy. Immunotherapy approach based on checkpoint inhibitors is evolving as the election therapy following failure to platinum therapy.

SEOM clinical guideline on hereditary colorectal cancer (2019).

In the last 2 decades, clinical genetics on hereditary colorectal syndromes has shifted from just a molecular characterization of the different syndromes to the estimation of the individual risk of cancer and appropriate risk reduction strategies. In the last years, new specific therapies for some subgroups of patients have emerged as very effective alternatives. At the same time, germline multigene panel testing by next-generation sequencing (NGS) technology has become the new gold standard for molecular genetics.

SEOM clinical guideline of venous thromboembolism (VTE) and cancer (2019).

In 2011, the Spanish Society of Medical Oncology (SEOM) first published a clinical guideline of venous thromboembolism (VTE) and cancer. This guideline was updated in 2014, and since then, multiple studies and clinical trials have changed the landscape of the treatment and prophylaxis of VTE in cancer patients. To incorporate the most recent evidence, including data from direct oral anticoagulants (DOACs) randomized clinical trials, SEOM presents a new update of the guideline.

De vuelta a la clínica. Métodos I. Diseños de investigación. Mayor calidad de información, mayor certeza a la respuesta.

Research designs refer to the way information is obtained and are limited by ethical, economic and temporal viability. Research designs are standardized strategies to reduce biases, which in the architectural model of research are identified in the baseline state, the maneuver and the outcome; hence, there are no specific designs for each question. The design with the lowest probability of bias is the clinical trial, followed by cohort and case-control studies and, finally, by cross-sectional surveys. Among the main characteristics that give merit to research designs are the following: population inquiry, which refers to the situation of the population in relation to the clinical course/natural history of the disease; the maneuver, or action that is expected to modify the baseline state, which can be observational or experimental; follow-up, or documented monitoring that is given to each subject, which can be longitudinal or cross-sectional; and directionality, which can prolective or retrolective and refers to the timing of data collection for research purposes. It will always be better having a valuable question, even when answered with a design with higher risk of bias, than a question that is irrelevant or has no applicability.

Los diseños de investigación se refieren a la forma como se obtiene la información y están limitados por viabilidad ética, económica y temporal. Son estrategias estandarizadas para disminuir los sesgos que en el modelo arquitectónico de la investigación se identifican en el estado basal, maniobra y desenlace; de ahí que no hay diseños específicos para cada pregunta. El diseño con menor probabilidad de sesgos es el ensayo clínico, seguido de la cohorte, el estudio de casos y controles y, finalmente, la encuesta transversal. Entre las principales características que dan mérito a los diseños están las siguientes: la pesquisa de la población, que se refiere a la ubicación de la población en relación con el curso clínico o historia natural de la enfermedad; la maniobra, o acción que se espera modifique la condición basal, que puede ser observacional o experimental; el seguimiento, o monitoreo documentado que se le da a cada sujeto, que puede ser longitudinal o transversal; y la direccionalidad, prolectiva o retrolectiva, que alude al tiempo de recopilación de la información con fines de investigación. Siempre será mejor tener una pregunta valiosa, incluso cuando se responda con un diseño con mayor riesgo de sesgos, que una pregunta irrelevante o sin aplicabilidad.

De vuelta a la clínica. Métodos I. Diseños de investigación. Mayor calidad de información, mayor certeza a la respuesta / Back to the clinic. Methods I. Research designs. Higher quality of information, greater certainty to the answer

Resumen Los diseños de investigación se refieren a la forma como se obtiene la información y están limitados por viabilidad ética, económica y temporal. Son estrategias estandarizadas para disminuir los sesgos que en el modelo arquitectónico de la investigación se identifican en el estado basal, maniobra y desenlace; de ahí que no hay diseños específicos para cada pregunta. El diseño con menor probabilidad de sesgos es el ensayo clínico, seguido de la cohorte, el estudio de casos y controles y, finalmente, la encuesta transversal. Entre las principales características que dan mérito a los diseños están las siguientes: la pesquisa de la población, que se refiere a la ubicación de la población en relación con el curso clínico o historia natural de la enfermedad; la maniobra, o acción que se espera modifique la condición basal, que puede ser observacional o experimental; el seguimiento, o monitoreo documentado que se le da a cada sujeto, que puede ser longitudinal o transversal; y la direccionalidad, prolectiva o retrolectiva, que alude al tiempo de recopilación de la información con fines de investigación. Siempre será mejor tener una pregunta valiosa, incluso cuando se responda con un diseño con mayor riesgo de sesgos, que una pregunta irrelevante o sin aplicabilidad.

Abstract Research designs refer to the way information is obtained and are limited by ethical, economic and temporal viability. Research designs are standardized strategies to reduce biases, which in the architectural model of research are identified in the baseline state, the maneuver and the outcome; hence, there are no specific designs for each question. The design with the lowest probability of bias is the clinical trial, followed by cohort and case-control studies and, finally, by cross-sectional surveys. Among the main characteristics that give merit to research designs are the following: population inquiry, which refers to the situation of the population in relation to the clinical course/natural history of the disease; the maneuver, or action that is expected to modify the baseline state, which can be observational or experimental; follow-up, or documented monitoring that is given to each subject, which can be longitudinal or cross-sectional; and directionality, which can prolective or retrolective and refers to the timing of data collection for research purposes. It will always be better having a valuable question, even when answered with a design with higher risk of bias, than a question that is irrelevant or has no applicability.

So You Want to Give Stem Cells to Babies? Neonatologists and Parents' Views to Optimize Clinical Trials.

OBJECTIVE: To identify barriers and enablers that may influence parents' and neonatologists' participation in clinical trials of mesenchymal stromal cells for bronchopulmonary dysplasia. STUDY DESIGN: This qualitative study involved one-on-one semistructured interviews with parents of extremely preterm infants (n = 18) and neonatologists (n = 16). Interview guides and directed content analysis were framed using the theoretical domains framework, a tool specifically developed for implementation research to identify influences on behavior. RESULTS: Key barriers for parents included their lack of knowledge about clinical trial processes in general, stem cells, and concerns about their risks and side effects. Importantly, parents preferred to be approached for recruitment directly by a neonatologist, either before delivery or 1 or 2 weeks after birth. However, the majority of neonatologists felt that approaching parents was not part of their role. Neonatologists reported competing priorities, time commitment, costs, and lack of institutional support as significant barriers to their ability to recruit patients. CONCLUSIONS: By integrating stakeholders early into the development of a clinical trial of mesenchymal stromal cell therapy, we identified and can address important barriers to enrollment. Some identified barriers were unanticipated and could have compromised recruitment had they not been identified by this study. We suggest that this approach can be used more broadly for other early phase clinical trials in pediatrics.