scholarly journals Sources of bias in signals of pharmaceutical safety in pregnancy

2010 ◽  
Vol 33 (6) ◽  
pp. 349 ◽  
Author(s):  
Gideon Koren ◽  
Sheri Nickel
Keyword(s):  
Null Hypothesis ◽  
Case Reports ◽  
Safety Data ◽  
Case Series ◽  
Case Control ◽  
Recall Bias ◽  
Fetal Exposure ◽  
Case Control Studies ◽  
Fetal Safety ◽  
Pharmaceutical Molecules

Every year scores of new pharmaceuticals enter the market, almost never with human fetal safety data. Such data typically accumulate during the first years of clinical use, in the form of case reports, case series, prospective and retrospective cohorts and case control studies. All of these methods suffer from serious sources of bias, often leading to alarming signals of teratogenicity that are later found to be false. This review highlights major sources of bias, including the bias against the null hypothesis in its different forms, ascertainment and recall bias, in fetal exposure to pharmaceutical molecules.

Association between antipsychotic medication and venous thromboembolism

2010 ◽  
Vol 27 (1) ◽  
pp. 22-26
Author(s):  
Santhana Gunasekaran
Keyword(s):  
Venous Thromboembolism ◽  
Observational Studies ◽  
Case Reports ◽  
Case Series ◽  
Case Control ◽  
Case Control Studies ◽  
Antipsychotic Medications ◽  
Strength Of Evidence ◽  
Increased Risk ◽  
Strength Of Association

AbstractObjective: This study aims to identify and review available evidence in the literature to determine the strength of association between antipsychotic medications and thromboembolism as an adverse effect.Method: Electronic databases were searched for evidence.Results: A total of 15 case reports, 14 case series, two observational studies and three case-control studies were found in the literature. Two case control studies found significantly increased risk of venous thromboembolism (OR 13.3 and 7.1 respectively). The risk was high for low potency antipsychotics. Studies were critically appraised to determine the strength of evidence.Conclusion: The studies reviewed indicate a significant association between antipsychotics and venous thromboembolism. Patients using the antipsychotics and those who prescribe them should be aware of this association.

scholarly journals Is the Simplicity of the Evidence Pyramid Actually Detrimental for Understanding Evidence?

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Annette O'Connor
Keyword(s):  
Cohort Studies ◽  
Real World ◽  
Disease Risk ◽  
Case Reports ◽  
Meta Analysis ◽  
Information Source ◽  
Case Series ◽  
Case Control ◽  
Current Evidence ◽  
Case Control Studies

The evidence pyramid for assessing the efficacy of interventions under real world conditions has been used in various forms for many years, and to a lesser extent the pyramid has been used for assessing evidence for disease risk factors. While acknowledging minor differences, many pyramids list the following information sources for interventions in decreasing order of “validity”: systematic review and meta-analysis of randomised control trials, randomised controlled trials, cohort studies, case control studies, case series and case reports. The evidence pyramid is often used as a teaching aid to help clinicians and students visualise the concept that all studies might not have equal evidentiary value when evaluating real world efficacy.The rationale for the hierarchy of the pyramid is partially based on the potential for bias in some designs and partially based on the external validity of the information source. Designs with greater potential for bias “on average” are placed lower on the pyramid. The greater risk of bias means a greater risk that effect size estimates from studies lower on the pyramid may be systematically incorrect (overestimated or underestimated). As such, the evidence pyramid makes very broad statements about the design “on average”. Of course, for any particular study or topic, the pyramid may not be correct. Regardless, the generalisations described in the evidence pyramid have over the years been considered useful and use of the tool continues likely because of its simplicity. However, the validity of most pyramids that we have seen (and used ourselves, and published ourselves) is predicated on two potentially false concepts. The first potentially false concept conveyed by most evidence pyramids, is that there is only one case-control design and it is of lesser evidentiary value than cohort studies. The second potentially false concept conveyed by evidence pyramids is that the terms cohort, case control, and case series can be used to “filter” out studies of lower evidentiary value.In this presentation Annette discusses the validity of the evidence pyramid on the interpretation of evidence from primary research. She proposes a new way to think about evidence from primary studies using the framework for classifying epidemiologic studies proposed by Pearce (2012) based on incident and prevalent cases. This would also result in a rethinking of the current evidence pyramid.

Types of trials

2017 ◽  
Author(s):  
Mark Harrison
Keyword(s):  
Emergency Medicine ◽  
Cohort Studies ◽  
Case Reports ◽  
Meta Analysis ◽  
Case Series ◽  
Case Control ◽  
Controlled Trials ◽  
Case Control Studies ◽  
Advantages And Disadvantages ◽  
Randomized Controlled

This chapter describes types of trials as applied to Emergency Medicine, and in particular the Primary FRCEM examination. The chapter outlines the key details and advantages and disadvantages of case reports, case series, cohort studies, case–control studies, randomized controlled trials, crossover trials, systematic reviews, and meta-analysis. This chapter is laid out exactly following the RCEM syllabus, to allow easy reference and consolidation of learning.

scholarly journals Adverse effects of spinal manipulation: a systematic review

2007 ◽  
Vol 100 (7) ◽  
pp. 330-338 ◽  
Author(s):  
E Ernst
Keyword(s):  
Systematic Review ◽  
Adverse Effects ◽  
Vertebral Artery ◽  
Spinal Manipulation ◽  
Case Reports ◽  
Vertebral Artery Dissection ◽  
Case Series ◽  
Case Control ◽  
Artery Dissection ◽  
Case Control Studies

Objective To identify adverse effects of spinal manipulation. Design Systematic review of papers published since 2001. Setting Six electronic databases. Main outcome measures Reports of adverse effects published between January 2001 and June 2006. There were no restrictions according to language of publication or research design of the reports. Results The searches identified 32 case reports, four case series, two prospective series, three case-control studies and three surveys. In case reports or case series, more than 200 patients were suspected to have been seriously harmed. The most common serious adverse effects were due to vertebral artery dissections. The two prospective reports suggested that relatively mild adverse effects occur in 30% to 61 % of all patients. The case-control studies suggested a causal relationship between spinal manipulation and the adverse effect. The survey data indicated that even serious adverse effects are rarely reported in the medical literature. Conclusions Spinal manipulation, particularly when performed on the upper spine, is frequently associated with mild to moderate adverse effects. It can also result in serious complications such as vertebral artery dissection followed by stroke. Currently, the incidence of such events is not known. In the interest of patient safety we should reconsider our policy towards the routine use of spinal manipulation.

scholarly journals Deep Venous Thrombosis with Pulmonary Embolism Related to IVIg Treatment: A Case Report and Literature Review

2015 ◽  
Vol 2015 ◽  
pp. 1-3 ◽  
Author(s):  
Michael T. Flannery ◽  
Deborah Humphrey
Keyword(s):  
Risk Factors ◽  
Pulmonary Embolism ◽  
Case Report ◽  
Case Reports ◽  
Case Series ◽  
Ivig Therapy ◽  
Case Control ◽  
Ivig Treatment ◽  
Case Control Studies ◽  
Traditional Risk Factors

IVIg therapy has potentially been related to arterial and venous therapy. We performed an Ovid review focusing on IVIg and thrombotic events. While a few case reports were reviewed case series and case control studies were particularly reviewed in relation to thrombotic events. Outcomes demonstrate a correlation between underlying cardiovascular risk factors with predominately arterial events which typically occurred within 4–24 hours of infusion. While venous events occurred less commonly they were associated with traditional risk factors and occurred later, typically, 1–7 days following infusion of IVIg. Potential causation of thrombotic events was discussed.

scholarly journals Genotype Pattern Mining for Pairs of Interacting Variants Underlying Digenic Traits

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1160
Author(s):  
Atsuko Okazaki ◽  
Sukanya Horpaopan ◽  
Qingrun Zhang ◽  
Matthew Randesi ◽  
Jurg Ott
Keyword(s):  
Null Hypothesis ◽  
Pattern Mining ◽  
Genetic Diseases ◽  
Frequent Pattern Mining ◽  
Case Control ◽  
Frequent Pattern ◽  
Permutation Testing ◽  
Case Control Studies ◽  
P Values ◽  
Dna Variants

Some genetic diseases (“digenic traits”) are due to the interaction between two DNA variants, which presumably reflects biochemical interactions. For example, certain forms of Retinitis Pigmentosa, a type of blindness, occur in the presence of two mutant variants, one each in the ROM1 and RDS genes, while the occurrence of only one such variant results in a normal phenotype. Detecting variant pairs underlying digenic traits by standard genetic methods is difficult and is downright impossible when individual variants alone have minimal effects. Frequent pattern mining (FPM) methods are known to detect patterns of items. We make use of FPM approaches to find pairs of genotypes (from different variants) that can discriminate between cases and controls. Our method is based on genotype patterns of length two, and permutation testing allows assigning p-values to genotype patterns, where the null hypothesis refers to equal pattern frequencies in cases and controls. We compare different interaction search approaches and their properties on the basis of published datasets. Our implementation of FPM to case-control studies is freely available.

scholarly journals Genotype Pattern Mining for Pairs of Interacting Variants Underlying Digenic Traits

2021 ◽  
Author(s):  
Atsuko Okazaki ◽  
Sukanya Horpaopan ◽  
Qingrun Zhang ◽  
Matthew Randesi ◽  
Jurg Ott
Keyword(s):  
Null Hypothesis ◽  
Pattern Mining ◽  
Genetic Diseases ◽  
Frequent Pattern Mining ◽  
Case Control ◽  
Frequent Pattern ◽  
Permutation Testing ◽  
Case Control Studies ◽  
P Values ◽  
Dna Variants

Some genetic diseases (“digenic traits”) are due to the interaction between two DNA variants, which presumably reflects biochemical interactions. For example, certain forms of Retinitis Pigmentosa, a type of blindness, occur in the presence of two mutant variants, one each in the ROM1 and RDS genes, while occurrence of only one such variant results in a normal phenotype. Detecting variant pairs underlying digenic traits by standard genetic methods is difficult and is downright impossible when individual variants alone have minimal effects. Frequent Pattern Mining (FPM) methods are known to detect patterns of items. We make use of FPM approaches to find pairs of genotypes (from different variants) that can discriminate between cases and controls. Our method is based on genotype patterns of length two, and permutation testing allows assigning p-values to genotype patterns, where the null hypothesis refers to equal pattern frequencies in cases and controls. We compare different interaction search approaches and their properties on the basis of published datasets. Our implementation of FPM to case-control studies is freely available.

scholarly journals Probable Neuropsychological & Cognitive Complications due to Cytokine Storm in Patients With COVID-19

2021 ◽  
Vol 0 (0) ◽  
pp. 1-37
Author(s):  
Zahra Keshtgar ◽  
◽  
GH. Reza Chalabianloo ◽  
Niloofar Esmaeili ◽  
◽  
...  
Keyword(s):  
Nervous System ◽  
Case Reports ◽  
Case Series ◽  
Executive Dysfunction ◽  
Inflammatory Factors ◽  
Cytokine Storm ◽  
Case Control Studies ◽  
Necrosis Factor Alpha ◽  
Cross Sectional ◽  
Tnf Α

Introduction: COVID-19 (coronavirus disease 2019) was identified in China in December 2019 for the first time and is rapidly spreading throughout the world as a pandemic. As COVID-19 causes mild to severe acute respiratory syndrome, most studies in this context have focused on pathogenesis primarily in the respiratory system. However, evidence shows that the central nervous system (CNS) may also be affected by COVID-19. Since COVID-19 is spreading, it is imperative to study its possible cognitive effects in patients suffering and recovering from COVID-19. Methods: The articles used in this study were searched by keywords such as Cytokine storm and covid-19, covid-19 and executive dysfunction, cognitive disorder and covid-19, CNS and covid 19, Coronavirus, Neuroinvasion in science direct, Scopus, PubMed, Embase, and Web of Science databases based on Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) checklist. The study will assess all observational studies published between December 2019 and April 2021 in peer-reviewed journals, including cross-sectional, cohort, case-control studies, case reports and case series. The search result was 106 articles, of which 73 articles related to Covid-19, the stages of infection by this virus, its effect on the nervous system and neurological symptoms, the cytokine storm caused by this infection, and the possible cognitive consequences caused by this virus in patients, has been reviewed. Other articles were not checked due to their limited relevance to the topic under discussion. Results: Studies show that neurons may be directly affected by SARS-CoV-1 and SARS-CoV-2. Furthermore, various studies indicate that systemic inflammation (so-called "cytokine storm") is also responsible for brain damage induced by infection with SARS-CoV-1 and SARS-CoV-2. Such a way that this patients showed elevated levels of interleukin (IL-), 6, 8, and 10 and of tumor necrosis factor-alpha (TNF- α) in their blood. Conclusion: Various cognitive defects following an increase level of cytokines such as TNF-α and IL-6,8 have been observed. Therefore, due to the increase level of these pro-inflammatory factors in the brains of these patients, cognitive deficits can be expected, which need further investigation.

scholarly journals Usefulness of surgical treatment for asymptomatic patients with extra-peritoneal desmoid-type fibromatosis: a systematic review and meta-analysis

2020 ◽  
Vol 50 (5) ◽  
pp. 574-580
Author(s):  
Munehisa Kito ◽  
Akira Ogose ◽  
Masahiro Yoshida ◽  
Yoshihiro Nishida
Keyword(s):  
Surgical Treatment ◽  
Treatment Group ◽  
Progressive Disease ◽  
Meta Analysis ◽  
Case Series ◽  
Case Control ◽  
Case Control Studies ◽  
Exacerbation Rate ◽  
Asymptomatic Patients ◽  
Non Surgical Treatment

Abstract Objective The purpose of this systematic review is to assess and compare the efficacy of surgical treatment for patients with asymptomatic extra-peritoneal desmoid-type fibromatosis to the wait-and-see policy by evaluating (1) the exacerbation rate (exacerbation; recurrence after surgery or progressive disease following non-surgical treatment) and (2) treatment-associated complications in extra-peritoneal desmoid-type fibromatosis. Methods We evaluated documents published between 1 January 1990 and 31 August 2017. The risk of bias in the selected literature was analyzed using the Cochrane Collaboration Risk of Bias Tool. Quality of evidence was evaluated using Grading of Recommendation, Assessment, Development and Evaluation approach. Results One prospective cohort study, four case–control studies and five case series studies were identified. Meta-analysis was performed to evaluate the exacerbation rate after treatment on one prospective cohort study and four case–control studies. In comparing surgical and non-surgical treatments, the exacerbation rate was significantly higher in the surgical treatment group (odds ratio: 1.32, 95% confidence interval 1.01–1.73, P = 0.05). However, in the case series study, the recurrence rate was 23.4% for the surgical treatment group, while the progressive disease rate was 28.1% for the non-surgical treatment group. The postoperative complication rates associated with surgical treatment in the two studies were 20.8 and 17.2%, respectively. Conclusions When considering the exacerbation rate, non-surgical treatment might be appropriate for asymptomatic patients with extra-peritoneal desmoid-type fibromatosis. However, if patients with tumor-related symptoms opt for surgery, including those who face difficulties due to the presence of tumors, it is important to fully explain to them the possibility that the recurrence rate and treatment-associated functional failures may increase depending on the site of occurrence.

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