scholarly journals Churras y merinas. Metanálisis (I).

2018 ◽  
Vol 10 (10) ◽  
pp. 5
Author(s):  
Manuel Molina
Keyword(s):  
Statistical Methods ◽  
Random Effects ◽  
Meta Analysis ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Random Effects Model ◽  
Effect Model ◽  
Global Result

El metanálisis es una técnica que permite obtener un resultado resumen a partir de varios estudios individuales. Esto solo puede hacer tras comprobar que los estudios se parecen lo suficiente como para poder combinarse, lo cual se hará con métodos estadísticos específicos, siendo los más usados el modelo de efecto fijo y el modelo de efectos aleatorios. ABSTRACT Meta-analysis is a technique that allows obtaining a global result from several individual studies. This can only be done after checking that the studies are similar enough to be combined, which will be done with specific statistical methods, the most used being the fixed effect model and the random effects model.

Racial disparity in OncotypeDX score in early stage, hormone receptor positive, HER-2 negative, node negative breast cancers: A systemic review and meta-analysis.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e12555-e12555
Author(s):  
Yi Lee ◽  
Ruolin Liu ◽  
Alexis K. Bean ◽  
Madison J. Garshasebi ◽  
Qasim Jehangir ◽  
...  
Keyword(s):  
High Risk ◽  
Random Effects ◽  
Racial Disparity ◽  
Random Effect ◽  
Recurrence Score ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Random Effects Model ◽  
Effect Model ◽  
To Receive

e12555 Background: Oncotype DX Breast Recurrence Score (RS) is the currently used risk-assessment tool for early-stage, hormone receptor-positive, HER-2 negative, node-negative breast cancer in the US. Studies showed inconsistency in RS distribution and treatment among races. Causes may include variations in somatic mutations like Ki-67, which have been reported to express higher in African American (AA) and Asian populations than in Non-Hispanic White (NHW) population, germline mutations in BRCA and TP53, that are not in the RS algorithm, and financial burden of the testing. We analyzed data from different countries to investigate racial disparity in RS. Methods: We searched Medline, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials, indexed from January 2010 to January 2021. More than 85% of studies were conducted in the pre-TAILORx study phase. To include data that are available and better represent different races, we included studies that used the previous cutoff value, low-risk ( < 18), intermediate-risk (18-30), high-risk ( > 30). Retrospective studies using Surveillance, Epidemiology, and End Results or National Cancer Database were excluded to avoid overlap data. A total of 17 studies, 9789 patients from seven countries (US, Japan, China, Taiwan, Kuwait, UAE, Israel) were pooled. The Odds Ratio (OR) was extracted with a 95% confidence interval (CI) for RS distribution and post-RS treatment. Both fixed-effect and random-effect meta-analysis were performed. Results: Among AA and NHW, AA were 1.7 times more likely to have high recurrence score (OR = 1.75; 95% CI = 1.46 - 2.10; P < 0.0001), with no heterogeneity among studies (I2 = 0%, heterogeneity P = 0.59). Asian were 1.59 more likely than NHW to be high-risk using a random effects model (OR = 1.59; 95% CI = 1.06 - 2.40; P = 0.0259). High-risk Asian were two times more likely to receive adjuvant chemotherapy post-RS comparing to NHW (OR: 2.31, CI: 1.07 - 4.98, fixed effect model; OR: 2.85, CI: 0.48, 17.05, random effects model), while high-risk AA were less likely to receive chemotherapy comparing to NHW (OR: 0.74, CI: 0.54-1.01, fixed effect model; OR: 0.73, CI: 0.54-0.99, random effects model). Intermediate-risk Asian and AA were more likely to receive chemotherapy compared to NHW (Asian to NHW; OR: 1.68, CI: 1.16-2.43, with fixed effect model, OR: 1.68, CI: 0.94-3.02, with random effects model; AA to NHW; OR: 1.16, CI: 0.93-1.46 with fixed effect model; OR: 1.06, CI: 0.62-1.79 with random effect model). Conclusions: We identified racial disparity in RS and post-RS treatment. Future research is required to elucidate the causes for AA and Asian receiving higher recurrence scores, a need for tailoring RS cutoffs for different races, and the utilization in adequate post-RS treatment.

Efficacy and Safety of N-acetylcysteine for the Management of Chronic Pain in Adults: A Systematic Review & Meta-analysis

Pain Medicine ◽  
2021 ◽  
Author(s):  
Mohammed Mohiuddin ◽  
Bianca Pivetta ◽  
Ian Gilron ◽  
James S Khan
Keyword(s):  
Chronic Pain ◽  
Sensitivity Analysis ◽  
Random Effects ◽  
Comparative Studies ◽  
Meta Analysis ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Risk Of Bias ◽  
Efficacy And Safety ◽  
Effect Model

Abstract Objective To assess the efficacy and safety of N-acetylcysteine in the treatment of chronic pain. Methods A systematic search was carried out until April 2020 for clinical studies of N-acetylcysteine in the management of any persistent or recurrent chronic pain condition for adults ≥ 18 years old. Risk of Bias was assessed using the validated risk of bias tools. When appropriate, a meta-analysis using a random-effects model was performed, with a fixed-effect model for sensitivity analysis. Results Nine studies (n = 863) were included (5 randomized controlled trials [RCTs], 2 open-label non-comparative studies and 2 comparative studies), that evaluated patients with sickle cell disease (3), complex regional pain syndrome (1), pelvic pain/endometriosis (2), rheumatoid arthritis (1), diabetic neuropathy (1), and chronic neuropathic pain (1). In the pooled analysis of 3 RCTs, N-acetylcysteine did not reduce pain intensities (SMD -0.21, 95% CI -0.33 to 0.75, random-effects), improve functional outcomes (SMD 0.21, 95% CI -0.33 to 0.75) or quality of life (SMD 0.60, 95% CI -4.44 to 5.64); however, sensitivity analysis with a fixed effect model demonstrated an effect for pain intensities and function. Due to adverse events being inconsistently reported, no conclusion could be made regarding safety of N-acetylcysteine in chronic pain. Conclusions While there is some evidence to indicate N-acetylcysteine may provide analgesic efficacy for certain pain conditions, there is insufficient evidence to provide definitive evidence on NAC in chronic pain management. Larger-size RCTs spanning a variety of chronic pain conditions are needed to determine N-acetylcysteine’s role, if any, in pain medicine.

Vitamin D Receptor Gene Polymorphisms and the Risk of Metabolic Syndrome (MetS): A Meta-Analysis

2020 ◽  
Vol 20 ◽  
Author(s):  
Hamidreza Totonchi ◽  
Ramazan Rezaei ◽  
Shokoofe Noori ◽  
Negar Azarpira ◽  
Pooneh Mokarram ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Vitamin D ◽  
Vitamin D Receptor ◽  
Protective Factor ◽  
Meta Analysis ◽  
Receptor Gene ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Vdr Gene ◽  
Effect Model

Introduction: Several studies have assessed the association between the vitamin D receptor (VDR) polymorphism and risk of metabolic syndrome (MetS). However, the results were inconsistent and inconclusive. Therefore, we conducted a meta-analysis to clarify the exact association between the vitamin D receptor (VDR) polymorphisms and the risk of MetS. Methods: All accessible studies reporting the association between the FokI (rs2228570) or / and TaqI (rs731236) or/and BsmI (rs1544410) or/and ApaI (rs7975232 polymorphisms of the Vitamin D Receptor and susceptibility to MetS published prior to February 2019 were systematically searched in Web of Science, Scopus, and PubMed. After that, Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated to evaluate the strength of the association in five genetic models. Results: A total of 9 articles based on four gene variations, and comprising 3348 participants with 1779 metabolic syndrome patients were included. The overall results suggested a significant association between BsmI (rs1544410) polymorphism and MetS susceptibility in recessive model (OR, 0.72, 95% CI, 0.55-0.95, fixed effect model), allelic model (OR, 0.83, 95% CI, 0.72-0.95, fixed effect model), and bb vs BB (OR, 0.65, 95% CI, 0.46-0.93, fixed effect). However, no significant association was identified between TaqI (rs731236) polymorphism, ApaI (rs7975232) polymorphism, and FokI (rs2228570) polymorphism and MetS. Conclusion: This meta-analysis suggested an association between the BsmI (rs1544410) polymorphism and MetS. Indeed, BsmI (rs1544410) acts as a protective factor in the MetS. As a result, the VDR gene could be regarded as a promising pharmacological and physiological target in prevention or treatment of the MetS.

scholarly journals Effects of hydrokinesitherapy on balance and walking ability in stroke survivors: a systematic review and meta-analysis of randomized controlled studies

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Guanli Xie ◽  
Tao Wang ◽  
Bo Jiang ◽  
Yan Su ◽  
Xiaoxia Tang ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Sufficient Evidence ◽  
Cochrane Library ◽  
Stroke Survivors ◽  
Walking Ability ◽  
Balance Function ◽  
Effect Model ◽  
Positive Effect

Abstract Background Balance and walking impairment are common dysfunctions after stroke. Emerging data has demonstrated that hydrokinesitherapy may have a positive influence on improvement of balance and walking ability. However, there is no firm evidence to support these results. Therefore, the aim of this review is to evaluate the effects of hydrokinesitherapy in stroke survivors systematically. Methods Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, CINAHL and SPORTDiscus were systemic searched from their inception to Septemter 30, 2018. RevMan 5.3 software was used to perform data synthesis. The fixed-effect model or random-effect model was employed according to the results of heterogeneity test. The mean differences (MD) or standardized mean difference (SMD) was used to evaluate the pooled effect of hydrokinesitherapy on balance function, walking ability and activty of daily life (ADL). Results A total of 13 studies were included involving 381 stroke survivors. Meta-analysis results indicated that hydrokinesitherapy could improve balance ability based on three test: Berg balance scale (BBS: MD = 3.84, 95% confidence interval (95% CI) 2.84 to 4.86, P < 0.001), Time Up To Go Test (TUGT: MD = − 1.22, 95% CI − 2.25 to − 0.18, P = 0.02, fixed-effect model), Functional Reach Test (FRT: MD = 2.41, 95% CI 1.49 to 3.33, P < 0.001). Additionally, we found a weakly positive effect on walking speed (SMD = 0.75, 95% CI 0.26 to 1.25, P = 0.003) and walking ability test (SMD = 0.36, 95% CI 0.04 to 0.68, P = 0.03). There was no significant difference between experimental group and control group in terms of ADL. Short conclusion Hydrokinesitherapy can improve balance function and had a weakly positive effect on walking ability in stroke survivors. We did not find sufficient evidence to indicate that hydrokinesitherapy could improve the ADL of stroke survivors. However, due to the methodological shortcoming and small number of included studies, caution is needed when interpreting these results. Due to imprecision and publication bias, the quality of the evidence was downgraded to “low-quality” for the primary outcomes of balance and walking ability. Trial registration CRD42018110787.

scholarly journals Identifying small-effect genetic associations overlooked by the conventional fixed-effect model in a large-scale meta-analysis of coronary artery disease

2019 ◽  
Author(s):  
Lerato E Magosi ◽  
Anuj Goel ◽  
Jemma C Hopewell ◽  
Martin Farrall
Keyword(s):  
Random Effects ◽  
Complex Traits ◽  
Large Scale ◽  
Meta Analysis ◽  
Genetic Effect ◽  
High Sensitivity ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Supplementary Information ◽  
Genetic Associations

Abstract Motivation Common small-effect genetic variants that contribute to human complex traits and disease are typically identified using traditional fixed-effect (FE) meta-analysis methods. However, the power to detect genetic associations under FE models deteriorates with increasing heterogeneity, so that some small-effect heterogeneous loci might go undetected. A modified random-effects meta-analysis approach (RE2) was previously developed that is more powerful than traditional fixed and random-effects methods at detecting small-effect heterogeneous genetic associations, the method was updated (RE2C) to identify small-effect heterogeneous variants overlooked by traditional fixed-effect meta-analysis. Here, we re-appraise a large-scale meta-analysis of coronary disease with RE2C to search for small-effect genetic signals potentially masked by heterogeneity in a FE meta-analysis. Results Our application of RE2C suggests a high sensitivity but low specificity of this approach for discovering small-effect heterogeneous genetic associations. We recommend that reports of small-effect heterogeneous loci discovered with RE2C are accompanied by forest plots and standardized predicted random-effects statistics to reveal the distribution of genetic effect estimates across component studies of meta-analyses, highlighting overly influential outlier studies with the potential to inflate genetic signals. Availability and implementation Scripts to calculate standardized predicted random-effects statistics and generate forest plots are available in the getspres R package entitled from https://magosil86.github.io/getspres/. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Association of microRNAs genes polymorphisms with arthritis: a systematic review and meta-analysis

2019 ◽  
Vol 39 (7) ◽  
Author(s):  
Yingqi Xiao ◽  
Hui Liu ◽  
Li Chen ◽  
Yang Wang ◽  
Xiang Yao ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Meta Analysis ◽  
Fixed Effect Model ◽  
Case Control ◽  
Cochrane Library ◽  
Random Effects Model ◽  
Inclusion Criteria ◽  
Case Control Studies ◽  
Effect Model ◽  
Meta Analyses

Abstract Objective: To investigate whether microRNAs genes’ polymorphisms are associated with arthritis. Methods: The PubMed, Cochrane Library et al. were systematically searched to identify case–control studies, systematic reviews and meta-analyses. A meta-analysis was performed to calculate odds ratios (ORs), and confidence intervals (CIs) at 95% using fixed-effect model or random-effects model. Results: Twenty-two case–control studies involving 10489 participants fulfilled the inclusion criteria. MiR-146a rs2910164 (G/C) was not significantly associated with the risk of rheumatoid arthritis (RA) in any model. Significant associations were found between miR-146a rs2910164 (G/C) and the risk of psoriatic arthritis (PsA) in the heterozygous model and the dominant model. The heterozygous model showed a significant association between the miR-146a rs2910164 (G/C) polymorphism and ankylosing spondylitis (AS). And there was no significant association of miR-146a rs2910164 (G/C) with risk of juvenile rheumatoid arthritis (JRA) at any model. Additionally, there was a significant association of miR-499 rs3746444 (T/C) with risk of RA at two genetic models, and with a moderate heterogeneity. When subgroup analysis by ethnicity, significant associations were almost found between miR-499 rs3746444 (T/C) and the risk of RA in any model in Caucasian populations, and there is no heterogeneity. Conclusions: The association of miR-146a rs2910164 (G/C) with RA was not found. And there was a significant association between miR-146a rs2910164(G/C) and PsA or AS. MiR-499 rs3746444 (T/C) was associated with RA in Caucasian populations. These findings did not support the genetic association between miR-146a rs2910164 (G/C) and JRA susceptibility, as well as the association of miR-196a-2 rs11614913 (C/T), miR-146a rs2431697, miR-146a rs57095329, miR-149 rs22928323 with arthritis.

Expression of microRNA-210 and the prognosis in glioma patients: a meta-analysis

2020 ◽  
Vol 14 (9) ◽  
pp. 795-805
Author(s):  
Xuezhi Hu ◽  
Pengfei Yan ◽  
Jun Feng ◽  
Fangcheng Zhang
Keyword(s):  
Overall Survival ◽  
Predictive Power ◽  
Meta Analysis ◽  
Fixed Effect Model ◽  
Hazard Ratio ◽  
Fixed Effect ◽  
Poor Survival ◽  
Effect Model ◽  
Subgroup Analyses ◽  
Meta Analyses

Aim: To evaluate the predictive power of tumor microRNA-210 (miR-210) on overall survival (OS) in glioma patients. Materials & methods: Studies were identified through searching PubMed, Embase and China National Knowledge Internet electronic databases. Meta-analyses were performed with a random- or fixed-effect model according to the heterogeneity. Results: Six studies were included. Results showed that increased miR-210 expression in tumor independently predicted poor OS in glioma patients (hazard ratio [HR]: 1.38; p = 0.001). Subgroup analyses showed that the prognostic efficacy of tumor miR-210 levels for OS was stronger in overall patients with glioma (HR: 2.22; p < 0.001) than in those with glioblastoma (HR: 1.13; p = 0.01). Conclusion: Expression of miR-210 may predict poor survival in patients with glioma.

scholarly journals Meta-analysis: Fixed-effect model

2020 ◽  
Vol 157 (1) ◽  
pp. 134-137
Author(s):  
Loukia M. Spineli ◽  
Nikolaos Pandis
Keyword(s):  
Meta Analysis ◽  
Fixed Effect Model ◽  
Fixed Effect ◽  
Effect Model

scholarly journals A Primer on Bayesian Model-Averaged Meta-Analysis

2020 ◽  
Author(s):  
Quentin Frederik Gronau ◽  
Daniel W. Heck ◽  
Sophie Wilhelmina Berkhout ◽  
Julia M. Haaf ◽  
Eric-Jan Wagenmakers
Keyword(s):  
Random Effects ◽  
Null Hypothesis ◽  
Bayesian Model ◽  
Alternative Hypothesis ◽  
Meta Analysis ◽  
Fixed Effect ◽  
Random Effects Model ◽  
Psychological Science ◽  
Analysis Models ◽  
Key Questions

Meta-analysis is the predominant approach for quantitatively synthesizing a set of studies. If the studies themselves are of high quality, meta-analysis can provide valuable insights into the current scientific state of knowledge about a particular phenomenon. In psychological science, the most common approach is to conduct frequentist meta-analysis. In this primer, we discuss an alternative method, Bayesian model-averaged meta-analysis. This procedure combines the results of four Bayesian meta-analysis models: (1) fixed-effect null hypothesis, (2) fixed-effect alternative hypothesis, (3) random-effects null hypothesis, and (4) random-effects alternative hypothesis. These models are combined according to their plausibilities in light of the observed data to address the two key questions "Is the overall effect non-zero?" and "Is there between-study variability in effect size?". Bayesian model-averaged meta-analysis therefore avoids the need to select either a fixed-effect or random-effects model and instead takes into account model uncertainty in a principled manner.

scholarly journals Aspirin and death in Covid-19 A systematic review and meta-analysis

2021 ◽  
Author(s):  
Nicholas Moore (NO NEW ASSIGNMENTS) ◽  
Nicolas Thurin ◽  
Pauline Bosco-Lévy ◽  
Patrick Blin ◽  
cecile Droz
Keyword(s):  
Systematic Review ◽  
Random Effects ◽  
Odds Ratio ◽  
Data Extraction ◽  
Meta Analysis ◽  
Cochrane Collaboration ◽  
Fixed Effect Model ◽  
Random Effects Model ◽  
Risk Of Death ◽  
Relative Risks

Thrombotic events are common during COVID-19 infection. Aspirin might be beneficial. Objective: Systematic review and meta-analysis of deaths in users and non-users of aspirin. Data sources: Pubmed Medline, Google scholar, Clinicaltrials.gov, Cochrane, to June 8, 2021, Study selection: Studies providing adjusted or matched evaluation of association of exposure to aspirin and death in COVID-19 patients were included. Data extraction and synthesis: Data were used as published, as Odds ratio, hazard ratio or relative risks and 95% CI from which log(OR) and SE were recalculated. These were entered in an inverse variance odds ratios random-effects model, using RevMan 5.4 (the Cochrane Collaboration). Main outcomes and measure: The prespecified outcome studied was death. Results: Nine studies (8 observational, one interventional) included 14989 patients exposed to aspirin and 15857 unexposed. Overall Odds Ratio of death in aspirin exposed patients in a random effects model was 0.63, 95% confidence interval [0.40-0.99], I2 94%. Using a fixed-effect model did not change much the result (0.76 [0.71-0.81], removing the Recovery trial (OR 0.43 [0.38-0.49], I271%, or the two largest studies (0.66 [0.47-0.93], I2 38%) reduced heterogeneity without materially altering the results. The funnel plot showed no evident publication bias Conclusion: this meta-analysis suggests that the use of aspirin may be associated with a lower risk of death in COVID-19. Considering the results of the Recovery Study, it would appear preferable to continue aspirin in patients who have a non-covid indication, but possibly useless to add it if they don’t.

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