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 A Primer on Bayesian Model-Averaged Meta-Analysis

2021 ◽  
Vol 4 (3) ◽  
pp. 251524592110312
Author(s):  
Quentin F. Gronau ◽  
Daniel W. Heck ◽  
Sophie W. 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: (a) fixed-effect null hypothesis, (b) fixed-effect alternative hypothesis, (c) random-effects null hypothesis, and (d) random-effects alternative hypothesis. These models are combined according to their plausibilities given the observed data to address the two key questions “Is the overall effect nonzero?” 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.

How to interpret meta-analysis models: fixed effect and random effects meta-analyses

2014 ◽  
Vol 17 (2) ◽  
pp. 64-64 ◽  
Author(s):  
Adriani Nikolakopoulou ◽  
Dimitris Mavridis ◽  
Georgia Salanti
Keyword(s):  
Random Effects ◽  
Meta Analysis ◽  
Fixed Effect ◽  
Meta Analyses ◽  
Analysis Models

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.

scholarly journals Gunshot Wounds to the Lumbosacral Spine: Systematic Review and Meta-Analysis

2021 ◽  
pp. 219256822110308
Author(s):  
Andrew Platt ◽  
Mostafa H. El Dafrawy ◽  
Michael J. Lee ◽  
Martin H. Herman ◽  
Edwin Ramos
Keyword(s):  
Systematic Review ◽  
Random Effects ◽  
Surgical Intervention ◽  
Meta Analysis ◽  
Gunshot Wounds ◽  
Operative Management ◽  
Operative Intervention ◽  
Lumbosacral Spine ◽  
Random Effects Model ◽  
Significant Difference

Study Design: Systematic review and meta-analysis. Objectives: Indications for surgical decompression of gunshot wounds to the lumbosacral spine are controversial and based on limited data. Methods: A systematic review of literature was conducted to identify studies that directly compare neurologic outcomes following operative and non-operative management of gunshot wounds to the lumbosacral spine. Studies were evaluated for degree of neurologic improvement, complications, and antibiotic usage. An odds ratio and 95% confidence interval were calculated for dichotomous outcomes which were then pooled by random-effects model meta-analysis. Results: Five studies were included that met inclusion criteria. The total rate of neurologic improvement was 72.3% following surgical intervention and 61.7% following non-operative intervention. A random-effects model meta-analysis was carried out which failed to show a statistically significant difference in the rate of neurologic improvement between surgical and non-operative intervention (OR 1.07; 95% CI 0.45, 2.53; P = 0.88). In civilian only studies, a random-effects model meta-analysis failed to show a statistically significant difference in the rate of neurologic improvement between surgical and non-operative intervention (OR 0.75; 95% CI 0.21, 2.72; P = 0.66). Meta-analysis further failed to show a statistically significant difference in the rate of neurologic improvement between patients with either complete (OR 4.13; 95% CI 0.55, 30.80; P = 0.17) or incomplete (OR 0.38; 95% CI 0.10, 1.52; P = 0.17) neurologic injuries who underwent surgical and non-operative intervention. There were no significant differences in the number of infections and other complications between patients who underwent surgical and non-operative intervention. Conclusions: There were no statistically significant differences in the rate of neurologic improvement between those who underwent surgical or non-operative intervention. Further research is necessary to determine if surgical intervention for gunshot wounds to the lumbosacral spine, including in the case of retained bullet within the spinal canal, is efficacious.

P–022 Improvement in sperm concentration and motility after oral antioxidant supplementation in infertile men with varicocele who have not undergone surgical repair: systematic review and meta-analys

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
P Ioannidou ◽  
J Bosdou ◽  
D Papanikolaou ◽  
D Goulis ◽  
A Lambropoulos ◽  
...  
Keyword(s):  
Systematic Review ◽  
Folic Acid ◽  
Random Effects ◽  
Surgical Repair ◽  
Meta Analysis ◽  
Sperm Concentration ◽  
Random Effects Model ◽  
Antioxidant Supplementation ◽  
Infertile Men ◽  
Single Study

Abstract Study question Does oral antioxidant supplementation improve sperm quality in infertile men with varicocele who have not undergone surgical repair? Summary answer Oral antioxidant supplementation improves sperm concentration and motility in infertile men with varicocele who have not undergone surgical repair. What is known already: Benefit from oral antioxidant supplementation has been shown in infertile men with varicocele following surgical repair. Similarly, oral antioxidant supplementation has been suggested in infertile men with varicocele who have not undergone surgical repair. However, its effect currently remains controversial. Study design, size, duration A literature search was performed until January 2021 aiming to identify prospective studies evaluating the use of oral antioxidant supplementation alone or in combination in men with varicocele who have not undergone surgical repair. Participants/materials, setting, methods Seven prospective studies were identified, published between 1987 and 2018, including 278 infertile men with varicocele who had not undergone surgical repair. The number of patients included ranged from 20 to 65. Sperm analysis, evaluating sperm concentration, motility and morphology was performed in these studies before and after oral antioxidant supplementation. Meta-analysis of weighted data was performed using random effects model. Results are reported as weighted mean difference (WMD) with 95% confidence interval (CI). Main results and the role of chance Seven studies were included in the systematic review. Oral antioxidant supplementation was performed by a combination of pentoxifylline, zinc and folic acid (single study), a combination of l-carnitine, fumarate, acetyl-l-carnitine, fructose, CoQ, vitamin C, zinc, folic acid and vitamin B12 (single study), a combination of L-Carnitine, vitamin C, coenzyme Q10, vitamin E, vitamin B9, vitamin B12, zinc , and selenium, l-carnitine (single study), or sole treatment with acetyl-l-carnitine (single study), L-Carnitine (single study), Coenzyme Q10 (single study) or zinc sulfate (single study). For the purpose of meta-analysis, the effect of oral antioxidant supplementation was evaluated after three months of treatment. Oral antioxidant supplementation significantly increased sperm concentration (WMD +5.65x106/ml 95% CI: +1.11 to + 10.12 p = 0.01, random effects model) and motility (WMD +4.30%, 95% CI: +0.86 to + 7.74 p = 0.01, random effects model) in infertile men with varicocele who had not undergone surgical repair. On the other hand, no significance difference was observed in sperm morphology (WMD +3.9%, 95% CI: –0.16 to + 8.04 p = 0.06, random effects model) and volume (WMD +0.53ml, 95% CI: 0.0 to + 1.0 p = 0.052, random effects model). Limitations, reasons for caution The number of relevant trials and that of patients included is small to allow for solid conclusions to be drawn. Moreover, although different oral antioxidants have been administered in infertile who had not undergone surgical repair, subgroup analysis was not feasible. Wider implications of the findings: Currently, limited evidence supports the use of oral antioxidants in the treatment of men with varicocele, who have not undergone surgical repair. Although the benefit in sperm concentration and motility appears to be modest, it might be important regarding achievement of pregnancy in these men. Trial registration number Not applicable

The relationship between migraine and infant colic: A systematic review and meta-analysis

Cephalalgia ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Amy A Gelfand ◽  
Peter J Goadsby ◽  
I Elaine Allen
Keyword(s):  
Systematic Review ◽  
Random Effects ◽  
Odds Ratio ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Random Effects Model ◽  
Fixed Effects Model ◽  
Primary Analysis ◽  
Infant Colic ◽  
The Relationship

Context Infant colic is a common and distressing disorder of early infancy. Its etiology is unknown, making treatment challenging. Several articles have suggested a link to migraine. Objective The objective of this article was to perform a systematic review and, if appropriate, a meta-analysis of the studies on the relationship between infant colic and migraine. Data sources Studies were identified by searching PubMed and ScienceDirect and by hand-searching references and conference proceedings. Study selection For the primary analysis, studies specifically designed to measure the association between colic and migraine were included. For the secondary analysis, studies that collected data on colic and migraine but were designed for another primary research question were also included. Data extraction Data were abstracted from the original studies, through communication with study authors, or both. Two authors independently abstracted data. Main outcomes and measures The main outcome measure was the association between infant colic and migraine using both a fixed-effects model and a more conservative random-effects model. Results Three studies were included in the primary analysis; the odds ratio for the association between migraine and infant colic was 6.5 (4.6–8.9, p < 0.001) for the fixed-effects model and 5.6 (3.3–9.5, p = 0.004) for the random-effects model. In a sensitivity analysis wherein the study with the largest effect size was removed, the odds ratio was 3.6 (95% CI 1.7–7.6, p = 0.001) for both the fixed-effects model and random-effects model. Conclusions In this meta-analysis, infant colic was associated with increased odds of migraine. If infant colic is a migrainous disorder, this would have important implications for treatment. The main limitation of this meta-analysis was the relatively small number of studies included.

Meta-Analysis of Meta-Analyses in Communication: Comparing Fixed Effects and Random Effects Analysis Models

2010 ◽  
Vol 58 (3) ◽  
pp. 257-278 ◽  
Author(s):  
Ashley Anker ◽  
Amber Marie Reinhart ◽  
Thomas Hugh Feeley
Keyword(s):  
Random Effects ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Meta Analyses ◽  
Analysis Models

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.

scholarly journals A systematic analysis on prevalence and sub-regional distribution of undiagnosed diabetes mellitus among adults in African countries

2020 ◽  
Author(s):  
Getenet Dessie ◽  
Henok Mulugeta ◽  
Desalegne Amare ◽  
Ayenew Negesse ◽  
Fasil Wagnew ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Random Effects ◽  
Meta Analysis ◽  
Eastern Africa ◽  
Undiagnosed Diabetes ◽  
Random Effects Model ◽  
Western Africa ◽  
Pooled Prevalence ◽  
High Prevalence ◽  
Undiagnosed Diabetes Mellitus

Abstract Background Despite the high prevalence of diabetes in Africa, the extent of undiagnosed diabetes in the region is still poorly understood. This systematic review and meta-analysis was designed to determine the pooled prevalence of undiagnosed diabetes mellitus among adults in Africa. Methods We conducted a systematic desk review and electronic web-based search of PubMed, Google Scholar, EMBASE, and the World Health Organization’s Hinari portal (which includes the SCOPUS, African Index Medicus, and African Journals Online databases), identifying peer-reviewed research studies on the prevalence of undiagnosed diabetes among adult individuals using pre-defined quality and inclusion criteria. We ran our search from June 1, 2018 to Jun 14, 2020. We extracted relevant data and presented descriptive summaries of the studies in tabular form. The I2 test was used to assess heterogeneity across studies. A random effects model was used to estimate the pooled prevalence of undiagnosed diabetes mellitus at a 95% confidence interval (CI). Funnel plot asymmetry and Egger’s tests were used to check for publication bias. The final effect size was determined by applying a trim and fill analysis in a random-effects model. Results Our search identified 1442 studies amongst which 23 articles were eligible for inclusion in the final meta-analysis. The average pooled prevalence of undiagnosed diabetes mellitus among adults was 3.85 (95% CI: 3.10–4.60). The pooled prevalence of undiagnosed diabetes mellitus based on geographic location was 4.43 (95% CI: 3.12–5.74) in Eastern Africa; 4.72 (95% CI: 2.64–6.80) in Western Africa; 4.27 (95% CI: 1.77–6.76) in Northern Africa and 1.46 (95%CI: 0.57–2.34) in southern Africa respectively. Conclusion Our findings indicate a high prevalence of undiagnosed diabetes in Africa and suggest that it may be more prevalent in Western Africa than the rest of the regions. Given the high levels of undiagnosed diabetes in the Africa region, more attention should be paid to incorporating diabetes screening and treatment services into existing diabetes related programs to reduce the prevalence of undiagnosed cases.

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