No solution yet for combining two independent studies in the presence of heterogeneity

Gonnermann, Andrea; Framke, Theodor; Großhennig, Anika; Koch, Armin

doi:10.1002/sim.6473

Cited by 65 publications

(87 citation statements)

References 21 publications

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“…For some time, the DerSimonian‐Laird method is criticized due to its unfavorable statistical properties, especially in the case of few available studies . The main problem of the DerSimonian‐Laird method is that the uncertainty of the estimation of the between‐study and within‐study variance is ignored .…”

Section: Methods For Evidence Synthesismentioning

confidence: 99%

“…However, in the extreme case of only k = 2 studies, the Knapp‐Hartung method with variance correction tends to be over‐conservative. Therefore, the situation of k = 2 studies was considered as effectively unsolved . Wiksten et al recommended to apply the RE meta‐analysis based upon the Knapp‐Hartung method and to conduct a sensitivity analysis using the CE meta‐analysis in practice to avoid misleading results.…”

Section: Methods For Evidence Synthesismentioning

confidence: 99%

“…This assumption is frequently challenged in practice. Applying a CE model in a situation where the basic CE assumption is violated may lead to far too narrow CIs and substantially increased type 1 error . Usually, whenever heterogeneity cannot be excluded, the CE model should not be used.…”

Section: Generic Models For Meta‐analysismentioning

confidence: 99%

“…However, an unsolved problem in this context is the case of very few (ie, 2‐4) studies . As heterogeneity cannot be reliably estimated if only very few studies are available, the Knapp‐Hartung method, while correctly accounting for the corresponding uncertainty, has very low power and leads to wide confidence intervals (CIs) .…”

Section: Introductionmentioning

confidence: 99%

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Methods for evidence synthesis in the case of very few studies

Bender

Friede

Koch

et al. 2018

Research Synthesis Methods

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In systematic reviews, meta‐analyses are routinely applied to summarize the results of the relevant studies for a specific research question. If one can assume that in all studies the same true effect is estimated, the application of a meta‐analysis with common effect (commonly referred to as fixed‐effect meta‐analysis) is adequate. If between‐study heterogeneity is expected to be present, the method of choice is a meta‐analysis with random effects. The widely used DerSimonian and Laird method for meta‐analyses with random effects has been criticized due to its unfavorable statistical properties, especially in the case of very few studies. A working group of the Cochrane Collaboration recommended the use of the Knapp‐Hartung method for meta‐analyses with random effects. However, as heterogeneity cannot be reliably estimated if only very few studies are available, the Knapp‐Hartung method, while correctly accounting for the corresponding uncertainty, has very low power. Our aim is to summarize possible methods to perform meaningful evidence syntheses in the situation with only very few (ie, 2‐4) studies. Some general recommendations are provided on which method should be used when. Our recommendations are based on the existing literature on methods for meta‐analysis with very few studies and consensus of the authors. The recommendations are illustrated by 2 examples coming from dossier assessments of the Institute for Quality and Efficiency in Health Care.

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Section: Methods For Evidence Synthesismentioning

confidence: 99%

Section: Methods For Evidence Synthesismentioning

confidence: 99%

Section: Generic Models For Meta‐analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Methods for evidence synthesis in the case of very few studies

Bender

Friede

Koch

et al. 2018

Research Synthesis Methods

Self Cite

179

150

View full text Add to dashboard Cite

show abstract

“…There were no outcome variables available that were measured with the same assessment method in five or more of the included studies. A serious meta‐analysis, therefore, was not possible as results are considered unreliable when a small number of heterogeneous studies is assessed …”

Section: Methodsmentioning

confidence: 99%

The effect of resistance exercise on strength and safety outcome for people with haemophilia: A systematic review

et al. 2020

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Introduction Haemophilia is a congenital bleeding disorder with severe musculoskeletal complications. Resistance exercise is important to increase joint stability and to improve physical performance. Aim This review aimed to investigate the safety and efficacy of resistance exercise interventions on people with haemophilia (PwH) and evaluate whether the American College of Sports Medicine resistance exercise criteria for healthy adults are valid for this population. Methods A systematic search in literature was conducted, using the databases PubMed, MEDLiNE, CINAHL, SCOPUS, PEDro and Cochrane Library. Out of 2.440 studies published between 1960 and November 2019, 14 studies (9 randomized controlled trials, 1 controlled trial, 4 single‐group prospective studies) applying resistance exercise in juvenile and adult PwH corresponded to the inclusion criteria. Results Studies performed dynamic, isokinetic or a combination of isometric and dynamic resistance training. Most interventions were carried out in the context of a multimodal training. Resistance was provided using fixed and free weights, body weight, resistance bands and water resistance. Study protocols included clinical and home‐based settings. Several studies suggest that training intensities lower than those known to increase the strength of healthy people are effective in increasing the strength of PwH. Resistance exercise seems to be a safe intervention if it is adequately monitored, individually adapted and applied with sufficient factor therapy. Due to the heterogeneity of study designs, training interventions and outcome measures a meta‐analysis could not be performed. Conclusions Further studies of higher methodological quality are needed to determine the optimal types of exercise, optimal dosage and timing.

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Anesthetic Exposure During Childhood and Neurodevelopmental Outcomes

et al. 2022

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Key Points Question Is exposure to general anesthesia during childhood associated with deficits in specific neurodevelopmental domains? Findings In this systematic review and meta-analysis of 31 studies, childhood exposure to general anesthesia was associated with statistically significantly more behavioral problems and neurodevelopmental disorder diagnoses, as well as deficits in executive function, nonverbal reasoning, motor function, and, to a lesser extent, language, general development, and academics. Cognition score differences, while statistically significant, had the weakest association. Meaning These findings suggest that the associations between anesthetic exposure during childhood and subsequent neurodevelopmental deficits differ based on neurodevelopmental domain.

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No solution yet for combining two independent studies in the presence of heterogeneity

Cited by 65 publications

References 21 publications

Methods for evidence synthesis in the case of very few studies

Methods for evidence synthesis in the case of very few studies

The effect of resistance exercise on strength and safety outcome for people with haemophilia: A systematic review

Anesthetic Exposure During Childhood and Neurodevelopmental Outcomes

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