Exploring heterogeneity in meta‐analyses: needs, resources and challenges

Xu, Hairong; Platt, Robert W.; Luo, Zhong‐Cheng; Wei, Shuqin; Fraser, William D.

doi:10.1111/j.1365-3016.2007.00908.x

Cited by 30 publications

(20 citation statements)

References 97 publications

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“…Particularly, this was the case with these meta-analyses that varied and/or contained unclear data pertaining to a wide range of factors and strata of programs, for example, relating to clinical populations, providers, location, mode of delivery, numbers of components, and length. These multiple ambiguities made pooling, sensitivity analysis, and meta-regression inappropriate [38-40]. …”

Section: Resultsmentioning

confidence: 99%

A meta-review of evidence on heart failure disease management programs: the challenges of describing and synthesizing evidence on complex interventions

Savard

Thompson

Clark

2011

Trials

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BackgroundDespite favourable results from past meta-analyses, some recent large trials have not found Heart Failure (HF) disease management programs to be beneficial. To explore reasons for this, we evaluated evidence from existing meta-analyses.MethodsSystematic review incorporating meta-review was used. We selected meta-analyses of randomized controlled trials published after 1995 in English that examined the effects of HF disease management programs on key outcomes. Databases searched: MEDLINE, EMBASE, Cochrane Database of Systematic Reviews (CDSR), DARE, NHS EED, NHS HTA, Ageline, AMED, Scopus, Web of Science and CINAHL; cited references, experts and existing reviews were also searched.Results15 meta-analyses were identified containing a mean of 18.5 randomized trials of HF interventions +/- 10.1 (range: 6 to 36). Overall quality of the meta-analyses was very mixed (Mean AMSTAR Score = 6.4 +/- 1.9; range 2-9). Reporting inadequacies were widespread around populations, intervention components, settings and characteristics, comparison, and comparator groups. Heterogeneity (statistical, clinical, and methodological) was not taken into account sufficiently when drawing conclusions from pooled analyses.ConclusionsMeta-analyses of heart failure disease management programs have promising findings but often fail to report key characteristics of populations, interventions, and comparisons. Existing reviews are of mixed quality and do not adequately take account of program complexity and heterogeneity.

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Section: Resultsmentioning

confidence: 99%

A meta-review of evidence on heart failure disease management programs: the challenges of describing and synthesizing evidence on complex interventions

Savard

Thompson

Clark

2011

Trials

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“…Heterogeneity across studies was assessed with I 2 metric and chi square statistics [18]. A meta-regression analysis was performed in cases of high heterogeneity (i.e., I 2 ≥ 50%) [19]. Eventual outlier studies were removed in a sensitivity analysis.…”

Section: Methodsmentioning

confidence: 99%

Alternative lengthening of telomeres (ALT) influences survival in soft tissue sarcomas: a systematic review with meta-analysis

Lawlor¹,

Veronese

Pea³

et al. 2019

BMC Cancer

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BackgroundAlternative lengthening of telomeres (ALT) is a telomerase-independent mechanism used by a broad range of neoplasms to maintain telomere length, permitting uncontrolled replication during their progression. ALT has been described in different types of sarcoma, but a comprehensive analysis of its clinical significance is still lacking. Therefore, we provide here the first meta-analysis on this topic.MethodsWe searched SCOPUS and PubMed through July 2018 to identify all studies that investigated the prognostic role of ALT in sarcomas. We considered the risk of death (risk ratio, RR) calculated as the number of death vs. total participants during follow-up in ALT+ versus ALT- patients as the primary outcome. The secondary outcome was the hazard ratio (HR), adjusted for the maximum number of covariates available, using ALT- patients as reference.ResultsEight articles comprising a total of 551 patients with sarcomas (226 ALT+ and 325 ALT-) were selected. The ALT+ group showed a higher mitotic count and a higher tumor grade compared with the ALT- group (p < 0.01). Furthermore, we demonstrate a strong impact of ALT on survival. In fact, ALT+ patients showed a statistically significant higher risk of death than ALT- patients, when also considering data from multivariate analyses (RR = 1.50; 95% CI: 1.15–1.96; p = 0.003; HR = 2.02; 95% CI: 1.22–3.38; p = 0.007).ConclusionsOur results indicate that ALT is associated with an increased risk of death in patients with sarcoma. In these neoplasms, ALT should be taken into account for a precise prognostic stratification and design of potential therapeutic strategies.Electronic supplementary materialThe online version of this article (10.1186/s12885-019-5424-8) contains supplementary material, which is available to authorized users.

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“…As the overall effect estimate has been found to be infl uenced by between-study variance (τ 2 -variation coeffi cient), a likelihood-based approach was used [41]. For evaluation of the global estimate of treatment effects, ESs from EUs were pooled.…”

Section: Random Effect Meta-regressionmentioning

confidence: 99%

Intravenous Route of Cell Delivery for Treatment of Neurological Disorders: A Meta-Analysis of Preclinical Results

Janowski

Walczak

Date

2010

Stem Cells and Development

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The last decade has been marked by a growing interest in an employment of intravenous cell delivery for treatment of neurological disorders. Numerous preclinical experimental studies have reported functional benefits, and have recently been followed by clinical trials. Some early clinical studies have indicated only modest positive effects, suggesting that the optimal conditions have not been defined yet. Thus, the evaluation of factors that influence outcomes, on the level of the whole population of preclinical studies by advanced statistical analysis, is warranted. PubMed search was conducted from the inception through 2006, and 60 preclinical studies were found and subjected to analysis. Categorical and continuous independent variables (IVs) were extracted. Three distinct outcomes of interest were selected as dependent variables (DVs) and named treatment effects: morphological, behavioral, and molecular, respectively. Mean outcomes, standard deviations (SDs), and animal numbers were retrieved and calculated by individual comparisons of experimental and control groups, based on the Hedges g formula, and were expressed as effect sizes (ESs) and variances. Publication bias and homogeneity were evaluated. The mainspring analyses were performed under a random effect model using Proc Mixed (SAS, version 9.2). A significant heterogeneity and publication bias were found. The ES pooling revealed large treatment effects. Univariate and multivariate meta-regression revealed that cell-related variables explained most of the heterogeneity. Cells retrieved from established lines and genetic modification of cells warrants the highest efficiency, in a dose-dependent manner. The stratified analysis of molecular effect measures revealed that apoptosis inhibition is the strongest brain tissue-positive change induced by cell therapy.

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Exploring heterogeneity in meta‐analyses: needs, resources and challenges

Cited by 30 publications

References 97 publications

A meta-review of evidence on heart failure disease management programs: the challenges of describing and synthesizing evidence on complex interventions

A meta-review of evidence on heart failure disease management programs: the challenges of describing and synthesizing evidence on complex interventions

Alternative lengthening of telomeres (ALT) influences survival in soft tissue sarcomas: a systematic review with meta-analysis

Intravenous Route of Cell Delivery for Treatment of Neurological Disorders: A Meta-Analysis of Preclinical Results

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