ArticleJournal of clinical epidemiology2013
Individual participant data meta-analyses should not ignore clustering.
Article in Journal of clinical epidemiology, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 58 papers, 29 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
58 citing papers in PubMed, 29 syntheses or guidelines pooled it, 132 citations in OpenAlex.
- Evaluating Reduced Use and Abstinence as Outcomes in Pharmacotherapy Trials for Stimulant Use Disorder: A Meta-Analysis of 12 Randomized Controlled Trials.JAMA psychiatry · 2026Pooled it
- Gender differences in the impact of psychological distress on methamphetamine use disorder outcomes and treatment effect.Addiction (Abingdon, England) · 2026Pooled it
- IPDMA - RADICAL - NSCLC: individual participant data meta-analysis and systematic review of radical local therapy for oligometastatic NSCLC.BMJ open respiratory research · 2025Pooled it
- Does early non-improvement predict treatment failure in pharmacotherapy for obsessive-compulsive disorder? A diagnostic test accuracy meta-analysis with individual participant data.Psychological medicine · 2025Pooled it
- Neoplastic Progression Risk in Females With Barrett's Esophagus: A Systematic Review and Meta-Analysis of Individual Patient Data.Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association · 2025Pooled it
- Factors associated with tuberculosis treatment initiation among bacteriologically negative individuals evaluated for tuberculosis: An individual patient data meta-analysis.PLoS medicine · 2025Pooled it
- Prevalence of non-communicable diseases among household contacts of people with tuberculosis: A systematic review and individual participant data meta-analysis.Tropical medicine & international health : TM & IH · 2024Pooled it
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- Two-stage or not two-stage? That is the question for IPD meta-analysis projects.Research synthesis methods · 2023Pooled it
- An Introduction to Individual Participant Data Meta-analysis.Neurology · 2023Pooled it
- Incorporating historical control information in ANCOVA models using the meta-analytic-predictive approach.Research synthesis methods · 2022Pooled it
- What is the prevalence of fear of cancer recurrence in cancer survivors and patients? A systematic review and individual participant data meta-analysis.Psycho-oncology · 2022Pooled it
- Comparison of surgical and endovascular treatments for fusiform intracranial aneurysms: systematic review and individual patient data meta-analysis.Neurosurgical review · 2021Pooled it
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- Exploring consequences of simulation design for apparent performance of methods of meta-analysis.Statistical methods in medical research · 2021Pooled it
- The methodological quality of individual participant data meta-analysis on intervention effects: systematic review.BMJ (Clinical research ed.) · 2021Pooled it
- Hypofractionated radiotherapy in locally advanced bladder cancer: an individual patient data meta-analysis of the BC2001 and BCON trials.The Lancet. Oncology · 2021Pooled it
- Individual participant data meta-analysis of intervention studies with time-to-event outcomes: A review of the methodology and an applied example.Research synthesis methods · 2020Pooled it
- Gestational weight gain outside the Institute of Medicine recommendations and adverse pregnancy outcomes: analysis using individual participant data from randomised trials.BMC pregnancy and childbirth · 2019Pooled it
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors at 5 institutions in 2 countries.
Funding
Abstract
objectivesIndividual participant data (IPD) meta-analyses often analyze their IPD as if coming from a single study. We compare this approach with analyses that rather account for clustering of patients within studies. STUDY DESIGN AND
settingComparison of effect estimates from logistic regression models in real and simulated examples.
resultsThe estimated prognostic effect of age in patients with traumatic brain injury is similar, regardless of whether clustering is accounted for. However, a family history of thrombophilia is found to be a diagnostic marker of deep vein thrombosis [odds ratio, 1.30; 95% confidence interval (CI): 1.00, 1.70; P = 0.05] when clustering is accounted for but not when it is ignored (odds ratio, 1.06; 95% CI: 0.83, 1.37; P = 0.64). Similarly, the treatment effect of nicotine gum on smoking cessation is severely attenuated when clustering is ignored (odds ratio, 1.40; 95% CI: 1.02, 1.92) rather than accounted for (odds ratio, 1.80; 95% CI: 1.29, 2.52). Simulations show models accounting for clustering perform consistently well, but downwardly biased effect estimates and low coverage can occur when ignoring clustering.
conclusionResearchers must routinely account for clustering in IPD meta-analyses; otherwise, misleading effect estimates and conclusions may arise.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.