ArticleClinical epidemiology2018
Adjusting for confounding by indication in observational studies: a case study in traumatic brain injury.
Article in Clinical epidemiology, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 22 papers.
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Who cites it
22 citing papers in PubMed, 45 citations in OpenAlex.
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- Perioperative Outcomes of Robotic Versus Conventional Total Laparoscopic Hysterectomy in Surgically Complex Cases: A Propensity Score-Matched Study.Journal of clinical medicine · 2026Article
- An international multi-centre study to develop and validate federated learning-based prognostic models for anal cancer.Nature communications · 2026Article
- The effectiveness of decompressive craniectomy size in traumatic brain injury; an international, observational, comparative effectiveness study.Brain & spine · 2026Article
- Treatment variation in acute management of patients with aneurysmal subarachnoid hemorrhage: a multicenter case vignette study.Brain & spine · 2026Article
- Acute Surgery vs Conservative Treatment for Traumatic Acute Subdural Hematoma.JAMA network open · 2025Observational
- Early vs Late Fixation of Extremity Fractures Among Adults With Traumatic Brain Injury.JAMA network open · 2024Article
- Comparative effectiveness of decompressive craniectomy versus craniotomy for traumatic acute subdural hematoma (CENTER-TBI): an observational cohort study.EClinicalMedicine · 2023Article
- Dealing with confounding in observational studies: A scoping review of methods evaluated in simulation studies with single-point exposure.Statistics in medicine · 2023Article
- Traumatic brain injury: progress and challenges in prevention, clinical care, and research.The Lancet. Neurology · 2022Review
- Comparative effectiveness of intracranial hypertension management guided by ventricular versus intraparenchymal pressure monitoring: a CENTER-TBI study.Acta neurochirurgica · 2022Observational
- Estimation of treatment effects in observational stroke care data: comparison of statistical approaches.BMC medical research methodology · 2022Observational
- Pharmaceutical Venous Thrombosis Prophylaxis in Critically Ill Traumatic Brain Injury Patients.Neurotrauma reports · 2022Article
- Management of arterial partial pressure of carbon dioxide in the first week after traumatic brain injury: results from the CENTER-TBI study.Intensive care medicine · 2021Observational
- Anticonvulsant use and fracture: a case-control study.Journal of musculoskeletal & neuronal interactions · 2021Article
- Association Between Digoxin Use and Cancer Incidence: A Propensity Score-Matched Cohort Study With Competing Risk Analysis.Frontiers in pharmacology · 2021Article
- Can statistical adjustment guided by causal inference improve the accuracy of effect estimation? A simulation and empirical research based on meta-analyses of case-control studies.BMC medical informatics and decision making · 2020Article
- Defining Undertreatment and Overtreatment in Older Adults With Cancer: A Scoping Literature Review.Journal of clinical oncology : official journal of the American Society of Clinical Oncology · 2020Article
- Article
- International prospective observational study on intracranial pressure in intensive care (ICU): the SYNAPSE-ICU study protocol.BMJ open · 2019Article
Corrections and comments
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Authors and funding
15 authors at 8 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
introductionObservational studies of interventions are at risk for confounding by indication. The objective of the current study was to define the circumstances for the validity of methods to adjust for confounding by indication in observational studies. PATIENTS AND
methodsWe performed post hoc analyses of data prospectively collected from three European and North American traumatic brain injury studies including 1,725 patients. The effects of three interventions (intracranial pressure [ICP] monitoring, intracranial operation and primary referral) were estimated in a proportional odds regression model with the Glasgow Outcome Scale as ordinal outcome variable. Three analytical methods were compared: classical covariate adjustment, propensity score matching and instrumental variable (IV) analysis in which the percentage exposed to an intervention in each hospital was added as an independent variable, together with a random intercept for each hospital. In addition, a simulation study was performed in which the effect of a hypothetical beneficial intervention (OR 1.65) was simulated for scenarios with and without unmeasured confounders.
resultsFor all three interventions, covariate adjustment and propensity score matching resulted in negative estimates of the treatment effect (OR ranging from 0.80 to 0.92), whereas the IV approach indicated that both ICP monitoring and intracranial operation might be beneficial (OR per 10% change 1.17, 95% CI 1.01-1.42 and 1.42, 95% CI 0.95-1.97). In our simulation study, we found that covariate adjustment and propensity score matching resulted in an invalid estimate of the treatment effect in case of unmeasured confounders (OR ranging from 0.90 to 1.03). The IV approach provided an estimate in the similar direction as the simulated effect (OR per 10% change 1.04-1.05) but was statistically inefficient.
conclusionThe effect estimation of interventions in observational studies strongly depends on the analytical method used. When unobserved confounding and practice variation are expected in observational multicenter studies, IV analysis should be considered.
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