Evidence map›Paper›PMID 31795945›Full record

ArticleBMC medical research methodology2019

A comparison of methods to estimate the survivor average causal effect in the presence of missing data: a simulation study.

Myra B McGuinness, Jessica Kasza, Amalia Karahalios, Robyn H Guymer, Robert P Finger, Julie A Simpson

Erratum issuedAbstract readComparative Study
In one paragraph

Article in BMC medical research methodology, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 5 papers.

0numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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.

2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

5 citing papers in PubMed.

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4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

6 authors.

Myra B McGuinnessCentre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia. myra.mcguinness@unimelb.edu.au.ORCID http://orcid.org/0000-0002-5422-040X
Jessica KaszaDepartment of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, 3010, Australia.
Amalia KarahaliosCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia.
Robyn H GuymerCentre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.
Robert P FingerDepartment of Ophthalmology, University of Bonn, Bonn, Germany.
Julie A SimpsonCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundAttrition due to death and non-attendance are common sources of bias in studies of age-related diseases. A simulation study is presented to compare two methods for estimating the survivor average causal effect (SACE) of a binary exposure (sex-specific dietary iron intake) on a binary outcome (age-related macular degeneration, AMD) in this setting.

methodsA dataset of 10,000 participants was simulated 1200 times under each scenario with outcome data missing dependent on measured and unmeasured covariates and survival. Scenarios differed by the magnitude and direction of effect of an unmeasured confounder on both survival and the outcome, and whether participants who died following a protective exposure would also die if they had not received the exposure (validity of the monotonicity assumption). The performance of a marginal structural model (MSM, weighting for exposure, survival and missing data) was compared to a sensitivity approach for estimating the SACE. As an illustrative example, the SACE of iron intake on AMD was estimated using data from 39,918 participants of the Melbourne Collaborative Cohort Study.

resultsThe MSM approach tended to underestimate the true magnitude of effect when the unmeasured confounder had opposing directions of effect on survival and the outcome. Overestimation was observed when the unmeasured confounder had the same direction of effect on survival and the outcome. Violation of the monotonicity assumption did not increase bias. The estimates were similar between the MSM approach and the sensitivity approach assessed at the sensitivity parameter of 1 (assuming no survival bias). In the illustrative example, high iron intake was found to be protective of AMD (adjusted OR 0.57, 95% CI 0.40-0.82) using complete case analysis via traditional logistic regression. The adjusted SACE odds ratio did not differ substantially from the complete case estimate, ranging from 0.54 to 0.58 for each of the SACE methods.

conclusionsOn average, MSMs with weighting for exposure, missing data and survival produced biased estimates of the SACE in the presence of an unmeasured survival-outcome confounder. The direction and magnitude of effect of unmeasured survival-outcome confounders should be considered when assessing exposure-outcome associations in the presence of attrition due to death.

Indexed as

CausalityData Interpretation, StatisticalDietIron, DietaryBiasComputer SimulationFemaleHumansMacular DegenerationMaleModels, StatisticalSensitivity and SpecificitySex FactorsSurvival AnalysisIron, DietaryCausal inferenceDeathIronMacular degenerationMissing dataPrincipal stratificationSensitivity analysisSimulation studySurvival biasUnmeasured confounding

Identifiers

PMID31795945
PMCPMC6892197

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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.