Anders Huitfeldt

Anders Huitfeldt
École Polytechnique Fédérale de Lausanne | EPFL · Biostatistics

ScD, MB BCh BAO

About

14
Publications
1,359
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121
Citations
Additional affiliations
November 2015 - January 2016
Stanford University
Position
  • PostDoc Position

Publications

Publications (14)
Preprint
In the 1958 paper ``Shall we count the living or the dead'', Mindel C. Sheps proposed a principled solution to the familiar problem of asymmetry of the relative risk. We provide causal models to clarify the scope and limitations of Sheps' line of reasoning, and show that her preferred variant of the relative risk will be stable between patient grou...
Article
Full-text available
Importance Understanding the safety profile of medications used in pregnancy is crucial for clinical decision-making. Few studies exist on the associations of exposure to benzodiazepines and benzodiazepine-like hypnotic drugs (z-hypnotics) in pregnancy with pregnancy outcomes. Objective To determine whether exposure to benzodiazepines or z-hypnoti...
Article
Full-text available
The participants in randomized trials and other studies used for causal inference are often not representative of the populations seen by clinical decision-makers. To account for differences between populations, researchers may consider standardizing results to a target population. We discuss several different types of homogeneity conditions that a...
Article
Full-text available
A measure of association is said to be collapsible over a set of baseline covariates if the marginal value of the measure of association is equal to a weighted average of the stratum-specific measures of association. In this paper, we consider measures of effect based on counterfactual variables and show how these counterfactual parameters lead to...
Article
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Introduction Because a comparison of noninitiators and initiators of treatment may be hopelessly confounded, guidelines for the conduct of observational research often recommend using an “active” comparator group consisting of people who initiate a treatment other than the medication of interest. In this paper, we discuss the conditions under which...
Article
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Standard measures of effect, including the risk ratio, the odds ratio, and the risk difference, are associated with a number of well-described shortcomings, and no consensus exists about the conditions under which investigators should choose one effect measure over another. In our approach, effects are defined in terms of "counterfactual outcome st...
Article
Full-text available
Randomized trials are rarely representative of the general population. To account for this, results may be standardized to a target population which may be different from the one in which the trial was conducted. In this paper, we discuss three different approaches for reasoning about which covariates must be standardized over. This includes the tr...
Article
BACKGROUND Questionnaire surveys are important for surveying the health and disease behaviour of the population, but recent years have seen a fall in participation. Our study tested whether incentives can increase participation in these surveys.MATERIAL AND METHOD We sent a questionnaire on risk factors for colorectal cancer (height, weight, smokin...
Article
Background: Questionnaire surveys are important for surveying the health and disease behaviour of the population, but recent years have seen a fall in participation. Our study tested whether incentives can increase participation in these surveys. Material and Method: We sent a questionnaire on risk factors for colorectal cancer (height, weight, smo...
Article
Full-text available
Clinical guidelines that rely on observational data due to the absence of data from randomized trials benefit when the observational data or its analysis emulates trial data or its analysis. In this paper, we review a methodology for emulating trials that compare the effects of different timing strategies, that is, strategies that vary the frequenc...
Conference Paper
Purpose: To show how modern methods for causal inference can be used to determine the effectiveness and optimal implementation interval of a screening or surveillance test. Method: During the NORCCAP randomized trial on the effects of sigmoidoscopy screening, 2197 patients with adenomas were identified. We have observational follow-up data on the...