A (Flexible) Synthetic Control Method for Count Data and Other Nonnegative Outcomes
The synthetic control method is a covariate balancing method that exploits data from untreated regions to construct a synthetic control that approximates a single, aggregate treatment unit on a time series of preintervention outcomes and covariates. The method is increasingly being used to evaluate population-level interventions in epidemiology. Although the original version can be used with bounded outcomes, it imposes strong constraints on the balancing weights to ensure that the counterfactuals are based solely on interpolation. This feature, while attractive from a causal inference perspective, is sometimes too conserv...
Source: Epidemiology - August 3, 2021 Category: Epidemiology Tags: Methods Source Type: research
Decreased Susceptibility of Marginal Odds Ratios to Finite-sample Bias
Parameters representing adjusted treatment effects may be defined marginally or conditionally on covariates. The choice between a marginal or covariate-conditional parameter should be driven by the study question. However, an unappreciated benefit of marginal estimators is a reduction in susceptibility to finite-sample bias relative to the unpenalized maximum likelihood estimator of the covariate-conditional odds ratio (OR). Using simulation, we compare the finite-sample bias of different marginal and conditional estimators of the OR. We simulated a logistic model to have 15 events per parameter and two events per paramete...
Source: Epidemiology - August 3, 2021 Category: Epidemiology Tags: Methods Source Type: research
Proof of Concept Example for Use of Simulation to Allow Data Pooling Despite Privacy Restrictions
Discussion:
Our approach has advantages over meta-analysis or individual-level pooling/data harmonization when privacy concerns preclude data sharing and key confounders are not uniformly measured across datasets. (Source: Epidemiology)
Source: Epidemiology - August 3, 2021 Category: Epidemiology Tags: Methods Source Type: research
To Bound or Not to Bound: Is That the Question?
No abstract available (Source: Epidemiology)
Source: Epidemiology - August 3, 2021 Category: Epidemiology Tags: Methods Source Type: research
Multiple-bias Sensitivity Analysis Using Bounds
Confounding, selection bias, and measurement error are well-known sources of bias in epidemiologic research. Methods for assessing these biases have their own limitations. Many quantitative sensitivity analysis approaches consider each type of bias individually, although more complex approaches are harder to implement or require numerous assumptions. By failing to consider multiple biases at once, researchers can underestimate—or overestimate—their joint impact. We show that it is possible to bound the total composite bias owing to these three sources and to use that bound to assess the sensitivity of a risk ratio to a...
Source: Epidemiology - August 3, 2021 Category: Epidemiology Tags: Methods Source Type: research
The Importance of Making Assumptions in Bias Analysis
We describe the mathematical meaning of bounding factors and E-values and the plausibility of these methods in an applied context. We encourage researchers to pay particular attention to the assumption made, when using E-values, that the prevalence of the uncontrolled confounder among the exposed is 100% (or, equivalently, the prevalence of the exposure among those without the confounder is 0%). We contrast methods that attempt to bound biases or effects and alternative approaches such as quantitative bias analysis. We provide an example where failure to make this distinction led to erroneous statements. If the primary con...
Source: Epidemiology - August 3, 2021 Category: Epidemiology Tags: Methods Source Type: research
Erratum: Explaining the Sex Effect on Survival in Cystic Fibrosis: A Joint Modeling Study of UK Registry Data
No abstract available (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Erratum Source Type: research
Erratum: A Graphical Description of Partial Exchangeability
No abstract available (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Erratum Source Type: research
Erratum: Regression Discontinuity Designs in Health: A Systematic Review
No abstract available (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Erratum Source Type: research
Re. A Cautionary Note on Extended Kaplan–Meier Curves for Time-varying Covariates
No abstract available (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Letters Source Type: research
The Authors Respond
No abstract available (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Letters Source Type: research
Re. In Defense of the Weight-of-evidence Approach to Literature Review in the Integrated Science Assessment
No abstract available (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Letters Source Type: research
An Aggregated Comorbidity Measure Based on History of Filled Drug Prescriptions: Development and Evaluation in Two Separate Cohorts
Conclusions:
A new drug comorbidity index based on filled drug prescriptions improved prediction of survival beyond age and the CCI alone. The index will allow a more accurate baseline estimation of expected survival for comparing treatment outcomes and evaluating treatment guidelines in populations of people with cancer. (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Pharmacoepidemiology Source Type: research
Estimating the Effectiveness of Rotavirus Vaccine Schedules
Conclusions:
The proposed approach can generate important evidence about the consequences of delaying or skipping vaccine doses, and the impact of interventions to improve vaccine schedule adherence. (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Pharmacoepidemiology Source Type: research
Validation of Hypertensive Disorders During Pregnancy: ICD-10 Codes in a High-burden Southeastern United States Hospital
Conclusions:
We provide bias parameters for future US-based studies of hypertensive outcomes during pregnancy in high-burden populations using hospital ICD-10 codes. (Source: Epidemiology)
Source: Epidemiology - June 8, 2021 Category: Epidemiology Tags: Perinatal Epidemiology Source Type: research
