Roger Logan
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View article: Risk of Hepatocellular Carcinoma After Direct-Acting Antiviral Treatment for Hepatitis C Virus Infection in People With Human Immunodeficiency Virus
Risk of Hepatocellular Carcinoma After Direct-Acting Antiviral Treatment for Hepatitis C Virus Infection in People With Human Immunodeficiency Virus Open
Background To inform hepatocellular carcinoma (HCC) surveillance after hepatitis C virus (HCV) cure with direct-acting antivirals (DAA), we estimated HCC risk post-DAA in people with human immunodeficiency virus (HIV) with advanced liver f…
View article: Antipsychotic drugs in first-episode psychosis: a target trial emulation in the FEP-CAUSAL Collaboration
Antipsychotic drugs in first-episode psychosis: a target trial emulation in the FEP-CAUSAL Collaboration Open
Good adherence to antipsychotic therapy helps prevent relapses in first-episode psychosis (FEP). We used data from the FEP-CAUSAL Collaboration, an international consortium of observational cohorts, to emulate a target trial comparing anti…
View article: Combining high quality data with rigorous methods: emulation of a target trial using electronic health records and a nested case-control design
Combining high quality data with rigorous methods: emulation of a target trial using electronic health records and a nested case-control design Open
Emulating a target trial reduces the potential for bias in observational comparative effectiveness research. Owing to feasibility constraints, large cohort studies often use electronic health records without validating key variables or col…
View article: Evaluating Model Specification When Using the Parametric G-Formula in the Presence of Censoring
Evaluating Model Specification When Using the Parametric G-Formula in the Presence of Censoring Open
The noniterative conditional expectation (NICE) parametric g-formula can be used to estimate the causal effect of sustained treatment strategies. In addition to identifiability conditions, the validity of the NICE parametric g-formula gene…
View article: Evaluating Metformin Strategies for Cancer Prevention: A Target Trial Emulation Using Electronic Health Records
Evaluating Metformin Strategies for Cancer Prevention: A Target Trial Emulation Using Electronic Health Records Open
Background: Metformin users appear to have a substantially lower risk of cancer than nonusers in many observational studies. These inverse associations may be explained by common flaws in observational analyses that can be avoided by expli…
View article: Sustained virological response after treatment with direct antiviral agents in individuals with HIV and hepatitis C co‐infection
Sustained virological response after treatment with direct antiviral agents in individuals with HIV and hepatitis C co‐infection Open
Introduction Randomized trials and observational studies have consistently reported rates of sustained virological response (SVR), equivalent to hepatitis C virus (HCV) cure, as high as 95% following treatment with direct‐acting antiviral …
View article: Tenofovir disoproxil fumarate and coronavirus disease 2019 outcomes in men with HIV
Tenofovir disoproxil fumarate and coronavirus disease 2019 outcomes in men with HIV Open
Objective: To compare the risk of coronavirus disease 2019 (COVID-19) outcomes by antiretroviral therapy (ART) regimens among men with HIV. Design: We included men with HIV on ART in the Veterans Aging Cohort Study who, between February 20…
View article: Risk for Non–AIDS-Defining and AIDS-Defining Cancer of Early Versus Delayed Initiation of Antiretroviral Therapy
Risk for Non–AIDS-Defining and AIDS-Defining Cancer of Early Versus Delayed Initiation of Antiretroviral Therapy Open
Highly Active Antiretroviral Therapy Oversight Committee.
View article: Emulating a target trial of statin use and risk of dementia using cohort data
Emulating a target trial of statin use and risk of dementia using cohort data Open
Individuals with sustained statin use, but not statin initiation alone, had reduced 10-year risks of dementia and dementia or death. Our results should be interpreted with caution due to the small number of initiators and events and potent…
View article: Emulating a target trial in case-control designs: an application to statins and colorectal cancer
Emulating a target trial in case-control designs: an application to statins and colorectal cancer Open
Background Previous case-control studies have reported a strong association between statin use and lower cancer risk. It is unclear whether this association reflects a benefit of statins or is the result of design decisions that cannot be …
View article: Comparison of dynamic monitoring strategies based on CD4 cell counts in virally suppressed, HIV-positive individuals on combination antiretroviral therapy in high-income countries: a prospective, observational study
Comparison of dynamic monitoring strategies based on CD4 cell counts in virally suppressed, HIV-positive individuals on combination antiretroviral therapy in high-income countries: a prospective, observational study Open
BACKGROUND Clinical guidelines vary with respect to the optimal monitoring frequency of HIV-positive individuals. We compared dynamic monitoring strategies based on time-varying CD4 cell counts in virologically suppressed HIV-positive indi…
View article: When to Monitor CD4 Cell Count and HIV RNA to Reduce Mortality and AIDS-Defining Illness in Virologically Suppressed HIV-Positive Persons on Antiretroviral Therapy in High-Income Countries: A Prospective Observational Study
When to Monitor CD4 Cell Count and HIV RNA to Reduce Mortality and AIDS-Defining Illness in Virologically Suppressed HIV-Positive Persons on Antiretroviral Therapy in High-Income Countries: A Prospective Observational Study Open
To illustrate an approach to compare CD4 cell count and HIV-RNA monitoring strategies in HIV-positive individuals on antiretroviral therapy (ART).
View article: Using observational data to emulate a randomized trial of dynamic treatment switching strategies
Using observational data to emulate a randomized trial of dynamic treatment switching strategies Open
BACKGROUND: When a clinical treatment fails or shows suboptimal results, the question of when to switch to another treatment arises. Treatment switching strategies are often dynamic because the time of switching depends on the evolution of…
View article: The per-protocol effect of immediate versus deferred antiretroviral therapy initiation
The per-protocol effect of immediate versus deferred antiretroviral therapy initiation Open
The START trial found a lower risk of a composite clinical outcome in HIV-positive individuals assigned to immediate initiation of antiretroviral therapy (ART) compared with those assigned to deferred initiation. However, 30% of those assi…
View article: Estimates of Overall Survival in Patients With Cancer Receiving Different Treatment Regimens
Estimates of Overall Survival in Patients With Cancer Receiving Different Treatment Regimens Open
The present estimates were similar to those from randomized clinical trials that studied adding the same cancer drugs to existing regimens. The published HR was 1.02 (95% CI, 0.70-1.48) in the fluorouracil trial for individuals aged 70 or …
View article: Effectiveness of Transmitted Drug Resistance Testing Before Initiation of Antiretroviral Therapy in HIV-Positive Individuals
Effectiveness of Transmitted Drug Resistance Testing Before Initiation of Antiretroviral Therapy in HIV-Positive Individuals Open
Background: For people living with HIV, major guidelines in high-income countries recommend testing for transmitted drug resistance (TDR) to guide the choice of first-line antiretroviral therapy (ART). However, individuals who fail a first…
View article: gfoRmula: An R package for estimating effects of general time-varying treatment interventions via the parametric g-formula
gfoRmula: An R package for estimating effects of general time-varying treatment interventions via the parametric g-formula Open
Researchers are often interested in using longitudinal data to estimate the causal effects of hypothetical time-varying treatment interventions on the mean or risk of a future outcome. Standard regression/conditioning methods for confoundi…
View article: Effect Estimates in Randomized Trials and Observational Studies: Comparing Apples With Apples
Effect Estimates in Randomized Trials and Observational Studies: Comparing Apples With Apples Open
Effect estimates from randomized trials and observational studies might not be directly comparable because of differences in study design, other than randomization, and in data analysis. We propose a 3-step procedure to facilitate meaningf…
View article: Emulating a trial of joint dynamic strategies: An application to monitoring and treatment of HIV‐positive individuals
Emulating a trial of joint dynamic strategies: An application to monitoring and treatment of HIV‐positive individuals Open
Decisions about when to start or switch a therapy often depend on the frequency with which individuals are monitored or tested. For example, the optimal time to switch antiretroviral therapy depends on the frequency with which HIV‐positive…
View article: Supplementary Material for: Sex-Specific Effects of Stress on Mood-Related Gene Expression
Supplementary Material for: Sex-Specific Effects of Stress on Mood-Related Gene Expression Open
Women are twice as likely as men to be diagnosed with major depressive disorder (MDD). Recent studies report distinct molecular changes in depressed men and women across mesocorticolimbic brain regions. However, it is unclear which sex-rel…
View article: Inverse Probability Weighted Estimation of Risk Under Representative Interventions in Observational Studies
Inverse Probability Weighted Estimation of Risk Under Representative Interventions in Observational Studies Open
Researchers are often interested in using observational data to estimate the effect on a health outcome of maintaining a continuous treatment within a prespecified range over time, for example, “always exercise at least 30 minutes per day.…