Jesse Yenchih Hsu

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Although subjects with chronic kidney disease (CKD) are at markedly increased risk for cardiovascular mortality, the relation between CKD and aortic valve calcification has not been fully elucidated. Also, few data are available on the relation of aortic valve calcification and earlier stages of CKD. We sought to assess the relation of aortic valve calcium(More)
An effect modifier is a pretreatment covariate such that the magnitude of the treatment effect or its stability changes with the level of the covariate. Generally, other things being equal, larger treatment effects and less heterogeneous treatment effects are less sensitive to unmeasured biases in observational studies. It is known that when there is effect(More)
A frequent concern in making statistical inference for causal effects of a policy or treatment based on observational studies is that there are unmeasured confounding variables. The instrumental variable method is an approach to estimating a causal relationship in the presence of unmeasured confounding variables. A valid instrumental variable needs to be(More)
In medical sciences, statistical analyses based on observational studies are common phenomena. One peril of drawing inferences about the effect of a treatment on subjects using observational studies is the lack of randomized assignment of subjects to the treatment. After adjusting for measured pretreatment covariates, perhaps by matching, a sensitivity(More)
In an observational study of treatment e¤ects, subjects are not randomly assigned to treatment or control, so di¤ering outcomes in treated and control groups may re ‡ect a bias from nonrandom assignment rather than a treatment e¤ect. After adjusting for measured pretreatment covariates, perhaps by matching, a sensitivity analysis determines the magnitude of(More)
BACKGROUND The laborist model of obstetric care represents a change in care delivery with the potential of improving maternal and neonatal outcomes. OBJECTIVE We evaluated the effectiveness of the laborist model of care compared to the traditional model of obstetric care using specific maternal and neonatal outcome measures. STUDY DESIGN This is a(More)
BACKGROUND A surrogate marker is a variable commonly used in clinical trials to guide treatment decisions when the outcome of ultimate interest is not available. A good surrogate marker is one where the treatment effect on the surrogate is a strong predictor of the effect of treatment on the outcome. We review the situation when there is one treatment(More)
Survival analysis is commonly used to evaluate factors associated with time to an event of interest (e.g., ESRD, cardiovascular disease, and mortality) among CKD populations. Time to the event of interest is typically observed only for some participants. Other participants have their event time censored because of the end of the study, death, withdrawal(More)
INTRODUCTION The failure to rescue (FTR) rate is the probability of death after a major complication and was defined in elective surgical cohorts. In elective surgery, the precedence rate (proportion of deaths preceded by major complications) approaches 100%, but recent studies in trauma report rates of only 20-25%. We hypothesised that use of high quality(More)
BACKGROUND Admission physiology predicts mortality after injury, but may be improved by resuscitation before transfer. This phenomenon, which has been termed lead-time bias, may lead to underprediction of mortality in transferred patients and inaccurate benchmarking in centers receiving large numbers of transfer patients. We sought to determine the impact(More)