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- Bayesian hierarchical model (2)
- Data augmentation (2)
- Point-of-service health plan (2)
- Referral to specialists (2)
- Air pollution (1)
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- Cardiovascular and respiratory mortality (1)
- Causal inference (1)
- Diagnostic test (1)
- Direct and mediated effects (1)
- Distributed lag model (1)
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- Hereditary nonpolyposis colorectal cancer (HNPCC) (1)
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- Microsatellite instability (MSI) (1)
- Models/Statistical (1)
- Mortality (1)
- Ozone (1)
- Percentile-specific effects (1)
- Post-treatment variables (1)
- Primary care (1)
- Provider profiling (1)
- Ranks/percentile (1)
- Rejection sampling (1)
- Sensitivity (1)
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- Uncertainty assessments (1)
Articles 1 - 9 of 9
Full-Text Articles in Medicine and Health Sciences
Estimating Percentile-Specific Causal Effects: A Case Study Of Micronutrient Supplementation, Birth Weight, And Infant Mortality, Francesca Dominici, Scott L. Zeger, Giovanni Parmigiani, Joanne Katz, Parul Christian
Estimating Percentile-Specific Causal Effects: A Case Study Of Micronutrient Supplementation, Birth Weight, And Infant Mortality, Francesca Dominici, Scott L. Zeger, Giovanni Parmigiani, Joanne Katz, Parul Christian
Johns Hopkins University, Dept. of Biostatistics Working Papers
In developing countries, higher infant mortality is partially caused by poor maternal and fetal nutrition. Clinical trials of micronutrient supplementation are aimed at reducing the risk of infant mortality by increasing birth weight. Because infant mortality is greatest among the low birth weight infants (LBW) (• 2500 grams), an effective intervention may need to increase the birth weight among the smallest babies. Although it has been demonstrated that supplementation increases the birth weight in a trial conducted in Nepal, there is inconclusive evidence that the supplementation improves their survival. It has been hypothesized that a potential benefit of the treatment …
Ranking Usrds Provider-Specific Smrs From 1998-2001, Rongheng Lin, Thomas A. Louis, Susan M. Paddock, Greg Ridgeway
Ranking Usrds Provider-Specific Smrs From 1998-2001, Rongheng Lin, Thomas A. Louis, Susan M. Paddock, Greg Ridgeway
Johns Hopkins University, Dept. of Biostatistics Working Papers
Provider profiling (ranking, "league tables") is prevalent in health services research. Similarly, comparing educational institutions and identifying differentially expressed genes depend on ranking. Effective ranking procedures must be structured by a hierarchical (Bayesian) model and guided by a ranking-specific loss function, however even optimal methods can perform poorly and estimates must be accompanied by uncertainty assessments. We use the 1998-2001 Standardized Mortality Ratio (SMR) data from United States Renal Data System (USRDS) as a platform to identify issues and approaches. Our analyses extend Liu et al. (2004) by combining evidence over multiple years via an AR(1) model; by considering estimates …
Bayesian Hierarchical Distributed Lag Models For Summer Ozone Exposure And Cardio-Respiratory Mortality, Yi Huang, Francesca Dominici, Michelle L. Bell
Bayesian Hierarchical Distributed Lag Models For Summer Ozone Exposure And Cardio-Respiratory Mortality, Yi Huang, Francesca Dominici, Michelle L. Bell
Johns Hopkins University, Dept. of Biostatistics Working Papers
In this paper, we develop Bayesian hierarchical distributed lag models for estimating associations between daily variations in summer ozone levels and daily variations in cardiovascular and respiratory (CVDRESP) mortality counts for 19 U.S. large cities included in the National Morbidity Mortality Air Pollution Study (NMMAPS) for the period 1987 - 1994.
At the first stage, we define a semi-parametric distributed lag Poisson regression model to estimate city-specific relative rates of CVDRESP associated with short-term exposure to summer ozone. At the second stage, we specify a class of distributions for the true city-specific relative rates to estimate an overall effect by …
Studying Effects Of Primary Care Physicians And Patients On The Trade-Off Between Charges For Primary Care And Specialty Care Using A Hierarchical Multivariate Two-Part Model, John W. Robinson, Scott L. Zeger, Christopher B. Forrest
Studying Effects Of Primary Care Physicians And Patients On The Trade-Off Between Charges For Primary Care And Specialty Care Using A Hierarchical Multivariate Two-Part Model, John W. Robinson, Scott L. Zeger, Christopher B. Forrest
Johns Hopkins University, Dept. of Biostatistics Working Papers
Objective. To examine effects of primary care physicians (PCPs) and patients on the association between charges for primary care and specialty care in a point-of-service (POS) health plan.
Data Source. Claims from 1996 for 3,308 adult male POS plan members, each of whom was assigned to one of the 50 family practitioner-PCPs with the largest POS plan member-loads.
Study Design. A hierarchical multivariate two-part model was fitted using a Gibbs sampler to estimate PCPs' effects on patients' annual charges for two types of services, primary care and specialty care, the associations among PCPs' effects, and within-patient associations between charges for …
A Hierarchical Multivariate Two-Part Model For Profiling Providers' Effects On Healthcare Charges, John W. Robinson, Scott L. Zeger, Christopher B. Forrest
A Hierarchical Multivariate Two-Part Model For Profiling Providers' Effects On Healthcare Charges, John W. Robinson, Scott L. Zeger, Christopher B. Forrest
Johns Hopkins University, Dept. of Biostatistics Working Papers
Procedures for analyzing and comparing healthcare providers' effects on health services delivery and outcomes have been referred to as provider profiling. In a typical profiling procedure, patient-level responses are measured for clusters of patients treated by providers that in turn, can be regarded as statistically exchangeable. Thus, a hierarchical model naturally represents the structure of the data. When provider effects on multiple responses are profiled, a multivariate model rather than a series of univariate models, can capture associations among responses at both the provider and patient levels. When responses are in the form of charges for healthcare services and sampled …
Ozone And Mortality: A Meta-Analysis Of Time-Series Studies And Comparison To A Multi-City Study (The National Morbidity, Mortality, And Air Pollution Study), Michelle L. Bell, Jonathan M. Samet, Francesca Dominici
Ozone And Mortality: A Meta-Analysis Of Time-Series Studies And Comparison To A Multi-City Study (The National Morbidity, Mortality, And Air Pollution Study), Michelle L. Bell, Jonathan M. Samet, Francesca Dominici
Johns Hopkins University, Dept. of Biostatistics Working Papers
While many time-series studies of ozone and daily mortality identified positive associations,others yielded null or inconclusive results. We performed a meta-analysis of 144 effect estimates from 39 time-series studies, and estimated pooled effects by lags, age groups,cause-specific mortality, and concentration metrics. We compared results to estimates from the National Morbidity, Mortality, and Air Pollution Study (NMMAPS), a time-series study of 95 large U.S. cities from 1987 to 2000. Both meta-analysis and NMMAPS results provided strong evidence of a short-term association between ozone and mortality, with larger effects for cardiovascular and respiratory mortality, the elderly, and current day ozone exposure as …
Accuracy Of Msi Testing In Predicting Germline Mutations Of Msh2 And Mlh1: A Case Study In Bayesian Meta-Analysis Of Diagnostic Tests Without A Gold Standard, Sining Chen, Patrice Watson, Giovanni Parmigiani
Accuracy Of Msi Testing In Predicting Germline Mutations Of Msh2 And Mlh1: A Case Study In Bayesian Meta-Analysis Of Diagnostic Tests Without A Gold Standard, Sining Chen, Patrice Watson, Giovanni Parmigiani
Johns Hopkins University, Dept. of Biostatistics Working Papers
Microsatellite instability (MSI) testing is a common screening procedure used to identify families that may harbor mutations of a mismatch repair gene and therefore may be at high risk for hereditary colorectal cancer. A reliable estimate of sensitivity and specificity of MSI for detecting germline mutations of mismatch repair genes is critical in genetic counseling and colorectal cancer prevention. Several studies published results of both MSI and mutation analysis on the same subjects. In this article we perform a meta-analysis of these studies and obtain estimates that can be directly used in counseling and screening. In particular we estimate the …
Seasonal Analyses Of Air Pollution And Mortality In 100 U.S. Cities, Roger D. Peng, Francesca Dominici, Roberto Pastor-Barriuso, Scott L. Zeger, Jonathan M. Samet
Seasonal Analyses Of Air Pollution And Mortality In 100 U.S. Cities, Roger D. Peng, Francesca Dominici, Roberto Pastor-Barriuso, Scott L. Zeger, Jonathan M. Samet
Johns Hopkins University, Dept. of Biostatistics Working Papers
Time series models relating short-term changes in air pollution levels to daily mortality counts typically assume that the effects of air pollution on the log relative rate of mortality do not vary with time. However, these short-term effects might plausibly vary by season. Changes in the sources of air pollution and meteorology can result in changes in characteristics of the air pollution mixture across seasons. The authors develop Bayesian semi-parametric hierarchical models for estimating time-varying effects of pollution on mortality in multi-site time series studies. The methods are applied to the updated National Morbidity and Mortality Air Pollution Study database …
Self-Reported Memory Symptoms With Coronary Artery Disease: A Prospective Of Cabg Patients And Nonsurgical Controls, Ola A. Selnes, Maura A. Grega, Louis M. Borowicz, Jr., Sarah Barry, Scott L. Zeger, Guy M. Mckhann
Self-Reported Memory Symptoms With Coronary Artery Disease: A Prospective Of Cabg Patients And Nonsurgical Controls, Ola A. Selnes, Maura A. Grega, Louis M. Borowicz, Jr., Sarah Barry, Scott L. Zeger, Guy M. Mckhann
Johns Hopkins University, Dept. of Biostatistics Working Papers
Background. Subjective memory complaints are common after coronary artery bypass grafting (CABG), but previous studies have concluded that such symptoms are more closely associated with depressed mood than objective cognitive dysfunction. We compared the incidence of self-reported memory symptoms at 3 and 12 months after CABG with that of a control group of patients with comparable risk factors for coronary artery disease but without surgery.
Methods. Patients undergoing CABG (n = 140) and a demographically similar nonsurgical control group with coronary artery disease (n = 92) were followed prospectively at 3 and 12 months. At each follow-up time, participants were …