Medicine and Health Sciences Commons^™

The Statistics Of Sensitivity Analyses, Alexander R. Luedtke, Ivan Diaz, Mark J. Van Der Laan

Alex Luedtke

Suppose one wishes to estimate a causal parameter given a sample of observations. This requires making unidentifiable assumptions about an underlying causal mechanism. Sensitivity analyses help investigators understand what impact violations of these assumptions could have on the causal conclusions drawn from a study, though themselves rely on untestable (but hopefully more interpretable) assumptions. Díaz and van der Laan (2013) advocate the use of a sequence (or continuum) of interpretable untestable assumptions of increasing plausibility for the sensitivity analysis so that experts can have informed opinions about which are true. In this work, we argue that using appropriate statistical procedures …

Ideas For A Healthy Baby--Reducing Disparities In Use Of Publicly Reported Quality Data: Study Protocol For A Randomized Controlled Trial, Sarah L. Goff, Penelope S. Pekow, Katharine O. White, Tara Lagu, Kathleen M. Mazor, Peter K. Lindenauer

Sarah L. Goff MD

BACKGROUND: Publicly reported performance on quality measures is intended to enable patients to make more informed choices. Despite the growing availability of these reports, patients' use remains limited and disparities exist. Low health literacy and numeracy are two barriers that may contribute to these disparities. Patient navigators have helped patients overcome barriers such as these in other areas, such as cancer care and may prove useful for overcoming barriers to using publicly reported quality data. METHODS/DESIGN: The goals of this study are: to determine the efficacy of a patient navigator intervention to assist low-income pregnant women in the use of …

The Spatial Dynamics Of Dengue Virus In Kamphaeng Phet, Thailand, Piraya Bhoomiboonchoo, Robert V. Gibbons, Angkana Huang, In-Kyu Yoon, Darunee Buddhari, Ananda Nisalak, Natkamol Chansatiporn, Mathuros Thipayamongkolgul, Siripen Kalanarooj, Timothy Endy, Alan L. Rothman, Anon Srikiatkhachorn, Sharone Green, Mammen P. Mammen, Derek A. Cummings, Henrik Salje

Sharone Green

BACKGROUND: Dengue is endemic to the rural province of Kamphaeng Phet, Northern Thailand. A decade of prospective cohort studies has provided important insights into the dengue viruses and their generated disease. However, as elsewhere, spatial dynamics of the pathogen remain poorly understood. In particular, the spatial scale of transmission and the scale of clustering are poorly characterized. This information is critical for effective deployment of spatially targeted interventions and for understanding the mechanisms that drive the dispersal of the virus.

METHODOLOGY/PRINCIPAL FINDINGS: We geocoded the home locations of 4,768 confirmed dengue cases admitted to the main hospital in Kamphaeng Phet …

Post-Operative Extended Volume External Beam Radiation Therapy Is Safe For High Risk Esophageal Cancer Patients, Edward Yu, Patricia Tai, Jawaid Younus, Richard Malthaner, Larry Stitt, Pauline Truong, George Rodrigues, Robert Ash, Rashid Dar, Anna Tomiak, Mark Vincent, Walter Kocha, Brian Dingle, Richard Inculet

Richard A. Malthaner

Post-operative radiation therapy (RT) (1) and post-operative chemoradiation (2) have been used for esophageal cancer patients deemed high risk for recurrence after esophagectomy. Defining opitmal RT target volume after esophagectomy is difficult due to significant changes in patient anatomy and function. Some radiationon cologists advocated the inclusion of the anastomotic site within the irradiation volume due to concerns for potential increased relapse risk, while others did not subscribe to this practice due to concerns for increased treatment related toxicity. We have previously reported patient outcome benefit using extended volume RT In management with high risk esophageal cancer patients underwent esopagectomy(3). …

Extended Vs. Small Field Irradiation In High Risk Post Esophagectomy Patients Receiving Combined Chemoradiation Therapy: A Decade Experience In Treatment Of Esophageal Cancer, Edward Yu, Patricia Tai, George Rodrigues, Robert Ash, Larry Stitt, Rashid A. Dar, Pauline Truong, Gregory M. Videtic, Richard Malthaner, Richard Inculet, Anna Tomiak, Jawaid Younus, Brian Dingle, Walter Kocha, Mark Vincent

Richard A. Malthaner

OBJECTIVE: To assess the impact of extended field irradiation with anastomotic coverage on local recurrence in high risk resected esophageal cancerpatients. METHODS: From 1989-1999, high risk resected esophageal cancer cases receiving post-resection chemoradiation were reviewed. Adjuvant chemotherapy consisted of four cycles of fluorouracil-based regimens. Loco-regional irradiation with or without coverage of anastomotic site had radiation a dose range from 45-60 Gyat 1.8-2.0 Gy/fraction given with initial anterior-posterior/posterior-anterior arrangement with either extended (with anastomotic coverage), or small (without anastomotic coverage) field followed by oblique fields for boost. RESULTS: One hundred eighty-eight charts were reviewed. Seventy-two patients were eligible for post-resection chemoradiation. …

The Role Of Radiation Therapy On Medically Inoperable Clinically Localized Non-Small Cell Lung Patients: London Regional Cancer Program (Lrcp) Clinical Experience, Michael Lee, Edward Yu, Robert Ash, Patricia Tai, Larry Stitt, George Rodrigues, Rashid Dar, Mark Vincent, Richard Inculet, Richard Malthaner

Richard A. Malthaner

Lung cancer is the most frequent cause of cancer death in both men and women in North America. In 2006, an estimated 22,700 Canadians will be diagnosed with lung cancer and 19,300 will die of it (Canadian Cancer Statistics 2006). Approximately 15-20% of NSCLC patients present with early or localized disease. Surgical resection of T1-2N0 NSCLC remains the treatment of choice for this population, and results in a 5-year survival rate of 50-70%. Patients deemed medically inoperable have been treated with non-surgical therapies, such as radiation therapy(RT), while some patients have simply been observed without any tumor therapy because of …

Post-Operative Extended Volume External Beam Radiation Therapy Is Safe For High Risk Esophageal Cancer Patients, Edward Yu, Patricia Tai, Jawaid Younus, Richard Malthaner, Larry Stitt, Pauline Truong, George Rodrigues, Robert Ash, Rashid Dar, Anna Tomiak, Mark Vincent, Walter Kocha, Brian Dingle, Richard Inculet

Richard A. Malthaner

Post-operative radiation therapy (RT) (1) and post-operative chemoradiation (2) have been used for esophageal cancer patients deemed high risk for recurrence after esophagectomy. Defining opitmal RT target volume after esophagectomy is difficult due to significant changes in patient anatomy and function. Some radiationon cologists advocated the inclusion of the anastomotic site within the irradiation volume due to concerns for potential increased relapse risk, while others did not subscribe to this practice due to concerns for increased treatment related toxicity. We have previously reported patient outcome benefit using extended volume RT In management with high risk esophageal cancer patients underwent esopagectomy(3). …

Extended Vs. Small Field Irradiation In High Risk Post Esophagectomy Patients Receiving Combined Chemoradiation Therapy: A Decade Experience In Treatment Of Esophageal Cancer, Edward Yu, Patricia Tai, George Rodrigues, Robert Ash, Larry Stitt, Rashid A. Dar, Pauline Truong, Gregory M. Videtic, Richard Malthaner, Richard Inculet, Anna Tomiak, Jawaid Younus, Brian Dingle, Walter Kocha, Mark Vincent

Richard A. Malthaner

OBJECTIVE: To assess the impact of extended field irradiation with anastomotic coverage on local recurrence in high risk resected esophageal cancerpatients. METHODS: From 1989-1999, high risk resected esophageal cancer cases receiving post-resection chemoradiation were reviewed. Adjuvant chemotherapy consisted of four cycles of fluorouracil-based regimens. Loco-regional irradiation with or without coverage of anastomotic site had radiation a dose range from 45-60 Gyat 1.8-2.0 Gy/fraction given with initial anterior-posterior/posterior-anterior arrangement with either extended (with anastomotic coverage), or small (without anastomotic coverage) field followed by oblique fields for boost. RESULTS: One hundred eighty-eight charts were reviewed. Seventy-two patients were eligible for post-resection chemoradiation. …

The Role Of Radiation Therapy On Medically Inoperable Clinically Localized Non-Small Cell Lung Patients: London Regional Cancer Program (Lrcp) Clinical Experience, Michael Lee, Edward Yu, Robert Ash, Patricia Tai, Larry Stitt, George Rodrigues, Rashid Dar, Mark Vincent, Richard Inculet, Richard Malthaner

Richard A. Malthaner

Lung cancer is the most frequent cause of cancer death in both men and women in North America. In 2006, an estimated 22,700 Canadians will be diagnosed with lung cancer and 19,300 will die of it (Canadian Cancer Statistics 2006). Approximately 15-20% of NSCLC patients present with early or localized disease. Surgical resection of T1-2N0 NSCLC remains the treatment of choice for this population, and results in a 5-year survival rate of 50-70%. Patients deemed medically inoperable have been treated with non-surgical therapies, such as radiation therapy(RT), while some patients have simply been observed without any tumor therapy because of …

Assessment Of Obesity As A Cardiovascular Disease Risk Factor In A Geriatric Rural Texas Community - A Six Month Follow-Up, Alberto Coustasse Md, Mba

Alberto Coustasse, DrPH, MD, MBA, MPH

Coustasse, Alberto, Assessment of Obesity as a Cardiovascular Disease Risk Factor in a Geriatric Rural Texas Community – A Six Month Follow-up. Master of Public Health Track, Public Health Administration, December 1999, 22 pp., 9 tables, 9 illustrations, bibliography, 7 titles. The health fair approach was used as a method to establish individual and population health status baselines and to provide a mechanism to follow-up with an elderly population in a rural Texas community. A controlled trial sample of forty-four seniors was initially screened in a primary care clinic in August 1998. Patients were reevaluated at six months and results …

The National Health Security Preparedness Index: Harnessing Evidence & Experience To Drive Improvement, Glen P. Mays

Glen Mays

This presentation profiles the National Health Security Preparedness Index as a mechanism for measuring preparedness and resiliency levels across the U.S. Forthcoming enhancements in measurement and analytic methodologies will allow the Index to play heightened roles in informing policies and practices that protect the U.S. population from a broad range of hazards.

Hospital-Based Surveillance Of Invasive Pneumococcal Disease And Pneumonia In South Bangalore, India., R Nisarga, R Premalatha, Shivananda, Kl Ravikumar, U Shivappa, A Gopi, Sb Chikkadasarahalli, R Batuwanthudawe, Paul E. Kilgore, Sa Kim, I Balter, S Jouve, J Ye, M Moscariello

Paul E. Kilgore

OBJECTIVE: To estimate the incidence of invasive pneumococcal disease and pneumonia, distribution of pneumococcal serotypes, and antibiotic susceptibility in children aged 28 days to <60 months. DESIGN: Hospital-based surveillance. SETTING: South Bangalore, India. PARTICIPANTS: 9950 children aged 28 days to <60 months with clinical suspicion of invasive pneumococcal disease or pneumonia. RESULTS: The estimated at-risk population included 224,966 children <5 years of age. Forty cases of invasive pneumococcal disease were identified. Estimated invasive pneumococcal disease incidence was 17.8/100,000 with incidence being highest among children aged 6 months to <12 months (49.9/100,000). Clinical pneumonia syndrome was the most frequent diagnosis (12.5/100,000). Pneumococcal serotypes included: 6A (n=6, 16.7%); 14 (n=5, 13.9%); 5 (n=4, 11.1%); 6B (n=4, 11.1%); 1, 18C, and 19A (n=3 each, 8.3%); 9V (n=2, 5.6%); and 3, 4, 10C, 18A, 18F, and 19F (n=1 each, 2.8%). Serotypes 6A, 14, 6B, 1, 18C, 19A, 9V, 4, 10C, and 18A showed antibiotic resistance. Clinical pneumonia incidence was 2109/100,000, with incidence being highest among children aged 28 days to <6 months (5033/100,000). Chest radiograph-confirmed pneumonia incidence was 1114/100,000, with incidence being highest among children aged 28 days to <6 months (2413/100,000). CONCLUSIONS: Invasive pneumococcal disease and pneumonia were found to be common causes of morbidity in young children living in South Bangalore, India.

Challenges And Best Practices In Real-Time Prediction Of Infectious Disease: A Case Study Of Dengue In Thailand, Nicholas Reich, Stephen Lauer, Krzysztof Sakrejda, Sopon Iamsirithaworn, Soawapak Hinjoy, Paphanij Suangtho, Suthanun Suthachana, Hannah Clapham, Henrik Salje, Derek Cummings, Justin Lessler

Nicholas G Reich

Epidemics of communicable diseases place a huge burden on public health infrastructures across the world. Producing accurate and actionable forecasts of infectious disease incidence at short and long time scales will improve public health response to outbreaks. However, scientists and public health officials face many obstacles in trying to create accurate and actionable real-time forecasts of infectious disease incidence. Dengue is a mosquito-borne virus that annually infects over 400 million people worldwide. We developed a real-time forecasting model for dengue hemorrhagic fever in the 77 provinces of Thailand. We created an operational and computational infrastructure that generated multi-step predictions of …

Timely Health Service Utilization: A Longitudinal Cohort Study Of Older Foster Youth., Angelique G. Day

Angelique G Day

Purpose: To evaluate the impact of a policy change for older foster care youth from a fee-for-service (FFS) Medicaid program to health maintenance organization (HMO) providers on the timeliness of well-child visits (health care physicals). Methods: A three year observational study using linked administrative data collected by the Michigan Departments of Human Services and Community Health of 2,016 youth who were in foster care on or after their 14th birthdays during 2009-2012 was used to examine the odds of receiving a timely well-child visit within the recommended 30 day time frame (logistic regression) as well as days to the first …

Estimating Controlled Direct Effects Of Restrictive Feeding Practices In The `Early Dieting In Girls' Study, Yeying Zhu, Debashis Ghosh, Donna L. Coffman, Jennifer S. Williams

Debashis Ghosh

In this article, we examine the causal effect of parental restrictive feeding practices on children’s weight status. An important mediator we are interested in is children’s self-regulation status. Traditional mediation analysis (Baron and Kenny, 1986) applies a structural equation modelling (SEM) approach and decomposes the intent-to-treat (ITT) effect into direct and indirect effects. More recent approaches interpret the mediation effects based on the potential outcomes framework. In practice, there often exist confounders that jointly influence the mediator and the outcome. Inverse probability weighting based on propensity scores are used to adjust for confounding and reduce the dimensionality of confounders simultaneously. …

Case Studies In Evaluating Time Series Prediction Models Using The Relative Mean Absolute Error, Nicholas G. Reich, Justin Lessler, Krzysztof Sakrejda, Stephen A. Lauer, Sopon Iamsirithaworn, Derek A T Cummings

Nicholas G Reich

Statistical prediction models inform decision-making processes in many real-world settings. Prior to using predictions in practice, one must rigorously test and validate candidate models to ensure that the proposed predictions have sufficient accuracy to be used in practice. In this paper, we present a framework for evaluating time series predictions that emphasizes computational simplicity and an intuitive interpretation using the relative mean absolute error metric. For a single time series, this metric enables comparisons of candidate model predictions against naive reference models, a method that can provide useful and standardized performance benchmarks. Additionally, in applications with multiple time series, this …

Creating Healthy Community In The Postindustrial City, Brian A. Hoey

Brian A. Hoey, Ph.D.

Epidemiology Of Latency And Relapse In Plasmodium Vivax Malaria, Andrew A. Lover

Andrew Lover

Considerations For Comprehensive Analyses Of Sporozoite-Based Controlled Human Malaria Infection Studies, Andrew A. Lover

Andrew Lover

Short Report: Study Variability In Recent Human Challenge Experiments With Plasmodium Falciparum Sporozoites (Pfspz Challenge), Andrew A. Lover

Andrew Lover