Research Topics
| Stephen L HillisSummaryAffiliation: University of Iowa Country: USA Publications
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Detail Information
Publications
A comparison of the Dorfman-Berbaum-Metz and Obuchowski-Rockette methods for receiver operating characteristic (ROC) dataStephen L Hillis
Center for Research in the Implementation of Innovative Strategies in Practice, Iowa City VA Medical Center, Iowa City, IA, USA
Stat Med 24:1579-607. 2005..The methods are compared using data from a factorial study with two modalities, five readers, and 114 patients...- A comparison of denominator degrees of freedom methods for multiple observer ROC analysisStephen L Hillis
Center for Research in the Implementation of Innovative Strategies in Practice, Iowa City VA Medical Center, Iowa City, IA 52246 2208, USA
Stat Med 26:596-619. 2007..I propose a new ddf method that overcomes both of these problems and can be used with either the OR or DBM procedure... - Power estimation for multireader ROC methods an updated and unified approachStephen L Hillis
Iowa City VA Medical Center, IA 52246 2208, USA
Acad Radiol 18:129-42. 2011..This procedure updates previous approaches by incorporating recent methodological developments and unifies the approaches by allowing inputs to be conjectured parameter values or outputs from either a DBM or OR pilot-study analysis... - Simulation of Unequal-Variance Binormal Multireader ROC Decision Data: An Extension of the Roe and Metz Simulation ModelStephen L Hillis
Departments of Radiology and Biostatistics, University of Iowa, 3170 Medical Laboratories, 200 Hawkins Drive, Iowa City, IA 52242 1077 Comprehensive Access and Delivery Research and Evaluation CADRE Center, Iowa City VA Health Care System, Iowa City, IA Electronic address
Acad Radiol 19:1518-28. 2012..This article extends the RM model by allowing the diseased and nondiseased decision-variable distributions to have unequal variances for each reader... - An Analytic Expression for the Binormal Partial Area under the ROC CurveStephen L Hillis
Departments of Radiology and Biostatistics, University of Iowa, 3170 Medical Laboratories, 200 Hawkins Drive, Iowa City, IA 52242 1077, and Comprehensive Access and Delivery Research and Evaluation CADRE Center, Iowa City VA Health, Iowa City, IA Electronic address
Acad Radiol 19:1491-8. 2012..Instead, the pAUC has been computed using numerical integration or a rational polynomial approximation. Our purpose is to provide analytic expressions for the two forms of pAUC... - Using the mean-to-sigma ratio as a measure of the improperness of binormal ROC curvesStephen L Hillis
Department of Veterans Affairs Iowa City Medical Center, IA 52246 2208, USA
Acad Radiol 18:143-54. 2011..Presently, standard statistical software does not provide diagnostics for assessing the magnitude of the improperness... - Recent developments in the Dorfman-Berbaum-Metz procedure for multireader ROC study analysisStephen L Hillis
Center for Research in the Implementation of Innovative Strategies in Practice CRIISP, Iowa City VA Medical Center 152, Iowa City, IA, USA
Acad Radiol 15:647-61. 2008..Recently, solutions to these problems have been presented in three papers. Our purpose is to summarize and provide an overview of these recent developments... - Monte Carlo validation of the Dorfman-Berbaum-Metz method using normalized pseudovalues and less data-based model simplificationStephen L Hillis
Center for Research in the Implementation of Innovative Strategies in Practice CRIISP, Iowa City VA Medical Center 152, 601 Highway 6 West, Iowa City, IA 52246 2208, USA
Acad Radiol 12:1534-41. 2005..Our purpose is to empirically investigate if these two modifications--normalized pseudovalues and less data-based model simplification--result in improved performance... - Power estimation for the Dorfman-Berbaum-Metz methodStephen L Hillis
Center for Research in the Implementation of Innovative Strategies in Practice CRIISP, Iowa City VA Medical Center, Iowa, USA
Acad Radiol 11:1260-73. 2004.... - Impact of functional limitations and medical comorbidity on subsequent weight changes and increased depressive symptoms in older adultsValerie L Forman-Hoffman
Department of Internal Medicine, Iowa City Veterans Affairs Medical Center, University of Iowa College of Medicine, SE 605 GH, 200 Hawkins Drive, Iowa City, IA 52242, USA
J Aging Health 20:367-84. 2008..The primary goal of this study was to determine the effect of the onset of major medical comorbidity and functional decline on subsequent weight change and increased depressive symptoms... - Instability dependency of osteoarthritis development in a rabbit model of graded anterior cruciate ligament transectionYuki Tochigi
Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, Iowa 52242, USA
J Bone Joint Surg Am 93:640-7. 2011..In a survival rabbit knee model of graded joint instability, the relationship between the magnitude of instability and the intensity of cartilage degeneration was studied at the organ level in vivo... - Changes in diet behavior when adults become parentsHelena H Laroche
Department of Internal Medicine, University of Iowa, and Iowa City Veterans Administration Medical Center, Iowa City, IA 52246, USA
J Acad Nutr Diet 112:832-9. 2012..Cross-sectional studies suggest that parents eat more saturated fat than nonparents. Few studies exist on other dietary factors or using longitudinal data... - Retirement and weight changes among men and women in the health and retirement studyValerie L Forman-Hoffman
Department of Internal Medicine, University of Iowa College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA
J Gerontol B Psychol Sci Soc Sci 63:S146-53. 2008..The purpose of this study was to determine whether retirement was associated with either weight gain or weight loss... - Motion versus fixed distraction of the joint in the treatment of ankle osteoarthritis: a prospective randomized controlled trialCharles L Saltzman
University of Iowa Hospital and Clinics, Iowa City, Iowa, USA
J Bone Joint Surg Am 94:961-70. 2012..We hypothesized that allowing ankle motion during distraction would result in significant improvements in outcomes compared with distraction without ankle motion... - A prospective study of the PUSH tool in diabetic foot ulcersSue E Gardner
The University of Iowa, College of Nursing, Iowa City, IA, USA
J Wound Ostomy Continence Nurs 38:385-93. 2011..The purpose of this study was to examine the predictive validity of Pressure Ulcer Scale for Healing (PUSH; v. 3.0) in monitoring healing of neuropathic foot ulcers in patients with diabetes mellitus... - Effectiveness of home telehealth in comorbid diabetes and hypertension: a randomized, controlled trialBonnie J Wakefield
Department of Veterans Affairs Health Services Research and Development Center for Comprehensive Access and Delivery Research and Evaluation CADRE, Iowa City, Iowa 52246, USA
Telemed J E Health 17:254-61. 2011..Increased emphasis is being placed on the critical need to control hypertension (HTN) in patients with diabetes... - Clinical signs of infection in diabetic foot ulcers with high microbial loadSue E Gardner
Center for Research in the Implementation of Innovative Strategies in Practice, Iowa City VA Medical Center, Iowa City Iowa, USA
Biol Res Nurs 11:119-28. 2009.... - Objective CT-based metrics of articular fracture severity to assess risk for posttraumatic osteoarthritisThaddeus P Thomas
Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, IA, USA
J Orthop Trauma 24:764-9. 2010..It was hypothesized that an injury severity metric that included objective measures of articular disruption, of fracture energy, and of fragment displacement/dispersal would be a useful predictor of PTOA... - Distribution and progression of chondrocyte damage in a whole-organ model of human ankle intra-articular fractureYuki Tochigi
Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, 52242, USA
J Bone Joint Surg Am 93:533-9. 2011..In this study, the distribution and progression of fracture-associated cell-level cartilage damage were assessed using a novel whole-organ model of human ankle intra-articular fracture... - Patient and physician beliefs about control over health: association of symmetrical beliefs with medication regimen adherenceAlan J Christensen
Department of Psychology, The University of Iowa, 11 Seashore Hall East, Iowa City, IA 52242, USA
J Gen Intern Med 25:397-402. 2010..Past work suggests that the degree of similarity between patient and physician attitudes may be an important predictor of patient-centered outcomes... - Gleason score and laterality concordance between prostate biopsy and prostatectomy specimensKenneth G Nepple
Department of Urology, University of Iowa, Iowa City, Iowa 52242 1089, USA
Int Braz J Urol 35:559-64. 2009..We evaluated concordance in Gleason score and laterality between biopsy and radical retropubic prostatectomy (RRP) specimens and factors that influenced this relationship... - 4.5-gram monofilament sensation beneath both first metatarsal heads indicates protective foot sensation in diabetic patientsCharles L Saltzman
Department of Orthopaedic Surgery, University of Iowa, UIHC, 200 Hawkins Drive, Iowa City, IA 52246, USA
J Bone Joint Surg Am 86:717-23. 2004..The objective of the present study was to determine whether testing of fewer than ten sites could provide accuracy comparable with that obtained by testing all ten sites... - Effects of weekend admission and hospital teaching status on in-hospital mortalityPeter Cram
Division of General Internal Medicine, Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242, USA
Am J Med 117:151-7. 2004..We compared mortality rates between patients admitted on weekends and weekdays and whether weekend-weekday variation in rates differed between patients admitted to teaching and nonteaching hospitals in California... - An empirically derived taxonomy of factors affecting physicians' willingness to disclose medical errorsLauris C Kaldjian
Division of General Internal Medicine, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
J Gen Intern Med 21:942-8. 2006..However, the variables that may facilitate or impede disclosure are diverse and lack conceptual organization... - The role of the interosseous talocalcaneal ligament in subtalar joint stabilityYuki Tochigi
Department of Orthopaedics and Rehabilitation, University of Iowa, USA
Foot Ankle Int 25:588-96. 2004..Clinical effects of ITCL failure remain unclear because of insufficient understanding of the role of the ligament... - The Emergency Department Action in Smoking Cessation (EDASC) trial: impact on delivery of smoking cessation counselingDavid A Katz
Department of Medicine, University of Iowa, Iowa City, USA
Acad Emerg Med 19:409-20. 2012.... - Organ-level histological and biomechanical responses from localized osteoarticular injury in the rabbit kneeTanawat Vaseenon
Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, Iowa, USA
J Orthop Res 29:340-6. 2011..Immediate injury-associated alterations in the medial compartment contact mechanics were also demonstrated. Localized osteoarticular injury in this survival animal model resulted in global joint histological changes... - Health beliefs toward cardiovascular risk reduction in patients admitted to chest pain observation unitsDavid A Katz
Departments of Medicine and Emergency Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
Acad Emerg Med 16:379-87. 2009..The aim of this study was to evaluate the premise that evaluation in an observation unit for symptoms of possible ACS is a "teachable moment" with regard to modification of CRFs... - Health perceptions in patients who undergo screening and workup for prostate cancerDavid A Katz
Department of Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
Urology 69:215-20. 2007..This study was designed to determine whether a positive screening test with negative biopsy findings for prostate cancer is associated with worsened mental health during short-term follow-up... - Prevalence of delayed clinician response to elevated prostate-specific antigen valuesKenneth G Nepple
Department of Urology, University of Iowa, Iowa City, IA, USA
Mayo Clin Proc 83:439-45. 2008..To assess the frequency of delayed response to an abnormal prostate-specific antigen (PSA) value... - Primary tooth fluorosis and fluoride intake during the first year of lifeSteven M Levy
Department of Preventive and Community Dentistry, University of Iowa College of Dentistry, Iowa City, IA 52242, USA
Community Dent Oral Epidemiol 30:286-95. 2002..The purpose of this paper is to report on analyses relating estimated prenatal fluoride intake and fluoride intake during different parts of the first year of life to primary tooth fluorosis... - Prevalence and correlates of illness worry in the general populationRussell Noyes
Department of Psychiatry, University of Iowa, Roy J and Lucille A Carver College of Medicine, Iowa City, IA 52242 1000, USA
Psychosomatics 46:529-39. 2005..Worry about serious illness was associated with functional impairment and health care utilization... - Diagnostic validity of three swab techniques for identifying chronic wound infectionSue E Gardner
Center for Research in the Implementation of Innovative Strategies in Practice CRIISP, Iowa City VA Medical Center, IA, USA
Wound Repair Regen 14:548-57. 2006..The diagnostic validity of Levine's technique needs further study using an alternative reference standard, such as the development of infection-related complications... - Weight and depressive symptoms in older adults: direction of influence?Valerie L Forman-Hoffman
Center for Research in the Implementation of Innovative Stategies in Practice, Iowa City Veteran s Affairs Medical Center, Iowa, USA
J Gerontol B Psychol Sci Soc Sci 62:S43-51. 2007..Discussion. Based on our findings, it is apparent that researchers need to examine the pathways between changes in weight and increases in depressive symptoms in the context of functional limitations and medical comorbidity... - Automated objective scoring of histologically apparent cartilage degeneration using a custom image analysis programS Farshid Moussavi-Harami
Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, Iowa 52242 1100, USA
J Orthop Res 27:522-8. 2009..While limitations exist with image processing techniques, the new algorithm provides an objective and automated method for analyzing cartilage histology sections, consistent with human observer grading... - Patient and physician attitudes in the health care context: attitudinal symmetry predicts patient satisfaction and adherenceJamie A Cvengros
Department of Psychology, University of Iowa, Iowa City, IA 52242, USA
Ann Behav Med 33:262-8. 2007..There is increasing interest in the role that patient and physician health-related attitudes may play in predicting patient outcomes... - Do emergency department patients with possible acute coronary syndrome have better outcomes when admitted to cardiology versus other services?David A Katz
Department of Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
Ann Emerg Med 51:561-70, 570.e1. 2008.... - Multireader, multicase receiver operating characteristic analysis: an empirical comparison of five methodsNancy A Obuchowski
Departments of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
Acad Radiol 11:980-95. 2004..The objective of this article is to increase awareness of these methods and determine if their results are concordant for published datasets... - Laser fluorescence detection of occlusal cariesMatthew B Tonioli
College of Dentistry, The University of Iowa, Iowa City 52242-1001, USA
Am J Dent 15:268-73. 2002..DLF use offers improved detection of suspected hidden caries that have not become radiographically evident... - Hepatitis C virus-infected patients report communication problems with physiciansSusan Zickmund
Department of Medicine, University of Pittsburgh College of Medicine, Pittsburgh, PA, USA
Hepatology 39:999-1007. 2004..These should target both specialists and primary care providers to inform them about the psychosocial challenges facing these patients...