Brandon S. Walker
ARUP Laboratories
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Publication
Featured researches published by Brandon S. Walker.
Prenatal Diagnosis | 2015
Brandon S. Walker; Brian R. Jackson; Danielle Lagrave; Edward R. Ashwood; Robert L. Schmidt
The aim of this article is to determine the cost effectiveness of cell free DNA (cfDNA) as a replacement for integrated screening using a societal cost perspective.
Digestive Diseases and Sciences | 2013
Robert L. Schmidt; Brandon S. Walker; Kirsten Howard; Lester J. Layfield; Douglas G. Adler
BackgroundThe effectiveness of endoscopic ultrasound-guided fine-needle aspiration increases with the number of needle passes but needle passes are also associated with increased risk of adverse events. The trade-off between needle passes and adequacy has not been well-characterized.AimsThe purpose of this study was to compare the risk–benefit tradeoff of different sampling protocols with and without rapid onsite evaluation (ROSE).Patients and MethodsWe used a discrete-event simulation model to compare eight different sampling protocols. Each sampling protocol was simulated 10,000 times to obtain the average performance for each scenario. The per-pass adequacy rates, ROSE, accuracy of the assessor and sampling limits were varied to determine the impact of these factors on the number of needle passes and adequacy rates.ResultsIncreasing per-class adequacy can be achieved at a cost of increased needle passes. Sampling with ROSE achieved higher adequacy with fewer needle passes than policies using a fixed number of needle passes without ROSE.ConclusionsVariable sampling policies using ROSE generally achieve greater per-case adequacy with fewer needle passes than non-ROSE sampling policies using a fixed number of passes.
Journal of Clinical Microbiology | 2016
Brandon S. Walker; Margaret V. Powers-Fletcher; Robert L. Schmidt; Kimberly E. Hanson
ABSTRACT Candida bloodstream infections (BSI) are associated with significant morbidity, mortality, and increased health care costs. Early treatment is essential, because delayed therapy detrimentally impacts clinical outcomes. The FDA recently approved the first culture-independent direct molecular detection method for Candida BSIs (T2Candida). The speed and sensitivity of this assay give it the potential to improve patient care, but the reagents and instrumentation are expensive. We used an analytic decision tree model to compare the cost-effectiveness of T2Candida-directed antifungal therapy (T2DT) to that of either empirical therapy (ET) or blood culture-directed therapy (BCDT). The costs included those of T2Candida testing, antifungal treatment, and hospital length of stay. The effectiveness measure was survival status at hospital discharge. T2DT was less costly and more effective than BCDT but was less costly and less effective than ET with an echinocandin (incremental cost-effectiveness ratio,
PLOS ONE | 2015
Brandon S. Walker; Richard E. Nelson; Brian R. Jackson; David G. Grenache; Edward R. Ashwood; Robert L. Schmidt
111,084 per additional survivor). One-way sensitivity analyses demonstrated that the cost-effectiveness of T2DT was highly dependent on Candida BSI prevalence and the cost of antifungal therapy and T2Candida test reagents. The use of T2DT reduced the number of unnecessarily treated patients by 98% relative to that with ET. Reduced drug exposure might lessen the possibility of drug-related adverse events and may also prevent the development of antifungal resistance or emergence of drug-resistant Candida species. The greatest benefit of T2Candida appears to be the ability to confidently withhold or stop empirical antifungal therapy in low-to-moderate-risk patients who are unlikely to benefit from treatment.
PLOS ONE | 2015
Robert L. Schmidt; Brandon S. Walker; Michael B. Cohen
Background Non-invasive prenatal testing (NIPT) is a relatively new technology for diagnosis of fetal aneuploidies. NIPT is more accurate than conventional maternal serum screening (MSS) but is also more costly. Contingent NIPT may provide a cost-effective alternative to universal NIPT screening. Contingent screening used a two-stage process in which risk is assessed by MSS in the first stage and, based on a risk cutoff, high-risk pregnancies are referred for NIPT. The objective of this study was to (1) determine the optimum MSS risk cutoff for contingent NIPT and (2) compare the cost effectiveness of optimized contingent NIPT to universal NIPT and conventional MSS. Study Design Decision-analytic model using micro-simulation and probabilistic sensitivity analysis. We evaluated cost effectiveness from three perspectives: societal, governmental, and payer. Results From a societal perspective, universal NIPT dominated both contingent NIPT and MSS. From a government and payer perspective, contingent NIPT dominated MSS. Compared to contingent NIPT, adopting a universal NIPT would cost
Labmedicine | 2015
Heather Signorelli; Joely A. Straseski; Jonathan R. Genzen; Brandon S. Walker; Brian R. Jackson; Robert L. Schmidt
203,088 for each additional case detected from a government perspective and
Prenatal Diagnosis | 2013
Brandon S. Walker; Edward R. Ashwood; Brian R. Jackson; Danielle Lagrave
263,922 for each additional case detected from a payer perspective. Conclusions From a societal perspective, universal NIPT is a cost-effective alternative to MSS and contingent NIPT. When viewed from narrower perspectives, contingent NIPT is less costly than universal NIPT and provides a cost-effective alternative to MSS.
Acta Cytologica | 2018
Lauren Pearson; Rachel E. Factor; Sandra K. White; Brandon S. Walker; Lester J. Layfield; Robert L. Schmidt
Background Rapid on-site evaluation (ROSE) can improve adequacy rates of fine-needle aspiration biopsy (FNAB) but increases operational costs. The performance of ROSE relative to fixed sampling depends on many factors. It is not clear when ROSE is less costly than sampling with a fixed number of needle passes. The objective of this study was to determine the conditions under which ROSE is less costly than fixed sampling. Methods Cost comparison of sampling with and without ROSE using mathematical modeling. Models were based on a societal perspective and used a mechanistic, micro-costing approach. Sampling policies (ROSE, fixed) were compared using the difference in total expected costs per case. Scenarios were based on procedure complexity (palpation-guided or image-guided), adequacy rates (low, high) and sampling protocols (stopping criteria for ROSE and fixed sampling). One-way, probabilistic, and scenario-based sensitivity analysis was performed to determine which variables had the greatest influence on the cost difference. Results ROSE is favored relative to fixed sampling under the following conditions: (1) the cytologist is accurate, (2) the total variable cost (
American Journal of Clinical Pathology | 2017
Robert L. Schmidt; Jorie M. Colbert-Getz; Caroline K. Milne; Daniel J Vargo; Jerry W Hussong; John R. Hoidal; Boaz A. Markewitz; Brandon S. Walker; Kensaku Kawamoto
/hr) is low, (3) fixed costs (
Clinica Chimica Acta | 2018
Robert L. Schmidt; Brandon S. Walker; Lauren Pearson
/procedure) are high, (4) the setup time is long, (5) the time between needle passes for ROSE is low, (6) when the per-pass adequacy rate is low, and (7) ROSE stops after observing one adequate sample. The model is most sensitive to variation in the fixed cost, the per-pass adequacy rate, and the time per needle pass with ROSE. Conclusions Mathematical modeling can be used to predict the difference in cost between sampling with and without ROSE.