scholarly journals Sequential Multiple Assignment Randomized Trial (SMART) To Identify Optimal Sequences Of Telemedicine Interventions For Improving Initiation of Insulin Therapy: A Simulation Study

Author(s):  
Xiaoxi Yan ◽  
David B. Matchar ◽  
Aastha Goel ◽  
Nirmali Sivapragasam ◽  
John P. Ansah ◽  
...  

Abstract Background: To examine the value of a Sequential Multiple Assignment Randomized Trial (SMART) design compared to a conventional randomized control trial (RCT) for telemedicine strategies to support titration of insulin therapy for Type 2 Diabetes Mellitus (T2DM) patients new to insulin. Methods: Microsimulation models were created in R using a synthetic sample based on primary data from 63 subjects enrolled in a pilot study of a smartphone application (App), Diabetes Pal compared to a nurse-based telemedicine strategy (Nurse). For comparability, the SMART and an RCT design were constructed to allow comparison of four (embedded) adaptive interventions (AIs). Results: In the base case scenario, the SMART has similar overall mean expected HbA1c and cost per subject compared with RCT, for sample size of n = 100 over 10000 simulations. SMART has lower (better) standard deviations of the mean expected HbA1c per AI, and higher efficiency of choosing the correct AI across various sample sizes. The differences between SMART and RCT become apparent as sample size decreases. For both trial designs, the threshold value at which a subject was deemed to have been responsive at an intermediate point in the trial had an optimal choice (i.e., the sensitivity curve had a U-shape). SMART design dominates the RCT, in the overall mean HbA1c (lower value) when the threshold value is close to optimal. Conclusions: SMART is suited to evaluating the efficacy of different sequences of treatment options, in addition to the advantage of providing information on optimal treatment sequences.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaoxi Yan ◽  
David B. Matchar ◽  
Nirmali Sivapragasam ◽  
John P. Ansah ◽  
Aastha Goel ◽  
...  

Abstract Background To examine the value of a Sequential Multiple Assignment Randomized Trial (SMART) design compared to a conventional randomized control trial (RCT) for telemedicine strategies to support titration of insulin therapy for Type 2 Diabetes Mellitus (T2DM) patients new to insulin. Methods Microsimulation models were created in R using a synthetic sample based on primary data from 63 subjects enrolled in a pilot study of a smartphone application (App), Diabetes Pal compared to a nurse-based telemedicine strategy (Nurse). For comparability, the SMART and an RCT design were constructed to allow comparison of four (embedded) adaptive interventions (AIs). Results In the base case scenario, the SMART has similar overall mean expected HbA1c and cost per subject compared with RCT, for sample size of n = 100 over 10,000 simulations. SMART has lower (better) standard deviations of the mean expected HbA1c per AI, and higher efficiency of choosing the correct AI across various sample sizes. The differences between SMART and RCT become apparent as sample size decreases. For both trial designs, the threshold value at which a subject was deemed to have been responsive at an intermediate point in the trial had an optimal choice (i.e., the sensitivity curve had a U-shape). SMART design dominates the RCT, in the overall mean HbA1c (lower value) when the threshold value is close to optimal. Conclusions SMART is suited to evaluating the efficacy of different sequences of treatment options, in addition to the advantage of providing information on optimal treatment sequences.


2015 ◽  
Vol 24 (5) ◽  
pp. 723 ◽  
Author(s):  
Brian J. Viner ◽  
Tim Jannik ◽  
Daniel Stone ◽  
Allan Hepworth ◽  
Luke Naeher ◽  
...  

Firefighters responding to wildland fires where surface litter and vegetation contain radiological contamination will receive a radiological dose by inhaling resuspended radioactive material in the smoke. This may increase their lifetime risk of contracting certain types of cancer. Using published data, we modelled hypothetical radionuclide emissions, dispersion and dose for 70th and 97th percentile environmental conditions and for average and high fuel loads at the Savannah River Site. We predicted downwind concentration and potential dose to firefighters for radionuclides of interest (137Cs, 238Pu, 90Sr and 210Po). Predicted concentrations exceeded dose guidelines in the base case scenario emissions of 1.0 × 107 Bq ha–1 for 238Pu at 70th percentile environmental conditions and average fuel load levels for both 4- and 14-h shifts. Under 97th percentile environmental conditions and high fuel loads, dose guidelines were exceeded for several reported cases for 90Sr, 238Pu and 210Po. The potential for exceeding dose guidelines was mitigated by including plume rise (>2 m s–1) or moving a small distance from the fire owing to large concentration gradients near the edge of the fire. This approach can quickly estimate potential dose from airborne radionuclides in wildland fire and assist decision-making to reduce firefighter exposure.


2020 ◽  
Author(s):  
Sabine Vogler ◽  
Peter Schneider ◽  
Lena Lepuschütz

Abstract Background: Several governments apply the policy of external price referencing (EPR), which considers the prices of a medicine in one or more other countries for the purpose of setting the price in the own country. Different methodological choices can be taken to design EPR. The study aimed to analyse whether, or not, and how changes in the methodology of EPR can impact medicine prices.Methods: The real-life EPR methodology as of Q1/2015 was surveyed in all European Union Member States (where applicable), Iceland, Norway and Switzerland through a questionnaire responded by national pricing authorities. Different scenarios were developed related to the parameters of the EPR methodology. Discrete-event simulations of fictitious prices in the 28 countries of the study that had EPR were run over 10 years. The continuation of the real-life EPR methodology in the countries as surveyed in 2015, without any change, served as base case.Results: In most scenarios, after ten years, medicine prices in all or most surveyed countries were – sometimes considerably – lower than in the base case scenario. But in a few scenarios medicine prices increased in some countries. Consideration of discounts (an assumed 20% discount in five large economies and the mandatory discount in Germany, Greece and Ireland) and determining the reference price based on the lowest price in the country basket would result in higher price reductions (on average -47.2% and -34.2% compared to the base case). An adjustment of medicine price data of the reference countries by purchasing power parities would lead to higher prices in some more affluent countries (e.g. Switzerland, Norway) and lower prices in lower-income economies (Bulgaria, Romania, Hungary, Poland). Regular price revisions and changes in the basket of reference countries would also impact medicine prices, however to a lesser extent.Conclusions: EPR has some potential for cost-containment. Medicine prices could be decreased if certain parameters of the EPR methodology were changed. If public payers aim to apply EPR to keep medicine prices at more affordable levels, they are encouraged to explore the cost-containment potential of this policy by taking appropriate methodological choices in the EPR design.


PETRO ◽  
2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Muhamad Taufan Azhari

<p>Reservoir simulation is an area of reservoir engineering in which computer models are used to predict the flow of fluids through porous media. Reservoir simulation process starts with several steps; data preparation, model and grid construction, initialization, history matching and prediction. Initialization process is done for matching OOIP or total initial hydrocarbon which fill reservoir with hydrocarbon control volume with volumetric method.</p><p>To aim the best encouraging optimum data, these development scenarios of TR Field Layer X will be predicted for 30 years (from 2014 until January 2044). Development scenarios in this study consist of 4 scenarios : Scenario 1 (Base Case), Scenario 2 (Base Case + Reopening non-active wells), Scenario 3 (scenario 2 + infill production wells), Scenario 4 (Scenario 2 + 5 spot pattern of infill injection wells).</p>


Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Valy Fontil ◽  
Kirsten Bibbins-Domingo ◽  
Dhruv Kazi ◽  
Pamela Coxson ◽  
Steve Sidney ◽  
...  

Background: Only half of hypertensive adults achieve blood pressure (BP) control in the United States. Methods: We developed the BP Control Model to simulate physician- and patient-level processes relevant in achieving BP control. We validated the model by simulating the intervention arm of a recent multicenter clinical trial and used the validated model to examine the effects of isolated improvements in three modifiable processes on BP control. Data from national surveys, cohort studies, and trials were used to parameterize the model. We simulated 5,000 hypothetical adult patients with uncontrolled hypertension (systolic BP≥ 140) using probability sampling of participants from the 2009-2010 National Health and Nutrition Examination Survey. We modeled 50% improvements and ideal scenarios for each process parameter. Outcome: We reported outcomes in terms of BP control (% with SBP < 140 mmHg), and average change in BP at 52 weeks. Results: In our validation analysis, the model-predicted BP control was similar to what was achieved in the VIPER-BP clinical trial (63.5% vs. 63.8%). In our base case scenario, 24% of the NHANES-derived cohort achieved BP control at 52 weeks. In scenarios with 50% improvements, the model predicted small increases in BP control, but substantially larger and more variable effects when processes were idealized (Table). Control was reached in 77% with ideal treatment intensification, 44% with ideal encounter frequency, only 32% with ideal adherence, and 97% when all three processes were idealized. Conclusion: While improving patient adherence to medications would improve BP control, healthcare systems can achieve similar or greater success by focusing on increasing the frequency of clinical encounters and improving physicians’ prescribing behavior. The BP Control Model can be used to predict how much improvement to expect from such interventions.


2019 ◽  
Vol 70 (9) ◽  
pp. 1966-1972
Author(s):  
Nicolas Voirin ◽  
Camille Allam ◽  
Caroline Charre ◽  
Christine Fernandez ◽  
Matthieu Godinot ◽  
...  

Abstract Background International guidelines recommend the systematic screening for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infections in all men who have sex with men (MSM) who have engaged in unprotected sex. However, the optimal screening strategy remains unclear. We developed a modeling approach to optimize NG/CT screening strategy in MSM. Methods A compartmental model of NG/CT screening and infection was implemented. NG/CT anal, pharyngeal, and urine (APU) samples from MSM attending the sexually transmitted infections clinic were used to estimate the screening rate, prevalence, and incidence in a base case scenario. Different screening strategies (scenarios; S) were then evaluated: APU samples every 12 months (S1); APU samples every 3 months (S2); APU samples every 6 months (S3); anal and pharyngeal (AP) samples every 6 months (S4); and AP samples every 3 months (S5). Results We analyzed 2973 triplet APU samples from 1255 patients. We observed 485 NG and 379 CT diagnoses. NG/CT prevalence and incidence estimates were 12.0/11.1% and 40/29 per 100 person-years, respectively, in the base case scenario. As compared to S2, the reference strategy, the proportions of missed NG/CT diagnoses were 42.0/41.2% with S1, 21.8/22.5% with S3, 25.6/28.3% with S4, and 6.3/10.5% with S5, respectively. As compared to S2, S1 reduced the cost of the analysis by 74%, S3 by 50%, S4 by 66%, and S5 by 33%. The numbers needed to screen for catching up the missed NG/CT diagnoses were 49/67 with S1, 62/82 with S3, 71/87 with S4, and 143/118 with S5. Conclusions S5 appears to be the best strategy, missing only 6.3/10.5% of NG/CT diagnoses, for a cost reduction of 33%.


2020 ◽  
pp. 070674372098013
Author(s):  
Gonzalo Martínez-Alés ◽  
José B. Cruz Rodríguez ◽  
Pablo Lázaro ◽  
Arce Domingo-Relloso ◽  
María Luisa Barrigón ◽  
...  

Objective: To determine the cost-effectiveness of 2 strategies for post-discharge suicide prevention, an Enhanced Contact intervention based on repeated in-person and telephone contacts, and an individual 2-month long problem-solving Psychotherapy program, in comparison to facilitated access to outpatient care following a suicide attempt. Methods: We conducted a cost-effectiveness analysis based on a decision tree between January and December 2019. Comparative effectiveness estimates were obtained from an observational study conducted between 2013 and 2017 in Madrid, Spain. Electronic health care records documented resource use (including extra-hospital emergency care, mortality, inpatient admission, and disability leave). Direct cost data were derived from Madrid’s official list of public health care prices. Indirect cost data were derived from Spain’s National Institute of Statistics. Results: Both augmentation strategies were more cost-effective than a single priority outpatient appointment considering reasonable thresholds of willingness to pay. Under the base-case scenario, Enhanced Contact and Psychotherapy incurred, respectively, €2,340 and 6,260 per averted attempt, compared to a single priority appointment. Deterministic and probabilistic sensitivity analyses showed both augmentation strategies to remain cost-effective under several scenarios. Enhanced Contact was slightly cost minimizing in comparison to Psychotherapy (base-case scenario: €−196 per averted attempt). Conclusions: Two post-discharge suicide prevention strategies based on Enhanced Contact and Psychotherapy were cost-effective in comparison to a single priority appointment. Increasing contacts between suicide attempters and mental health-care providers was slightly cost minimizing compared to psychotherapy.


2009 ◽  
Vol 13 (1) ◽  
pp. 69-77 ◽  
Author(s):  
E. Kalbus ◽  
C. Schmidt ◽  
J. W. Molson ◽  
F. Reinstorf ◽  
M. Schirmer

Abstract. The spatial distribution of groundwater fluxes through a streambed can be highly variable, most often resulting from a heterogeneous distribution of aquifer and streambed permeabilities along the flow pathways. Using a groundwater flow and heat transport model, we defined four scenarios of aquifer and streambed permeability distributions to simulate and assess the impact of subsurface heterogeneity on the distribution of groundwater fluxes through the streambed: (a) a homogeneous low-K streambed within a heterogeneous aquifer; (b) a heterogeneous streambed within a homogeneous aquifer; (c) a well connected heterogeneous low-K streambed within a heterogeneous aquifer; and (d) a poorly connected heterogeneous low-K streambed within a heterogeneous aquifer. The simulation results were compared with a base case scenario, in which the streambed had the same properties as the aquifer, and with observed data. The results indicated that the aquifer has a stronger influence on the distribution of groundwater fluxes through the streambed than the streambed itself. However, a homogeneous low-K streambed, a case often implemented in regional-scale groundwater flow models, resulted in a strong homogenization of fluxes, which may have important implications for the estimation of peak mass flows. The flux distributions simulated with heterogeneous low-K streambeds were similar to the flux distributions of the base case scenario, despite the lower permeability. The representation of heterogeneous distributions of aquifer and streambed properties in the model has been proven to be beneficial for the accuracy of flow simulations.


2018 ◽  
Vol 192 ◽  
pp. 02060
Author(s):  
Vuchlung Chhorn ◽  
Jaruwit Prabnasak ◽  
Chow Chompoo-Inwai

This study aims at investigation the potential impacts of a public truck terminal implementation along with truck ban policy adaptation in Khon Kaen City, Thailand. A four-step model is developed and used for examining traffic condition changes due to the terminal relocation. Three different terminal locations are set. Truck traffic of each scenario are estimated and converted to total network cost, and then compared with the base-case scenario. The most suitable truck terminal location is suggested. Also, several concerns regarding the public truck terminal and truck ban policy in the study area are given.


2020 ◽  
Vol 12 (2) ◽  
pp. 253-264
Author(s):  
Yusuf Varli ◽  
Gokhan Ovenc

Purpose This paper aims to present the theoretical and conceptual framework of a new method in public finance called “participation based tax increment financing (P-TIF)” by combining conventional tax increment financing (TIF) within the Sharīʿah-compliance structure. Design/methodology/approach This study develops a benchmark model for P-TIF, which offers a participative contract between both lender and borrower. With the help of this model, a financing schema in P-TIF is established by incorporating stochastic modelling. Possible implications and alternative options of application are also explored with a discussion of challenges. Findings The results mainly indicate that P-TIF promises lenders to be a part of increment from tax earnings, in return for a reduced interest rate. They show how a rise in participation of the lender in a given contract lowers the interest rate. Under the base case scenario, the interest rate is reduced to zero when the participation of the lender in tax increment is set at 50%. Practical implications With the feature of being interest-free, P-TIF can be implied also within the Sharīʿah-compliance framework, thanks to the model it is based on. Additionally, as the model in this paper is parametric, it can be applicable to various cases in Islamic finance. Originality/value To the best of our knowledge, this is the first paper in the literature in the sense that it provides a conceptual idea and respective model for TIF method within a Sharīʿah-compliance framework.


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