Analytical Markov Model Research Articles

Analysis of reliability of a prefabricated conductive rail joint in context of heavy traffic

In this paper, the calculation of reliability indicators has been carried out in the article for two configurations of a prefabricated conductive rail joint: with fish plates, a welded and bypass connector, and a spring rail bond. The sections of the track where the probability of failure of the prefabricated conductive rail joint is increasing are identified. The destabilizing factors influencing the onset of failure of a prefabricated conductive rail joint earlier than the calculated values of the durability indicators are considered. A model for evaluating the reliability of the second configuration of a prefabricated conductive rail joint based on the Markov analytical model has been developed, and such reliability indicators have been calculated as the probability of its being in working condition, as well as the probability of failure of the prefabricated conductive rail joint due to the inoperability of the fish plates and the spring rail bond. The features of the configuration of a prefabricated conductive rail joint with a spring rail bond are taken into account, which consist in the fact that in order to eliminate the failure due to the inoperability of the spring rail bond, it is necessary to remove the fish plates.

Analytical Markov Model to Calculate TDDB at Any Voltage and Temperature Stress Condition

Analytical Markov Model to Calculate TDDB at Any Voltage and Temperature Stress Condition

Cost-effectiveness analysis of pediatric immunization program with 15-valent pneumococcal conjugate vaccine in Japan

BackgroundThe 15-valent pneumococcal conjugate vaccine (PCV15 or V114) has recently been approved for pediatric vaccination against pneumococcal diseases (PDs) in Japan. The study aims to evaluate the cost-effectiveness of pediatric vaccination with V114 versus 13-valent PCV (PCV13) in Japan.MethodsThe study used a decision analytical Markov model to estimate the cost and effectiveness outcomes for a birth cohort in Japan over a 10-year time horizon. The model tracked the occurrences of acute PD events, including invasive PD (IPD), non-bacteremic pneumococcal pneumonia (NBPP) and pneumococcal acute otitis media (AOM) and the long-term impact of post-meningitis sequalae. Vaccine effectiveness was estimated based on literature and assumptions, and accounted for indirect effects and vaccine waning. The base case took the societal perspective, including both direct and indirect costs, while a healthcare payer perspective was modeled in a scenario analysis. Additional scenario analyses and sensitivity analyses were conducted.ResultsIn the base case, V114 was associated with an incremental gain of 24 quality-adjusted life years and a reduction of ¥365,610,955 in total costs compared to PCV13. It was expected to reduce the number of pneumococcal AOM, NBPP, and IPD cases by 1,832, 1,333 and 25, respectively. All scenario analyses and most sensitivity analyses showed that V114 was a dominant strategy compared to PCV13.ConclusionsPediatric vaccination with V114 is expected to lead to cost savings and more health benefits compared to PCV13 in Japan from both societal and healthcare payer perspectives. The findings are robust under plausible assumptions and inputs.

Cost-Effectiveness Analysis of Personalized Hypertension Prevention.

While a population-wide strategy involving lifestyle changes and a high-risk strategy involving pharmacological interventions have been described, the recently proposed personalized medicine approach combining both strategies for the prevention of hypertension has increasingly gained attention. However, a cost-effectiveness analysis has been hardly addressed. This study was set out to build a Markov analytical decision model with a variety of prevention strategies in order to conduct an economic analysis for tailored preventative methods. The Markov decision model was used to perform an economic analysis of four preventative strategies: usual care, a population-based universal approach, a population-based high-risk approach, and a personalized strategy. In all decisions, the cohort in each prevention method was tracked throughout time to clarify the four-state model-based natural history of hypertension. Utilizing the Monte Carlo simulation, a probabilistic cost-effectiveness analysis was carried out. The incremental cost-effectiveness ratio was calculated to estimate the additional cost to save an additional life year. The incremental cost-effectiveness ratios (ICER) for the personalized preventive strategy versus those for standard care were -USD 3317 per QALY gained, whereas they were, respectively, USD 120,781 and USD 53,223 per Quality-Adjusted Life Year (QALY) gained for the population-wide universal approach and the population-based high-risk approach. When the ceiling ratio of willingness to pay was USD 300,000, the probability of being cost-effective reached 74% for the universal approach and was almost certain for the personalized preventive strategy. The equivalent analysis for the personalized strategy against a general plan showed that the former was still cost-effective. To support a health economic decision model for the financial evaluation of hypertension preventative measures, a personalized four-state natural history of hypertension model was created. The personalized preventive treatment appeared more cost-effective than population-based conventional care. These findings are extremely valuable for making hypertension-based health decisions based on precise preventive medication.

DSME-LoRa: Seamless Long-range Communication between Arbitrary Nodes in the Constrained IoT

Long-range radio communication is preferred in many IoT deployments, as it avoids the complexity of multi-hop wireless networks. LoRa is a popular, energy-efficient wireless modulation but its networking substrate LoRaWAN introduces severe limitations to its users. In this article, we present and thoroughly analyze DSME-LoRa, a system design of LoRa with IEEE 802.15.4 Deterministic Synchronous Multichannel Extension (DSME) as a MAC layer. DSME-LoRa offers the advantage of seamless client-to-client communication beyond the pure gateway-centric transmission of LoRaWAN. We evaluate its feasibility via a full-stack implementation on the popular RIOT operating system, assess its steady-state packet flows in an analytical stochastic Markov model, and quantify its scalability in massive communication scenarios using large-scale network simulations. Our findings indicate that DSME-LoRa is indeed a powerful approach that opens LoRa to standard network layers and outperforms LoRaWAN in many dimensions.

Non-invasive monitoring and treat-to-target approach are cost-effective in patients with mild-moderate ulcerative colitis.

There are no data to assess the value associated with a treat-to-target (T2T) strategy based on tight control of mild-moderate ulcerative colitis (UC). To assess the cost-effectiveness of a T2T approach based on the normalisation of clinical signs and faecal calprotectin (FC) METHODS: A decision analytical Markov model was developed to compare T2T algorithm combining clinical symptoms and FC levels to define treatment response and the possible switch to the next treatment line (T2T-FC), and the reference strategy based only on symptoms. The model included five treatment lines and was conducted from the Italian national health service (NHS) perspective using a 3-year time horizon. The model calculated the incremental cost-effectiveness ratio as € per relapse avoided. Deterministic and probabilistic sensitivity analyses were conducted. The cost-effectiveness analysis produced an increased time spent by a patient in clinical remission and FC ≤ 100 level (+0.177 years; about 2months) and a decreasing number of relapses (-0.1937; -20.9%) per patient using a T2T-FC approach compared to only symptoms. Furthermore, the T2T-FC was associated with higher cost (+€1795). The ICER estimated was €9263 per relapse avoided. These results were confirmed by sensitivity analyses. T2T-FC approach resulted in a higher benefit for mild-moderate UC patients in terms of time in remission and incidence of relapse but was associated with higher costs. Clinical trials and real-world clinical studies are needed to provide additional data on the cost-benefit of this approach.

Cost-effectiveness and budget impact analysis of siponimod in the treatment of secondary progressive multiple sclerosis in Italy.

Siponimod is an effective treatment for patients with secondary progressive multiple sclerosis (SPMS), with active disease evidenced by relapses or imaging features characteristic of multiple sclerosis inflammatory activity, however there is a need to evaluate its economic value and sustainability compared to other disease modifying-therapies (DMTs). To estimate the siponimod cost-effectiveness profile and its relative budget impact compared with other DMTs, by using the Italian National Healthcare System perspective. We performed: 1) a cost-effectiveness analysis (CEA) vs interferon beta-1b using an analytical Markov model and a life time-horizon, and 2) a budget impact analysis by using 3-years time-horizon. The results were reported as incremental cost-effectiveness ratio (ICER) and net-monetary benefit (NMB) for CEA, using a willingness to pay threshold of €40,000 per QALY gained, and as difference in the overall budget (Euro) between the scenario with and without siponimod for budget impact. In the base case scenario siponimod resulted cost-effective compared with interferon beta-1b 28,891€ per QALY. Overall, the market access of siponimod was associated to an increased budget of about 3€ millions (+0.9%) in the next 3 years simulated. Compared to interferon beta-1b, siponimod seems to be cost-effective in SPMS patients and sustainable, with less than 1% overall budget increased in the next 3 years. Future studies need to confirm our results in the real word setting and in other countries.

Choosing Optimal Antibiotics for the Treatment of Patients Infected With Enterobacteriaceae: A Network Meta-analysis and Cost-Effectiveness Analysis.

Overuse of carbapenems has led to the increasing carbapenem-resistant Enterobacteriaceae. It is still unknown whether other antibiotics [especially novel β-lactam/β-lactamase inhibitor combinations (BL/BLIs)] are better than carbapenems in the treatment of Enterobacteriaceae. A systematic literature search was performed to identify randomized controlled trials (RCTs) assessing the efficacy and safety of any antibiotics on Enterobacteriaceae infections. We carried out a traditional paired meta-analysis to compare ceftazidime/avibactam to comparators. Network meta-analysis (NMA) was conducted to integrate direct and indirect evidence of all interventions. Moreover, cost-effectiveness analysis using a combined decision analytical Markov model was completed for the treatment of patients with complex urinary tract infection (cUTI). A total of 25 relevant RCTs were identified, comprising 15 different interventions. Ceftazidime/avibactam exhibited comparable efficacy and safety with comparators (carbapenems) in the paired meta-analysis. In the NMA, the surface under the cumulative ranking curve probabilities showed that in terms of efficacy, the interventions with the highest-ranking were meropenem/vaborbactam, meropenem, imipenem/cilastatin, ceftriaxone, ceftazidime/avibactam, and ceftolozane/tazobactam [but no significant difference between any two antibiotics (p > 0.05)]. Regarding safety, ceftazidime/avibactam had a higher incidence of adverse events than that of piperacillin/tazobactam (relative risk = 0.74, 95% confidence interval = 0.59–0.94). Based on drug and hospitalization costs in China, the incremental cost-effectiveness ratio per quality-adjusted life-year gained in the patients with cUTI for meropenem, ceftazidime/avibactam, and ceftolozane/tazobactam compared to imipenem/cilastatin were US$579, US$24569, and US$29040, respectively. The role of these BL/BLIs to serve as alternatives to carbapenems requires large-scale and high-quality studies to validate.

A Markov chain model for IEEE 802.15.4 in time critical wireless sensor networks under periodic traffic with reneging packets

Nowadays, wireless sensor networks (WSNs) and Internet of Things (IoT) employ the IEEE 802.15.4 media access control (MAC) protocol in many applications. In time critical applications with periodic traffic model when the packets have a specified time to live (TTL), if the packet stays in the queue of a sensor node more than time to live, the node should drop that packet, which called reneging packet, to improve the network performance. This paper presents a new analytical Markov model for the IEEE 802.15.4 protocol in non-beacon enabled mode for the periodic traffic considering the reneging packets. The proposed model is applied to the both acknowledged and non-acknowledged modes under heterogeneous traffic for time critical sensor network applications. We obtain the probability distribution function (PDF) of packet delay (PD) and packet delivery ratio (PDR) under periodic and high data rate traffic model. The effects of packet generation period and reneging packets on the performance of sensor network is investigated. The results confirm that dropping an unusable reneging packet increases the network performance, and the non-acknowledged mode can be used for high data rate applications in which the delay is more critical than the packet delivery ratio.

Ідентифікація моделей маркетингу взаємодії сільськогосподарських підприємств з виробництва біопалива

The purpose of the article is to study the formation factors of the biofuels domestic market in the network of Ukrainian agricultural enterprises based on interaction marketing. The materials of the article are focused on the study of both the causes of dysfunction of the biofuels domestic market and the search for new factors in the formation of such a market. Research methods. The research methodology considered the motivation factor implemented in the form of a separate marketing policy of «interaction» as the basis for the formation of the biofuels market in Ukraine, where the main market agents were considered agricultural enterprises (as biofuel producers, consumers and business partners).In the course of the research, in addition to a number of general scientific methods of economic research, an experiment was used to assess the interest of managers in typical (for Vinnytsia region) agricultural enterprises in partnerships in the business of biofuels production. The solution of the problem provided influence modeling of separate factors on attitudes of the enterprises-recipients concerning partnership interaction in researched business on manufacture of biofuels on: 1) linear Markov analytical model; 2) a nonlinear Markov model with a nonstationary matrix of transition probabilities; 3) generalized Markov imitation (multi-version) model of transitions; 4) linear Markov simulation model with individual parameters of the elements; 5) nonlinear Markov simulation model with «training» of the elements. Thus, the dynamics of the model was determined by the change in the attitudes of many recipients about cooperation depending on: 1) the intensity of information links about the benefits and risks of cooperation; 2) the presence of the implementation system of motivational factors (production standards, a special type of marketing policy and partnership scheme). Research results. An empirical reflection of the agency base among this category is determined, which allows us to conclude that the number of potential business participants significantly exceeds the critical level, and the motivational factors for the partnership are at least significant. In contrast to the national biofuels market, where – in the absence of any protectionist policy – the business economy has shown low competitiveness in recent years, these results suggest the possibility of forming a new market type – agency, where business will be formed among agricultural enterprises, united by certain integration schemes on the basis of interaction marketing policy of the enterprise-business initiator. The efficiency basis of this market will obviously be the effect of minimizing the value chain both in terms of the participants’ number and the value added itself, which will significantly reduce the cost of production. Scientific novelty. Firstly, the question of the forming possibility – as an alternative – a new type of biofuels market in Ukraine in the absence, unlike all other countries, a state policy to support the industry; secondly, substantiation of the idea of a special marketing policy of the organizational level of the agricultural enterprise as a business initiator – the policy of «interaction»; third, the identification of the agency basis of this market in relation to domestic agricultural enterprises. Practical significance. The applied value of the results is considered as a basis for forming a business for the production of biofuels in the network of agricultural enterprises in the context of empirical forecasting of potential partners and the role of motivating factors for building such partnership schemes. Tabl.: 2. Figs.: 6. Refs.: 17.

PIN61 Cost-Effectiveness Study of the Use of Dolutegravir Compared with Efavirenz in Combination with Tenofovir and Emtricitabine, As the First LINE for the Care of Patients NEWLY Diagnosed with HIV or WHO Have NOT Started ART in Colombia.

Determine the cost effectiveness of using the dolutegravir compared to efavirenz in combination with tenofovir and emtricitabine, as the first line for the attention of newly diagnosed patients or not have started ART in Colombia. Cost-effectiveness analysis from the perspective of the third payer based on a hypothetical cohort Markov analytical model (n = 100) evaluate achievement of viral suppression, discontinuity, years of life saved in ten years how time horizon. The target population was adult frontline patients for the care of patients newly diagnosed with HIV or who did not start ART. The response parameters used were obtained from the literature and the cost contributions were obtained from the official dates (SISMED, CAC, ISS manual). Univariate sensitivity analysis and Monte Carlo type sensitivity analysis with 1000 iterations were performed. A 5% annual discount rate was applied for costs and results. Total costs of treatment were $2,708,810 USD for dolutegravir, $3,324,685 USD for efavirenz; savings from $-615,875 USD. Incremental effectiveness was years of life saved (-0,24), viral suppression (0,11) discontinuity (1.26). The cost effectiveness ratio for years of life saved was $2,589,679 USD and for discontinuity it was $490,658 USD. For viral suppression the cost effectiveness ratio dolutegravir was dominant over efavirenz. dolutegravir compared to efavirenz was shown to be a cost-effective strategy for managing PLHIV that they start antiretroviral therapy for the first time since perspective of the Colombian health system in base case conditions being dominant for the decrease in viral suppression.

МАТЕМАТИЧНА МОДЕЛЬ ВИКОНАННЯ ВОГНЕВИХ ЗАДАЧ ЕКІПАЖЕМ ТАНКА НА ПОЛІ БОЮ

Reconnaissance and defeat of enemy targets on the battlefield depends on the technical characteristics of surveillance and sighting devices, and it is important to ensure their effective operation, during both the day and night, especially in adverse weather conditions. Therefore, in the field of modernization and development of surveillance and sighting devices, by both domestic and foreign manufacturers, in recent years there has been a major trend towards the development of multi-channel sighting systems on armored vehicles. To determine the optimal parameters of the sighting systems of armored vehicle samples, it is necessary to develop a mathematical model that would take into account the entire process of target reconnaissance, including the impact of full range of natural and man-made obstacles, to determine the ways for the improvement of combat effectiveness of weapons samples. In this work, a mathematical model is developed for description of fire tasks execution on the battlefield by a tank crew, which is equipped with a multi-channel sight-monitoring system, to assess the work of the sighting system as whole as well as of each of its channels. The analysis of the functional scheme of solving the combat task shows that the stage of data acquisition should be divided into, at least three, separate states, namely: detection, recognition and identification such that the transitions between these states will be described by the corresponding probabilities. The developed model describes the sequence of events that in terms of probability theory form a Markov chain. The proposed analytical Markov model allows for modeling the solution of fire tasks by the tank crew equipped with a multi-channel sighting and observation system with separate consideration of the stages of target reconnaissance, its recognition and identification, which in turn are considered as separate states of the Markov chain. The model opens a possibility for the development of an extended model to determine a quantitative indicator to assess the effectiveness of a given sighting system in comparison with its analogs.

Enhancing the Performance of Low Priority SUs Using Reserved Channels in CRN

Cognitive radio networks (CRNs) are considered a promising solution for spectrum resources scarcity and efficient channel utilization. In this letter, multi-dimensional analytical Markov model based on reservation channel access scheme and channel aggregation method is proposed to enhance spectrum utilization, capacity of low priority secondary users (SUs) and reducing handoff probability of SUs. Moreover, the proposed method improves the performance of high priority SUs by providing the capability to resume the connection after dropping. The numerical results indicate that the modified reservation access model can enhance the performance of SUs compared to the traditional basic random access model.

PUK19 COST CONSEQUENCE ANALYSIS OF A REMOTE MONITORING PROGRAM FOR AUTOMATED PERITONEAL DYALISIS IN US

To estimate from the payer perspective, the cost and clinical consequences of a Remote Patient Monitoring (RPM) program, supported in Sharesource® technology, to improve the clinical practice in automated peritoneal dialysis (APD) from different US payer perspectives. A one year Markov analytic model, structured in five health states, was used to project costs and clinical outcomes from a hypothetical cohort of 100 APD patients with and without RPM. Hospitalization rates, length of stay and complication rates were estimated from literature and the United States Renal Data System (USRDS). Base case associated health state costs were estimated from literature and 2006 AHRQ report (1). Model results were reported as net costs, months free of complications, avoided hospitalizations, reduction in hospitalization days and avoided peritonitis episodes. Both deterministic and probabilistic sensitivity analyses were done to analyze the effect of parameter uncertainty and cost variability in the model results. Secondary análisis will be done to capture different sub-systems costs and emerging information. The implementation of a RPM program in a hypothetical cohort of 100 APD patients during one year resulted in: net savings of USD -$ 5,572,103 (USD -$ 55,721 per patient per year); 48 months free of complications; 45 hospitalization episodes avoided; reduction in 1,098 hospitalization days and 7 peritonitis episodes avoided. Cost saving results were maintained in all the scenarios of the deterministic sensitivity analysis, with the differences in hospitalization rate, hospitalization costs and length of stay being the most sensitive drivers of the model results. In the probabilistic sensitivity analysis, there was a 100% of chance of dominance. APD with RPM supported by Sharesource® technology is a cost saving alternative, potentially improving patient time free of complication, hospitalization burden and peritonitis risk. (1) Inpatient Hospital Stays for Principal Diagnosis: Average Length of Stay and Average Charges, 2006 Obtained from https://www.hcup-us.ahrq.gov/reports/factsandfigures/figures/2006/2006_4_3.jsp.

Comparative Cost-effectiveness of Surgery, Collagenase Clostridium Histolyticum, and Penile Traction Therapy in Men with Peyronie’s Disease in an Era of Effective Clinical Treatment

BackgroundTraditionally, surgery has been considered the gold standard treatment for Peyronie’s disease (PD). Less-invasive alternatives, such as collagenase Clostridium histolyticum (CCH) and traction therapy, have been proposed and proven effective. AimTo compare cost-effectiveness of management options for PD. MethodsA Markov analytic model was created to compare the cost-effectiveness of treatment with a novel traction device, RestoreX (RXPTT), vs CCH vs surgery. Outcomes were derived from single-institution, prospective data of 63 men treated with RXPTT, 115 with CCH, and 23 with plication or incision and grafting. Costs were based on 2017 Medicare reimbursement and utility values from the literature. Main Outcome MeasuresModel outcomes included complications for each treatment arm, as well as the probability of success, which was defined as ≥20% improvement in curvature. Univariable and multivariable sensitivity analyses were performed to test the robustness of the model. ResultsOverall success rates were 96% (surgery), 66% (CCH), and 48% (RXPTT). At 10 years after treatment, RXPTT was the most cost-effective, with mean costs per patient of $883 (RXPTT), $11,419 (surgery), and $33,628 (CCH). CCH and surgery both resulted in a gain of quality adjusted life years (QALYs) relative to RXPTT (9.44 and 9.36 vs 9.27, respectively). Sensitivity analysis demonstrated greater cost-effectiveness for surgery if lower (≤46%) rates of postoperative erectile dysfunction or length loss (≤3%). CCH became more cost-effective at lower costs (≤$16,726) or higher success rates (≥76%). On multivariable sensitivity analysis at a willingness to pay threshold of $100,000/QALY, the most cost-effective strategy was RXPTT in 49%, surgery in 48%, and CCH in 3% of simulations. At a willingness to treat threshold of $150,000/QALY, the most cost-effective treatment option was RXPTT in 33%, surgery in 55%, and CCH in 12% of simulations. Clinical ImplicationsIn an era of value-based care, this model can guide cost-effective treatment selection on the basis of provider, patient, and payer characteristics. Strengths & LimitationsThe current study represents the first cost-effectiveness comparison of treatment modalities for PD and is strengthened by prospective data collection, large CCH and traction sample sizes, and robust sensitivity analyses. Consistent with cost-effective models, the model is limited by assumptions and may not apply to all scenarios. ConclusionsRXPTT represents a more cost-effective method for achieving ≥20% curvature improvement compared with surgery or CCH. Depending on treatment goals, rate of surgical complications, and willingness to pay threshold, surgery and CCH may become more cost-effective in select scenarios.Wymer K, Kohler T, Trost L. Comparative Cost-effectiveness of Surgery, Collagenase Clostridium Histolyticum, and Penile Traction Therapy in Men with Peyronie’s Disease in an Era of Effective Clinical Treatment. J Sex Med 2019;16:1421–1432.

The Value and Sustainability of Ocrelizumab in Relapsing Multiple Sclerosis: A Cost-Effectiveness and Budget Impact Analysis

INTRODUCTION: The availability of ocrelizumab for the relapsing forms of multiple sclerosis (MS) in the Italian markets raised some questions about its economic impact and value compared to the alternative treatment options available.AIM: To assess the cost-effectiveness and budget impact of ocrelizumab compared to the most used second line disease modifying therapies (DMTs) in Italy.METHODS: The study was divided in two phases: Phase 1 – based on the development of a decision analytical Markov model to assess the cost-effectiveness of ocrelizumab compared to natalizumab and fingolimod, and Phase 2 – based on the development of a budget impact model to assess the economic impact of ocrelizumab in Italy. Both models used the National Health System perspective; a lifetime horizon was applied in the cost-effectiveness analysis and a 3-year time horizon in the budget impact. The cost-effectiveness analysis results were reported as incremental cost-effectiveness ratio (ICER) expressed as € per Quality Adjusted Life Year (QALY) gained, the budget impact analysis results were reported as difference in the overall budget (€) between a scenario with and without ocrelizumab.RESULTS: The two analyses reported ocrelizumab as a cost-effective option compared to natalizumab and fingolimod with a positive impact on the overall NHS budget. In the base-case analysis, the ICER was € 2,023 for ocrelizumab compared to fingolimod; while ocrelizumab resulted cost-saving compared to natalizumab. The sensitivity analysis confirmed the base-case analysis results. Further, the use of ocrelizumab was associated to a budget decrease of € 21 million (-2.6%) in a 3-year time horizon.CONCLUSION: The results of our cost-effectiveness and budget impact models reported ocrelizumab as an effective and efficient treatment in patients with relapsing forms of MS who failed a first line DMTs from the Italian NHS perspective.

Economic and ethical implications of improving access to health care for older people with intellectual disabilities in England: a cost-effectiveness modelling study of health checks

BackgroundAn increasing number of people with intellectual disabilities are reaching old age. Knowledge has emerged internationally about the complex and largely unmet health needs of this specific ageing population, and associated costs. Annual health checks, incentivised but not mandatory for primary care in England, seek to reduce health inequities for this population. However, their cost-effectiveness is unknown. Our study aimed to address this evidence gap. MethodsWe developed a decision analytical Markov model to compare a strategy in which older people with intellectual disabilities received annual health checks with standard care. The model, developed to inform a guideline for the National Institute for Health and Care Excellence (NICE), followed hypothetical cohorts of 1000 people in England from when they were 40 years old until they died. Outcome measure was cost per quality-adjusted life-year (QALY) gained. We calculated incremental cost-effectiveness ratios (ICER). Costs were assessed from a health provider perspective and expressed in 2016 British pounds. Costs and QALYs were discounted at 3·5%. We carried out probabilistic sensitivity analysis. Data from published studies as well as expert opinions informed parameters. FindingsAnnual health checks led to a mean QALY gain of 0·072 (95% CI 0·069–0·113) and mean incremental costs of £4911 (4897–5133). For a threshold of £30 000, annual health checks were not cost effective (mean ICER £89 200, 95% CI 86 252 to 136 769). Costs of intervention needed to reduce from £258 to under £100 per year for annual health checks to be cost effective. InterpretationAlthough our findings need to be considered with caution since the model was based on assumptions to overcome evidence gaps, they suggest that providing cost-effective annual health checks is difficult. This immediately raises ethical questions about equitable access to health checks and health itself. Additional resources are needed if health systems are to contribute to a fairer society. FundingNICE.

Discrete time model of a two-station one-buffer serial system with inventory level-dependent operation

The paper deals with the discrete-time discrete-state modeling of two-station one-buffer serial systems in which the condition of the first station (operative/idle) is controlled according to the inventory level of the intermediate buffer. Briefly, the first station is forced to remain idle each time the buffer fills up until it empties to a predefined inventory level (referred to as restarting-inventory level). Previous works have proved that this control policy, called restart policy, is effective when outage costs (e.g., waste production) are generated each time the first station restarts production after an interruption.While the works currently available in the literature assume that the buffer has to become completely empty before allowing the first station to resume production, the proposed paper develops a new analytical Markov model in which the restarting-inventory level can be greater than zero and arbitrarily set in the range 2,N-2, where N is the buffer size. The proposed model is solved in closed form by means of a partitioning procedure and a solution technique described in detail. Then, the most important performance measures are obtained as a function of the restarting-inventory level, the buffer size and the reliability parameters of both stations.Finally, some numerical results are discussed in order to validate the model and draw some concluding remarks about the values of the restarting-inventory level which maximize the effective efficiency of the system.

Head-of-Line Access Delay-Based Scheduling Algorithm for Flow-Level Dynamics

Scheduling algorithm design is a critical and challenging issue in multiuser wireless networks with dynamic flows. The well-known Queue-length-based MaxWeight (QMW) scheduling algorithm can achieve throughput-optimality if there only exist persistent flows that are long-lived with infinite traffic arrival. In this paper, we propose a head-of-line access delay (HAD)-based scheduling algorithm and show that it is throughput-optimal when the flows are dynamic, i.e., they are short-lived with finite data to transmit. HAD is an online algorithm and does not require prior knowledge of the statistics of the arrival traffic and channel information. We also develop the Markov analytic model to study system performance and reveal important properties of the proposed HAD scheduling algorithm. To reduce the complexity of the analysis, we further study two approximation methods corresponding to different arrival traffic intensity. Performance evaluation shows that the HAD scheduling algorithm can outperform the classic QMW and stabilize the system at the presence of flow-level dynamics. Compared to the other existing algorithms, HAD is practical to implement with a better delay performance.

Effects of naloxone distribution alone or in combination with addiction treatment with or without pre-exposure prophylaxis for HIV prevention in people who inject drugs: a cost-effectiveness modelling study

In the USA, an epidemic of opioid overdose deaths is occurring, many of which are from heroin. Combining naloxone distribution with linkage to addiction treatment or pre-exposure prophylaxis (PrEP) for HIV prevention through syringe service programmes has the potential to save lives and be cost-effective. We estimated the outcomes and cost-effectiveness of five alternative strategies: no additional intervention, naloxone distribution, naloxone distribution plus linkage to addiction treatment, naloxone distribution plus PrEP, and naloxone distribution plus linkage to addiction treatment and PrEP. We developed a decision analytical Markov model to simulate opioid overdose, HIV incidence, overdose-related deaths, and HIV-related deaths in people who inject drugs in Connecticut, USA. Model input parameters were derived from published sources. We compared each strategy with no intervention, as well as simultaneously considering all strategies. Sensitivity analysis was done for all variables. Linkage to addiction treatment was referral to an opioid treatment programme for methadone. Endpoints were survival, life expectancy, quality-adjusted life-years (QALYs), number and percentage of overdose deaths averted, number of HIV-related deaths averted, total costs (in 2015 US$) associated with each strategy, and incremental cost per QALY gained. In the base-case analysis, compared with no additional intervention, the naloxone distribution strategy yielded an incremental cost-effectiveness ratio (ICER) of $323 per QALY, and naloxone distribution plus linkage to addiction treatment was cost saving compared with no additional intervention (greater effectiveness and less expensive). The most efficient strategies (ie, those conferring the greatest health benefit for a particular budget) were naloxone distribution combined with linkage to addiction treatment (cost saving), and naloxone distribution combined with PrEP and linkage to addiction treatment (ICER $95 337 per QALY) at a willingness-to-pay threshold of $100 000. In probabilistic sensitivity analysis, the combination of naloxone distribution, PrEP, and linkage to addiction treatment was the optimal strategy in 37% of iterations and the combination of naloxone distribution and linkage to addiction treatment was the optimal strategy in 34% of iterations. Naloxone distribution through syringe service programmes is cost-effective compared with syringe distribution alone, but when combined with linkage to addiction treatment is cost saving compared with no additional services. A strategy that combines naloxone distribution, PrEP, and linkage to addiction treatment results in greater health benefits in people who inject drugs and is also cost-effective. State of Connecticut Department of Public Health and the National Institute of Mental Health.