The cost-effectiveness of a bimekizumab versus IL-17A inhibitors treatment-pathway in patients with active axial spondyloarthritis in Scotland.

OBJECTIVE: To estimate the cost-effectiveness of a treatment-pathway initiated with bimekizumab, a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F and IL-17A, in patients with axial spondyloarthritis (axSpA) compared with IL-17Ai's, ixekizumab, and secukinumab, from the NHS Scotland perspective. METHODS: The axSpA treatment-pathway was modeled using a decision tree followed by a lifetime Markov model. The pathway included first- and second-line biologic disease-modifying antirheumatic drugs (bDMARD), followed by best supportive care (bDMARD, nonbiologic). Bimekizumab followed by any bDMARD ("BKZ") was compared with IL-17Ai's: secukinumab 150 mg followed by a blend ("SEC") of dose up-titration to secukinumab 300 mg and any bDMARD, or ixekizumab followed by any bDMARD ("IXE"). Transition to the next therapy was triggered by Bath Ankylosing Spondylitis Disease Activity Index-50% (BASDAI50) non-response or any-cause discontinuation. A published network meta-analysis provided efficacy data. EuroQoL-5-dimensions utilities were derived by mapping from Ankylosing Spondylitis Disease Activity Score. Costs included disease management (linked to functional limitations), biologics acquisition (list prices), administration and monitoring (NHS 2021/22). Discounting was 3.5%/year. Probabilistic results from patients with non-radiographic axSpA and ankylosing spondylitis were averaged to reflect the axSpA disease spectrum. Scenario and sensitivity analyses were performed. RESULTS: The incremental cost-effectiveness ratio (ICER) of BKZ was £24,801/quality-adjusted life-year (QALY) vs. SEC (95% credible interval £24,163-£25,895). BKZ had similar costs (Δ -£385 [-£15,239-£14,468]) and QALYs (Δ 0.039 [-0.748-0.825]) to IXE, with £1,523 (£862-£2,222) net monetary benefit. Conclusions remained unchanged in most scenarios. Results' drivers included BASDAI50 response rate and disease management cost. LIMITATIONS: Results were based on list prices. Data concerning up-titration to secukinumab 300 mg was scarce. CONCLUSIONS: The bimekizumab treatment-pathway represents a cost-effective option across the axSpA disease spectrum in Scotland. Bimekizumab is cost-effective compared to a secukinumab-pathway that includes dose up-titration, and has similar costs and QALYs to an ixekizumab-pathway.

Cost-Utility Analysis of Vericiguat in Heart Failure with Reduced Ejection Fraction After Worsening Heart Failure Events in China.

OBJECTIVE: Vericiguat is a new medication to demonstrate clinical efficacy in heart failure with reduced ejection fraction (HFrEF) after worsening heart failure (WHF) events, but its cost-utility was unknown. We aimed to assess the cost-utility of combining the application of vericiguat with standard treatment in HFrEF patients who had WHF events. METHODS: A multistate Markov model was implemented to mimic the economic results of HFrEF patients who had WHF events in China after receiving vericiguat or placebo. An analysis of cost-utility was conducted; most parameters were set according to the published studies and related databases. All the utilities and costs were decreased at a rate of 5% annually. The incremental cost-effectiveness ratios (ICERs) were the primary outcome measure. We also conducted sensitivity analyses. RESULTS: Over a 20 year lifetime horizon, additional use of vericiguat led to an elevated cost from US$9725.03 to US$20,660.76 at the current vericiguat costs. This was related to increased quality-adjusted life years (QALYs) from 2.50 to 2.66, along with an ICER of US$65,057.24 per QALY, which was over the willingness-to-pay (WTP) threshold of US$36,096.30 per QALY. If the vericiguat costs were discounted at 80%, it contributed to an ICER of US$12,226.77 per QALY. Additional use of vericiguat for patients with plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) of ≤ 5314 pg per ml produced an ICER of US$23,688.46 per QALY. The outcomes of the one-way sensitivity analysis showed the risk of death from cardiovascular disease in both groups was variable with the highest sensitivity. The probabilistic sensitivity analysis showed that 41.6% of the mimicked population receiving vericiguat combined with standard therapy was cost-effective at the WTP threshold of US$36,096.30 per QALY. CONCLUSIONS: From the perspective of Chinese public healthcare system, the combined use of vericiguat and standard treatment in patients with HFrEF following WHF events did not generate advantages in cost-utility in China but was a cost-effective therapeutic strategy for those who with plasma NT-proBNP of ≤ 5314 pg per ml.

A cost-effectiveness analysis of fluoride varnish application in preventing Root caries in elderly persons: a Markov simulation study.

BACKGROUND: Root caries are prevalent issues that affect dental health, particularly among elderly individuals with exposed root surfaces. Fluoride therapy has shown effectiveness in preventing root caries, but limited studies have addressed its cost-effectiveness in elderly persons population. This study aimed to evaluate the cost-effectiveness of a fluoride treatment program for preventing root caries in elderly persons within the context of Chinese public healthcare. METHODS: A Markov simulation model was adopted for the cost-effectiveness analysis in a hypothetical scenario from a healthcare system perspective. A 60-year-old subject with 23 teeth was simulated for 20 years. A 5% sodium fluoride varnish treatment was compared with no preventive intervention in terms of effectiveness and cost. Tooth years free of root caries were set as the effect. Transition probabilities were estimated from the data of a community-based cohort and published studies, and costs were based on documents published by the government. The incremental cost-effectiveness ratio (ICER) was calculated to evaluate cost-effectiveness. Univariate and probabilistic sensitivity analyses were performed to evaluate the influence of data uncertainty. RESULTS: Fluoride treatment was more effective (with a difference of 10.20 root caries-free tooth years) but also more costly (with a difference of ¥1636.22). The ICER was ¥160.35 per root caries-free tooth year gained. One-way sensitivity analysis showed that the risk ratio of root caries in the fluoride treatment group influenced the result most. In the probabilistic sensitivity analysis, fluoride treatment was cost-effective in 70.5% of the simulated cases. CONCLUSIONS: Regular 5% sodium fluoride varnish application was cost-effective for preventing root caries in the elderly persons in most scenarios with the consideration of data uncertainty, but to a limited extent. Improved public dental health awareness may reduce the incremental cost and make the intervention more cost-effective. Overall, the study shed light on the economic viability and impact of such preventive interventions, providing a scientific basis for dental care policies and healthcare resource allocation.

Deconvolution and Analysis of the 1H NMR Spectra of Crude Reaction Mixtures.

Nuclear magnetic resonance (NMR) spectroscopy is an important analytical technique in synthetic organic chemistry, but its integration into high-throughput experimentation workflows has been limited by the necessity of manually analyzing the NMR spectra of new chemical entities. Current efforts to automate the analysis of NMR spectra rely on comparisons to databases of reported spectra for known compounds and, therefore, are incompatible with the exploration of new chemical space. By reframing the NMR spectrum of a reaction mixture as a joint probability distribution, we have used Hamiltonian Monte Carlo Markov Chain and density functional theory to fit the predicted NMR spectra to those of crude reaction mixtures. This approach enables the deconvolution and analysis of the spectra of mixtures of compounds without relying on reported spectra. The utility of our approach to analyze crude reaction mixtures is demonstrated with the experimental spectra of reactions that generate a mixture of isomers, such as Wittig olefination and C-H functionalization reactions. The correct identification of compounds in a reaction mixture and their relative concentrations is achieved with a mean absolute error as low as 1%.

Cost-effectiveness of rimegepant oral lyophilisate compared to best supportive care for the acute treatment of migraine in the UK.

AIMS: Migraine is the most common disabling headache disorder and is characterized by recurrent throbbing head pain and symptoms of photophobia, phonophobia, nausea, and vomiting. Rimegepant 75 mg, an oral lyophilisate calcitonin gene-related peptide antagonist, is the first treatment approved for both the acute and preventative treatment of migraine, and the first acute therapy approved in over 20-years. The objective was to assess the cost-utility of rimegepant compared with best supportive care (BSC) in the UK, for the acute treatment of migraine in the adults with inadequate symptom relief after taking at least 2 triptans, or for whom triptans are contraindicated or not tolerated. MATERIALS AND METHODS: A de novo model was developed to estimate incremental costs and quality-adjusted life years (QALYs), structured as a decision tree followed by Markov model. Patients received rimegepant or BSC for a migraine attack and were assessed for response (pain relief at 2-h). Responders and non-responders followed different pain trajectories over 48-h cycles. Non-responders discontinued treatment while responders continued treatment for subsequent attacks, with a proportion discontinuing over time. Data sources included a post-hoc pooled analysis of the phase 3 acute rimegepant trials (NCT03235479, NCT03237845, NCT03461757), and a long-term safety study (NCT03266588). The analysis was conducted from the perspective of the UK National Health Service and Personal Social Services over a 20-year time horizon. RESULTS: Rimegepant resulted in an incremental cost-utility ratio (ICUR) of £10,309 per QALY gained vs BSC, which is cost-effectiveness at a willingness to pay threshold of £30,000/QALY. Rimegepant generated +0.44 incremental QALYs and higher incremental lifetime costs (£4,492). Improved QALYs for rimegepant were a result of less time spent with severe and moderate headache pain. CONCLUSION: This study highlights the economic value of rimegepant which was found to be cost-effective for the acute treatment of migraine in adults unsuitable for triptans.

Evaluating the health and economic outcomes of a PCV15 vaccination program for adults aged 65 years-and-above in Switzerland.

OBJECTIVE: To assess the health and economic outcomes of a PCV13 or PCV15 age-based (65 years-and-above) vaccination program in Switzerland. INTERVENTIONS: The three vaccination strategies examined were:Target population: All adults aged 65 years-and-above. Perspective(s): Switzerland health care payer. TIME HORIZON: 35 years. Discount rate: 3.0%. Costing year: 2023 Swiss Francs (CHF). STUDY DESIGN: A static Markov state-transition model. DATA SOURCES: Published literature and publicly available databases or reports. OUTCOME MEASURES: Pneumococcal diseases (PD) i.e., invasive pneumococcal diseases (IPD) and non-bacteremic pneumococcal pneumonia (NBPP); total quality-adjusted life-years (QALYs), total costs and incremental cost-effectiveness ratios (CHF/QALY gained). RESULTS: Using an assumed coverage of 60%, the PCV15 strategy prevented a substantially higher number of cases/deaths than the PCV13 strategy when compared to the No vaccination strategy (1,078 IPD; 21,155 NBPP; 493 deaths). The overall total QALYs were 10,364,620 (PCV15), 10,364,070 (PCV13), and 10,362,490 (no vaccination). The associated overall total costs were CHF 741,949,814 (PCV15), CHF 756,051,954 (PCV13) and CHF 698,329,579 (no vaccination). Thus, the PCV13 strategy was strongly dominated by the PCV15 strategy. The ICER of the PCV15 strategy (vs. no vaccination) was CHF 20,479/QALY gained. In two scenario analyses where the vaccine effectiveness for serotype 3 were reduced (75% to 39.3% for IPD; 45% to 23.6% for NBPP) and NBPP incidence was increased (from 1,346 to 1,636/100,000), the resulting ICERs were CHF 29,432 and CHF 13,700/QALY gained, respectively. The deterministic and probabilistic sensitivity analyses demonstrated the robustness of the qualitative results-the estimated ICERs for the PCV15 strategy (vs. No vaccination) were all below CHF 30,000/QALYs gained. CONCLUSIONS: These results demonstrate that using PCV15 among adults aged 65 years-and-above can prevent a substantial number of PD cases and deaths while remaining cost-effective over a range of inputs and scenarios.

Cost-effectiveness analysis of fluticasone furoate/umeclidinium bromide/vilanterol and umeclidinium bromide/vilanterol in the management of moderate and severe COPD in China.

OBJECTIVE: A study has analyzed the long-term cost-effectiveness of fluticasone furoate/umeclidinium bromide/vilanterol combination therapy (FF/UMEC/VI) versus umeclidinium bromide/vilanterol dual therapy (UMEC/VI) in the treatment of moderate or severe chronic obstructive pulmonary disease (COPD), providing evidence for decision-making in COPD treatment. METHODS: From the perspective of the whole society, a Markov model based on the severity of COPD was established, consisting of four states: moderate, severe, very severe, and death. The cycle of the model is three months, and the time frame of the study is 20 years. Data such as initial states, transition probabilities, costs, and utilities were collected from published literature, the National Institute for Health and Care Excellence (NICE) COPD economic report, Yaozh database, and the National Statistics Office. The discount rate is 5 %, and the willingness to pay threshold is set at three times the per capita GDP of China in 2022. TreeAge Pro 2011 was used to obtain the results of multiplication analyses, and one-way factor analysis and probability sensitivity analysis were conducted. RESULTS: The study findings demonstrate that for patients treated with FF/UMEC/VI and UMEC/VI, the 20-year treatment costs amount to $10,126.46 and $10,685.74, respectively. Similarly, the effectiveness is 32.94 quality-adjusted life years (QALYs) and 32.19 QALYs, respectively. The incremental cost-effectiveness ratio is $-745.70/QALY, which is lower than the willingness to pay threshold. The tornado plot from one-way factor analysis indicates that the first two factors impacting the results are the utility values for severe COPD of UMEC/VI and FF/UMEC/VI. Probability sensitivity analysis indicates that FF/UMEC/VI compared to UMEC/VI can be considered a more cost-effective treatment at the willingness to pay threshold of $35,806.96. CONCLUSION: The triple therapy (FF/UMEC/VI) is more affordable than dual therapy (UMEC/VI) when compared to China's three times GDP per capita criterion.

A Comparison of Markov and Mechanistic Models for Soil-Transmitted Helminth Prevalence Projections in the Context of Survey Design.

Globally, there are over 1 billion people infected with soil-transmitted helminths (STHs), mostly living in marginalized settings with inadequate sanitation in sub-Saharan Africa and Southeast Asia. The World Health Organization recommends an integrated approach to STH morbidity control through improved access to sanitation and hygiene education and the delivery of preventive chemotherapy (PC) to school-age children delivered through schools. Progress of STH control programs is currently estimated using a baseline (pre-PC) school-based prevalence survey and then monitored using periodical school-based prevalence surveys, known as Impact Assessment Surveys (IAS). We investigated whether integrating geostatistical methods with a Markov model or a mechanistic transmission model for projecting prevalence forward in time from baseline can improve IAS design strategies. To do this, we applied these 2 methods to prevalence data collected in Kenya, before evaluating and comparing their performance in accurately informing optimal survey design for a range of IAS sampling designs. We found that, although both approaches performed well, the mechanistic method more accurately projected prevalence over time and provided more accurate information for guiding survey design. Both methods performed less well in areas with persistent STH hotspots where prevalence did not decrease despite multiple rounds of PC. Our findings show that these methods can be useful tools for more efficient and accurate targeting of PC. The general framework built in this paper can also be used for projecting prevalence and informing survey design for other neglected tropical diseases.

Cost saving analysis of prediabetes intervention modalities in comparison with inaction using Markov state transition model-A multiregional case study.

BACKGROUND: Prediabetes management is a priority for policymakers globally, to avoid/delay type 2 diabetes (T2D) and reduce severe, costly health consequences. Countries moving from low to middle income are most at risk from the T2D "epidemic" and may find implementing preventative measures challenging; yet prevention has largely been evaluated in developed countries. METHODS: Markov cohort simulations explored costs and benefits of various prediabetes management approaches, expressed as "savings" to the public health care system, for three countries with high prediabetes prevalence and contrasting economic status (Poland, Saudi Arabia, Vietnam). Two scenarios were compared up to 15 y: "inaction" (no prediabetes intervention) and "intervention" with metformin extended release (ER), intensive lifestyle change (ILC), ILC with metformin (ER), or ILC with metformin (ER) "titration." RESULTS: T2D was the highest-cost health state at all time horizons due to resource use, and inaction produced the highest T2D costs, ranging from 9% to 34% of total health care resource costs. All interventions reduced T2D versus inaction, the most effective being ILC + metformin (ER) "titration" (39% reduction at 5 y). Metformin (ER) was the only strategy that produced net saving across the time horizon; however, relative total health care system costs of other interventions vs inaction declined over time up to 15 y. Viet Nam was most sensitive to cost and parameter changes via a one-way sensitivity analysis. CONCLUSIONS: Metformin (ER) and lifestyle interventions for prediabetes offer promise for reducing T2D incidence. Metformin (ER) could reduce T2D patient numbers and health care costs, given concerns regarding adherence in the context of funding/reimbursement challenges for lifestyle interventions.

Inference of genomic landscapes using ordered Hidden Markov Models with emission densities (oHMMed).

BACKGROUND: Genomes are inherently inhomogeneous, with features such as base composition, recombination, gene density, and gene expression varying along chromosomes. Evolutionary, biological, and biomedical analyses aim to quantify this variation, account for it during inference procedures, and ultimately determine the causal processes behind it. Since sequential observations along chromosomes are not independent, it is unsurprising that autocorrelation patterns have been observed e.g., in human base composition. In this article, we develop a class of Hidden Markov Models (HMMs) called oHMMed (ordered HMM with emission densities, the corresponding R package of the same name is available on CRAN): They identify the number of comparably homogeneous regions within autocorrelated observed sequences. These are modelled as discrete hidden states; the observed data points are realisations of continuous probability distributions with state-specific means that enable ordering of these distributions. The observed sequence is labelled according to the hidden states, permitting only neighbouring states that are also neighbours within the ordering of their associated distributions. The parameters that characterise these state-specific distributions are inferred. RESULTS: We apply our oHMMed algorithms to the proportion of G and C bases (modelled as a mixture of normal distributions) and the number of genes (modelled as a mixture of poisson-gamma distributions) in windows along the human, mouse, and fruit fly genomes. This results in a partitioning of the genomes into regions by statistically distinguishable averages of these features, and in a characterisation of their continuous patterns of variation. In regard to the genomic G and C proportion, this latter result distinguishes oHMMed from segmentation algorithms based in isochore or compositional domain theory. We further use oHMMed to conduct a detailed analysis of variation of chromatin accessibility (ATAC-seq) and epigenetic markers H3K27ac and H3K27me3 (modelled as a mixture of poisson-gamma distributions) along the human chromosome 1 and their correlations. CONCLUSIONS: Our algorithms provide a biologically assumption free approach to characterising genomic landscapes shaped by continuous, autocorrelated patterns of variation. Despite this, the resulting genome segmentation enables extraction of compositionally distinct regions for further downstream analyses.

stDiff: a diffusion model for imputing spatial transcriptomics through single-cell transcriptomics.

Spatial transcriptomics (ST) has become a powerful tool for exploring the spatial organization of gene expression in tissues. Imaging-based methods, though offering superior spatial resolutions at the single-cell level, are limited in either the number of imaged genes or the sensitivity of gene detection. Existing approaches for enhancing ST rely on the similarity between ST cells and reference single-cell RNA sequencing (scRNA-seq) cells. In contrast, we introduce stDiff, which leverages relationships between gene expression abundance in scRNA-seq data to enhance ST. stDiff employs a conditional diffusion model, capturing gene expression abundance relationships in scRNA-seq data through two Markov processes: one introducing noise to transcriptomics data and the other denoising to recover them. The missing portion of ST is predicted by incorporating the original ST data into the denoising process. In our comprehensive performance evaluation across 16 datasets, utilizing multiple clustering and similarity metrics, stDiff stands out for its exceptional ability to preserve topological structures among cells, positioning itself as a robust solution for cell population identification. Moreover, stDiff's enhancement outcomes closely mirror the actual ST data within the batch space. Across diverse spatial expression patterns, our model accurately reconstructs them, delineating distinct spatial boundaries. This highlights stDiff's capability to unify the observed and predicted segments of ST data for subsequent analysis. We anticipate that stDiff, with its innovative approach, will contribute to advancing ST imputation methodologies.

A Mathematical Model for the Impact of 3HP and Social Programme Implementation on the Incidence and Mortality of Tuberculosis: Study in Brazil.

In this paper, we presented a mathematical model for tuberculosis with treatment for latent tuberculosis cases and incorporated social implementations based on the impact they will have on tuberculosis incidence, cure, and recovery. We incorporated two variables containing the accumulated deaths and active cases into the model in order to study the incidence and mortality rate per year with the data reported by the model. Our objective is to study the impact of social program implementations and therapies on latent tuberculosis in particular the use of once-weekly isoniazid-rifapentine for 12 weeks (3HP). The computational experimentation was performed with data from Brazil and for model calibration, we used the Markov Chain Monte Carlo method (MCMC) with a Bayesian approach. We studied the effect of increasing the coverage of social programs, the Bolsa Familia Programme (BFP) and the Family Health Strategy (FHS) and the implementation of the 3HP as a substitution therapy for two rates of diagnosis and treatment of latent at 1% and 5%. Based of the data obtained by the model in the period 2023-2035, the FHS reported better results than BFP in the case of social implementations and 3HP with a higher rate of diagnosis and treatment of latent in the reduction of incidence and mortality rate and in cases and deaths avoided. With the objective of linking the social and biomedical implementations, we constructed two different scenarios with the rate of diagnosis and treatment. We verified with results reported by the model that with the social implementations studied and the 3HP with the highest rate of diagnosis and treatment of latent, the best results were obtained in comparison with the other independent and joint implementations. A reduction of the incidence by 36.54% with respect to the model with the current strategies and coverage was achieved, and a greater number of cases and deaths from tuberculosis was avoided.

Comparison of stochastic and deterministic models for gambiense sleeping sickness at different spatial scales: A health area analysis in the DRC.

The intensification of intervention activities against the fatal vector-borne disease gambiense human African trypanosomiasis (gHAT, sleeping sickness) in the last two decades has led to a large decline in the number of annually reported cases. However, while we move closer to achieving the ambitious target of elimination of transmission (EoT) to humans, pockets of infection remain, and it becomes increasingly important to quantitatively assess if different regions are on track for elimination, and where intervention efforts should be focused. We present a previously developed stochastic mathematical model for gHAT in the Democratic Republic of Congo (DRC) and show that this same formulation is able to capture the dynamics of gHAT observed at the health area level (approximately 10,000 people). This analysis was the first time any stochastic gHAT model has been fitted directly to case data and allows us to better quantify the uncertainty in our results. The analysis focuses on utilising a particle filter Markov chain Monte Carlo (MCMC) methodology to fit the model to the data from 16 health areas of Mosango health zone in Kwilu province as a case study. The spatial heterogeneity in cases is reflected in modelling results, where we predict that under the current intervention strategies, the health area of Kinzamba II, which has approximately one third of the health zone's cases, will have the latest expected year for EoT. We find that fitting the analogous deterministic version of the gHAT model using MCMC has substantially faster computation times than fitting the stochastic model using pMCMC, but produces virtually indistinguishable posterior parameterisation. This suggests that expanding health area fitting, to cover more of the DRC, should be done with deterministic fits for efficiency, but with stochastic projections used to capture both the parameter and stochastic variation in case reporting and elimination year estimations.

Simulated cost-effectiveness of a novel precision-guided dosing strategy in adult patients with Crohn's disease initiating infliximab maintenance therapy.

BACKGROUND: Patients with Crohn's disease (CD) who lose response to biologics experience reduced quality of life (QoL) and costly hospitalizations. Precision-guided dosing (PGD) provides a comprehensive pharmacokinetic (PK) profile that allows for biologic dosing to be personalized. We analyzed the cost-effectiveness of infliximab (IFX) PGD relative to two other dose intensification strategies (DIS). METHODS: We developed a hybrid (Markov and decision tree) model of patients with CD who had a clinical response to IFX induction. The analysis had a US payer perspective, a base case time horizon of 5 years, and a 4-week cycle length. There were three IFX dosing comparators: PGD; dose intensification based on symptoms, inflammatory markers, and trough IFX concentration (DIS1); and dose intensification based on symptoms alone (DIS2). Patients that failed IFX initiated ustekinumab, followed by vedolizumab, and conventional therapy. Transition probabilities for IFX were estimated from real-world clinical PK data and interventional clinical trial patient-level data. All other transition probabilities were derived from published randomized clinical trials and cost-effectiveness analyses. Utility values were sourced from previous health technology assessments. Direct costs included biologic acquisition and infusion, surgeries and procedures, conventional therapy, and lab testing. The primary outcomes were incremental cost-effectiveness ratios (ICERs). The robustness of results was assessed via one-way sensitivity, scenario, and probabilistic sensitivity analyses (PSA). RESULTS: PGD was the cost-effective IFX dosing strategy with an ICER of 122,932 $ per quality-adjusted life year (QALY) relative to DIS1 and dominating DIS2. PGD had the lowest percentage (1.1%) of patients requiring a new biologic through 5 years (8.9% and 74.4% for DIS1 and DIS2, respectively). One-way sensitivity analysis demonstrated that the cost-effectiveness of PGD was most sensitive to the time between IFX doses. PSA demonstrated that joint parameter uncertainty had moderate impact on some results. CONCLUSIONS: PGD provides clinical and QoL benefits by maintaining remission and avoiding IFX failure; it is the most cost-effective under conservative assumptions.

The entropy rate of Linear Additive Markov Processes.

This work derives a theoretical value for the entropy of a Linear Additive Markov Process (LAMP), an expressive but simple model able to generate sequences with a given autocorrelation structure. Our research establishes that the theoretical entropy rate of a LAMP model is equivalent to the theoretical entropy rate of the underlying first-order Markov Chain. The LAMP model captures complex relationships and long-range dependencies in data with similar expressibility to a higher-order Markov process. While a higher-order Markov process has a polynomial parameter space, a LAMP model is characterised only by a probability distribution and the transition matrix of an underlying first-order Markov Chain. This surprising result can be explained by the information balance between the additional structure imposed by the next state distribution of the LAMP model, and the additional randomness of each new transition. Understanding the entropy of the LAMP model provides a tool to model complex dependencies in data while retaining useful theoretical results. To emphasise the practical applications, we use the LAMP model to estimate the entropy rate of the LastFM, BrightKite, Wikispeedia and Reuters-21578 datasets. We compare estimates calculated using frequency probability estimates, a first-order Markov model and the LAMP model, also considering two approaches to ensure the transition matrix is irreducible. In most cases the LAMP entropy rates are lower than those of the alternatives, suggesting that LAMP model is better at accommodating structural dependencies in the processes, achieving a more accurate estimate of the true entropy.

Spatial-temporal Bayesian accelerated failure time models for survival endpoints with applications to prostate cancer registry data.

Prostate cancer is the most common cancer after non-melanoma skin cancer and the second leading cause of cancer deaths in US men. Its incidence and mortality rates vary substantially across geographical regions and over time, with large disparities by race, geographic regions (i.e., Appalachia), among others. The widely used Cox proportional hazards model is usually not applicable in such scenarios owing to the violation of the proportional hazards assumption. In this paper, we fit Bayesian accelerated failure time models for the analysis of prostate cancer survival and take dependent spatial structures and temporal information into account by incorporating random effects with multivariate conditional autoregressive priors. In particular, we relax the proportional hazards assumption, consider flexible frailty structures in space and time, and also explore strategies for handling the temporal variable. The parameter estimation and inference are based on a Monte Carlo Markov chain technique under a Bayesian framework. The deviance information criterion is used to check goodness of fit and to select the best candidate model. Extensive simulations are performed to examine and compare the performances of models in different contexts. Finally, we illustrate our approach by using the 2004-2014 Pennsylvania Prostate Cancer Registry data to explore spatial-temporal heterogeneity in overall survival and identify significant risk factors.

A Bayesian model-based reduced major axis regression.

Reduced major axis (RMA) regression, widely used in the fields of zoology, botany, ecology, biology, spectroscopy, and among others, outweighs the ordinary least square regression by relaxing the assumption that the covariates are without measurement errors. A Bayesian implementation of the RMA regression is presented in this paper, and the equivalence of the estimates of the parameters under the Bayesian and the frequentist frameworks is proved. This model-based Bayesian RMA method is advantageous since the posterior estimates, the standard deviations, as well as the credible intervals of the estimates can be obtained through Markov chain Monte Carlo methods directly. In addition, it is straightforward to extend to the multivariate RMA case. The performance of the Bayesian RMA approach is evaluated in the simulation study, and, finally, the proposed method is applied to analyze a dataset in the plantation.

Markov chain-based impact analysis of the pandemic Covid-19 outbreak on global primary energy consumption mix.

The historic evolution of global primary energy consumption (GPEC) mix, comprising of fossil (liquid petroleum, gaseous and coal fuels) and non-fossil (nuclear, hydro and other renewables) energy sources while highlighting the impact of the novel corona virus 2019 pandemic outbreak, has been examined through this study. GPEC data of 2005-2021 has been taken from the annually published reports by British Petroleum. The equilibrium state, a property of the classical predictive modeling based on Markov chain, is employed as an investigative tool. The pandemic outbreak has proved to be a blessing in disguise for global energy sector through, at least temporarily, reducing the burden on environment in terms of reducing demand for fossil energy sources. Some significant long term impacts of the pandemic occurred in second and third years (2021 and 2022) after its outbreak in 2019 rather than in first year (2020) like the penetration of other energy sources along with hydro and renewable ones in GPEC. Novelty of this research lies within the application of the equilibrium state feature of compositional Markov chain based prediction upon GPEC mix. The analysis into the past trends suggests the advancement towards a better global energy future comprising of cleaner fossil resources (mainly natural gas), along with nuclear, hydro and renewable ones in the long run.

Cost-effectiveness analysis of transcatheter aortic valve implantation in aortic stenosis patients at low- and intermediate-surgical risk in Japan.

OBJECTIVE: To analyze the cost-effectiveness of transcatheter aortic valve implantation (TAVI) using the SAPIEN 3 (Edwards Lifesciences, Irvine, CA) compared to surgical aortic valve replacement (SAVR) in low- and intermediate-risk patients from a Japanese public healthcare payer perspective. METHODS: A Markov model cost-effectiveness analysis was developed. Clinical and utility data were extracted from a systematic literature review. Cost inputs were obtained from analysis of the Medical Data Vision claims database and supplemented with a targeted literature search. The robustness of the results was assessed using sensitivity analyses. Scenario analyses were performed to determine the impact of lower mean age (77.5 years) and the effect of two different long-term mortality hazard ratios (TAVI versus SAVR: 0.9-1.09) on both risk-level populations. This analysis was conducted according to the guidelines for cost-effectiveness evaluation in Japan from Core 2 Health. RESULTS: In intermediate-risk patients, TAVI was a dominant procedure (TAVI had lower cost and higher effectiveness). In low-risk patients, the incremental cost effectiveness ratio (ICER) for TAVI was ¥750,417/quality-adjusted-life-years (QALY), which was below the cost-effectiveness threshold of ¥5 million/QALY. The ICER for TAVI was robust to all tested sensitivity and scenario analyses. CONCLUSIONS: TAVI was dominant and cost-effective compared to SAVR in intermediate- and low-risk patients, respectively. These results suggest that TAVI can provide meaningful value to Japanese patients relative to SAVR, at a reasonable incremental cost for patients at low surgical risk and potentially resulting in cost-savings in patients at intermediate surgical risk.

Aortic Stenosis (AS) is the most common valvular heart disease in Japan, and, if left untreated, severe symptomatic AS (sSAS) is associated with a dramatic increase in mortality and morbidity. Transcatheter Aortic Valve Implantation (TAVI) is a minimally invasive treatment option for replacing the aortic valve in patients with sSAS and has been associated with similar or better outcomes compared to Surgical Aortic Valve Replacement (SAVR), which involves open-heart surgical replacement of the aortic valve. The objective of this study was to compare the costs and health outcomes associated with TAVI compared to SAVR in Japanese patients deemed low- or intermediate-risk for surgery. Despite the expanding use of TAVI in Japan, a cost-effectiveness analysis (CEA) does not exist that evaluates the economics of TAVI with the current generation SAPIEN 3 implant in patients with low- and intermediate-risk from a public perspective. Our study suggests that TAVI represents strong value for money among low- and intermediate-risk patients in Japan: compared to SAVR, TAVI is associated with better clinical outcomes and quality of life for patients, at a reasonable additional cost for low-risk patients and at a lower cost for intermediate-risk patients.

Cost-Utility Analysis of Early Detection with Ultrasonography of Differentiated Thyroid Cancer: A Retrospective Study on a Korean Population.

BACKGRUOUND: There is debate about ultrasonography screening for thyroid cancer and its cost-effectiveness. This study aimed to evaluate the cost-effectiveness of early screening (ES) versus symptomatic detection (SD) for differentiated thyroid cancer (DTC) in Korea. METHODS: A Markov decision analysis model was constructed to compare the cost-effectiveness of ES and SD. The model considered direct medical costs, health outcomes, and different diagnostic and treatment pathways. Input data were derived from literature and Korean population studies. Incremental cost-effectiveness ratio (ICER) was calculated. Willingness-to-pay (WTP) threshold was set at USD 100,000 or 20,000 per quality-adjusted life year (QALY) gained. Sensitivity analyses were conducted to address uncertainties of the model's variables. RESULTS: In a base case scenario with 50 years of follow-up, ES was found to be cost-effective compared to SD, with an ICER of $2,852 per QALY. With WTP set at $100,000, in the case with follow-up less than 10 years, the SD was cost-effective. Sensitivity analysis showed that variables such as lobectomy probability, age, mortality, and utility scores significantly influenced the ICER. Despite variations in costs and other factors, all ICER values remained below the WTP threshold. CONCLUSION: Findings of this study indicate that ES is a cost-effective strategy for DTC screening in the Korean medical system. Early detection and subsequent lobectomy contribute to the cost-effectiveness of ES, while SD at an advanced stage makes ES more cost-effective. Expected follow-up duration should be considered to determine an optimal strategy for DTC screening.