Development of a dynamic interactive web tool to enhance understanding of multi-state model analyses: MSMplus

Background Multi-state models are used in complex disease pathways to describe a process where an individual moves from one state to the next, taking into account competing states during each transition. In a multi-state setting, there are various measures to be estimated that are of great epidemiological importance. However, increased complexity of the multi-state setting and predictions over time for individuals with different covariate patterns may lead to increased difficulty in communicating the estimated measures. The need for easy and meaningful communication of the analysis results motivated the development of a web tool to address these issues. Results MSMplus is a publicly available web tool, developed via the Shiny R package, with the aim of enhancing the understanding of multi-state model analyses results. The results from any multi-state model analysis are uploaded to the application in a pre-specified format. Through a variety of user-tailored interactive graphs, the application contributes to an improvement in communication, reporting and interpretation of multi-state analysis results as well as comparison between different approaches. The predicted measures that can be supported by MSMplus include, among others, the transition probabilities, the transition intensity rates, the length of stay in each state, the probability of ever visiting a state and user defined measures. Representation of differences, ratios and confidence intervals of the aforementioned measures are also supported. MSMplus is a useful tool that enhances communication and understanding of multi-state model analyses results. Conclusions Further use and development of web tools should be encouraged in the future as a means to communicate scientific research.

Development of a dynamic interactive web tool to enhance understanding of multi-state model analyses: MSMplus

Background: Multi-state models are used in complex disease pathways to describe a process where an individual moves from one state to the next, taking into account competing states during each transition. In a multi-state setting, there are various measures to be estimated that are of great epidemiological importance. However, increased complexity of the multi-state setting and predictions over time for individuals with different covariate patterns may lead to increased difficulty in communicating the estimated measures. The need for easy and meaningful communication of the analysis results motivated the development of a web tool to address these issues. Results: MSMplus is a publicly available web tool, developed in RShiny, with the aim of enhancing the understanding of multi-state model analyses results. The results from any multi-state model analysis are uploaded to the application in a pre-specified format. Through a variety of user-tailored interactive graphs, the application contributes to an improvement in communication, reporting and interpretation of multi-state analysis results as well as comparison between different approaches. The predicted measures that can be supported by MSMplus include, among others, the transition probabilities, the transition intensity rates, the length of stay in each state, the probability of ever visiting a state and user defined measures. Representation of differences, ratios and confidence intervals of the aforementioned measures are also supported. MSMplus is a useful tool that enhances communication and understanding of multi-state model analyses results. Conclusions: Further use and development of web tools should be encouraged in the future as a means to communicate scientific research.

New Europium(III)-TTA Complex Containing 2-Pyrrolidone as Coligand to Application as Luminescent Sensor: PbII and Ethanol in Gasoline

This work describes the synthesis and application of an europium(III) complex, [Eu(TTA)3(2-pyr)(H2O)], containing 2-thenoyltrifluoroacetonate (TTA) and 2-pyrrolidone (2-pyr) as ligands, obtained as white solid and soluble in ethanol. In solution, the complex showed red emission, characteristic of the EuIII emission in the solid state (λexc = 375 nm and λem = 612 nm). The complex was tested with PbII, CdII, and HgII ions in water. The effect of metal ions was monitored and evaluated by hypersensitive transition 5D0 → 7F2 (612 nm). The results show that PbII suppresses the complex luminescence and present high sensitivity, according to the values for the Stern-Volmer constant (KSV = 2300 L mol-1), showing good linearity, i.e., determination coefficient (R2) of 0.9913, and low limit of detection (LOD = 6.03 µM). Luminescence quenching increased with the increasing concentration of PbII. These results indicate that the synthesized complex is a potential luminescent sensor for detecting PbII in a simple and fast way, being applicable for routine environmental analysis. When applied as an ethanol sensor in gasoline, the complex hypersensitive transition intensity decreased with the increasing volume of ethanol in gasoline, reaching the values of R2 = 0.9815 and LOD = 4.94% v/v.

Abstract 284: Looking Back to Glance Ahead: The Impact of Last Minute's Qrs Width & Frequency in Pulseless Electrical Activity

Background: Observed heart rate and QRS-width during CPR in Pulseless Electrical Activity (PEA) develop differently in patients who gain ROSC compared to those who do not. In this study we investigated the impact of heart rate and QRS width on the transition from PEA to ROSC. Method: Defibrillator data from 293 episodes of cardiac arrest at two US and one Norwegian hospital were reviewed. The files contained ECG, impedance signal and compression depth. In total 178 episodes containing PEA intervals were included. Episodes with excessive ECG noise and signs of an active pacemaker were excluded. The files were processed in a MATLAB graphical application, and the clinical states were determined based on clinical documentation and the visual appearance of the ECG. ROSC was defined as an organized rhythm lasting longer than 1 minute without ongoing compressions. During pauses in compressions, heart rate and QRS-width was automatically measured and averaged over the preceding minute until current time and controlled and corrected manually. The results were analyzed using Aalen’s additive model for time-to-event data, using R version 3.6.3. Results: The average transition intensity, corresponding to the probability of gaining ROSC in one minute, was about 0.20 per min of CPR peaking at approximately 7 min. An increase in the average heart rate by 10/min increased the transition intensity by 0.03/min (p <0.01). Narrowing of the QRS in average by 100 milliseconds (ms) increased the transition intensity by 0.14/min (p <0.01). Our figure shows QRS width and heart rate for one patient with PEA approaching ROSC (gray area), with smoothed curves overlaid. Conclusion: Higher heart rates and narrower QRS complexes during PEA are strongly and significantly associated with a transition from PEA to ROSC. These changes could indicate whether a patient responds to ongoing CPR. In addition, there is a potential for predicting the immediate outcome based on these ECG characteristics.

Abstract 157: Multicenter Evaluation of Etiology and Observed Transition Intensities Between Pulseless Electrical Activity and Return of Spontaneous Circulation

Background: Cardiac arrest presents with one of three clinical states; Cardiac standstill (asystole), Pulseless Electrical Activity (PEA), or ventricular fibrillation/tachycardia (VF/VT). PEA results from multiple etiologies and accounts for most in-hospital cardiac arrests. We quantified the dynamic nature of transitions in and out of PEA, in terms of hospital sites and presumed etiology. Methods: We analyzed 538 episodes of cardiac arrest at one Norwegian hospital and three U.S. hospitals. ECG, chest compressions and ventilations were recorded by defibrillators during CPR. Each event was assessed using a graphical application. We quantified the transition intensity, i.e. the immediate probability of a transition given the current state, between PEA and ROSC using Aalen’s additive model for time-to-event data. Results: The overall transition intensity from PEA to ROSC was about 0.10 min -1 , so an average patient in PEA has about 10 % chance to gain ROSC the following 1 minute. The intensity peaked at 7 minutes of CPR (Figure), with some heterogeneity between hospitals (0.07 to 0.11 min -1 ). The reverse transition intensity from ROSC to PEA was rather constant at 0.10 min -1 (range 0.05-0.11). Information regarding assumed cardiac or non-cardiac etiology was available in 208 episodes (123 cardiac). Patients with a cardiac etiology had a marginally smaller (-0.03 min -1 ) chance of making the transition from PEA to ROSC (p=0.049), but etiology did not impact on the ROSC to PEA transition (p=0.39). Discussion: For transitions between PEA and ROSC we observed an overall intensity of 0.1 min -1 , with some hospital heterogeneity. This may be due to heterogeneity in the underlying patient populations. We found the probability of transitioning from PEA to ROSC to increase from the start event recording until an average peak intensity at 7 minutes. This information may increase the clinicians’ understanding of the process from PEA to ROSC.

Modeling effects of banking regulations and supervisory practices on capital adequacy state transition in developing countries

Purpose The FDIC Improvement Act of 1991 sets out five categories of capital and mandates corrective action for banks. Each bank based on its capital amount fall in the certain categories or states. The purpose of this paper is to consider the effect of banking regulations and supervisory practices on capital state transition. Design/methodology/approach First, the authors investigate how much the practices influence banks' capital adequacy using a dynamic panel data method, the generalized method of moments. Then, to scrutinize the results of the first phase, the authors estimate the effect of practices on some characteristics of capital state transition such as transition intensity, transition probability and state sojourn time using multi-state models for panel data in 107 developing countries over the period 2000 to 2012. Findings The dynamic regression results show that capital guidelines, supervisory power and supervisory structure can have significantly positive effects on the capital adequacy state. Moreover, the multi-state Markov panel data model estimation results show that the significantly positive-effect practices can change the capital state transition intensity considerably; for example, they can transmit the critical-under-capitalized (the lowest) capital state of banks directly to a well or the adequate-capitalized (the highest) capital state without passing through middle states (under-capitalized and significantly-undercapitalized). Moreover, the results present some new evidence on transition probability and state sojourn time. Originality/value The main contribution of this paper, unlike the existing literature, is to consider the power of banking regulations and supervisory practices to improve the capital state using a multi-state Markov panel data model.

EFFORT EXPENDITURE FOR CASH FLOW IN A MEAN-FIELD EQUILIBRIUM

We study a mean-field game framework in which agents expend costly effort in order to transition into a state where they receive cash flows. As more agents transition into the cash flow receiving state, the magnitude of all remaining cash flows decreases, introducing an element of competition whereby agents are rewarded for transitioning earlier. An equilibrium is reached if the optimal expenditure of effort produces a transition intensity which is equal to the flow rate at which the continuous population enters the receiving state. We give closed-form expressions which yield equilibrium when the cash flow horizon is infinite or exponentially distributed. When the cash flow horizon is finite, we implement an algorithm which yields equilibrium if it converges. We show that in some cases, a higher cost of effort results in the agents placing greater value on the potential cash flows in equilibrium. We also present cases where the algorithm fails to converge to an equilibrium.