Modelling syllepse in medical knowledge bases with application in the domain of organ failure and transplantation

Abstract. The Etablissement français des Greffes (EfG) is a public health agency in charge of organs, tissues and cells transplantation in France. Among EfG's missions is the evaluation of the organ retrieval and transplantation activities, which relies on a national information system (IS). In order to facilitate data recording, to improve information quality and homogeneity, to allow data interchange and semantic interoperability with hospital information systems and other registries, a specific work as been initiated dealing with ontological foundations of medical terminology in the domain of organ failure and transplantation. The aim of this paper is to describe how the syllepse appeared to us as a key figure that accounts for medical knowledge acquisition.

Toward Organ Shortage Resilient Allocation Policies Using Real-Time Queueing Models For Liver Transplantation

We report in this paper on the potential interest of real-time queueing models to optimize organ allocation policies. We especially focus on building organ shortage resilient policies in terms of equity, as we experienced differential impact of the COVID epidemic organ shortage on transplant access, according to the cause of liver failure. Patient's death on the waiting list or dropout for being too sick, resulting from the absence of a timely available organ, is chosen as the main equity metric. Results obtained with the composite allocation score used in France is challenged against the so-called Early Simulated Deadline First (ESDF) real-time queueing discipline, under increasing levels of organ shortage, by extensive simulations. The ESDF policy is a variant of the well-know Earliest Deadline First (EDF) policy, which was shown as optimal in various contexts in the queueing literature. In the present case, the time to the deadline represents the remaining life duration of patients-which is of course unknown. So we propose to simulate a fictional life-duration, and give priority to the earliest simulated deadline. This leads to a simple and comprehensive representation of the system at hand by a Markov process. Our simulation results clearly show that the ESDF policy allows to maintain equity between indications, conversely to the scoring policy, which was not resilient to increasing levels of organ shortage

Toward Organ Shortage Resilient Allocation Policies Using Real-Time Queueing Models For Liver Transplantation

We report in this paper on the potential interest of real-time queueing models to optimize organ allocation policies. We especially focus on building organ shortage resilient policies in terms of equity, as we experienced differential impact of the COVID epidemic organ shortage on transplant access, according to the cause of liver failure. Patient's death on the waiting list or dropout for being too sick, resulting from the absence of a timely available organ, is chosen as the main equity metric. Results obtained with the composite allocation score used in France is challenged against the so-called Early Simulated Deadline First (ESDF) real-time queueing discipline, under increasing levels of organ shortage, by extensive simulations. The ESDF policy is a variant of the well-know Earliest Deadline First (EDF) policy, which was shown as optimal in various contexts in the queueing literature. In the present case, the time to the deadline represents the remaining life duration of patients-which is of course unknown. So we propose to simulate a fictional life-duration, and give priority to the earliest simulated deadline. This leads to a simple and comprehensive representation of the system at hand by a Markov process. Our simulation results clearly show that the ESDF policy allows to maintain equity between indications, conversely to the scoring policy, which was not resilient to increasing levels of organ shortage

The essential of 2012 results from the French Renal Epidemiology and Information Network (REIN) ESRD registry

International audienceThe French Renal Epidemiology and Information Network (REIN) registry began in 2002 to provide a tool for public health decision support, evaluation and research related to renal replacement therapies (RRT) for end-stage renal disease (ESRD). It is relying on a network of nephrologists, epidemiologists, patients and public health representatives. Continuous registration covers all dialysis and transplanted patients. In 2012, in France, 10,048 patients started a RRT (154 per million inhabitants). Elders provided majority of new patients (median age at RRT start: 70 years old). New patients had a high and age increasing rate of comorbidities, especially diabetes (42% of the new patients) and cardiovascular comorbidities (>50% of the new patients). Like previous years, incidence is stabilized. On December 31, 2012, 73,491 patients were receiving a RRT in France (1127 per million inhabitants, 56% on dialysis and 44% living with a functional renal transplant). More than 50% of patients were undergoing in-center hemodialysis with significant variations among regions. An increase in medical satellite unit hemodialysis but a decrease in self-care unit hemodialysis rates were noticed across the time, whereas peritoneal dialysis remained stable at 7%. Five years after starting RRT, the overall survival rate was 51% but only 16% among patients over 85 years. Mortality rate was highly dependent on treatment and age; transplanted patients aged 60-69 had a 27/1000 patients-year mortality rate versus 133 for a dialysis patient. Patients who started dialysis had a probability of first wait-listing of 4.8% at the start of dialysis (pre-emptive registrations) and 27% at 72 months. Whatever their diabetes status was, patients older than 60 had poor access to the waiting list. Seventeen percent of the patients received a first renal transplant within 15.4 month median time; 3% had received a pre-emptive graft. Ten years after the start of the French ESRD registry, this report provides a comprehensive and nation-wide overview of dialysis and transplantation cares in France, including overseas

Day-time declamping is associated with better outcomes in kidney transplantation: the circarein study

International audienceDespite improvements in organ preservation techniques and efforts to minimize the duration of cold ischemia, ischemia–reperfusion (IR) injury remains associated with poor graft function and long-term survival in kidney transplantation. We recently demonstrated a clinically significant day-time variation in myocardial tolerance to IR, transcriptionally orchestrated by the circadian clock. Patient and graft post-transplant survival were studied in a cohort of 10,291 patients first transplanted between 2006 and 2017 to test whether kidney graft tolerance to IR depends on the time-of-the-day of clamping/declamping, and thus impacts graft and patient survival. Post-transplant 1- and 3-year survival decreased with increasing ischemia duration. Time-of-the-day of clamping did not influence outcomes. However, night-time (vs. day-time) declamping was associated with a significantly worse post-transplant survival. After adjustment for other predictors, night-time (vs. day-time) declamping remained associated with a worse 1-year (HR = 1.26 (1.08–1.47), p = 0.0028 by Cox multivariable analysis) and 3-year (HR = 1.14 (1.02–1.27), p = 0.021) outcome. Interestingly, the deleterious impact of prolonged ischemia time (>15 h) was partially compensated by day-time (vs. night-time) declamping. Compared to night-time declamping, day-time declamping was associated with a better prognosis of kidney transplantation despite a longer duration of cold ischemia

Comparaison de deux enquêtes nationales sur la qualité de vie des patients atteints d’insuffisance rénale chronique terminale entre 2005–2007 et 2011 : des indicateurs sensiblement en baisse

International audienceBACKGROUND:The Epidemiology Network and Nephrology Information provides since 2001 the epidemiological monitoring of end stage renal disease (ESRD) in France. Two cross-sectional studies to estimate the level of quality of life in ESRD patients were performed in 2005 and 2007 and repeated in 2011. The main objective is to analyze the evolution of the quality of life of ESRD between these two surveys.METHODS:The studies were conducted on a representative sample of subjects aged 18 and over, prevalent dialysis or holders of a functioning kidney transplant last year, followed in center dialysis and/or transplantation in one of the eight French regions selected. The quality of life was measured by a generic questionnaire, and two specifics questionnaires.RESULTS:The evolution of the quality of life deteriorated slightly between 2005-2007 and 2011. There is however few dimensions affected. The variation in scores is not meaningful in general, with maximum decreases less than 4 points according to the statistical methods used. This diminution is not clinically significant.DISCUSSION:The quality of life in dialysis patients or transplant did not evolve between 2005-2007 and 2011. Currently, it is difficult to assess the benefits of the national plan for improving the quality of life of people with chronic diseases because the last data are too close to the end of the plan.IntroductionLe réseau épidémiologie et information en néphrologie (REIN) assure depuis 2001 le suivi épidémiologique et la prise en charge de l’insuffisance rénale chronique terminale (IRCT) en France. La connaissance d’indicateurs de qualité de vie (QDV) relative à la santé est capitale afin de mieux comprendre les domaines touchés par la maladie et ainsi proposer des actions appropriées visant à mieux vivre avec sa pathologie. Dans ce contexte, deux études transversales visant à estimer le niveau de QDV liée à la santé des patients en IRCT ont été mises en place en 2005 (enquête dialyse) et 2007 (enquête greffe) sur un échantillon de patients français, puis reconduites en 2011. L’objectif de cet article est de comparer ces deux enquêtes et d’analyser l’évolution de la qualité de vie des patients atteints d’IRCT entre ces deux enquêtes.MéthodesLes études ont été réalisées sur un échantillon représentatif de sujets âgés de 18 ans et plus, prévalents dialysés (quelles que soient les modalités de dialyse) ou porteurs d’un greffon rénal fonctionnel depuis un an, suivis dans un centre de dialyse et/ou de transplantation dans l’une des huit régions françaises sélectionnées. Le recueil des données a été réalisé par auto-questionnaire adressé par voie postale au domicile des patients. La qualité de vie (QDV) a été mesurée par un questionnaire générique, le MOS SF-36 et deux questionnaires spécifiques : le Kidney Disease Quality of Life (KDQOL) version courte pour les dialysés et le ReTransQol V2 (RTQ V2) pour les patients greffés. L’évolution des scores a été réalisée par des analyses multivariées, le calcul d’un score de propension et de pondération afin de prendre en compte les différences de profil des patients entre les périodes d’enquêtes.RésultatsLa QDV s’est légèrement dégradée entre 2005–2007 et 2011, et ce, quel que soit le questionnaire utilisé (générique ou spécifique). Il n’y a cependant que peu de dimensions affectées, avec 2 ou 3 domaines par outils de mesure. Pour le SF-36, ce sont les dimensions « santé générale », « douleurs physiques » ainsi que « vie et relation avec les autres » qui diminuent de manière significative (−3,2, −3,7 et −3,8 points). Pour les questionnaires spécifiques, la dimension « traitement » du RTQ V2 est la plus affectée (−2,5 points), ainsi que la dimension « symptôme/problèmes » du KDQOL (−2,4 points). La variation des scores de QDV est peu signifiante dans l’ensemble, allant de −1,6 point à −3,8 points pour la plus forte baisse, selon les méthodes statistiques utilisées. Cette diminution reste toujours inférieure au seuil des 5 points considérés comme cliniquement signifiant.DiscussionLa qualité de vie chez les patients dialysés ou greffés s’est légèrement dégradée entre 2005–2007 et 2011. Le recueil des dernières données de notre étude ayant été réalisé dès la fin du plan pour l’amélioration de la qualité de vie des personnes atteintes de maladies chroniques 2005–2011, le bénéfice du plan paraît donc difficile à évaluer dans sa globalité

Organ procurement and transplantation during the COVID-19 pandemic

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Effects of the dialysate calcium concentrations and mineral bone disease treatments on mortality in The French Renal Epidemiology and Information Network (REIN) registry

International audienceBackground: In patients on hemodialysis (HD), the various chemical elements in the dialysate may influence survival rates. In particular, calcium modifies mineral and bone metabolism and the vascular calcification rate. We studied the influence of the dialysate calcium concentration and the treatments prescribed for mineral bone disease (MBD) on survival.Methods: All patients in REIN having initiated HD from 2010 to 2013 were classified according to their exposure to the different dialysate calcium concentrations in their dialysis unit. Data on the individual patients' treatments for MBD were extracted from the French national health database. Cox proportional hazard models were used to estimate mortality hazard ratios (HR) associated with time-dependent exposure to dialysate calcium concentrations and MBD therapies, adjusted for comorbidities, laboratory and technical data.Results: Dialysate calcium concentration of 1.5 mmol/L was used by 81% of the dialysis centers in 2010 and in 83% in 2014. Most centers were using several formulas in up to 78% for 3 formulas in 2010 to 86% in 2014. In full adjusted Cox survival analyses, the percentage of calcium >1.5 mmol/L and <1.5 mmol/l by center and the number of formula used per center were not associated with survival. Depending on the daily dose used, the MBD therapies were associated with survival improvement for calcium, native vitamin D, active vitamin D, sevelamer, lanthanum and cinacalcet in the second and third tertiles of dose.Conclusion: No influence of the dialysate calcium concentration was evidenced on survival whereas all MBD therapies were associated with a survival improvement depending on the daily dose used