[Digital twins in healthcare: State of the art and potential use cases in a hospital setting]. / Le jumeau numérique en santé - État des lieux et perspectives d'application à l'hôpital.

The field of modeling and simulation including digital twins (DT) is getting a lot of traction in the health sector, with various benefits being outlined. Indeed, DT are designed to support the transformation of healthcare, ranging from the medical act itself to the organization of healthcare systems and hospitals, also including medical research. However, the technology is still in its infancy and needs to be evaluated according to medical standards. First and foremost, their clinical value remains to be assessed, taking into account the limits associated with AI tools. The aim of this review is to provide an overview of the use cases being tested in hospital settings. We go back to the definition of the DT concept and provide a summary of current studies. Finally, we outline the challenges to be taken into account in order to provide a framework for the deployment of DT tools, guaranteeing the trust and safety of those involved, especially of patients.

Title: Le jumeau numérique en santé - État des lieux et perspectives d'application à l'hôpital. Abstract: La recherche et développement en santé est très dynamique dans le champ de la simulation, et de nombreux projets se réclament du jumeau numérique (JN). Les JN sont voués à accompagner la transformation du soin, qu'il s'agisse de l'acte médical, du parcours de soins ou de leur organisation. Toutefois, cette technologie est naissante et nécessite d'être évaluée. L'objectif de cette synthèse est de dresser un état des lieux des cas d'usages du JN à l'hôpital. Nous revenons sur la définition du concept de JN et proposons un condensé des études en cours. Enfin, nous rappelons l'importance de créer un cadre propice au déploiement de ces outils, garantissant la confiance et la sécurité des acteurs et des patients.

Modelling monotonic effects of ordinal predictors in Bayesian regression models.

Ordinal predictors are commonly used in regression models. They are often incorrectly treated as either nominal or metric, thus under- or overestimating the information contained. Such practices may lead to worse inference and predictions compared to methods which are specifically designed for this purpose. We propose a new method for modelling ordinal predictors that applies in situations in which it is reasonable to assume their effects to be monotonic. The parameterization of such monotonic effects is realized in terms of a scale parameter b representing the direction and size of the effect and a simplex parameter ς modelling the normalized differences between categories. This ensures that predictions increase or decrease monotonically, while changes between adjacent categories may vary across categories. This formulation generalizes to interaction terms as well as multilevel structures. Monotonic effects may be applied not only to ordinal predictors, but also to other discrete variables for which a monotonic relationship is plausible. In simulation studies we show that the model is well calibrated and, if there is monotonicity present, exhibits predictive performance similar to or even better than other approaches designed to handle ordinal predictors. Using Stan, we developed a Bayesian estimation method for monotonic effects which allows us to incorporate prior information and to check the assumption of monotonicity. We have implemented this method in the R package brms, so that fitting monotonic effects in a fully Bayesian framework is now straightforward.

Meta-analytic estimation of measurement variability and assessment of its impact on decision-making: the case of perioperative haemoglobin concentration monitoring.

BACKGROUND: As a part of a larger Health Technology Assessment (HTA), the measurement error of a device used to monitor the hemoglobin concentration of a patient undergoing surgery, as well as its decision consequences, were to be estimated from published data. METHODS: A Bayesian hierarchical model of measurement error, allowing the meta-analytic estimation of both central and dispersion parameters (under the assumption of normality of measurement errors) is proposed and applied to published data; the resulting potential decision errors are deduced from this estimation. The same method is used to assess the impact of an initial calibration. RESULTS: The posterior distributions are summarized as mean ± sd (credible interval). The fitted model exhibits a modest mean expected error (0.24 ± 0.73 (-1.23 1.59) g/dL) and a large variability (mean absolute expected error 1.18 ± 0.92 (0.05 3.36) g/dL). The initial calibration modifies the bias (-0.20 ± 0.87 (-1.99 1.49) g/dL), but the variability remains almost as large (mean absolute expected error 1.05 ± 0.87 (0.04 3.21) g/dL). This entails a potential decision error ("false positive" or "false negative") for about one patient out of seven. CONCLUSIONS: The proposed hierarchical model allows the estimation of the variability from published aggregates, and allows the modeling of the consequences of this variability in terms of decision errors. For the device under assessment, these potential decision errors are clinically problematic.

Randomized Clinical Trial of Intraosseous Methylprednisolone Injection for Acute Pulpitis Pain.

INTRODUCTION: The present study reports the results of a randomized clinical trial comparing local intraosseous methylprednisolone injection and emergency pulpotomy in the management of acute pulpitis on efficacy, safety, and efficiency end points. METHODS: After providing prior informed written consent, 94 patients consulting for acute irreversible pulpitis pain at university-affiliated teaching hospital dental clinics in Dakar, Senegal were randomly assigned to either the methylprednisolone treatment group (n = 47) or the pulpotomy treatment group (n = 47). Patients were followed up at 1 week and assessed 6 months later to evaluate the therapeutic outcome of their treatment. RESULTS: At day 7 the patients in the methylprednisolone group reported less intense spontaneous and percussion pain in the day 0-day 7 period than the patients in the pulpotomy group. Methylprednisolone treatment took approximately 7 minutes (4.6-9.3) less to accomplish than pulpotomy (or about half the time). No difference in the therapeutic outcome was found between the 2 treatment groups at 6 months (all credible intervals span 0). CONCLUSIONS: This study establishes that methylprednisolone injection for acute pulpitis is relieved by a minimally invasive pharmacologic approach more effectively than by the reference pulpotomy and conserves scarce dental resources (ie, endodontic equipment and supplies, dental surgeon's time).

Fully bioresorbable drug-eluting coronary scaffolds: A review.

Following the development of stents, then drug-eluting stents (DES), bioresorbable scaffolds are proposed as a third evolution in coronary angioplasty, aiming to reduce the incidence of restenosis and stent thrombosis and to restore vascular physiology. At least 16 such devices are currently under development, but published clinical data were available for only three of them in September 2014. The first device is Abbott's BVS(®), a poly-L-lactic acid (PLLA)-based everolimus-eluting device, which has been tested in a registry and two non-randomized trials. Clinical results seem close to what is expected from a modern DES, but possibly with more post-procedural side-effects. Two randomized trials versus DES are underway. This device is already marketed in many European countries. The second device is Elixir's DESolve(®), a PLLA-based novolimus-eluting device, which has been evaluated in two single-arm trials. Results are not widely different from those expected from a DES. The third device is Biotronik's DREAMS(®), a metallic magnesium-based paclitaxel-eluting device, which has been assessed in an encouraging single-arm trial; its second version is currently undergoing evaluation in a single-arm trial. The available results suggest that the technological and clinical development of bioresorbable scaffolds is not yet complete: their possible clinical benefits are still unclear compared with third-generation DES; the impact of arterial physiology restoration has to be assessed over the long term; and their cost-effectiveness has to be established. From the perspective of a health technology assessment, there is no compelling reason to hasten the clinical use of these devices before the results of ongoing randomized controlled trials become available.

Clinical study evaluating the effect of bevacizumab on the severity of zoledronic acid-related osteonecrosis of the jaw in cancer patients.

This study aimed to evaluate the effect of bevacizumab (BVZ) on the severity of osteonecrosis of the jaw (ONJ) in a cohort of cancer patients treated with intravenous zoledronic acid (ZA). We reviewed 42 oncologic patients with ONJ between 2007 and 2010. Only patients with solids tumors and who had received ZA were included. Data analyses included age, sex, underlying disease, ZA and BVZ dosages, dental history and ONJ characteristics. Of the 42 ONJ patients treated with ZA, 10 also received BVZ. In the 10 ZA/BVZ patients, the mean duration of ZA treatment at the time of ONJ diagnosis was 12.4 months (±6.8), compared to 22.9 months (±4.8) in the 32 patients who received ZA only (p<0.05). Cox's model analysis of the delay to ONJ diagnosis confirmed the impact of BVZ on ONJ diagnosis. In the ZA/BVZ-treated group, 7 (70%) patients developed spontaneous osteonecrosis. Multiple logistic regression analysis showed that ZA/BVZ is associated with increased risk of developing spontaneous ONJ (OR 6.07; 95% CI, [1.3-28.2], p<0.05). And finally, the number of ONJ lesions was increased in the ZA/BVZ-treated group compared to the ZA group (p<0.01). Other clinical conditions as type of tumor (prostate, breast…), cancer severity or other chemotherapy drugs also could be involved in ONJ evolution. However, this study demonstrates for the first time the potential negative influence of BVZ on the incidence and severity of ONJ in patients receiving ZA. Within the study limits, our results suggest that combination ZA/BVZ treatment may possibly predispose to the development of spontaneous and earlier ONJ.

Post-orthodontic intra- and interarch changes at 1 year: a retrospective study assessing the impact of anterior fixed retention.

OBJECTIVES: The aim of this study is to evaluate intra- and interarch changes over the year following active treatment appliance removal, and to analyze the impact of anterior fixed retention on these changes. PATIENTS AND METHODS: This study is based on casts taken at appliance removal (T1) and one year after removal (T2) in two groups of 15 privately-treated adolescent patients. One group received anterior fixed retention (G2), and the other did not (G1). We applied the seven criteria of the American Board of Orthodontics Objective Grading System: alignment (anterior/posterior), vertical positioning of the posterior marginal ridges, interproximal contacts, buccolingual inclination of the posterior teeth, posterior occlusal contacts, sagittal occlusal relationships, and overjet (anterior/posterior). RESULTS: G1 and G2 together showed significant improvement in occlusal contacts, interproximal contacts, marginal ridges, and maxillary posterior alignment, but also a deterioration in anterior alignment, anterior overjet, and sagittal occlusal relationships. However, significant differences were found between the two groups, notably in terms of anterior alignment, which deteriorated more in G1. CONCLUSION: The relapse observed in anterior overjet and sagittal relationships seems independent of the retention modality, whereas the deterioration in anterior alignment was specific to the group without fixed retention. At the same time, there were spontaneous adjustments in posterior occlusion, favorable to treatment stability.