Prediction model building and evaluation : study of utilities

La médecine est demandeuse de prédictions. Cette question de la prédiction se pose à différents moments de la prise en charge du patient, au moment du diagnostic, au moment de l'évaluation du pronostic et au moment du suivi, pour prendre les meilleures décisions possibles en termes de choix d'examens complémentaires et de choix de thérapeutique. La prédiction permet d'apporter une information au médecin et au patient pour prendre la décision. Pour construire ces modèles de prédiction, on dispose de bases de données qui nous permettent d'évaluer l'association entre des données cliniques ou biologiques et la probabilité de survenue d'un évènement. Pour quantifier ces associations, on utilise des modèles de régression logistique qui sont estimés d'après la méthode du maximum de vraisemblance. Pour évaluer ces modèles, on dispose de différents critères, qui quantifient leur adéquation, leur capacité de discrimination, leur calibration. Ces modèles vont nous permettre de prendre une décision. Les erreurs de prédiction vont mener à des erreurs de décision. Les conséquences de ces décisions sont quantifiables grâce à la théorie des utilités. C'est donc un critère quantifiant l'utilité du modèle qui nous permet de choisir le modèle le plus utile. La construction de modèles de prédiction est particulièrement importante dans le domaine clinique de l'obstétrique. En effet, il est important dans le cas des hémorragies de la délivrance de prévenir l'aggravation de la situation, et donc de distinguer les patientes qui vont s'aggraver très rapidement. Le taux de fibrinogène a été étudié, comme prédicteur d'une évolution grave de l'hémorragie. Les variables cliniques disponibles au moment du diagnostic ont ensuite été étudiées. Dans la situation de la rupture prématurée des membranes, il existe un choix à faire entre deux décisions qui induisent une morbidité néonatale et maternelle : la naissance prématurée et le risque de chorioamniotite. Des marqueurs du risque de chorioamniotite pourraient donc faciliter la prise de décision en augmentant l'information pour le clinicien. De plus en plus de modèles de prédiction sont développés dans toutes les situations cliniques. Il faut rester critique vis-à-vis de ces modèles. Leur évaluation doit tenir compte de leur utilisation, et doit donc tenir compte de leur utilité en situation de prise de décisionMedicine asks for prediction. Prediction is needed at different point in the management of a patient. To take the best decision as possible for complementary exams, or therapeutics. Prediction gives an information to the practitioner and the patient, to take a decision. To build these prediction models, we have data bases. The association between clinical or biological data and the outcome probability can be estimated thanks to these data bases. To measure these associations, logistic regression models are used. They are estimated with maximum likelihood method. To evaluate these models, different criteria exist. These criteria quantify adequacy, discrimination capacity, calibration. These models help to take a decision. Prediction errors lead to decision errors. Consequences of these decisions are measurable with utility theory. Therefore, it is a criteria that measure utility of a model that enables us to select the most useful model. Prediction model building is an important point in obstetrics. Indeed, in case of postpartum haemorrhage, it is important to prevent worsening of the clinical situation, and therefore, to identify patient who will worsen fastly. Fibrinogen level was studied as a predictor of severe postpartum haemorrhage. Clinical variables availables at diagnosis of postpartum haemorrhage was then studied. In case of preterm premature rupture of membranes, there is a decision to take, between two choices that may lead to maternal of neonatal morbidity: preterm birth and chorioamnionitis risk with pregnancy continuation. Markers of chorioamnionitis risk may help the practitioners for decision making, by increasing the information. More and more prediction models are developed in all clinical situations. We must be critical before using these models in real life. Their evaluation must take into account their use, and therefore, their utility in case of decision makin

Facteurs cliniques et biologiques associés à la chorioamniotite histologique dans les ruptures prématurées des membranes

Objectif : identifier la meilleure combinaison de variables biologiques et cliniques associées à la chorioamniotite histologique dans les ruptures prématurées des membranes. Schéma d'études : étude descriptive prospective multicentrique menée entre 2007 et 2009 dans six maternités françaises. Population : toutes les patientes avec rupture prématurée des membranes confirmée entre 24 et 37 semaines d'aménorrhée (SA). Méthode : Les patientes et les nouveau-nés ont été inclus prospectivement. Les patientes ont été suivies jusqu'à la sortie de la maternité et les nouveau-nés de leur naissance à la sortie du service de néonatalogie. Les échantillons sanguins maternels ont été prélevés toutes les 48 heures de l'inclusion à l'accouchement. Les placentas ont été analysés en anatomo-pathologie. Les associations entre la chorioamniotite histologique et les variables cliniques et biologiques ont été étudiées une par une puis des modèles logistiques multivariés ont été estimés. Les modèles de régression logistiques ainsi obtenus ont été étudiés et comparés selon leurs aires sous la courbe ROC (receiver operator characteristic) et selon les tests du rapport de vraisemblance. Leurs sensibilités, spécificités et valeurs prédictives pour la chorioamniotite histologique ont également été estimées. Résultats : l'analyse a inclus 295 patientes, 126 (42,7%) d'entre elles présentaient une chorioamniotite histologique. En analyse univariée, les variables suivantes étaient statistiquement associées à la chorioamniotite histologique : C-reactive protein (CRP), leucocytémie, Interleukine 6 (IL-6), Matrix metalloprotease 8 (MMP-8), MMP-9 et Human Neutrophile peptide (HNP), ainsi que les variables cliniques suivantes : contractions utérines, tachycardie fœtale, aspect du liquide amniotique. La CRP augmentait significativement la vraisemblance et l'aire sous la courbe ROC du modèle de prédiction classique (qui inclut la leucocytémie, les contractions utérines, la tachycardie fœtale et maternelle et l'aspect du liquide amniotique) : les aires sous la courbe étaient respectivement de 0,78[0,73-0,85] et 0,71[0,64-0,78], p<0,01. IL-6, MMP-8, MMP-9 et HNP n'augmentaient pas la vraisemblance du modèle. Conclusion : le modèle développé était un bon prédicteur de la chorioamniotite histologique. La CRP améliorait significativement la prédiction de la chorioamniotite histologique dans les ruptures prématurées des membranes par rapport aux variables cliniques associées à la leucocytémieLYON1-BU Santé (693882101) / SudocSudocFranceF

OSCEs for ranking medical students

International audienc

Evaluation of an e-learning program for the diagnosis of rectosigmoid endometriosis with rectal water contrast transvaginal ultrasonography (rectosonography)

International audienceThis study aimed to evaluate the value of an e-learning program for the diagnosis of rectosigmoid endometriosis lesions using rectal water contrast transvaginal ultrasonography (rectosonography/RSG). Theoretical RSG training using videos with a commentary was offered online to healthcare professionals involved in ultrasound screening for endometriosis. A test (without correction) with 24 RSG video loops was used to assess the participants' baseline level before the training and their improvement afterwards. If the success rate post-training was below 80%, the participant could start over with another series of 24 videos. Between February and June 2020, thirty participants took the training course (of which 80% were obstetrics-gynaecology residents). The e-learning program resulted in a significant performance increase in the diagnosis of rectosigmoid endometriosis lesions, with a higher test success rate after the training compared to before (74.4% and 63.6% respectively; +10.8%; 95% CI [6,6; 15]; p< 0.001). Significant improvement was also observed regarding the overall skills involved in the ultrasound diagnosis of deep infiltrating endometriosis (+9.2%; p< 0.001), the accurate diagnosis of the height of bowel lesions (+14.7%; p< 0.001) and uterosacral ligament lesions (+8%; p< 0.005). In conclusion, our e-learning program led to a significant improvement of the diagnostic performance of digestive endometriosis using transvaginal ultrasound with intrarectal water contrast (rectosonography). Adding feedback to the post-test video loops could further increase the efficacy of the e-learning training

Methods and Designs of Modern Breast Cancer Confirmatory Trials

Background: The benefit–risk assessments of new drugs for breast cancer (BC) face several challenges, as all stakeholders do not agree on the evidence bar required for market authorization, and by the fragmentation of breast cancer diagnosis. The aim of this study was to describe the changes in methods and designs of breast cancer confirmatory trials. Methods: All phase III randomized trials published between 2001 and 2020 and assessing systemic BC therapies were included. Trials’ main characteristics, endpoints, and statistical methods were collected using a standardized data extraction form. Results: A total of 347 randomized controlled trials (RCTs) met the inclusion criteria. While most older trials (79%) included all subtypes of breast cancer, most recent trials populations were limited to one large intrinsic BC subgroup (69%). The use of gatekeeping testing strategies increased dramatically from 9% to 71%. The use of overall survival (OS) as an endpoint in the trials increased over time, but its use as a primary endpoint remained infrequent. The inclusion of OS testing in a hierarchical sequence in case of positive testing of a tumor-centered or composite endpoint appeared to have become the new standard. Conclusion: Our findings indicate some improvements in the quality of the evidence-base supporting new breast cancer drugs. The rigorous assessment of patient-relevant endpoints has increased over time, but this improvement is mainly related to the analysis of OS as a secondary endpoint analyzed in a hierarchical sequence

Trends in molecular subtypes of breast cancer: description of incidence rates between 2007 and 2012 from three French registries

Abstract Background The incidence and incidence trends of breast cancer according to molecular subtype are unknown at a population level in France. The registry data enables this study and may give this information, that is crucial to describe and understand breast cancer epidemiology. Methods We estimated the incidence rates of breast cancer for each molecular subtype using data from three cancer registries in France for the period from 2007 to 2012. Molecular subtypes were defined with immunohistochemical data. Poisson models were estimated to modelize the course of breast cancer incidence and to test the trends. Results The study included 12,040 patients diagnosed between 2007 and 2012 in the three administrative areas covered by the registries. There was no significant trends in the proportion of each molecular subtype year by year. The age distribution of incident cases was different depending on the molecular subtypes (p < 0.001). The course of incidence between 2007 and 2012 was also different depending on molecular subtype according to the multivariate Poisson model (p < 0.001). Conclusion The description of incident cases of breast cancer according to molecular subtype at a population level showed differences in trends. The trends in incidence differed according to molecular subtype, and this should improve our understanding of overall changes in incidence. This analysis is important to plan screening and treatment resources at a population level

Le vécu de la prise en charge en salle de naissance ::une étude qualitative comparative

Le but de cette étude était d’étudier le vécu des mères insatisfaites de la prise en charge en salle de naissance en le comparant avec celui de mères satisfaites, à partir des données recueillies par évocations hiérarchisées dans l’Étude du Vécu de l’Accouchement (EVA). Il s’agissait d’une étude qualitative, contrôlée par témoins, en population, réalisée au sein de 25 maternités françaises d’un même territoire (Réseau AURORE). Les expressions recueillies par l’évocation hiérarchisée, appelées verbatim, ont été regroupées en sous-thèmes, thèmes et méta-thèmes. Le critère principal de jugement était le pourcentage de patientes ayant cité au moins un mot appartenant à un sous-thème. Six cent quarante-deux mères ont été incluses dans l’étude EVA. Soixante et onze mères ont répondu « insuffisamment » et/ou « pas du tout » à au moins un des items du questionnaire de satisfaction. Elles ont toutes été incluses dans notre étude et constituaient le groupe de cas (insatisfaites). Le groupe témoin (satisfaites) appariés comprenait 144 mères. Le sous-thème de la peur a été significativement plus évoqué par le groupe de mères insatisfaites que par le groupe témoin (42 versus 22 %, p = 0,02). Concernant le sous-thème de la douleur, aucune différence significative n’a été observée entre les deux groupes (45 versus 33 %, p = 0,09). Les résultats incitent à porter plus d’attention à la réassurance des mères en salle de naissance. Identifier les mères inquiètes en cours de grossesse et au moment de l’accouchement doit être une priorité pour les soignants.The objective of our study was to analyze the experience of childbirth care in the delivery room of unsatisfied mothers by comparing it to satisfied mothers. The data was collected using the hierarchical evocation method from the EVA study (Étude du Vécu de l’Accouchement). It was a comparative qualitative study carried out in 25 French maternity hospitals (Réseau AURORE). The words collected using the hierarchical evocation method, called verbatim, have been regrouped into sub-themes, themes and metathemes. The primary outcome was the percentage of mothers who quoted at least one word belonging to a sub-theme. Six hundred and forty-two mothers were included in the EVA study. Seventy-one mothers reported dissatisfaction and they were included in our study. A control group was formed with 144 satisfied mothers selected on a propensity score. The contextual element that emerges as significantly associated with the declaration of dissatisfaction is the fear expressed by 42% of the mothers declaring themselves dissatisfied, compared to 22% of those declaring themselves satisfied with childbirth care (P = 0.02). Regarding the sub-theme of pain, there was no significant difference between the two samples (45 versus 33%, P = 0.09). The results suggest that more attention should be paid to preparing and reassuring mothers in the delivery room. The identification of fear during pregnancy and childbirth should be a priority for the caregivers

Dissatisfaction of women with induction of labour according to parity: Results of a population-based cohort study

International audienceObjective: To determine the factors associated with dissatisfaction in women whose labour was induced, according to parity.Design: Prospective population-based cohort study.Setting: Seven French perinatal health networks including 94 maternity units PARTICIPANTS: Among 3042 consecutive women who underwent induction of labour (IoL) with a live foetus from November 17 to December 20, 2015, in participating maternity units, this study included the 1453 who answered the self-administered questionnaire about their experience of IoL at two months post-delivery.Measurements: The associations between women's dissatisfaction at two months post-delivery and the characteristics of their pregnancy, labour, and delivery were assessed with multivariable logistic regression models. Analyses were stratified for nulliparous and parous women. Multivariable mixed models were used to take a random effect for the maternity unit into account.Findings: The response rate was 47.8% (n = 1453/3042). Overall, 30% of the nulliparous women were dissatisfied (n = 231/770) and 19.7% (n = 130/659) of the parous women. The specific independent determinants of dissatisfaction for nulliparous women were antenatal birth classes that failed to include discussion of IoL (OR: 2.68, 95% CI [1.37; 5.23]) and lack of involvement in the decision-making process (OR: 1.92, 95% CI [1.23; 3.02]). For the parous women, a specific determinant was a delivery that lasted more than 24 h (OR: 4.04, 95% CI [1.78; 9.14]). Determinants of maternal dissatisfaction common to both groups were unbearable vaginal discomfort (respectively, OR: 1.98, 95% CI [1.16; 3.37] and OR: 4.23, 95% CI [2.04; 8.77]), inadequate pain relief (respectively, OR: 5.55, 95% CI [3.48; 8.86] and OR: 9.17, 95% CI [5.24; 16.02]), lack of attention to requests (respectively OR: 3.81, 95% CI [2.35; 6.19] and OR: 5.01, 95% CI [2.38; 10.52]), caesarean delivery (respectively, OR: 5.55, 95% CI [3.41; 9.03] and OR: 4.61, 95% CI [2.02; 10.53]) and severe maternal complications (respectively, OR: 2.45, 95% CI [1.02; 5.88] and OR: 5.29, 95% CI [1.32; 21.21]).Key conclusions and implications for practice: To reduce dissatisfaction in nulliparous women, IoL should be discussed during antenatal birth classes and women should be made to feel that they shared in the medical decision to perform IoL. For parous women, care providers should inform them that the duration of delivery may exceed 24 h. Continuous support for all women during IoL should pay closer attention to vaginal discomfort, pain and women's requests. Postpartum discussions with mothers should be arranged to enable conversation about the experience of unexpected events

Projet de naissance : Construction d'un outil d'aide à la décision médicale partagée selon la méthode Delphi

National audienc