Utilisation des données du programme de médicalisation des systèmes d'information (PMSI) dans les études épidémiologiques Application à la Cohorte Enfant Scanner

National audienceBackground: The "Cohorte Enfant Scanner", a study designed to investigate the risk of radiation-induced cancer after childhood exposure to CT (computed tomography) examinations, used clinical information contained in the "programme de médicalisation des systèmes d'information" (PMSI) database, the French hospital activities national program based upon diagnosis related groups (DRG). However, the quality and adequacy of the data for the specific needs of the study should be verified. The aim of our work was to estimate the percentage of the cohort's children identified in the PMSI database and to develop an algorithm to individualize the children with a cancer or a disease at risk of cancer from medical diagnoses provided by the DRGs database. Methods: Of the 1519 children from the "Cohorte Enfant Scanner", who had had a CT scan in the radiology department of a university hospital in 2002, a cross linkage was performed with the DRGs database. All hospitalizations over the period 2002-2009 were taken into account. An algorithm was constructed for the items "cancer" and "disease at risk for cancer" on a sample of 150 children. The algorithm was then tested on the entire population. Results: Overall, 74% of our population was identified in the DRGs database. The algorithm individualized cancer diagnoses with 91% sensitivity (95% confidence interval [95%CI]: 86%; 97%) and 98% specificity (95%CI: 97%; 99%) and 86% positive predictive value (95%CI: 80%; 93%). For the diagnosis of disease at risk for cancer, the sensitivity, specificity and positive predictive value were respectively 91% (95%CI: 84%; 98%), 94% (95%CI: 92%; 95%) and 52% (95%CI: 43%; 61%). Conclusion: The DRG database identified with excellent sensitivity and specificity children with diagnoses of cancer or disease at risk for cancer. Hence, potential confounding factors related to the disease of the child can be taken into account for analyses performed with the cohort. © 2012 Elsevier Masson SASPosition du problème : la Cohorte Enfant Scanner, qui étudie le risque de cancer radio-induit après exposition dans l’enfance à des examens scanographiques, pourrait bénéficier des informations cliniques contenues dans le programme de médicalisation des systèmes d’information (PMSI). Cependant, la qualité et l’adéquation des données aux besoins de l’étude doivent être vérifiées. L’objectif de notre travail était d’estimer le pourcentage d’enfants de la cohorte identifiés dans la base PMSI et de construire un algorithme pour individualiser les enfants présentant un cancer ou une pathologie à risque de cancer à partir des diagnostics cliniques de la base PMSI.Méthodes : un croisement des identifiants des 1519 enfants de la Cohorte Enfant Scanner ayant eu un scanner dans un service de radiopédiatrie hospitalo-universitaire en 2002 a été fait avec la base PMSI. Toutes les hospitalisations de l’enfant sur la période 2002–2009 ont été analysées. Un algorithme a été construit pour les items « cancer » et « pathologie à risque de cancer » sur un échantillon de 150 enfants. L’algorithme a ensuite été appliqué à l’ensemble de la population.Résultats : au total, 74 % de notre population a été identifiée dans la base PMSI. L’algorithme a permis d’individualiser les diagnostics de cancer avec une sensibilité de 91 % (intervalle de confiance à 95 %, [IC 95 %], 86 % ; 97 %), une spécificité de 98 % (IC 95 %, 97 % ; 99 %) et une valeur prédictive positive (VPP) de 86 % (IC 95 %, 80 % ; 93 %). Pour le diagnostic de pathologie à risque de cancer, la sensibilité, la spécificité et la VPP étaient respectivement de 91 % (IC 95 %, 84 % ; 98 %), 94 % (IC 95 %, 92 % ; 95 %) et 52 % (IC 95 %, 43 % ; 61 %).Conclusion : le PMSI a permis d’identifier avec d’excellentes sensibilité et spécificité les enfants présentant un cancer ou une pathologie à risque de cancer. Cela permettra de prendre en compte les facteurs de confusion éventuels liés à la pathologie de l’enfant dans les analyses de la Cohorte Enfant Scanner

Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France

International audienceBackground Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk. Methods The cohort included 67 274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses. Results During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures. Conclusions This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans. © 2015 Cancer Research UK

B cell gene signature with massive intrahepatic production of antibodies to hepatitis B core antigen in hepatitis B virus–associated acute liver failure

Hepatitis B virus (HBV)-associated acute liver failure (ALF) is a dramatic clinical syndrome due to a sudden loss of hepatic cells leading to multiorgan failure. The mechanisms whereby HBV induces ALF are unknown. Here, we show that liver tissue collected at the time of liver transplantation in two patients with HBV-associated ALF is characterized by an overwhelming B cell response apparently centered in the liver with massive accumulation of plasma cells secreting IgG and IgM, accompanied by complement deposition. We demonstrate that the molecular target of these antibodies is the hepatitis B core antigen (HBcAg); that these anti-bodies display a restricted variable heavy chain (VH) repertoire and lack somatic mutations; and that these two unrelated individuals with ALF use an identical predominant VH gene with unmutated variable domain (IGHV1-3) for both IgG and IgM anti-HBc antibodies, indicating that HBcAg is the target of a germline human VH gene. These data suggest that humoral immunity may exert a primary role in the pathogenesis of HBV-associated ALF