Incidence and main factors associated with early unplanned hospital readmission among French medical inpatients aged 75 and over admitted through emergency units

Background: among elderly patients, readmission in the month following hospital discharge is a frequent occurrence which involves a risk of functional decline, particularly among frail subjects. While previous studies have identified risk factors of early readmission, geriatric syndromes, as markers of frailty have not been assessed as potential predictors. Objective: to evaluate the risk of early unplanned readmission, and to identify predictors in inpatients aged 75 and over, admitted to medical wards through emergency departments. Design: prospective multi-centre study. Setting: nine French hospitals. Subjects: one thousand three hundred and six medical inpatients, aged 75 and older admitted through emergency departments (SAFES cohort). Methods: using logistic regressions, factors associated with early unplanned re-hospitalisation (defined as first unplanned readmission in the thirty days after discharge) were identified using data from the first week of hospital index stay obtained by comprehensive geriatric assessment. Results: data from a thousand out of 1,306 inpatients were analysed. Early unplanned readmission occurred in 14.2% of inpatients and was not related with sociodemographic characteristics, comorbidity burden or cognitive impairment. Pressure sores (OR=2.05, 95% CI = 1.0-3.9), poor overall condition (OR = 2.01, 95% CI = 1.3-3.0), recent loss of ability for self-feeding (OR = 1.9, 95% CI = 1.2-2.9), prior hospitalisation during the last 3 months (OR = 1.6, 95% CI = 1.1-2.5) were found to be risk factors, while sight disorders appeared as negatively associated (OR = 0.5, 95% CI = 0.3--0.8). Conclusions: markers of frailty (poor overall condition, pressure sores, prior hospitalisation) or severe disability (for self-feeding) were the most important predictors of early readmission among elderly medical inpatients. Early identification could facilitate preventive strategies in risk grou

Loss of independence in Katz's ADL ability in connection with an acute hospitalization: early clinical markers in French older people

Background: The preservation of autonomy and the ability of elderly to carry out the basic activities of daily living, beyond the therapeutic care of any pathologies, appears as one of the main objectives of care during hospitalization. Objectives: To identify early clinical markers associated with the loss of independence in elderly people in short stay hospitals. Methods: Among the 1,306 subjects making up the prospective and multicenter SAFEs cohort study (Sujet Agé Fragile: Évolution et suivi—Frail elderly subjects, evaluation and follow-up), 619 medical inpatients, not disabled at baseline and hospitalized through an emergency department were considered. Data used in a multinomial logistic regression were obtained through a comprehensive geriatric assessment (CGA) conducted in the first week of hospitalization. Dependency levels were assessed at baseline, at inclusion and at 30days using Katz's ADL index. Baseline was defined as the dependence level before occurrence of the event motivating hospitalization. To limit the influence of rehabilitation on the level of dependence, only stays shorter than 30days were considered. Results: About 514 patients were eligible, 15 died and 90 were still hospitalized at end point (n=619). Two-thirds of subjects were women, with a mean age of 83. At day 30 162 patients (31%) were not disabled; 61 (12%) were moderately disabled and 291 severely disabled (57%). No socio-demographic variables seemed to influence the day 30 dependence level. Lack of autonomy (odds ratio (OR)=1.9, 95% confidence interval (CI)=1.2-3.6), walking difficulties (OR=2.7, 95% CI=1.3-5.6), fall risk (OR=2.1, 95% CI=1.3-6.8) and malnutrition risk (OR=2.2, 95% CI=1.5-7.6) were found in multifactorial analysis to be clinical markers for loss of independence. Conclusions: Beyond considerations on the designing of preventive policies targeting the populations at risk that have been identified here, the identification of functional factors (lack of autonomy, walking difficulties, risk of falling) suggests above all that consideration needs to be given to the organization per se of the French geriatric hospital care system, and in particular to the relevance of maintaining sector-type segregation between wards for care of acute care and those involved in rehabilitatio

Determination of the efficiency of high purity germanium and silicon diode detectors for improved assessment of emission spectra delivered by medical X-ray tubes

International audienceX-ray sources are widely used in medicine: brachytherapy, radiodiagnosis, mammography and contact radiotherapy. Kerma in air is the primary quantity measured to determine the dose to the patient. Accurate air kerma assessment is obtained using correction factors calculated using the emission spectrum. The Laboratoire National Henri Becquerel launched an in-depth study of the spectral emission of its reference X-ray beams used in dosimetry. Two semiconductor detectors are discussed here: a High-Purity germanium and a silicon PiN, both cooled and operated with dedicated electronics and software. In the low energy range (E < 50 keV), those spectrometers are complementary but require a careful calibration to deduce the emitted spectrum from the detected one. Indeed, both detectors were characterized in terms of spectral response and intrinsic efficiency using a tuneable monochromatic X-ray source (SOLEX at CEA Saclay) in the 5- to 20-keV energy range and various radionuclides. The characterization methods and results, including the first measured spectra of medical X-ray tubes (high voltage < 50 kV), are presented in this work. This paper presents the first step of a broader project, aiming at assessing the emission spectrum independently of the detector choice

Estimation de l'incertitude globale associée à une référence en terme de dose dans l'eau pour la curiethérapie bas débit de dose.

Depuis 2006, le LNE-LNHB a entrepris de mettre au point une référence primaire pour la curiethérapie bas débit de dose traitant des cancers prostatiques et ophtalmiques. Le détecteur à la base de cette référence est d'une conception innovante puisqu'il s'agit d'une chambre d'ionisation à parois d'air de forme toroïdale. Le but de cette référence est de déterminer la dose absorbée dans l'eau pour les grains de curiethérapie à l'iode 125 (énergie de la raie initiale la plus énergétique égale à 35,5 keV). Dans le cadre de la mise en place de cette référence, des calculs Monte Carlo ont été effectués à l'aide de trois codes afin de déterminer la valeur du facteur de conversion nécessaire à l'établissement de la référence primaire ainsi que son incertitude. Ce facteur, spécifique de la méthodologie de détermination, permet le passage des conditions de mesure à celles de référence telles que décrites par l'AAPM. Les codes egspp (code EGSnrc version V4-r2-3-2), MCNP (version 1.40) et PENELOPE (version parallèle MPI de la distribution PENELOPE 2006) ont été utilisés dans ce but. Le facteur de conversion (comprenant sa valeur et son incertitude) a été déterminé à partir de l'écart-type expérimental sur les valeurs des facteurs de conversion calculées à l'aide de ces trois codes

Using LiF:Mg,Cu,P TLDs to estimate the absorbed dose to water in liquid water around an 192^{192}Ir brachytherapy source

International audiencePurpose:The absorbed dose to water is the fundamental reference quantity for brachytherapy treatment planning systems and thermoluminescence dosimeters (TLDs) have been recognized as the most validated detectors for measurement of such a dosimetric descriptor. The detector response in a wide energy spectrum as that of an$^{192}$Ir brachytherapy source as well as the specific measurement medium which surrounds the TLD need to be accounted for when estimating the absorbed dose. This paper develops a methodology based on highly sensitive LiF:Mg,Cu,P TLDs to directly estimate the absorbed dose to water in liquid water around a high dose rate $^{192}$Ir brachytherapy source.Methods:Different experimental designs in liquid water and air were constructed to study the response of LiF:Mg,Cu,P TLDs when irradiated in several standard photon beams of the LNE‐LNHB (French national metrology laboratory for ionizing radiation). Measurement strategies and Monte Carlo techniques were developed to calibrate the LiF:Mg,Cu,P detectors in the energy interval characteristic of that found when TLDs are immersed in water around an$^{192}$Ir source. Finally, an experimental system was designed to irradiate TLDs at different angles between 1 and 11 cm away from an $^{192}$Ir source in liquid water. Monte Carlo simulations were performed to correct measured results to provide estimates of the absorbed dose to water in water around the $^{192}$Ir source.Results:The dose response dependence of LiF:Mg,Cu,P TLDs with the linear energy transfer of secondary electrons followed the same variations as those of published results. The calibration strategy which used TLDs in air exposed to a standard N‐250 ISO x‐ray beam and TLDs in water irradiated with a standard $^{137}$Cs beam provided an estimated mean uncertainty of 2.8% ($k$ = 1) in the TLD calibration coefficient for irradiations by the $^{192}$Ir source in water. The 3D TLD measurements performed in liquid water were obtained with a maximum uncertainty of 11% ($k$ = 1) found at 1 cm from the source. Radial dose values in water were compared against published results of the American Association of Physicists in Medicine and the European Society for Radiotherapy and Oncology and no significant differences (maximum value of 3.1%) were found within uncertainties except for one position at 9 cm (5.8%). At this location the background contribution relative to the TLD signal is relatively small and an unexpected experimental fluctuation in the background estimate may have caused such a large discrepancy.Conclusions:This paper shows that reliable measurements with TLDs in complex energy spectra require a study of the detector dose response with the radiation quality and specific calibration methodologies which model accurately the experimental conditions where the detectors will be used. The authors have developed and studied a method with highly sensitive TLDs and contributed to its validation by comparison with results from the literature. This methodology can be used to provide direct estimates of the absorbed dose rate in water for irradiations with HDR192Ir brachytherapy sources

Dosimetry formalism and calibration procedure for electronic brachytherapy sources in terms of absorbed dose to water

International audienceThe LNE-LNHB has developed a methodology to standardize electronic brachytherapy sources in terms of absorbed dose to water. It is based on the measurement of the air-kerma rate at a given distance from the source and the Monte Carlo calculation of a conversion factor. This factor converts the air kerma in measurement conditions into absorbed dose to water at a 1 cm reference depth in a water phantom. As a first application, the method was used to calibrate a Zeiss INTRABEAM system equippedwith its 4 cm diameter spherical applicator. The absorbed-dose rate value obtained in the current study was found significantly higher than that provided by the manufacturer in line with the observations already reported by a few other teams

Intracavitary in vivo dosimetry based on multichannel fiber-coupled Radioluminescence and Optically Stimulated Luminescence of Al2_2O3_3 :C

International audienceFiber Optic Dosimetric Catheters (FODCs) composed of chains of alumina crystals are investigated by the CEA LIST within the French ANR-INTRADOSE Project in the purpose of intracavitary in vivo dosimetry (IVD) during Brachytherapy (BT) with iridium sources and Intensity-Modulated Radiation Therapy (IMRT) with linear accelerators. A dedicated process involving PMMA fibers, casted altogether forming hexagonal bundle, is demonstrated. Optically Stimulated Luminescence (OSL) signals are recorded on-line after irradiation and absorbed doses are compared to planned dose distribution. Real-time dose measurements may also be performed by recording the RadioLuminescence (RL), spontaneously emitted by the crystals during irradiation. In this case, a correction method is implemented to correct for stem effect influence (Cerenkov and scintillation generated within the fibers). For BT, the dual-fiber subtraction method is used (using a reference fiber) whereas the time discrimination method is used for IMRT. The experimental dose distribution leads to an underestimation of the source-sensor distance presumably due to energy dependence of the alumina crystal at low photon energy. At the time being, Monte-Carlo modeling of the FODC is performed with the aim to estimate this energy dependence and finally correct for it. Finally, metrological and preclinical validations are still running at Centre Léon Bérard (Lyon, France) in the purpose of checking the compliance of the FODC prototypes with treatment specifications and medical constraints