Cross-validation of two prognostic trauma scores in severely injured patients

Introduction Trauma scoring systems are important tools for outcome prediction and severity adjustment that informs trauma quality assessment and research. Discrimination and precision of such systems is tested in validation studies. The German TraumaRegister DGU® (TR-DGU) and the Trauma Audit and Research Network (TARN) from the UK agreed on a cross-validation study to validate their prediction scores (RISC II and PS14, respectively). Methods Severe trauma patients with an Injury Severity Score (ISS) ≥ 9 documented in 2015 and 2016 were selected in both registries (primary admissions only). The predictive scores from each registry were applied to the selected data sets. Observed and predicted mortality were compared to assess precision; area under the receiver operating characteristic curve was used for discrimination. Hosmer–Lemeshow statistic was calculated for calibration. A subgroup analysis including patients treated in intensive care unit (ICU) was also carried out. Results From TR-DGU, 40,638 patients were included (mortality 11.7%). The RISC II predicted mortality was 11.2%, while PS14 predicted 16.9% mortality. From TARN, 64,622 patients were included (mortality 9.7%). PS14 predicted 10.6% mortality, while RISC II predicted 17.7%. Despite the identical cutoff of ISS ≥ 9, patient groups from both registries showed considerable difference in need for intensive care (88% versus 18%). Subgroup analysis of patients treated on ICU showed nearly identical values for observed and predicted mortality using RISC II. Discussion Each score performed well within its respective registry, but when applied to the other registry a decrease in performance was observed. Part of this loss of performance could be explained by different development data sets: the RISC II is mainly based on patients treated in an ICU, while the PS14 includes cases mainly cared for outside ICU with more moderate injury severity. This is according to the respective inclusion criteria of the two registries. Conclusion External validations of prediction models between registries are needed, but may show that prediction models are not fully transferable to other health-care settings

Effet maternel du gène sans cornes p sur le poids des chevrettes d'élevage

International audienc

Paramètres génétiques de la croissance des chevrettes saanen en station de testage

International audienc

Parathyroid hormone-stimulated calcium absorption in cTAL from vitamin D-deficient rabbits

Parathyroid hormone-stimulated calcium absorption in cTAL from vitamin D-deficient rabbits. Cortical thick ascending limbs of Henle's loop were dissected from the kidneys of chronically vitamin D-deficient or -replete rabbits and perfused in vitro. Unidirectional transepithelial calcium fluxes from lumen to bath were measured with 45Ca. The tubules were bathed in a solution containing 150mM sodium and perfused with a solution containing 60mM sodium to simulate conditions in the cortical thick ascending limb in vivo. Transepithelial voltages were equal across tubules from vitamin D-deficient and -replete rabbits. Likewise, baseline and parathyroid hormone-stimulated calcium fluxes were the same in tubules from the two groups. Because calcidiol and calcitriol were undetectable in the serum of the vitamin D-deficient rabbits, we suggest that neither of these endogenous vitamin D metabolites is essential in the regulation of calcium absorption in this portion of the rabbit nephron

Predictors of 25(OH)D half-life and plasma 25(OH)D concentration in The Gambia and the UK

Summary: Predictors of 25(OH)D3 half-life were factors associated with vitamin D metabolism, but were different between people in The Gambia and the UK. Country was the strongest predictor of plasma 25(OH)D concentration, probably as a marker of UVB exposure. 25(OH)D3 half-life may be applied as a tool to investigate vitamin D expenditure.  Introduction: The aim of this study was to investigate predictors of 25(OH)D3 half-life and plasma 25(OH)D concentration.  Methods: Plasma half-life of an oral tracer dose of deuterated-25(OH)D3 was measured in healthy men aged 24–39 years, resident in The Gambia, West Africa (n = 18) and in the UK during the winter (n = 18), countries that differ in calcium intake and vitamin D status. Plasma and urinary markers of vitamin D, calcium, phosphate and bone metabolism, nutrient intakes and anthropometry were measured.  Results: Normally distributed data are presented as mean (SD) and non-normal data as geometric mean (95 % CI). Gambian compared to UK men had higher plasma concentrations of 25(OH)D (69 (13) vs. 29 (11) nmol/L; P < 0.0001); 1,25(OH)2D (181 (165, 197) vs. 120 (109, 132) pmol/L; P < 0.01); and parathyroid hormone (PTH) (50 (42, 60) vs. 33 (27, 39); P < 0.0001). There was no difference in 25(OH)D3 half-life (14.7 (3.5) days vs. 15.6 (2.5) days) between countries (P = 0.2). In multivariate analyses, 25(OH)D, 1,25(OH)2D, vitamin D binding protein and albumin-adjusted calcium (Caalb) explained 79 % of variance in 25(OH)D3 half-life in Gambians, but no significant predictors were found in UK participants. For the countries combined, Caalb, PTH and plasma phosphate explained 39 % of half-life variability. 1,25(OH)2D, weight, PTH and country explained 81 % of variability in 25(OH)D concentration; however, country alone explained 74 %.  Conclusion: Factors known to affect 25(OH)D metabolism predict 25(OH)D3 half-life, but these differed between countries. Country predicted 25(OH)D, probably as a proxy measure for UVB exposure and vitamin D supply. This study supports the use of 25(OH)D half-life to investigate vitamin D metabolism