CPMCGLM: an R package for p-value adjustment when looking for an optimal transformation of a single explanatory variable in generalized linear models

International audienceBACKGROUND:In medical research, explanatory continuous variables are frequently transformed or converted into categorical variables. If the coding is unknown, many tests can be used to identify the "optimal" transformation. This common process, involving the problems of multiple testing, requires a correction of the significance level. Liquet and Commenges proposed an asymptotic correction of significance level in the context of generalized linear models (GLM) (Liquet and Commenges, Stat Probab Lett 71:33-38, 2005). This procedure has been developed for dichotomous and Box-Cox transformations. Furthermore, Liquet and Riou suggested the use of resampling methods to estimate the significance level for transformations into categorical variables with more than two levels (Liquet and Riou, BMC Med Res Methodol 13:75, 2013).RESULTS:CPMCGLM provides to users both methods of p-value adjustment. Futhermore, they are available for a large set of transformations. This paper aims to provide insight the user an overview of the methodological context, and explain in detail the use of the CPMCGLM R package through its application to a real epidemiological dataset.CONCLUSION:We present here the CPMCGLMR package providing efficient methods for the correction of type-I error rate in the context of generalized linear models. This is the first and the only available package in R providing such methods applied to this context. This package is designed to help researchers, who work principally in the field of biostatistics and epidemiology, to analyze their data in the context of optimal cutoff point determination

Package CPMCGLM : Correction de la pvaleur engendré par la recherche d'un codage d'une variable explicative dans un modèle linéaire généralisé

Package CPMCGLM : Correction de la pvaleur engendré par la recherche d'un codage d'une variable explicative dans un modèle linéaire généralis

A closed max-t test for multiple comparisons of areas under the ROC curve

Comparing areas under the ROC curve (AUCs) is a popular approach to compare prognostic biomarkers. The aim of this paper is to present an efficient method to control the family-wise error rate when multiple comparisons are performed. We suggest to combine the max-t test and the closed testing procedures. We build on previous work on asymptotic results for ROC curves and on general multiple testing methods to efficiently take into account both the correlations between the test statistics and the logical constraints between the null hypotheses. The proposed method results in an uniformly more powerful procedure than both the single-step max-t test procedure and popular stepwise extensions of the Bonferroni procedure, such as Bonferroni-Holm. As demonstrated in this paper, the method can be applied in most usual contexts, including the time-dependent context with right censored data. We show how the method works in practice through a motivating example where we compare several psychometric scores to predict the t-year risk of Alzheimer's disease. The example illustrates several multiple testing settings and demonstrates the advantage of using the proposed methods over common alternatives. R code has been made available to facilitate the use of the methods by others

Association between serum 25-hydroxyvitamin D concentration and severity of first-diagnosed bullous pemphigoid in older adults

International audienceBackgroundHigher vitamin D status has been associated with symptom improvement and decreased risk of various autoimmune disorders. Our objective was to determine whether higher serum 25-hydroxyvitamin D (25OHD) concentration correlated with less severe first-diagnosed bullous pemphigoid (BP) in older inpatients.MethodsThis cross-sectional study was performed from November 2012 to February 2014 among 30 consecutive older inpatients (21 women; mean ± SD, 83 ± 7 years; all Caucasian) with a de novo diagnosis of active BP recruited in the Department of Dermatology of Angers University Hospital, France. The severity of BP was graded clinically on the basis of i) the number of bullae during the first three days of hospitalization (grade 0–4, worse), and ii) the extent of the lesions (grade 0–5, worse).ResultsSixteen participants had ≤ 5 bullae at the time of diagnosis, 8 had 6–20 bullae, 3 had 20–50 bullae, and 3 had &gt;50 bullae. The lesions were spread over 5 cutaneous areas in 5 participants (17%). The median 25OHD concentration was 23 [IQR, 16–42] nmol/L. Serum 25OHD concentration was inversely correlated with the bullae grade (ρ = − 0.38, p = 0.04) and the lesion extension grade (ρ = − 0.50, p = 0.005).ConclusionsHigher serum 25OHD concentration correlated with less severe BP prior to initiation of treatment among our sample of older inpatients. This result suggests that vitamin D may be involved in the pathophysiology of BP and could serve as prognostic biomarker of BP.</p

Anaemic women are more at risk of injectable contraceptive discontinuation due to side-effects in Ethiopia

International audienceBackground: This paper investigates the importance of women’s physiological condition, alongside sociocultural factors, for predicting the risk of discontinuation of the injectable contraceptive due to side-effects in Ethiopia.Methods: Contraceptive calendar data from the 2016 Ethiopian Demographic and Health Survey were analysed. Women aged 15-49 who had initiated the injectable contraceptive in the last two years were included in the analysis (n=1,513). Physiological factors investigated were body mass, iron status, reproductive depletion, and physical strain. After checking for reverse causality, associations between physiological risk factors and discontinuation of the injectable contraceptive due to either side-effects (DSE) or other reasons (DOR) were estimated using multivariate Cox proportional regression analyses. Results: Anaemia status was associated with DSE, but not DOR. Anaemic women were two times more at risk of discontinuation due to side-effects (DSE) compared with non-anaemic women (aHR=2.38, CI=1.41-4.00). DOR was predicted by religion, wealth, and relationship status.Conclusions: Accounting for diversity in physiological condition is key for understanding contraceptive discontinuation due to side-effects. To reduce side-effects, family planning programs might benefit from providing hormonal contraception within an integrated package addressing anaemia

Pregnancy and tobacco: practice and knowledge of French midwives.

International audienceObjectives: Evaluate the midwives’ practices and knowledges with regard to the management of the smoking cessation in pregnant women and analyze the profile of midwives prescribing nicotine replacement therapy (NRT).Methods: A national practice survey among 23,541 French midwives was conducted from 1 September 2020 to 15 September 2021 using an online self-administered questionnaire.Results: The analysis of the 1,216 usable questionnaires (97, 7% women, mostly aged 30 to 49 years and non-smokers) showed that 93.4% of midwives frequently questioned pregnant women about their smoking consumption during pregnancy. The minimal counseling was known and practiced by 91% of midwives, the Fagerström test by 26.9% and the measurement of exhaled CO by 27.1%. Concerning NRT, 60% of the midwives prescribed them in a usual way and 36.8% were aware of the possibility of prescribing them to the pregnant woman&#039;s entourage. The profile of midwives prescribing NRT was significantly more concerned with smoking cessation in pregnant women; worked more frequently in a hospital; carried out 25% or more of antenatal monitoring consultations; and had significantly better knowledge of the evaluation tools, without influence of sex or smoking status.Conclusions: Improving the training of midwives in the screening and management of smoking cessation during pregnancy seems necessary

Clinical Identification of Geriatric Patients with Hypovitaminosis D: The ‘Vitamin D Status Predictor for Geriatrics’ Study

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Validation of risk assessment models predicting venous thromboembolism in acutely ill medical inpatients: A cohort study

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Clinical identification of older adults with hypovitaminosis D: Feasibility, acceptability and accuracy of the ‘Vitamin D Status Diagnosticator’ in primary care

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Behavior of poly(d,l-lactic-co-glycolic acid) (PLGA)-based droplets falling into a complex extraction medium simulating the prilling process

International audienceHypothesisPrilling process is one of advanced techniques for manufacturing microspheres of controlled and uniform size. In this process, homogenous polymer droplets fall into an extraction medium. The aim of this study was to identify the key parameters influencing the behavior of PLGA polymer-based droplets falling into a complex extraction medium, to select appropriate conditions for prilling.ExperimentsPolymer solutions and extraction media were characterized by determining their viscosity, density and surface tension. A simple model simulating the prilling process was developed to study droplet behavior. Particle shape and velocity at the air-liquid interface and during sedimentation in the container were analyzed step by step. The correlations between the variables studied were visualized by principal component analysis (PCA).FindingsDroplet deformation at the interface greatly affected the recovery and final particle shape. It depended on the viscosity ratio of polymer solution/extraction medium. The particle shape recovery depended on the viscosity and density of extraction media and polymer solutions. The solidification speed is also an important parameter. In media which the solvent diffused slowly, particles were able to relax and recover their shape, however, they can also deform during sedimentation and collision with the bottom of the cuvette