Oral Janus kinase inhibitors and venous thromboembolic events in atopic dermatitis: protocols for a case-time control study and a nested case-control study based on the French national health insurance (SNDS) cohort.

INTRODUCTION: Atopic dermatitis (AD) is a highly prevalent, chronic, inflammatory skin disease. Several orally administered Janus kinase inhibitors (JAKis, including baricitinib, upadacitinib and abrocitinib) have received a marketing authorisation for AD.Clinical trials in rheumatoid arthritis (RA) have flagged up a potential risk of JAKi-induced venous thromboembolic events (VTEs). Accordingly, the summary of product characteristics for a JAKi must mention VTEs as potential adverse drug reactions. In contrast to RA, AD per se is not associated with an elevated risk of VTEs. Assessing this potential risk among patients with AD would shed further light on the putative underlying relationship between JAKis and VTEs.Our research question is to investigate whether JAKi administration increases the risk of VTEs in adults with AD. Our primary objective is to assess the risk of VTEs in adults with AD exposed to JAKis compared to AD adults not exposed to JAKis, and our secondary objective is to evaluate whether JAKi initiation acts as a trigger of VTEs in adults with AD within 3 months. METHODS AND ANALYSIS: Hence, we have designed (1) a nested case-control study and (2) a case-time control study in a cohort of adults with AD with data from the French national health insurance system (2017-2025).Here, we describe the study protocol, our methodological choices and certain novel aspects, including the combined value of the two assumptions and the use of an exhaustive national health insurance database with potentially greater statistical power for studying rare events in the population of patients with AD at a low risk of VTEs (thus limiting the influence of confounding factors). ETHICS AND DISSEMINATION: The protocol has been approved by an independent ethics committee and registered with the French National Data Protection Commission. The study's findings will be published in peer-reviewed scientific journals and presented at international conferences.

Usefulness of Body Composition CT Analysis in Patients with Idiopathic Pulmonary Fibrosis: A Pilot Study.

PURPOSE: To evaluate the feasibility of a chest CT-based body composition analysis in idiopathic pulmonary fibrosis (IPF), and to investigate the respective contribution of lung and muscle CT quantitative analyses to the prognosis of IPF. METHOD: A total of 71 IPF patients were recruited at diagnosis. All patients underwent a standard chest CT-scan and a bioelectrical impedance analysis considered as reference standard for estimating malnutrition through the use of the fat-free mass index (FFMI). The skeletal muscle index (SMI) was measured on chest-CT at the level of the first lumbar vertebra by two radiologists. Lung fibrosis extent was quantified by three radiologists in consensus. The extent of emphysema, the pulmonary artery to aorta (PA/AO) diameter ratio and lymph node enlargement were also reported. Mortality and hospitalization over a 14-month follow-up were recorded. RESULTS: A low FFMI defining malnutrition was identified in 26.8% of patients. SMI was significantly lower in these patients (p<0.001) and was correlated with FFMI (r=0.637, p<0.001). Interobserver agreement of SMI measurement was very good (ICC=0.91). For diagnosing malnutrition, SMI showed a 0.79 sensitivity, a 0.69 specificity, a 0.48 PPV and a 0.90 NPV. In univariate analysis, fibrosis extent was significantly associated with death, while SMI did not reach significance. In multivariate analysis, fibrosis extent and PA/AO ratio were independently associated with hospitalization. CONCLUSIONS: SMI measured on chest CT could be a reliable tool to exclude malnutrition in IPF. A quantitative analysis of both fibrosis and skeletal muscle may allow holistic management of IPF patients.