Background There is a considerable diagnostic delay in the diagnosis 'benign acquired subglottic stenosis in adults' (SGS, diagnosed by the reference standard, i.e. laryngo- or bronchoscopy).... Show moreBackground There is a considerable diagnostic delay in the diagnosis 'benign acquired subglottic stenosis in adults' (SGS, diagnosed by the reference standard, i.e. laryngo- or bronchoscopy). Patients are frequently misdiagnosed since symptoms of this rare disease may mimic symptoms of 'asthma.' The 'Expiratory Disproportion Index' (EDI) obtained by spirometry, may be a simple instrument to detect an SGS-patient. The aim of this study was to evaluate the diagnostic accuracy of the EDI in differentiating SGS patients from asthma patients.Methods We calculated the EDI from spirometry results of all SGS-patients in the Leiden University Medical Center (LUMC), who had not received treatment 2 years before their spirometry examination. We compared these EDI results with the EDI results of all true asthma patients between 2011 and 2019, who underwent a bronchoscopy (exclusion of SGS by laryngo- or bronchoscopy).Results Fifty patients with SGS and 32 true asthma patients were included. Median and IQR ranges of the EDI for SGS and asthma patients were 67.10 (54.33-79.18) and 37.94 (32.41-44.63), respectively. Area under the curve (ROC) of the accuracy of the EDI at discriminating SGS and asthma patients was 0.92 (95% CI = 0.86-0.98). The best cut-off point for the EDI was > 48 (i.e. possible upper airway obstruction), with a sensitivity of 88.0%% (95%CI = 77.2-95.0%%) and specificity of 84.4% (95%CI = 69.4-94.1%).Conclusions The EDI has a good diagnostic accuracy discriminating subglottic stenosis patients from asthma patients, when compared to the reference standard. This measurement from spirometry may potentially shorten the diagnostic delay of SGS patients. Further studies are needed to evaluate clinical reproducibility. Show less
Primary endpoints in pediatric clinical trials are currently very similar to those in adult trials1, and focus on quantifying or counting hard endpoints like mortality, hospital admissions and... Show morePrimary endpoints in pediatric clinical trials are currently very similar to those in adult trials1, and focus on quantifying or counting hard endpoints like mortality, hospital admissions and length of stay. Additionally, biochemical biomarkers in serum are often measured to assess drug effects on a biochemical level. The occurrence of mortality and hospital admissions is rare thanks to the improvements in clinical care that have occurred in the last century, and adopting these as primary endpoints in clinical trials gives disproportional weight to rare events which most patients will not experience. Conversely, length of stay for many clinical conditions is short, and this duration only captures a small part of the clinical recovery trajectory that patients must undergo. This dissertation described the development, technical validation and clinical validation of a new type of clinical endpoints ('value based endpoints') and a new clinical trial paradigm (The remote clinical trial), consisting of digital endpoints and non-invasive pharmacokinetic sampling. Both have the potential to transform pediatric clinical trials and pediatric clinical care. The process towards implementation is challenging and can only proceed after a rigorous validation process. The current work provides a roadmap towards selection, validation, and implementation of digital endpoints, and describes preliminary steps taken for several candidates. The digital endpoints investigated in this work fulfill several validation criteria in a range of clinical conditions and, combined with non-invasive pharmacokinetics, may move the pediatric clinical trial completely towards the home. Show less
