Do clinimetric properties of LCI change after correction of signal processing?

Abstract

Background: The recently described sensor-crosstalk error in the multiple-breath washout (MBW) device Exhalyzer D (Eco Medics AG) could highly influence clinimetric properties and the current interpretation of MBW results. This study reanalyzes MBW data from clinical routine in the corrected software version Spiroware ® 3.3.1 and evaluates the effect on outcomes. Methods: We included nitrogen-MBW data from healthy children and children with cystic fibrosis (CF) from previously published trials and ongoing cohort studies. We specifically compared lung clearance index (LCI) analyzed in Spiroware 3.2.1 and 3.3.1 with regard to (i) feasibility, (ii) repeatability, and (iii) validity as outcome parameters in children with CF. Results: (i) All previously collected measurements could be reanalyzed and resulted in unchanged feasibility in Spiroware 3.3.1. (ii) Short-and midterm repeatability of LCI was similar in both software versions. (iii) Clinical validity of LCI remained similar in Spiroware 3.3.1; however, this resulted in lower values. Discrimination between health and disease was comparable between both software versions. The increase in LCI over time was less pronounced with 0.16 LCI units/year (95% confidence interval [CI] 0.08; 0.24) versus 0.30 LCI units/year (95% CI 0.21; 0.38) in 3.2.1. Response to intervention in children receiving CF transmembrane conductancemodulator therapy resulted in a comparable improvement in LCI, in both Spiroware versions. Conclusion:Our study confirms that clinimetric properties of LCI remain unaffected after correction for the cross-sensitivity error in Spiroware software.

How Does the Corrected Exhalyzer Software Change the Predictive Value of LCI in Pulmonary Exacerbations in Children with Cystic Fibrosis?

“…Frauchiger and colleagues reanalyzed with their own script the raw data obtained in several studies including 303 participants from previous and ongoing trials including healthy children and cystic fibrosis patients [21]. They found a similar trend in LCI changes measured with both Spiroware software during exacerbations, although the magnitude of changes was smaller with the corrected Spiroware 3.3.1 software.…”

“…Subsequently, an updated software (Spiroware 3.3.1, Eco Medics AG, Dürnten, Switzerland) was introduced into the devices that allowed for the recalculation of already existing data. This raised concerns in the CF community about how this error correction would influence the results of the existing clinical studies and the diagnostic value of LCI in CF lung disease [21].…”

Pediatric pulmonology year in review 2021 and 2022: Physiology

“…3 Although this error has been corrected in the most recent versions of the software, the impact on clinimetric properties of LCI (i.e., the reliability and validity of the measurement) is unclear. To resolve these questions, Frauchiger et al 8 assessed the feasibility, repeatability, and validity of LCI measured using the corrected software. Clinimetric properties of LCI were still valid using the corrected software.…”