Quality of spirometry and diffusion of the lung (DLCO) data in patients with systemic sclerosis

Introduction: Spirometry quality assurance (QA) in clinical trials has been well described, however the quality of spirometry (FVC) and diffusion of the lung (DLCO) has not been reported in patients with systemic sclerosis (SSc) in a multicentre clinical trial. Objective: To assess the ability of subjects with systemic sclerosis to meet (target >85%) the 2005 ATS-ERS quality standards for FVC and DLCO. Method: 210 patients with active progressive SSc were enrolled at 76 international centres. A standard spirometer (Vitalograph COMPACT) was used, whereas the DLCO tests were performed with the site’s equipment. The 48 week treatment period study included 7 FVC and 4 DLCO test sessions. All testing personnel completed training on the equipment and protocol requirements, along with demonstrated ability to perform acceptable and repeatable tests prior to testing subjects. All results were captured into a customised software application (Spirotrac) for quality review. Expert reviewers checked for compliance with the 2005 ATS/ERS standards and provided test feedback. Results: A total of 1,430 FVC and 802 DLCO sessions were performed and completed the QA review process. 93.6% of the FVC and 92% of the DLCO test sessions met the 2005 ATS-ERS acceptability and repeatability criteria. Conclusion: This study demonstrates SSc patients can perform acceptable FVC and DLCO tests using a QA process that included test feedback.