Defining Chronic Mucus Hypersecretion Using the CAT in the SPIROMICS Cohort.

Background: Chronic cough and phlegm are frequently reported chronic obstructive pulmonary disease (COPD) symptoms. Prior research classified chronic mucus hypersecretion (CMH) based on the presence of these symptoms for ≥3 months, called chronic bronchitis (CB) if respiratory infection symptoms were present for 1-2 years (Medical Research Council [MRC] definition). We explored whether the COPD Assessment Test (CAT), a simple measure developed for routine clinical use, captures CMH populations and outcomes similarly to MRC and St. George's Respiratory Questionnaire (SGRQ) definitions.
Methods: We identified CMH in the SPIROMICS COPD cohort using (a) MRC definitions, (b) SGRQ questions for cough and phlegm (both as most/several days a week), and (c) CAT cough and phlegm questions. We determined optimal cut-points for CAT items and described exacerbation frequencies for different CMH definitions. Moderate exacerbations required a new prescription for antibiotics/oral corticosteroids or emergency department visit; severe exacerbations required hospitalization. Results were stratified by smoking status.
Results: In a population of 1431 participants (57% male; mean FEV ₁ % predicted 61%), 47% and 49% of evaluable participants had SGRQ- or CAT-defined CMH, respectively. A cut-point of ≥2 for cough and phlegm items defined CMH in CAT. Among SGRQ-CMH+ participants, 80% were also defined as CMH+ by the CAT. CMH+ participants were more likely to be current smokers. A higher exacerbation frequency was observed for presence of CMH+ versus CMH- in the year prior to baseline for all CMH definitions; this trend continued across 3 years of follow-up, regardless of smoking status.
Conclusion: Items from the CAT identified SGRQ-defined CMH, a frequent COPD trait that correlated with exacerbation frequency. The CAT is a short, simple questionnaire and a potentially valuable tool for telemedicine or real-world trials. CAT-based CMH is a novel approach for identifying clinically important characteristics in COPD that can be ascertained in these settings.
Competing Interests: MS-M, BM, ALL, MT, and TK are employees and shareholders of GlaxoSmithKline plc. HM, CEB and RT-S are former employees and shareholders of GlaxoSmithKline plc. HM is a current employee of AstraZeneca. CEB has also provided contracting for Eli Lilly, outside of the submitted work. RT-S also reports receipt of consulting fees from ImmunoMet outside of the submitted work. FJM reports a grant from NHLBI during the conduct of the study; serving on steering committees for GlaxoSmithKline plc., Afferent/Merck, AstraZeneca, Bayer, Boehringer Ingelheim, Gilead, Nitto, Patara/Respivant, Pearl Pharmaceuticals, ProMedior/Roche, ProMetic, Stromedix/Biogen and Veracyte; being a member of advisory boards for GlaxoSmithKline plc., AstraZeneca, Boehringer Ingelheim, Bioscale/Proterrix Bio, Chiesi, Gala, Genentech, Novartis, Pearl Pharmaceuticals, Physicians Education Resource, CSL Behring, Sunovion, Teva and Zambon; consulting for BristolMyersSquibb, Bridge Biotherapeutics and two XR; has received continuing medical education presentation support from the Canadian Respiratory Network, Chiesi, CME outfitters, Dartmouth University, France Foundation, Inova Fairfax, MD Magazine, Methodist Hospital, Miller Communications, National Association for Continuing Education/Haymarket, New York University, PeerView, Prime Education, Rare Diseases Healthcare Communication, Rockpointe, University of Alabama Birmingham, UpToDate, Vindico, WebMD/MedScape, Zambon; also DSMB for Boehringer Ingelheim and GlaxoSmithKline plc. MH reports a grant from NHLBI during the conduct of the study; personal fees from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline plc., Merck and Mylan; research support from Novartis and Sunovion outside of the submitted work. MD reports grants from NIH during the conduct of the study and from NIH, American Lung Association, Department of Veterans Affairs, and Department of Defense outside of the submitted work. He reports personal fees from Boehringer Ingelheim, GlaxoSmithKline plc., PneumRx/BTG, AstraZeneca, Quark Pharmaceuticals, and Mereo; has contracted clinical trials for Boehringer Ingelheim, GlaxoSmithKline plc., Novartis, AstraZeneca, Yungjin, PneumRx/BTG, Pulmonx, Boston Scientific, Gala and Nuveira; and has received non-financial support from Pulmonx, outside the submitted work. NNH reports research grants from AstraZeneca, Boehringer Ingelheim, COPD Foundation, GlaxoSmithKline plc., NIH; advisory board fees for AstraZeneca, GlaxoSmithKline plc., Mylan. CBC reports grants from NIH/NHLBI and the NIH Foundation during the conduct of the study; personal fees from MGC Diagnostics, NUVEIRA and PulmonX; and has acted as a global medical expert for GlaxoSmithKline plc., outside of the submitted work. VK has received personal fees from Gala Therapeutics, AstraZeneca, Boehringer Ingelheim, and the American Board of Internal Medicine over the last 3 years, outside of the submitted work. APC reports a grant from NIH and receipt of consulting fees from GlaxoSmithKline plc., and non-financial support from VIDA outside of the submitted work. RP III reports research grants from COPD Foundation and NHLBI, and from the Department of Veterans Affairs outside of the submitted work. MBD reports a grant from NIH-NHLBI during the conduct of the study and receipt of consulting fees from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline plc., Mylan Theravance, and Parion, outside of the submitted work. REK, PW, VEO and WA have no conflicts of interest to report. The authors report no other conflicts of interest in this work.
(© 2020 Stott-Miller et al.)