Background: Chronic bronchitis (CB) increases risk of COPD exacerbations. We have shown that the St. George's Respiratory Questionnaire (SGRQ) CB definition identifies patients with a similar clinical phenotype as classically defined CB. Whether the SGRQ CB definition is a predictor of future COPD exacerbations is unknown. Methods: We analyzed 7,557 smokers with normal spirometry and Global Initiative for Chronic Obstructive Lung Disease stage 1-4 COPD in the Genetic Epidemiology of COPD study with longitudinal follow-up data on exacerbations. Subjects were divided into classic CB+ or classic CB–, using the classic definition. In addition, subjects were divided into SGRQ CB+ or SGRQ CB–. Exacerbation frequency and severe exacerbation frequency were determined in each group. Multivariable linear regressions were performed for exacerbation frequency with either classic CB or SGRQ CB and relevant covariates. Results: There were 1,434 classic CB+ subjects and 2,290 SGRQ CB+ subjects. The classic CB+ group had a greater exacerbation frequency compared with the classic CB– group (0.69 ± 1.26 vs 0.36 ± 0.90 exacerbations per patient per year; P < .0001) and a greater severe exacerbation frequency (0.26 ± 0.74 vs 0.13 ± 0.46 severe exacerbations per patient per year; P < .0001). There were similar differences between the SGRQ CB+ and SGRQ CB– groups. In multivariable analysis, both SGRQ CB and classic CB were independent predictors of exacerbation frequency, but SGRQ CB had a higher regression coefficient. In addition, SGRQ CB was an independent predictor of severe exacerbation frequency whereas classic CB was not. Conclusions: The SGRQ CB definition identified more subjects at risk for future exacerbations than the classic CB definition. SGRQ CB was at least a similar if not better predictor of future exacerbations than classic CB.
Bibliographical noteFunding Information:
Financial/nonfinancial disclosures: V. K. has received personal fees from CSA Medical, AstraZeneca , Boehringer Ingelheim , and Concert Pharmaceuticals. V. K. has also received personal fees from the American Board of Internal Medicine and Gala Therapeutics. M. K. H. reports consulting for GlaxoSmithKline , Boehringer Ingelheim , and AstraZeneca . She has received research support from Novartis and Sunovion . B. J. M. reports funding from the NHLBI for the COPDGene study; grants and medical advisory boards from Boehringer Ingelheim , GlaxoSmithKline , AstraZeneca , and Sunovion; personal fees for DSMB from Spiration and Shire /Baxalta; CME personal fees from WebMD, National Jewish Health , the American College of Chest Physicians, Projects in Knowledge, Hybrid Communications, SPIRE Learning, Ultimate Medical Academy, Catamount Medical, Eastern Pulmonary Society, Catamount Medical Communications Medscape, Eastern VA Medical Center, Academy for Continued Healthcare Learning, and Mt. Sinai Medical Center; royalties from Up-To-Date; medical advisory boards from Novartis , Phillips, Third Pole, Science 24/7, and Vernoa; grants from Pearl; outside the submitted work. J. L. C. reports a grant from NHLBI directly related to this study, and grants from NIAID , NHLBI , the Department of Veterans Affairs , Department of Defense , and MedImmune Corp. Ltd, outside the scope of this study. E. K. S. received honoraria from Novartis for Continuing Medical Education Seminars and grant and travel support from GlaxoSmithKline. G. J. C. has received grants from the US NIH and the Department of Defense, consulting from AstraZeneca, Boehringer Ingelheim, Holaira, Mereo, Third Pole, PneumRx, Pulmonx, Pearl, Amirall, CSA Medical, Broncus, AVISA, Lungpacer, and GlaxoSmithKline; and contracted clinical trials from AstraZeneca, Avisa, Mereo, Boehringer Ingelheim, Broncus, GlaxoSmithKline, Lungpacer, Novartis, Pulmonx, PneumRx/BTG, and Yungjin. None declared (H. Z., E. R., J. D. C., P. W. J.).
- chronic bronchitis