All-cause and cause-specific mortality from restrictive and obstructive spirometric patterns in Chinese adults with and without dyspnea: Guangzhou Biobank Cohort Study

Objective: To study whether abnormal spirometric patterns were associated with differential mortality in Chinese adults with and without dyspnea.

Methods: Guangzhou Biobank Cohort Study (GBCS) participants were classified by spirometric patterns and presence of dyspnea into 6 groups: normal spirometry (NS), restriction on spirometry (ROS) and airflow obstruction (AO), each with and without dyspnea. Adjusted hazard ratios (aHRs) were calculated for mortality using Cox models.

Results: Among 16777 subjects, 1595 (9.5%) had ROS, 1036 (6.2%) had AO and 1009 (6.0%) had dyspnea. A total of 1993 deaths (11.9%) occurred during 11-year follow-up. Using NS without dyspnea as reference, NS with dyspnea was significantly associated with increased cardiovascular mortality risk (aHRs 1.61 (95% confidence interval (CI) 1.18-2.19); ROS with and without dyspnea were associated with increased risks of all-cause (aHRs 1.46 (95% CI 1.28-1.66) and 1.81 (95% CI 1.33-2.47)) and cardiovascular mortality (aHRs 1.89 (95% CI 1.55-2.31) and 1.85 (95% CI 1.12-3.03)), but not of lung cancer mortality (aHRs 1.33 (95% CI 0.91-1.94) and 1.35 (95% CI 0.49-3.70)); AO with and without dyspnea were associated with increased risks of all-cause (aHRs 1.59 (95% CI 1.36-1.86) and 2.36 (95% CI 1.77-3.15)), cardiovascular (aHRs 1.43 (95% CI 1.08-1.90) and 1.61 (95% CI 0.91-2.82)) and lung cancer mortality (aHRs 1.91 (95% CI 1.29-2.84) and 3.01 (95% CI 1.46-6.23)). These associations did not vary by sex or smoking status (all P-values for interaction >0.05).

Conclusion: Both ROS and AO, with and without dyspnea, were associated with increased all-cause and cardiovascular disease mortality. The increased risk of all-cause was greater and that of cardiovascular mortality was lower for AO than ROS. AO showed significantly increased risk of lung cancer but ROS did not. (272 words).