Study objectives: To determine if the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 0 (subjects at risk for COPD) provides information about long-term mortality risk.
Design, setting, and participants: From 1972 to 1975, clinical, physiologic, and biochemical parameters including respiratory symptoms, spirometry, and physical fitness were measured in 1,999 healthy men aged 40 to 59 years in an occupational cohort, of whom 1,623 had acceptable spirometry findings. In a proportional hazards model with follow-up until 2000, we assessed all-cause mortality according to GOLD stage 0, I, II, and III compared with "normal" subjects, after adjusting for known risk factors and potential confounders.
Results: After 26 years (range, 25 to 27 years), 615 men (38%) had died. In multivariate proportional hazards models, GOLD stage 0 subjects had a nonsignificantly increased hazard of death (hazard ratio [HR], 1.19; p = 0.21) after adjustment for age, smoking, physical fitness, body mass index, systolic BP, and serum cholesterol. Similarly, subjects in GOLD stage I (HR, 1.30; p = 0.05) and stage II (HR, 1.77; p < 0.0001) had increased all-cause mortality. When expanding GOLD stage 0 to comprise patients with any respiratory symptom in a sensitivity analysis, the HR for all-cause mortality increased (HR, 1.35; p = 0.03).
Conclusion: There probably is an excess mortality among GOLD stage 0 subjects compared to symptom-free subjects; however, this should be interpreted cautiously and the results vary with the definition of the GOLD stage 0. Subjects in GOLD stage I or stage II had higher mortality than symptom-free subjects.