Incidence rates and hazard ratios of death and hospitalisations due to chronic obstructive pulmonary disease (COPD) by quartile (Q) of forced expiratory volume in 1 s % predicted
| Q4#,¶ | Q3 | Q2 | Q1+ | p-value for trend | |
| Subjects n | 172 | 172 | 173 | 172 | |
| COPD events n (n per 1000 person-years) | 14 (3.35) | 11 (2.67) | 22 (5.75) | 41 (13.52) | |
| COPD events unadjusted hazard ratio (95% CI) | 1.00 | 0.86 (0.39–1.89) | 1.86 (0.95–3.65) | 4.88 (2.64–9.01) | <0.001 |
| COPD events adjusted hazard ratio§ (95% CI) | 1.00 | 0.74 (0.33–1.63) | 1.60 (0.81–3.16) | 3.84 (2.03–7.27) | <0.001 |
| Deaths unadjusted hazard ratio (95% CI) | 1.00 | 1.18 (0.95–1.46) | 1.29 (1.04–1.59) | 1.96 (1.58–2.43) | <0.001 |
| Deaths adjusted hazard ratio§,ƒ (95% CI) | 1.00 | 1.09 (0.87–1.35) | 1.20 (0.97–1.49) | 1.67 (1.34–2.10) | <0.001 |
Q4: 107–143% predicted; Q3: 98–107% predicted; Q2: 86–97% predicted; Q1: 42–86% predicted. #: highest quartile; ¶: reference quartile; +: lowest quartile; §: adjusted for smoking status (three groups: never, ex- and current smokers), diabetes, body mass index, height and physical activity (three groups: high, moderate and low physical activity); ƒ: additionally adjusted for systolic blood pressure and cholesterol.