Table 2

Results of the univariate Cox proportional hazards analyses of the predictors of mortality in patients with chronic obstructive pulmonary disease (COPD)

	RR	95% CI	p-value
All deaths
CRQ
Dyspnoea	0.946	0.902–0.993	0.02
Fatigue	0.943	0.880–1.010	0.09
Emotional function	0.956	0.916–0.997	0.04
Mastery	0.944	0.877–1.017	0.13
Total	0.981	0.965–0.997	0.02
Age yrs	1.089	1.037–1.143	<0.001
BMI kg·m⁻²	0.778	0.691–0.876	<0.001
Current smoking	0.862	0.452–1.657	0.66
Postbronchodilator FEV₁ % pred	0.969	0.952–0.987	<0.001
Total lung capacity % pred	1.020	1.001–1.038	0.04
K_CO mmol·min⁻¹·kPa⁻¹·L⁻¹	0.102	0.034–0.306	<0.001
COPD deaths
CRQ
Dyspnoea	0.945	0.883–1.011	0.10
Fatigue	0.968	0.876–1.071	0.53
Emotional function	0.957	0.898–1.019	0.17
Mastery	0.914	0.813–1.027	0.13
Total	0.981	0.957–1.005	0.12
Age yrs	1.076	0.997–1.162	0.06
BMI kg·m⁻²	0.648	0.536–0.782	<0.001
Current smoking	0.964	0.371–2.510	0.94
Postbronchodilator FEV₁ % pred	0.937	0.909–0.966	<0.001
Total lung capacity % pred	1.032	1.006–1.058	0.01
K_CO mmol·min⁻¹·kPa⁻¹·L⁻¹	0.052	0.009–0.312	0.001

All deaths (n=143); COPD deaths (n=123)
RR: relative risk
CI: confidence interval
CRQ: Chronic Respiratory Disease Questionnaire
BMI: body mass index
FEV₁: forced expiratory volume in one second
% pred: % predicted
K_CO: carbon monoxide transfer coefficient