Results from the multivariate Cox model predicting COPD mortality risk (N=783, 80 deaths#)

HR (95% CI)p-value
CMV tertiles
 Medium1.65 (0.84–3.25)0.146
 High2.30 (1.18–4.50)0.015
Chlamydophila pneumoniae tertiles
 Medium0.73 (0.37–1.42)0.358
 High2.30 (1.28–4.10)0.005
Mycoplasma pneumoniae tertiles
 Medium0.94 (0.52–1.69)0.832
 High0.71 (0.39–1.30)0.266
C-reactive protein in z-scores1.02 (0.79–1.32)0.881
Age in years1.11 (1.07–1.15)<0.001
Sex (ref.: male)0.064
 Female0.57 (0.32–1.03)
Education level (ref.: ≥12 years)0.271
 <12 years1.36 (0.78–2.37)
BMI category (ref.: normal weight)
 Underweight6.16 (2.11–18.04)0.001
 Overweight0.48 (0.27–0.86)0.014
 Obese0.36 (0.12–1.10)0.073
Smoking status (ref.: never)
 Former0.86 (0.37–1.99)0.730
 Current2.98 (1.36–6.51)0.006
Smoking history pack-years1.01 (1.0–1.02)0.073
FEV1 % predicted0.95 (0.93–0.96)<0.001

Body mass index (BMI) was categorised as: underweight, <18.5 kg·m−2; normal weight, 18.5–24.9 kg·m−2; overweight, 25–29.9 kg·m−2; obese, BMI ≥30 kg·m−2. Level of education was categorised as ≤12 years or >12 years of formal education. Total numbers are lower than the 806 included participants because some individuals had missing information on covariates. HR: hazard ratio; CMV: cytomegalovirus; FEV1: forced expiratory volume in 1 s. #: includes death events with COPD listed as either the underlying cause or a coexisting condition on the death certificate.