Table 1—

Demographic and clinical data of the study population

Age groupp-value
<65 yrs≥65 yrs
Subjects n12981349
Age yrs47.2±12.777.1±7.5
Males/females n716/582770/5790.33
Body mass index kg·m−225.1±5.525.3±4.50.43
Smokers44.917.8<0.001
Body temperature °C37.9±1.237.7±1.1<0.001
Dyspnoea68.281.7<0.001
Purulent sputum53.362.3<0.001
Cough87.084.00.29
Pleuritic pain49.028.5<0.001
Pleuritic effusion12.618.3<0.001
Confusion5.216.4<0.001
BUN mM5.7±4.79.2±6.3<0.001
Respiratory frequency breaths·min−119.8±6.520.8±6.6<0.001
Blood pressure mmHg
 Systolic123.3±19.0134.6±24.4<0.01
 Diastolic74.7±11.875.9±13.6<0.001
Blood pH7.45±0.077.44±0.06<0.01
Pa,O2mmHg67.2±17.365.1±16.8<0.05
Pa,CO2mmHg35.4±8.236.9±8.7<0.05
Sa,O2 %92.6±6.191.4±5.7<0.01
Leukocytes cells·nL−112.6±6.213.3±6.1<0.01
C-reactive protein mg·L−1137.4±127.9139.6±118.60.68
Glucose mM6.6±2.98.1±3.8<0.001
  • Data are presented as mean±sd or %, unless otherwise indicated. BUN: blood urea nitrogen; Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension; Sa,O2: arterial oxygen saturation. 1 mmHg = 0.133 kPa.