Table 1

Demographics

Frimley parkSt Mary'sLeedsAll hospitals
Total number recruited7127293171758
Male (%)56524752
Median age (range)53 years (10 weeks–97 years)47 years (7 months–96 years)54 years (16–90 years)50 years (10 weeks–97 years)
<18 years (%)2.13.70.92.2
Smokers (%)188 (26)188 (26)103 (32)479 (27)
Median COHb (range) in smokers3.0% (0–33.3%)2.0% (0–21%)3.8% (0–11%)2.6% (0–33.3%)
Median COHb (range) in non–smokers1.3% (0–22.2%)1.0% (0–18.1%)1.5% (0–8%)1.0% (0–22.2%)
Percentage of positive cases (95% CI)4.6% (3.2% to 6.4%)1.8% (1.0% to 3.0%)9.5% (6.5% to 13.2%)4.3% (3.4% to 5.4%)
Median COHb (range) for positive cases5.9% (2.0–33.3%)
n=33
11.4% (4.9–21%)
n=13
6.3% (2.5–11%)
n=30
6.1% (2.0–33.3%)
n=76
Median COHb (range) for negative cases1.4% (0–8.3%)
n=679
1% (0–7.9%)
n=716
1.7% (0–7.7%)
n=287
1.2% (0–8.3%)
n=1682
  • COHb, carboxyhaemoglobin.