Table 3.

Predictors of SpO₂ ≤ 95% in 369 patients aged 40 years or over diagnosed in general practice with asthma and/or COPD.

Patient characteristics	Odds ratio (95% CI)	p-value
FEV1% predicted
> 80	Reference	0.002
50–80	2.9 (1.5–5.8)	<0.001
< 50	6.8 (2.8–16.4)
Coronary heart disease	2.0 (1.1–3.8)	0.03
Age	1.0 (1.0–1.1)	0.004
Sex male	0.8 (0.4–1.4)	0.43
Asthma-only diagnosis	1.1 (0.6–2.1)	0.75
Haemoglobin above normal	2.5 (1.0–6.0)	0.04

Notes: CI = confidence interval; SpO₂ = arterial oxygen saturation measured by pulse oximetry; FEV₁ = forced expiratory volume in one second.