Table 5.

Multiple logistic regression results for prediction of insomnia among participants with chronic obstructive pulmonary disease

Variablea	OR	95% CI	P
Oxygen use	0.35	0.14–0.90	0.029
Smoking	2.13	1.02–4.44	0.044
β-agonist use	0.83	0.27–2.43	0.69
β-agonist within 2 hr of bedtime	0.91	0.34–2.45	0.85
Tiotropium/formoterol use	0.75	0.28–1.98	0.55
Sadness/anxiety	3.57	1.31–9.62	0.013

^aOxygen use was associated with lower odds of insomnia, whereas smoking and frequently feeling sad or anxious were associated with higher odds of insomnia. CI, confidence interval; OR, odds ratio.