Table 3.

Incidence of complications by risk factor.

Complication	Risk Factor	Rate of Complication, %	RR	95% CI
Pneumonia	None	1.35	Ref.
	COPD	3.54	2.63	2.33–2.97
	Diabetes	2.73	2.03	1.79–2.30
	Smoking	2.40	1.78	1.54–2.06
	All	4.34	3.22	2.59–4.02
Acute respiratory failure	None	1.37	Ref.
	COPD	3.43	2.50	2.21–2.82
	Diabetes	3.02	2.20	1.94–2.48
	Smoking	2.20	1.60	1.38–1.86
	All	4.30	3.13	2.51–3.90
Pulmonary collapse	None	3.42	Ref.
	COPD	5.60	1.64	1.50–1.78
	Diabetes	5.01	1.46	1.34–1.59
	Smoking	4.05	1.18	1.07–1.31
	All	6.00	1.75	1.47–2.09
Pleural effusion	None	1.28	Ref.
	COPD	2.55	1.99	1.74–2.27
	Diabetes	2.08	1.62	1.42–1.86
	Smoking	1.62	1.26	1.07–1.49
	All	2.82	2.20	1.68–2.87

Abbreviation: All, all 3 risk factors (chronic obstructive pulmonary disease [COPD], diabetes, smoking); RR, risk ratio.