Table 2. Risk factors for the early group determined by multivariate analysis.

Variables	OR	95% CI	P value
Age, > 65 yr	4.64	1.22–17.55	0.024
Uncertain exposure history	2.70	0.73–9.94	0.133
Cardiovascular disease	9.14	0.63–130.82	0.103
Febrile sensation	6.01	1.65–21.82	0.006
Chilling	0.85	0.21–3.45	0.827
General weakness	8.73	0.86–87.79	0.066
Sputum	1.12	0.30–4.16	0.863
Dyspnea	29.98	2.55–352.66	0.007
Leukocytosis	0.20	0.00–5.73	0.349
Elevated AST	3.04	0.83–11.13	0.092
Elevated LDH	2.93	0.85–10.02	0.086
Elevated CRP	7.86	1.37–45.09	0.021
Elevated procalcitonin	9.60	0.56–163.92	0.118
Chest X-ray abnormality	8.15	1.16–56.99	0.035
Symptom onset > 5 days	9.12	1.58–52.38	0.013

OR = odds ratio, CI = confidence interval, AST = aspartate transaminase, LDH = lactate dehydrogenase, CRP = C-reactive protein.