Table 3. Results of multivariate analyses.

Factors	Crude OR	95%CI	Adjusted OR	95% CI	p-value
Age	0.97	2.69–12.97	0.96	0.92–1.01	0.088
Previous OIs	4.78	2.16–10.61	14.87	2.36–93.86	0.004
Birthplace outside central region	8.61	2.80–26.48	19.19	3.86–95.35	<0.001
Lack of comorbidities	6.26	3.01–13.05	23.68	4.01–139.94	<0.001
HLA alleles*	41.94	9.33–188.59	153.28	16.87–139.88	<0.001

* HLA alleles: Presence of HLA-DRB1*15 or 16