Table 2.

Factors of gastrointestinal perforation in 6-month tracking by using Cox regression

Variables	Crude HR	95% CI	95% CI	P	Adjusted HR	95% CI	95% CI	P	Adjusted HR	95% CI	95% CI	P
Fluoroquinolones
Without	Reference				Reference				Reference
With	0.997	0.586	1.696	0.990	1.329	0.776	2.274	0.257	1.330	0.778	2.276	0.255
Gender
Male	1.153	0.753	1.764	0.513	1.040	0.791	1.340	0.062	1.033	0.809	1.382	0.064
Female	Reference				Reference				Reference
Age (years)	0.976	0.939	1.014	0.214	0.968	0.931	1.006	0.094
Age group (years)
< 1	Reference								Reference
1	1.835	0.708	4.756	0.212					2.047	0.784	5.345	0.123
2	0.620	0.106	2.290	0.473					0.669	0.810	2.488	0.556
3	1.802	0.715	4.540	0.212					1.822	0.752	4.648	0.189
4	0.368	0.079	1.703	0.201					0.381	0.880	1.778	0.225
5–9	0.441	0.193	1.008	0.052					0.433	0.179	0.952	0.040
10–14	0.415	0.177	0.971	0.043					0.386	0.163	0.909	0.028
≧15	0.944	0.442	2.014	0.881					0.831	0.384	1.789	0.661
Catastrophic illness
Without	Reference				Reference				Reference
With	5.972	0.014	161.782	0.985	2.740	0.292	13.421	0.928	2.739	0.291	13.411	0.938
Low-income household
Without	Reference				Reference				Reference
With	1.643	0.090	4.620	0.661	1.546	0.076	4.105	0.578	1.541	0.072	4.070	0.572
Season
Spring	Reference				Reference				Reference
Summer	0.218	0.127	0.377	< 0.001	0.209	0.121	0.362	< 0.001	0.022	0.126	0.374	< 0.001
Autumn	0.017	0.006	0.047	< 0.001	0.018	0.006	0.048	< 0.001	0.017	0.007	0.050	< 0.001
Winter	0.056	0.032	0.098	< 0.001	0.057	0.032	0.099	< 0.001	0.057	0.032	0.100	< 0.001
Urbanization level
1 (the highest)	1.993	1.032	3.849	0.040	2.034	1.033	4.002	0.033	2.043	1.031	4.024	0.029
2	0.596	0.276	1.288	0.188	0.526	0.239	1.144	0.115	0.527	0.242	1.146	0.116
3	2.357	1.184	4.691	0.015	2.581	1.294	5.146	0.003	2.586	1.294	5.153	0.006
4 (the lowest)	Reference				Reference				Reference
Level of care
Hospital center	2.909	1.232	6.871	0.015	2.768	1.132	6.759	0.014	2.757	1.124	6.734	0.010
Regional hospital	7.613	4.608	12.579	< 0.001	8.351	5.008	13.884	< 0.001	8.480	5.029	14.208	< 0.001
Local hospital	6.213	3.425	11.269	< 0.001	5.304	2.911	9.672	< 0.001	5.222	2.864	9.526	< 0.001
Physician clinics	Reference				Reference				Reference
Comorbidities (No reference)
Cerebrovascular accident	10.454	0.022	25.124	0.986	5.131	0.009	16.752	0.992	5.104	0.009	16.641	0.992
Diabetes mellitus	3.401	0.564	6.785	0.298	3.105	0.482	6.131	0.384	3.078	0.476	6.079	0.390
Hypertension	1.898	0.675	3.996	0.744	1.776	0.603	3.297	0.756	1.623	0.598	3.111	0.758
Hyperlipidemia	0.000	–	–	0.989	0.000	–	–	0.997	0.000	–	–	0.997
Drugs (No reference)
NSAID	1.264	0.842	1.677	0.562	1.189	0.675	1.597	0.599	1.187	0.673	1.589	0.598
Systemic steroid	1.101	0.765	1.297	0.438	1.086	0.567	1.273	0.501	1.085	0.561	1.270	0.497

HR Hazard ratio, CI Confidence interval, Adjusted HR Adjusted variables listed in the table, NSAID Non-steroidal anti-inflammatory drugs