Table 3. Negative binomial generalized estimation equation for the effect of continuity of care on DM-specific emergency room use.

	Incidence rate	Crude IRR	95% CI	Adjusted IRR	95% CI
Continuity of care index (COCI)
Low (reference)	0.14
Medium	0.11	0.85*	(0.74, 0.97)	0.86*	(0.75, 0.99)
High (COCI = 1)	0.06	0.50**	(0.44, 0.56)	0.54**	(0.47, 0.61)
Sex
Male (reference)	0.09
Female	0.09	0.94	(0.83, 1.08)	0.98	(0.86, 1.11)
Age, years
20–39 (reference)	0.12
40–65	0.08	0.64**	(0.51, 0.81)	0.56**	(0.45, 0.70)
>65	0.11	0.91	(0.71, 1.15)	0.65**	(0.51, 0.82)
Area
Taipei	0.09
North	0.10	1.05	(0.86, 1.30)	0.95	(0.77, 1.18)
Central	0.11	1.21*	(1.01, 1.44)	1.10	(0.92, 1.32)
South	0.08	0.92	(0.75, 1.13)	0.80*	(0.65, 0.99)
Kuoshong-Pingdong	0.08	0.84	(0.69, 1.03)	0.80*	(0.65, 0.97)
East	0.11	1.27	(0.88, 1.84)	1.23	(0.85, 1.78)
Charlson Comorbidity Index
1 (reference)	0.05
2	0.10	1.74**	(1.52, 2.00)	1.50**	(1.30, 1.73)
≥3	0.17	3.09**	(2.71, 3.52)	2.15**	(1.83, 2.52)
Diabetes Complication Severity Index
0 (reference)	0.06
1	0.09	1.37**	(1.19, 1.58)	1.05	(0.90, 1.23)
≥2	0.21	3.21**	(2.81, 3.65)	2.09**	(1.79, 2.44)
Income, New Taiwan $
<20 000 (reference)	0.11
20 000–39 999	0.08	0.75**	(0.65, 0.88)	0.86	(0.74, 1.00)
≥40 000	0.08	0.80*	(0.67, 0.96)	0.90	(0.75, 1.08)
Fishermen/farmers	0.09	0.93	(0.79, 1.10)	1.02	(0.86, 1.21)

CI, confidence interval; IRR, incidence rate ratio.

*P < 0.05.

**P < 0.01.

1 United States $ ≈ 30 New Taiwan $.