TABLE 4.

Incidence Rates of Stroke by Type of Health Care Encounters and Associations Between Stroke and Baseline HbA1c

Health Care Settings				Baseline HbA1c (%)
	< 6.0	6.0–6.5	6.5–7.0	7.0–7.9	8.0–8.9	9.0–9.9	≥ 10
Stroke cases diagnosed in all health care settings
No. of patients	9726	12,961	11,641	14,537	7371	3898	4721
No. cases	1282	1580	1372	1997	1015	530	513
Person-years	25,337	38,077	35,930	47,438	23,413	12,164	13,471
Incidence rate	50.60	41.49	38.19	42.10	43.35	43.57	38.08
Age-adjusted HR (95% CI)	1.22 (1.13–1.31)	1.00	0.96 (0.89–1.03)	1.10 (1.03–1.17)	1.23 (1.14–1.33)	1.42 (1.28–1.56)	1.39 (1.25–1.54)
Multivariable-adjusted HR (95% CI)	1.10 (1.03–1.19)	1.00	0.96 (0.90–1.04)	1.06 (0.99–1.13)	1.15 (1.06–1.25)	1.33 (1.20–1.47)	1.28 (1.15–1.42)
Stroke cases diagnosed only in inpatient and emergency encounters
No. patients	8697	11,606	10,484	12,847	6526	3465	4371
No. cases	253	225	215	307	170	97	163
Person-years	23,824	35,852	34,071	44,552	22,016	11,455	12,860
Incidence rate	10.62	6.28	6.31	6.89	7.72	8.47	12.67
Age-adjusted HR (95% CI)	1.65 (1.38–1.98)	1.00	1.02 (0.85–1.23)	1.15 (0.97–1.37)	1.47 (1.20–1.79)	1.77 (1.39–2.25)	3.00 (2.44–3.70)
Multivariable-adjusted HR (95% CI)	1.41 (1.18–1.70)	1.00	1.05 (0.87–1.27)	1.14 (0.96–1.36)	1.37 (1.12–1.68)	1.61 (1.26–2.06)	2.50 (2.01–3.10)
Difference in age-adjusted HR (95% CI)	1.36 (1.12–1.65)*	—	1.07 (0.88–1.31)	1.05 (0.87–1.27)	1.19 (0.96–1.48)	1.25 (0.97–1.62)	2.16 (1.72–2.73)*
Difference in multivariable-adjusted HR (95% CI)	1.28 (1.05–1.56)*	—	1.09 (0.89–1.33)	1.08 (0.89–1.30)	1.19 (0.95–1.49)	1.21 (0.93–1.59)	1.95 (1.53–2.48)*

The unit of incidence rate is the number of new cases per 1000 person-years.

^*P < 0.05.

CI indicates confidence interval; HbA1c, hemoglobin A1c; HR, hazard ratio.