Table 3b. Association between time-varying HbA1c values and incidence of ischemic stroke using different rules for classifying time-varying HbA1c values (i.e. valid for 6 months, valid for 1.5 years, and assessed using linear interpolation).

	HbA1c < 7.0%	HbA1c 7.0-8.9%	HbA1c > 9.0%
6-Months
Ischemic stroke events	32	33	7
Person-years (py)	1229.7	1173.5	431.8
Rate	2.6/100 py	2.8/100 py	1.6/100 py
Hazard Ratio (unadjusted)	-	1.15 (0.70-1.88)	0.62 (0.27-1.41)
Hazard Ratio (adjusted*)	-	1.13 (0.67-1.92)	0.68 (0.29-1.62)
1.5 Years
Ischemic stroke events	48	51	16
Person-years (py)	1905.7	1684.9	660.0
Rate	2.5/100 py	3.0/100 py	2.4/100 py
Hazard Ratio (unadjusted)	-	1.24 (0.83-1.85)	0.96 (0.55-1.69)
Hazard Ratio (adjusted*)	-	1.24 (0.81-1.88)	0.95 (0.53-1.72)
Linear Interpolation
Ischemic stroke events	55	59	20
Person-years (py)	1953.3	1953.1	712.8
Rate	2.8/100 py	3.0/100 py	2.8/100 py
Hazard Ratio (unadjusted)	-	1.10 (0.77-1.59)	0.94 (0.57-1.57)
Hazard Ratio (adjusted*)	-	1.12 (0.76-1.63)	0.93 (0.55-1.58)

^*Adjusted for age, gender, race, education, income, congestive heart failure, hypertension, prior thromboembolism, coronary artery disease, peripheral arterial disease, proteinuria, significant kidney dysfunction, insulin use, and diabetes duration. Py = person-years