Table 1.

Characteristics of the Study Patients^*

	Total Sample (N= 23,291)	With Index and Outcome HbA1c (N= 12,523)	Without Both Index and Outcome HbA1c (N= 10,768)	p-Value†
Age (years)	65.3±10.4	65.3±10.1	65.3±10.8	.69
Male gender (%)	97.2	97.4	97.0	.05
Diabetic complication (%)	41.6	43.1	39.7	<.0001
Additional cardiovascular risk factor (%)	78.2	79.5	76.7	<.0001
Charlson index‡	1.09±1.57	1.06±1.52	1.14±1.63	<.0001
On insulin at baseline (%)	28.6	32.2	24.5	<.0001
Index HbA1c§	7.8±1.9	7.8±1.9	7.6±1.9	—
Index HbA1c>8% (%)§	39.1	39.8	36.0	—
Outcome HbA1c¶	7.8±1.6	7.8±1.6	7.7±1.7	—
Outcome HbA1c>8% (%)¶	39.4	40.3	36.6	—
No. of visits	11.4±6.6	12.2±6.7	10.6±6.4	<.0001
Months between index and outcome visits	15.8±1.9	15.9±1.6	15.7±2.2	<.0001

^*Continuous variables described as mean±standard deviation

^†p-value compares group with index and outcome HbA1c to group without

^‡Charlson index excludes diabetes

^§N =15,437 for total sample and N =2,914 for without both sample

^¶N =16,800 for total sample and N =4,277 for sample without both.

HbA1c, hemoglobin A1c