TABLE 3.

Median parameter estimates from segmented regression models showing period starting glucose or intercept (B_o, mg/dL) and slope (B₁, mg/dL/h)

	HbA1c in target for age			HbA1c above target for age
Hours of day	8–14 years old	15–24 years old	≥25 years old	8–14 years old	15–24 years old	≥25 years old	P-value
Intercept	152.2 ± 1.8	143.5 ± 0.9	137.6 ± 0.9	188.6 ± 2.2	174.7 ± 1.5	162.1 ± 0.7	<.0001
12:00–5:59 am	−0.8 ± 0.5	−0.1 ± 0.2	−1.2 ± 0.2a	−2.4 ± 0.6a	−2.0 ± 0.4a	−1.9 ± 0.2a	.0003
6:00–9:59 am	2.0 ± 0.7a	−0.4 ± 0.3	1.5 ± 0.3a	3.3 ± 0.8a	1.4 ± 0.6a	1.1 ± 0.3a	.0002
10:00 am–12:59 pm	−4.4 ± 0.9a	−1.8 ± 0.4a	−0.7 ± 0.4	−3.4 ± 1.1a	0.7 ±0.8	0.1 ± 0.4	<.0001
1:00–4:59 pm	1.0 ± 0.7	0.5 ± 0.3	−0.5 ± 0.3	0.7 ± 0.9	−0.3 ± 0.6	−0.2 ± 0.3	.3210
5:00–8:59 pm	0.0 ± 0.7	1.5 ± 0.3a	0.1 ± 0.3	−0.2 0.9	1.1 0.6	0.8 0.3a	.2502
9:00–11:59 pm	1.5± 1.6	−0.6± 0.8	2.2± 0.8a	1.5 2.1	3.1 1.4a	2.7 0.6a	.4485

Abbreviation: HbA1c, glycated hemoglobin.

^aDenotes that slope is significantly different than zero (P < .05).