β-Cell Function and the Development of Diabetes-Related Complications in the Diabetes Control and Complications Trial

Michael W. Steffes; Shalamar Sibley; Melissa Jackson; William Thomas

doi:10.2337/diacare.26.3.832

Pathophysiology/Complications

β-Cell Function and the Development of Diabetes-Related Complications in the Diabetes Control and Complications Trial

Michael W. Steffes, MD, PHD1,
Shalamar Sibley, MD, MPH2,
Melissa Jackson, MPH3 and
William Thomas, PHD3

¹Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota
²Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota
³Division of Biostatistics, University of Minnesota School of Public Health, Minneapolis, Minnesota

Diabetes Care 2003 Mar; 26(3): 832-836. https://doi.org/10.2337/diacare.26.3.832

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Figure 1—
Percentages of subjects who experienced at least one episode of severe hypoglycemia over the first 6 years of the DCCT. χ² analysis among the groups: intensive (P = 0.001); conventional (P = 0.006).

Tables

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Table 1—

Demographic characteristics of the DCCT subjects

	Stimulated C-peptide group
		Undetectable	Minimal	Baseline-only	Sustained
n (%)	634 (44)	519 (36)	130 (9)	159 (11)
Intensive therapy* (%)	52	48	36	55
Retinopathy at baseline* (%)	73	41	8	19
Female (%)	50	45	41	49
Age (years) (%)	26 ± .3^a	27 ± .3^a	27 ± .3^ab	29 ± .6^b
Duration (years)	8.2 ± .1^a	4.5 ± .1^b	1.9 ± .3^c	2.3 ± .3^c
HbA_1c at eligibility	9.3 ± .1^a	9.2 ± .1^a	8.4 ± .1^b	8.4 ± .1^b
HbA_1c at baseline	9.0 ± .1^a	9.0 ± .1^a	8.4 ± .1^b	8.2 ± .1^b
AER (mg/24 h) (95% CI)	13.5^a (12.6–14.4)	10.0^b (9.4–10.7)	9.2^b (8.3–10.7)	9.7^b (8.7–10.7)

*
↵* Percentages differ significantly (χ² test, P < 0.005). Where stimulated C-peptide group means differed significantly (P < 0.05), the groups with the same letter were indistinguishable. Data are n (%), %, means ± SE, or means (95% CI). All statistical comparisons are between stimulated C-peptide groups within a single row.

Table 2—

Retinopathy (a single three-step change on the ETDRS scale) and albuminuria (a single event >40 mg/24 h) during the first 6 years of the DCCT, by stimulated C-peptide group

	Stimulated C-peptide group					All
		Undetectable	Minimal	Baseline-only	Sustained	All
Retinopathy
All	7.8 ± 0.5^a	5.7 ± 0.5^b	5.2 ± 0.9^bc	3.5 ± 0.7^c	6.3 ± 0.3
Intensive	6.5 ± 0.7^a	3.5 ± 0.5^b	1.8 ± 0.9^bc	1.4 ± 0.6^c	4.5 ± 0.4
Conventional	9.2 ± 0.8^a	7.9 ± 0.8^a	7.3 ± 1.4^a	6.3 ± 1.4^a	8.2 ± 0.5
Albuminuria
All	4.4 ± 0.4^a	2.7 ± 0.3^b	3.1 ± 0.7^ab	1.4 ± 0.4^c	3.3 ± 0.2
Intensive	4.0 ± 0.5^a	2.3 ± 0.4^b	1.7 ± 0.9^bc	0.9 ± 0.5^c	2.9 ± 0.3
Conventional	4.9 ± 0.6^a	2.9 ± 0.5^b	3.9 ± 1.0^ab	2.1 ± 0.8^b	3.8 ± 0.3

Data are rates ± SE per 100 participant-years. Rates were compared (horizontally) between stimulated C-peptide groups. For each comparison, rates with different letters were significantly different (P < 0.05), while rates sharing the same letter were indistinguishable.

Table 3—

Hypoglycemia: first occurrence during the first 6 years of the DCCT, by stimulated C-peptide group and by treatment group

	Stimulated C-peptide group					All
		Undetectable	Minimal	Baseline-only	Sustained	All
All	13 ± 1^a	10 ± 1^b	7 ± 1^c	6 ± 1^c	12 ± 0.5
Intensive	21 ± 1^a	16 ± 1^b	17 ± 3^ab	7 ± 1^c	16 ± 0.8
Conventional	8 ± 1^a	6 ± 1^b	3 ± 1^c	5 ± 1^bc	6 ± 0.4

Data are rates ± SE per 100 participant-years. Rates were compared among stimulated C-peptide groups (horizontally) with each treatment group. For each comparison, rates with different letters were significantly different (P < 0.05), while rates sharing the same letter were indistinguishable.

Table 4—

Hypoglycemia: first occurrence during the first 6 years of the DCCT, by stimulated C-peptide group and by HbA_1c category

Stimulated C-peptide group	HbA_1c category
Stimulated C-peptide group		<7.5%	7.5–9.0%	>9.0%
Undetectable	23 ± 2^a	13 ± 1^b	4 ± 1^c
Minimal	20 ± 2^a	8 ± 1^b	3 ± 1^c
Baseline-only	21 ± 4^a	4 ± 1^b	2 ± 1^b
Sustained	8 ± 1^a	6 ± 0.2^a	1 ± 0.7^b
All	19 ± 1	9 ± 0.7	3 ± 0.4

Data are rates ± SE per 100 participant-years. Rates were compared among HbA_1c categories (horizontally) within each stimulated C-peptide group. For each comparison, rates with different letters were significantly different (P < 0.05), while rates sharing the same letter were indistinguishable.