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Fasting c‐peptide and insulin‐like growth factor‐binding protein‐1 levels help to distinguish childhood type 1 and type 2 diabetes at diagnosis
Author(s) -
Levitt Katz Lorraine E,
Jawad Abbas F,
Ganesh Jaya,
Abraham Máire,
Murphy Kathryn,
Lipman Terri H
Publication year - 2007
Publication title -
pediatric diabetes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.678
H-Index - 75
eISSN - 1399-5448
pISSN - 1399-543X
DOI - 10.1111/j.1399-5448.2007.00236.x
Subject(s) - medicine , type 1 diabetes , endocrinology , diabetes mellitus , c peptide , type 2 diabetes mellitus , insulin , urine
Background: Children with new onset diabetes (n = 175) were evaluated over 12‐months. Patients were presumptively diagnosed with type 2 diabetes mellitus (T2DM) (n = 26) based on obesity, a relative with T2DM, the ability to wean from insulin, and absence of glutamic acid decarboxylase‐65 (GAD‐65) antibodies. We hypothesized that markers of insulinization at diagnosis, including fasting C‐peptide and insulin‐like growth factor‐binding protein (IGFBP)‐1, in addition to initial CO 2 levels and urine ketones, would help in distinguishing type 1 diabetes mellitus (T1DM) from T2DM. Results: Children with T1DM (84 male, 65 female) had a mean age of 8.7 ± 4.3 yr and a racial background of 78% white, 19% black, and 3% other. In contrast, children with T2DM (13 female, 13 male) had a mean age of 14.2 ± 3.1 yr with a racial background of 58% black, 27% white, and 15% other. Fasting C‐peptide level was 0.38 ± 0.37 ng/mL in T1DM vs. 2.66 ± 2.14 ng/mL in T2DM; a C‐peptide of 0.85 ng/mL had 83% sensitivity in distinguishing T1DM from T2DM. Fasting IGFBP‐1 level was 38.1 ± 39.1 ng/mL (T1DM) vs. 3.6 ± 4.5 ng/mL (T2DM); a value of 3.6 ng/dL could distinguish the two types of diabetes with 93% sensitivity. Urinary ketones were found in 79% of children with T1DM compared with 56% of those with T2DM, and the magnitude was associated with type of diabetes. Initial CO 2 level for T1DM was 17.9 ± 6.9 mmol/L vs. 22.7 ± 5.7 mmol/L for T2DM; a value of 21.5 mmol/L could distinguish the two types of diabetes with 83% sensitivity. Conclusions: In addition to obesity, family history of T2DM, and absence of GAD‐65 antibodies, children with new‐onset T2DM may be distinguished from those with T1DM by a combination of biochemical parameters (C‐peptide, IGFBP‐1, CO 2 , and urine ketones).