Original Article

Prevalence and Impact of Initial Misclassification of Pediatric Type 1 Diabetes Mellitus

Authors: Avnish Tripathi, MD, MPH, Ali A. Rizvi, MD, Lisa M. Knight, MD, Jeanette M. Jerrell, PhD


Purpose: To characterize rates of initial misclassification of type 1 diabetes mellitus as type 2/unspecified diabetes mellitus in a cohort of children/adolescents and to examine the impact of misclassification on the risk of diabetes-related complications.

Methods: An 11-year dataset (1996–2006) was analyzed. Inclusion criteria included age 17 years and younger, enrollees in South Carolina State Medicaid, and diagnosis of type 2/unspecified or type 1 diabetes mellitus for at least two visits, 15 days apart. Survival analysis was used to assess the association of “misclassification” with the incidence of diabetic ketoacidosis (DKA), and the cumulative incidence of neuropathy, nephropathy, and cardiovascular complications, after controlling for individual risk factors and comorbid conditions.

Results: A total of 1130 individuals meeting the inclusion criteria were studied for a median of 7 years. Of the 1130 individuals, 669 (59.2%) maintained a diagnosis of type 2/unspecified diabetes mellitus, 205 (18.1%) were consistently diagnosed as type 1 diabetes mellitus, and the remaining 256 individuals (22.7%) were misclassified. Insulin treatment was used in 100% of the type 1 diabetes mellitus group and 73% of the misclassified group. Compared with the type 2 diabetes mellitus group, being misclassified was associated with earlier development of DKA (adjusted hazard ratio [aHR] 5.08, 95% confidence interval [CI] 3.09–8.37), neuropathy (aHR 1.94, CI 1.31–2.88), and nephropathy (aHR 1.72, CI 1.19–2.50), whereas being consistently classified with type 1 diabetes mellitus was associated only with earlier development of DKA (aHR 4.96, CI 2.56–9.61).

Conclusions: Proper categorization of pediatric diabetes can be challenging, especially with comorbid obesity. Failure to ascertain type 1 diabetes mellitus in a timely manner in a pediatric population may increase the risk of substandard care and diabetes-related complications.

This content is limited to qualifying members.

Existing members, please login first

If you have an existing account please login now to access this article or view purchase options.

Purchase only this article ($15)

Create a free account, then purchase this article to download or access it online for 24 hours.

Purchase an SMJ online subscription ($75)

Create a free account, then purchase a subscription to get complete access to all articles for a full year.

Purchase a membership plan (fees vary)

Premium members can access all articles plus recieve many more benefits. View all membership plans and benefit packages.


1. Caprio S, Tamborlane WV. Metabolic impact of obesity in childhood. Endocrinol Metab Clin North Am 1999; 28: 731–747.
2. Gower BA, Nagy TR, Goran MI. Visceral fat, insulin sensitivity, and lipids in prepubertal children. Diabetes 1999; 48: 1515–1521.
3. Bacha F, Saad R, Gungor N, et al. Obesity, regional fat distribution, and syndrome X in obese black and white adolescents: race differential in diabetogenic and atherogenic risk factors. J Clin Endocrinol Metab 2003; 88: 2534–2540.
4. Rosenbloom AL, Silverstein JH, Amemiya S, et al. Type 2 diabetes in the child and adolescent.Pediatr Diabet 2008; 9: 512–526.
5. Gilliam LK, Liese AD, Bloch CA, et al. Family history of diabetes, autoimmunity, and risk factors for cardiovascular disease among children with diabetes in the SEARCH for Diabetes in Youth Study. Pediatr Diabet 2007; 8: 354–361.
6. Glastras SJ, Mohsin F, Donaghue KC. Complications of diabetes mellitus in childhood. Pediatr Clin North Am 2005; 52: 1735–1753.
7. Haller MJ, Atkinson MA, Schatz D. Type 1 diabetes mellitus: etiology, presentation, and management. Pediatr Clin North Am 2005; 52: 1553–1578.
8. Sosenko JM, Breslow JL, Miettinen OS, et al. Hyperglycemia and plasma lipid levels: a prospective study of young insulin-dependent diabetic patients. N Engl J Med 1980; 302: 650–654.
9. Lopes-Virella MF, Wohltmann HJ, Loadholt CB, et al. Plasma lipids and lipoproteins in young insulin-dependent diabetic patients: relationship with control. Diabetologia 1981; 21: 216–223.
10. Rhodes ET, Laffel LMB, Gonzalez TV, et al. Accuracy of administrative coding for type 2 diabetes in children, adolescents, and young adults. Diabet Care 2007; 30: 141–142.
11. Dabelea D, Bell RA, D’Agostino RB Jr, et al. Incidence of diabetes in youth in the United States. JAMA 2007; 297: 2716–2724.
12. Rosenbloom AL, Joe JR, Young RS, et al. Emerging epidemic of type 2 diabetes in youth. Diabet Care 1999; 22: 345–354.
13. Grinstein G, Muzumdar R, Aponte L, et al. Presentation and 5-year follow-up of type 2 diabetes mellitus in African-American and Caribbean-Hispanic adolescents. Horm Res 2003; 60: 121–126.