Comorbidity of type 1 diabetes and juvenile idiopathic arthritis.

ABSTRACT

OBJECTIVE: To analyze the prevalence of juvenile idiopathic arthritis (JIA) and diabetes end points in pediatric patients with type 1 diabetes. STUDY DESIGN: Patients with type 1 diabetes, recorded from 1995 up to September 2013 in the Diabetes Patienten Verlaufsdokumentation database (n = 54,911, <16 years of age, 47% girls), were analyzed. The patients' height, weight, and body mass index SDS, glycosylated hemoglobin A1c (HbA1c); insulin dose; hypertension and dyslipidemia prevalence; rate of hypoglycemic events; and ketoacidosis were compared between patients with and without JIA. To adjust for age, sex, diabetes duration, and migration background, data were analyzed in hierarchic multivariable regression models. RESULTS: The prevalence of JIA in type 1 diabetes was 106 of 54,911 patients; 66% were girls. Diabetes onset was earlier in children with JIA (7.2 years vs 8.3 years, P = .04). Children with JIA were smaller (SDS -0.22 vs 0.09, P = .004). Correspondingly, weight SDS was lower in patients with JIA (-0.02 vs 0.22, P = .01). Body mass index SDS did not differ. HbA1c was marginally lower in children with JIA (63 mmol/mol [8.0%] vs 67 mmol/mol [8.3%], P = .06). Insulin requirement was greater in patients with JIA (1.03 vs 0.93 insulin units/weight/day, P = .003). Hypertension and dyslipidemia were comparable in both groups. CONCLUSIONS: The JIA-prevalence in patients with type 1 diabetes (0.19%) was considerably greater than in the general population (0.05%). Growth is influenced negatively by JIA. Surprisingly, HbA1c was somewhat lower in children with JIA, possibly because of a more intensive treatment or a latent hemolysis caused by the inflammation.