Comorbidity of type 1 diabetes and juvenile idiopathic arthritis.

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, 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.