Background and objectives: To examine the frequency of endocrinopathies in children with systemic lupus erythematosus (SLE) and juvenile idiopathic arthritis (JIA).

Design and setting: A cross-sectional study.

Patients and methods: A study was conducted in Saudi children with SLE and JIA who were seen at King Faisal Specialist Hospital and Research Centre, Riyadh, between September 2013 and April 2015. All enrolled patients completed the clinical evaluation, which included information about family history of autoimmune disease, growth parameters and tanner stage, as well as the following assessments: vitamin D profile (parathyroid hormone and 25-OH vitamin D levels), TSH, FT4 and total T3, thyroglobulin antibodies, thyroperoxidase antibodies, random blood sugar, Hb_A1C, IGF₁, IGF_BP-3, LH, and FSH.

Results: A total of 42 patients, 22 with JIA and 20 with SLE, were included in the study. The mean participant age was 12.2 ± 5.3 years with a mean disease duration of 3.2 ± 3.4 years. Female gender was predominant (17 SLE, 13 JIA) in the patient population. Fifteen patients (35.7%) presented with a family history of autoimmune disease. The most frequently detected endocrinopathies were vitamin D insufficiency (35%) and thyroid disease (31%). Eight JIA patients and 7 SLE patients exhibited low vitamin D levels; 10 patients presented with hyperparathyroidism. Thyroid dysfunction was observed in 13 patients (8 SLE, 5 JIA), and 2 patients were found to be euthyroid (normal TSH, FT4) with positive thyroid autoantibodies. Furthermore, 7 patients presented with subclinical hypothyroidism (high TSH, normal FT4), and 4 patients presented with overt hypothyroidism (high TSH, low FT4). Seven patients (4 SLE and 3 JIA) presented with short stature due to growth hormone insufficiency (low IGF₁, IGF_BP-3). Two patients exhibited delayed puberty accompanied by low LH levels. Diabetes mellitus was more frequently observed in patients with JIA (4 patients) than in patients with SLE (1 patient).

Conclusion: Our findings demonstrated that coexistence of endocrinopathies is not uncommon in children diagnosed with JIA and SLE. Abnormal thyroid function occurs frequently and at a similar rate in children diagnosed with SLE and JIA. Thus, screening for endocrinopathies, namely thyroid disease, during the assessment of childhood SLE and JIA is worth consideration.