Prevalence of Growth Hormone Deficiency in Hashimoto’s Thyroiditis

摘要

Context: Autoimmune hypophysitis can result in GH deficiency (GHD) and is associated with other autoimmune endocrine diseases like Hashimoto’s thyroiditis. Recent studies suggest a high prevalence (5%) of GHD in Hashimoto’s thyroiditis.Objective: Our objective was to establish the prevalence of GHD in patients with treated autoimmune hypothyroidism (AIH).Patients: We included patients with spontaneous AIH [thyroid peroxidase antibodies (TPO-Ab) ≥100 kU/liter], who were adequately treated with T_(4) (TSH 0.2–5.0 mU/liter). Exclusion criteria were previous I~(131) treatment, thyroid surgery, or a history of hypothalamic or pituitary disease. Patients were recruited via our outpatient clinics and via patient self-help organizations.Design: We measured serum TSH, free T_(4), TPO-Ab, and IGF-I. If the IGF-I concentration was below the 10th percentile of age-specific reference values, a GHRH/GH-releasing peptide (GHRP)-6 test was done. GHD was defined as a GH peak after GHRH/GHRP-6 below the 2.5th percentile of age-specific reference values.Main Outcome Measures: IGF-I concentration and GH peak after GHRH/GHRP-6 test were measured.Results: From 860 patients who applied, 322 did not satisfy inclusion criteria (157 because TPO-Ab was <100 kU/liter, 165 because TSH was 5.0 mU/liter), and 23 had an exclusion criterion. In the remaining study population of 515 patients (476 female, 39 male), 49 patients (9.5%) had an IGF-I concentration below the 10th percentile. These patients underwent a GHRH/GHRP-6 test. Two patients had a GH peak below the 2.5th percentile.Conclusion: The prevalence of GHD in Dutch patients with AIH is 0.4% (two of 515).