High Prevalence of Growth Hormone Deficiency in Severe Fibromyalgia Syndromes

Context: Fibromyalgia (FM) is characterized by widespread pain and fatigue and is considered a syndrome with different pathogenic mechanisms. Controversial data on GH axis disturbances have been published. Some preliminary trials have shown promising effects of GH therapy on tender points and quality of life in FM. Aim: The aim was to study the patterns of GH secretion/sensitivity in a cohort of severe FM patients. Setting: The study was conducted in five tertiary hospitals. Methods: A total of 493 FM women (1990 American College of Rheumatology criteria) recruited from five centers, having more than 16 tender points, Fibromyalgia Impact Questionnaire scores above 75, more than 1 yr of stable medication (serotonin reuptake inhibitors, amitriptyline, and opioids), and body mass index below 35 kg/m(2) underwent baseline IGF-I/GH determinations; an insulin tolerance test (ITT) and a modified IGF-I generation test were performed in those cases showing IGF-I of 150 mu g/liter or less. Results: A total of 169 of the 493 patients (34.2%) showed IGF-I of 150 mu g/liter or less. Mean peak GH during ITT was 13.3 +/- 9.9 ng/ml in 127 patients in which the test was performed. In 22 of 127 (17.3%), ITT peak GH was 5 mu g/ml or less, and in eight of them (6.3%), the peak GH was 3 ng/ml or less. Mean baseline GH (n = 127) was 1.47 +/- 2.58 ng/dl, and eight of 120 (6.8%) showed an insufficient IGF-I response (<50% over baseline) to the IGF-I generation test. Conclusion: FM patients show a high prevalence of GH axis dysfunction. A significant number of patients show biochemical patterns of GH deficiency as well as some degree of GH resistance and might be potential candidates for substitution treatment. (J Clin Endocrinol Metab 95: 4331-4337, 2010)