How Common is Fibromyalgia in Patients with Hypothyroidism?

Background: Fibromyalgia (FM) is the most common cause of chronic generalized musculoskeletal pain and it is generally accompanied by the other nonspecific common symptoms. The etiology and the pathophysiology is still not clear but also there are some studies that show a relationship between FM and thyroid diseases. So, in this study we aimed to determine the frequency of FM in patients with hypothyroidism and the variables that may affect this frequency. Methods: This is a cross-sectional, single center and prospective study. A total of 180 patients -who were applied to internal medicine outpatient clinics- included in the study and the patients who described the generalized musculoskeletal pain were consulted to the physical medicine and rehabilitation outpatient clinics. We have evaluated demographic data, laboratory, presence of thyroid disease and FM, and Beck Depression Questionnaire (BDQ) and FM Impact Questionnaire (FIQ) for FM patients.Results: 39.4% (n = 71) of the patients had FM and 60.6% (n = 109) of them did not. There was a positive corelation between FIQ score and age at diagnosis and disease duration. As the age at diagnosis and duration of disease increased, the FIQ score increased by 37.3% and 25.7%, respectively. In addition, as BDQ increased, the FIQ score increased by 44.8%. Conclusion: Signs and symptoms of hypothyroidism is similar to signs and symptoms of FM, and approximately 40% of patients with hypothyroidism could have FM concomittantly. Therefore, all patients with hypothyroidism should also be examined for FM.