PURPOSE: To determine the association between thyroid disease and pulmonary hypertension (PH) based on screening thyroid function tests.
METHODS: This retrospective cohort study was performed on 358 consecutive patients with PH seen at Mayo Clinic-Jacksonville Pulmonary Hypertension Center from 1992-2006. Age and sex-matched controls were randomly selected from a list of patients seen in the Pulmonary Clinic for diseases other than PH. Thyroid disease was defined as abnormal thyroid stimulating hormone (TSH) (<0.1, >5.5) with or without abnormal free T4 (<0.8, >1.4) or total T4 (<5, >12.5), history of thyroid disease on replacement, or elevated thyroperoxidase antibody (TPO).
RESULTS: Average age was 62±14 years and 65% were women. Most (74%) were WHO Class 3-4 and the average pulmonary artery systolic pressure (PAS) by either echocardiography or catheterization was 73 mmHg. In the PH group, thyroid disease was present in 84 (31%) compared to 15% for controls (p < .05). Most (79 or 94%) were hypothyroid. At the time of initial PH evaluation, the hypothyroid patients: 47 were adequately treated (normal TSH), 17 were inadequately treated (mean TSH 12±12.9, median 8), 6 were over replaced (TSH<0.01), and 9 were not on treatment (mean TSH = 18.8±18, median 14.1). Two patients were hyperthyroid. Three patients were euthyroid by TSH and free or total T4 but had a positive TPO. Correction of the thyroid function did not change the WHO Class or PAS. Subset analysis of 91 (25%) patients with idiopathic PH revealed minor demographic differences (age 61±15, women 76%, Class 3-4 70%, PAS 81) but a similar prevalence of thyroid disease 30%.
CONCLUSION: Patients with PH have a higher prevalence of thyroid disease than the general population and comparable pulmonary patients. Despite the high prevalence of thyroid disease, treatment did not seem to affect the severity of the PH.
CLINICAL IMPLICATIONS: Screening for thyroid dysfunction in patients with PH may detect an increased prevalence of disease but the clinical impact on the PH is unclear.
DISCLOSURE: Jonathan Li, None.