Pulmonary hypertension and thyroid disease

BACKGROUND: The association between thyroid dysfunction and pulmonary hypertension (PH) has not been well characterized. METHODS: This retrospective study comprised 356 consecutive PH patients seen at Mayo Clinic Jacksonville Pulmonary Hypertension Center from 1992 to 2006 and 698 sex-matched control subjects without PH. Thyroid disease was defined as an abnormal thyroid-stimulating hormone level, with or without an abnormal free or total thyroxine level, a history of thyroid disease on replacement, or an elevated thyroperoxidase antibody level. The main outcome measure was prevalence of thyroid disease in each group. RESULTS: Median age of the 356 PH patients was 65 years; 230 patients (65%) were female. The control group of 698 patients had the same sex ratio and median age of 68 years. Most PH patients had severe PH, as categorized by World Health Organization (WHO) class (74% class 3-4) and pulmonary artery systolic pressure. Among those with PH, 85 patients (24%) had thyroid disease vs 107 control patients (15%). After adjusting for age and sex, the prevalence of thyroid disease was increased in PH patients compared with control patients. Increased prevalence was most prominent in WHO group 1, pulmonary artery hypertension confirmed by right-heart catheterization (odds ratio, 2.53; 95% confidence interval, 1.55 to 4.08; p < 0.001). Most patients had mild thyroid disease and were hypothyroid. Only 14 of 85 patients (16%) had previously undiagnosed thyroid disease. CONCLUSIONS: Patients with PH have a higher prevalence of thyroid disease than other pulmonary patients. Evaluation of thyroid function in PH patients may be warranted to detect and assess coexisting thyroid disease.