Systolic pulmonary artery pressure and serum uric acid levels in patients with hyperthyroidism

The aim of this study was to investigate systolic pulmonary artery pressure (SPAP) and serum uric acid (SUA) levels in patients with hyperthyroidism and after euthyroid state was reached.

Twenty five (10 male, 15 female, mean age 49.8 +/- 11.6 years) consecutive patients with hyperthyroidism (18 due to toxic nodular goiter, seven to Graves' disease) and 25 (eight male, 17 female, mean age 48.7 +/- 8.7 years) healthy controls were included in the study. Thyroid hormones, SUA, glucose, urea, creatinine, and transthoracic echocardiography were performed in all patients. All tests were repeated after treatment of hyperthyroidism.

Mean SPAP and SUA levels in patients with hyperthyroidism were significantly higher than in controls (30.4 +/- 8.5 vs. 22 +/- 3.7 mmHg, p <0.0001, and 5.1 +/- 1.1 vs. 4.3 +/- 0.5 mg/dL, p = 0.004, respectively). Elevated SPAP and SUA levels in patients with hyperthyroidism decreased significantly after treatment to levels comparable with controls (24.4 +/- 5.4 mmHg, p = 0.001 and 4.6 +/- 0.9 mg/dL, p = 0.002, respectively). Correlation between SPAP and SUA levels, however, was not significant in hyperthyroid population and after euthyroid stage was reached (r = 0.34, p = 0.097, and r = 0.256, p = 0.216, respectively), possibly due to relatively low number of patients (overall correlation of SPAPs and SUAs was r = 0.4, p <0.0001).

Hyperthyroidism should be included in differential diagnosis of pulmonary arterial hypertension. However, further investigations are needed to determine the exact mechanism between hyperthyroidism and pulmonary hypertension.