High prevalence of hypothyroidism in patients with primary pulmonary hypertension

Purpose: To characterize the prevalence of hypothyroidism in a population w ith primary pulmonary hypertension (PPH).Methods: Retrospective record revi ew of 41 patients with PPH seen between 1991 and 1997 at a tertiary care ce nter. Data abstracted included: history of previous thyroid disease, intake of thyroid supplement, and thyroid function tests. Hypothyroidism was defi ned as a serum thyroid stimulating hormone (TSH) level higher than 5.5 U/L, intake of thyroid supplement, or low serum thyroxine level. Results: Of th e 40 patients with PPH included in the study (11 men and 29 women), ages ra nged from 11 to 76 years (mean 43.5 years). The mean pulmonary artery press ure was 58.7 mm Hg. Thirty-three patients had normal serum TSH levels (3 of whom were on levothyroxine supplement); 1 had low TSH; 5 had high TSH (ran ge, 6.8-9.9 U/L, mean 8.4 U/L), and 1 had low thyroxine (T-4 < 1.0 mu g/dL) . Nine of 40 patients (22.5%) had evidence of hypothyroidism, which is much more than expected in the general population of similar age range (2.8% in men, 7.5% in women) (p = .002). Conclusions: The prevalence of hypothyroid ism in patients with PPH is high (22.5%). Patients with PPH should be inves tigated for the possibility of coexisting hypothyroidism.