Men with erectile dysfunction should be screened for thyroid disease before any ED-specific treatment is prescribed, researchers concluded based on a study of men treated at a thyroid clinic.
Among men with ED in whom thyroid dysfunction is identified and treated, specific ED treatment with selective phosphodiesterase-5 (PDE-5) inhibitors should be postponed for at least 6 months after euthyroidism is achieved because the thyroid problem may have been principally responsible for the ED, said Dr. Gerasimos E. Krassas of Panagia General Hospital, Thessaloniki, Greece, and his associates.
The study included 71 men (mean age 51 years) who presented to a thyroid clinic, 27 of whom had clinical hyperthyroidism (18 with Graves' disease, 9 toxic nodular or multinodular goiter) and 44 with clinical hypothyroidism (thyroid-stimulating hormone greater than 10 mU/L), including 37 with positive thyroid antibodies, they reported online in the Journal of Clinical Endocrinology and Metabolism (doi:10.1210/jc.2007-2259).
None of the patients were on thyroid medication prior to the study. Patients with diabetes, cardiovascular, or urological diseases were excluded, as were those with abnormal levels of total testosterone or sex hormone binding globulin. A similar number of age-matched normal men were recruited as controls.
All of the subjects filled out the validated Sexual Health Inventory for Males (SHIM), a five-item questionnaire that assesses a man's ability to attain and then maintain an erection. Scores of 21 or less, indicating some degree of ED, were found in 79% of the men with thyroid dysfunction (19 were hyperthyroid and 37 were hypothyroid), compared with 34% of the controls, a significant difference.
Among the men with any degree of ED, 38% of those with thyroid dysfunction had SHIM scores of 10 or less, indicative of severe ED, compared with 25% of the controls. Of the 21 patients with severe ED, 8 were hyperthyroid and 13 hypothyroid.
There was no difference in SHIM scores between hyperthyroid and hypothyroid patients. In the patients with hypothyroidism, SHIM scored correlated positively with free thyroxine (FT4) levels and negatively with thyroid-stimulating hormone (TSH) levels. In contrast, SHIM scores did not correlate with either FT4 or TSH levels in patients with hyperthyroidism, Dr. Krassas and his associates reported.
Scores on the SHIM improved significantly at 1 year after treatment of the thyroid dysfunction: Only 20 of the patients—7 with hyperthyroid and 13 hypothyroid—still had SHIM scores of 21 or less, and of those, only 7 had severe ED (SHIM less than 10), proportions similar to those among the controls.
In addition, no difference was found between hypothyroid patients having positive thyroid antibodies and those with negative antibodies, nor between patients with Graves' disease and those with nodular or multinodular toxic goiter, they said.