Case studies of patients with human immunodeficiency virus (HIV) infection have reported an increased incidence of thyroid dysfunction. There also have been more recent reports of Graves’ disease in patients taking highly active antiretroviral agents. Beltran and colleagues screened a cohort of HIV-infected patients to determine the prevalence of thyroid dysfunction.

A cohort of 350 patients with HIV was screened. Seven patients with hyperthyroidism and abnormal free triiodothyronine levels were not included in the final analysis. Overt hypothyroidism, defined as a thyroid-stimulating hormone (TSH) level above the normal range and a low free thyroxine (T₄) level, was detected in 2.6 percent of patients. Subclinical hypothyroidism (i.e., elevated TSH level and normal free T₄ level) was detected in an additional 6.6 percent of patients, and a low free T₄ level was found in another 6.8 percent.

A further case-control comparison was performed for the hypothyroid and euthyroid patients. Older age, longer duration of HIV infection, lower CD4+ T-lymphocyte count, and several different antiretroviral medications were associated with hypothyroidism. Multivariate analysis showed a significant association only for lower CD4+ T-lymphocyte count and use of stavudine.

The authors conclude that hypothyroidism occurs more often in HIV-infected patients treated with highly active antiretroviral therapy, especially in patients with lower CD4+ T-lymphocyte counts and those taking stavudine. A few cases of hyperthyroidism were detected in patients taking highly active antiretroviral drugs.