IAS: Routine thyroid testing advised for people taking antiretrovirals

Antiretroviral therapy may promote both hypothyroidism and hyperthyroidism, according to presentations at the Third International AIDS Society Conference on HIV Pathogenesis and Treatment. Thyroid-function screening of all HIV-infected people at Chelsea and Westminster Hospital in London, United Kingdom, linked protease inhibitors (PIs) to hyperthyroidism and non-nucleoside reverse transcriptase inhibitors (NNRTIs) to hypothyroidism.

Sen and colleagues conducted two patient surveys. The first survey involved everyone treated for thyroid dysfunction between April 1995 and June 2004. Of 33 patients, 25 had hypothyroidism and eight had hyperthyroidism. The median CD4 cell count was 228 cells/mm³ (interquartile range 156-325 cells/mm³).

The incidence of hypothyroidism jumped from 0.9 cases per 10,000 person-years before highly active antiretroviral therapy (HAART) to 10.7 cases per 10,000 person-years in the HAART era. The incidence of hyperthyroidism also climbed—from 0.4 to 3.4 cases per 10,000 person-years before and after HAART was introduced, respectively.

In the second survey, Chelsea and Westminster Hospital clinicians screened everyone in the clinic for thyroid dysfunction from August through November 2004. Of 2437 people, 28 (1.15%) had hypothyroidism and 26 (1.07%) had hyperthyroidism.

Sen and colleagues found that significantly more patients with hyperthyroidism than with hypothyroidism were taking protease inhibitors (46.2% versus 28.6%, p = .002), and significantly more patients with hypothyroidism than with hyperthyroidism were taking NNRTIs (57.1% versus 26.9%, p = .025).

The Chelsea and Westminster team presented a long list of possible causes of thyroid dysregulation in people taking antiretrovirals, ranging from abnormal antigen presentation and polyclonal activation of T- or B-cells to specific antiretroviral class effects on production or destruction of thyroid hormones. They recommended routine thyroid-function testing for people taking antiretroviral combinations, especially regimens including protease inhibitors or NNRTIs.

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