Thyroid checks recommended for people with HIV

Michael Carter
Published: 06 January 2009

Patients receiving HIV treatment should have routine tests to check thyroid function, doctors from the UK recommend in an article published in the January 1st edition of the Journal of Acquired Immune Deficiency Syndromes. Investigators from London’s Chelsea and Westminster Hospital found “a higher than expected incidence of hypothyroidism” (an under-active thyroid gland) amongst their patients.

They found that this condition was associated with treatment with a protease inhibitor and that hyperthyroidism (an over-active thyroid) was associated with non-nucleoside reverse transcriptase (NNRTI) therapy, particularly efavirenz (Sustiva).

The thyroid gland is located in the neck. An under-active thyroid is associated with symptoms such as weight gain and tiredness whereas an over-active thyroid can result in hyperactivity and nervousness.

There is little information about the effects of HIV treatment on thyroid function. Although the majority of patients with HIV develop no thyroid problems, there is some evidence to suggest that an increasing number of patients taking anti-HIV drugs are presenting with thyroid disorders.

Research into thyroid function amongst people taking antiretroviral therapy is, however, limited. A study at London’s Royal Free Hospital found a low rate of thyroid problems amongst patients taking anti-HIV drugs and the investigators concluded that routine thyroid screening was therefore not justified. But a study conducted by researchers from the University of Sassari, Italy, found that there was enough evidence of thyroid dysfunction amongst patients receiving antiretroviral therapy to justify routine screening.

Investigators from the Chelsea and Westminster Hospital in London therefore undertook a retrospective study to determine the prevalence and potential causes of both hyperthyroidism and hypothyroidism in their patient cohort.

A total of 2437 patients were included in the analysis. All received their HIV care at the clinic between 1995 and mid-2006 and had at least one test of thyroid function.

The incidence of hyperthyroidism was 3.4 per 10,000 and the incidence of hypothyroidism was 10.7 per 10,000.

A total of 54 patients (2.4%) were identified as having abnormal thyroid function, 26 with hyperthyroidism and 28 with hypothyroidism.

The prevalence of hyperthyroidism within the entire Chelsea and Westminster cohort was calculated at a little over 1% with a similar prevalence of hypothyroidism.

Of the patients tested, thyroid antibodies were detected in 67% of those with hyperthyroidism and 40% of those with hypothyroidism. The investigators believe that such prevalences may indicate immune restoration syndrome after the initiation of antiretroviral therapy.

The investigators then looked to see if they could find an association between treatment with particular classes of antiretroviral drug and thyroid problems.

They found a statistically significant relationship between an under-active thyroid and treatment with a protease inhibitor (p = 0.002) and that therapy with an NNRTI, particularly efavirenz (Sustiva) was associated with hyperthyroidism (p = 0.025).

“As patients with HIV infection are now typically treated with highly active antiretroviral therapy for decades, the metabolic complications of treatment require further study”, write the investigators.

They conclude, “we recommend routine screening of thyroid function in HIV-infected patients receiving highly active antiretroviral therapy.”

Reference

Nelson M et al. Thyroid dysfunction and relationship to antiretroviral therapy in HIV-positive individuals in the HAART era. J Acquir Immune Defic Syndr 50: 113-14, 2009.