Thyroid function of HIV patients should be checked; low CD4 count and d4T implicated

Michael Carter
Estimated reading time 2 minutes
This article is more than 21 years old.

HIV-infected individuals treated with d4T-containing HAART regimens, or with low CD4 cell counts are at increased risk of hypothyroidism, according to French investigators writing in the August 15th edition of Clinical Infectious Diseases, which is now available online.

Hypothyroidism is a condition in which the body lacks enough thyroid hormone, the hormone which regulates the body’s metabolism. An increased prevalence of subclinical hypothyroidism has been observed in HAART-treated patients. Investigators in Picardie, northern France wished to determine the prevalence of thyroid dysfunction in their patients and the risk factors for the development of the condition.

The study ran between May and December 2001, and included a cohort of 350 patients. Potential risk factors for hypothyroidism assessed by the investigators included age, sex, weight, body mass index, lipodystrophy, and smoking. Data were also collected on duration of HIV infection, stage of HIV disease, CD4 cell count, viral load, hepatitis C virus coinfection, and type and duration of anti-HIV therapy.

Glossary

hormone

A chemical messenger which stimulates or suppresses cell and tissue activity. Hormones control most bodily functions, from simple basic needs like hunger to complex systems like reproduction, and even the emotions and mood.

multivariate analysis

An extension of multivariable analysis that is used to model two or more outcomes at the same time.

subclinical

Describes an infection or disease which is not severe enough to present definite or readily observable symptoms.

metabolism

The physical and chemical reactions that produce energy for the body. Metabolism also refers to the breakdown of drugs or other substances within the body, which may occur during digestion or elimination.

lipodystrophy

A disruption to the way the body produces, uses and distributes fat. Different forms of lipodystrophy include lipoatrophy (loss of subcutaneous fat from an area) and lipohypertrophy (accumulation of fat in an area), which may occur in the same person.

Thyroid function was assessed by measuring thyroid-stimulating hormone levels and normal free T4 (FT4) and FT3.

Sixteen percent of patients (n=56) had hypothyroidism, of whom 2.6% had overt hypothyroidism, 6.6% subclinical hypothyroidism, and 6.8% a low FT4 level.

Patients with hypothyroidism were significantly older (43.9 years versus 40.8, p=.04), had been HIV-positive for longer (9.4 years versus 7.7 years, p=.01) and had a lower CD4 cell count (383 cells/mm3 versus 488 cells/mm3.

In univariate analysis HCV coinfection, low CD4 cell count, receipt of HAART, and treatment with efavirenz, amprenavir, ddI, ritonavir, lopinavir and d4T were all associated with hypothyroidism.

However, in multivariate analysis only treatment with d4T (OR 2.56, 95% CI, 1.3 – 4.9, p=.004) and low CD4 cell count (OR 2.5, 95% CI, 1.4 – 4.4, p<.001 factors.="" remained="" risk="" significant="">

The investigators conclude, “the prevalence of hypothyroidism is increased among HIV-positive patients, and we believe that screening is warranted, especially for patients treated with stavudine [d4T] and patients with decreased CD4 cell counts.”

Further information on this website

CD4 cell count

d4T - overview

References

Beltran S et al. Increased prevalence of hypothyroidism among human immunodeficiency virus-infected patients: a need for screening. Clinical Infectious Diseases 37 (online edition), 2003.

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