Thyroid function in human immunodeficiency virus patients treated with highly active antiretroviral therapy (HAART): a longitudinal study.

OBJECTIVE: Given that few and controversial data have been reported on thyroid function in human immunodeficiency virus (HIV) patients on highly active antiretroviral therapy (HAART), we further investigated whether HAART affects thyroid hormones.

DESIGN AND PATIENTS: Two hundred two consecutive adult HIV patients in stable clinical condition were enrolled, 182 on HAART and 20 naïve; 128 were rechecked during follow-up. Body mass index (BMI), CD4 cell count, HIV RNA, hepatitis C and B virus status and infection duration were determined in all HIV patients and HAART duration in treated patients. In all patients and in 60 controls, the following were measured: FT4 and FT3 by radioimmunoassay; TSH, antithyroid peroxidase (TPO) and antithyroglobulin (TG) antibodies by immunoradiometric assay.

RESULTS: Abnormalities in thyroid function tests were found in 23/182 (12.6%) HAART patients, but not in naïve patients. Most abnormalities were subclinical hypothyroidism, with mean FT4 and TSH levels lower and higher, respectively, in HAART patients compared to naïve patients and controls, FT4 levels being significantly lower than controls. TSH negatively correlated with CD4 count nadir and positively with HAART duration. During follow-up, FT4 and FT3 significantly decreased and TSH increased in patients continuing HAART, whereas CD4 counts were unmodified; subclinical hypothyroid conditions persisted and further cases occurred, whereas the only hypothyroid patient who interrupted HAART shows a normalization of thyroid tests. Patients on stavudine, included in most hypothyroid patient protocols, had significantly lower FT4 levels with prolonged treatment.

CONCLUSIONS: HAART, particularly stavudine, is associated with a high prevalence of subclinical hypothyroidism. Hypotheses are made regarding responsible mechanisms and risk factors. Thyroid function should be tested and sequentially rechecked in HAART patients.