Thyroid function abnormalities

9 December 2001. Related: Conference reports, Lipodystrophy Workshop (IWADRLH) 3rd Athens 2001.

E Billaud and colleagues from Nantes, France, reported on the prevalence of lipid abnormalities in 162 men and 59 women, mainly on HAART regimens in an 18month cross sectional study between December 1999 and June 2001. [6] Thyroid abnormalities have previously been reported in HIV and eight cases of hypothyroidism were reported by the same team at last year’s ICAAC and this study looked into links with lipodystrophy and lipid levels.

Hypothyroidism was defined as thyrotropin levels greater than 4 IU/l and free thyroxine below 8.5 pmol/l. Sub clinical hypothyroidism was defined as isolated elevation of thyrotropin that is asymptomatic and transient hypothyroidism as low free thyroxine not persisting after control.

At the time of the study 84% people were using NRTIs, 34% were using PI and 41% PIs in their combination. 20 people (9%) were treatment naive. Mean age was 40.5 years, mean CD4 count was 457 cells/mm3 and mean viral load was 3 log10 copies/ml.

29 patients (13%) were found to have thyroid abnormalities. There were 12 cases of hyperthyroidism (Grave’s disease) 13 people had free T4 below normal. Nine had TSH levels >4 UI/ml upper normal limit.

After control one month later 18 people (13 men, 5 women) had a confirmed diagnosis of hypothyroidism. About 30% of this group had physician diagnosed lipodystrophy.

Compared to Framingham Study, hypothyroidism in the general population is 0.1% in men and 1.0% in women. This study showed levels in HIV population of 7.9% and 8.6% respectively and is obviously a concern that deserves closer monitoring and study.

A poster presentation from Toma also highlighted a high rate of thyroid dysfunction in a prospective 18month Canadian study of 65 men and 15 women at HotelDieu du CHUM, Montreal. [7]

The following thyroid tests were performed with routine blood tests: antithyroblobulin, antithyroid peroxidase antibodies, thyroblobulin, serum thyrotropin (TSH), serumfree thyroxine (T4), triiodothyronine (T3).

Abnormal test results were present in 35% of patients (20 men and 8 women) and although this suggested a higher incidence in women statistical analysis by gender was not included in the abstract.

The following results were recorded:

This resulted in the following clinical diagnoses:

The most frequently associated metabolic complications included cases of hypertriglyceridemia (19), elevated Cpeptide (16), lactic acid (5) and abnormal retinol binding (15)

Comment

Incidence of thyroid disorders in the general population is relatively common, particularly among women over 40, but increased sensitivity of tests (ie TSH) now allow for presymptomatic diagnosis and treatment.

These studies in HIV-positive people were small and did not included comparative data to the general population, but they raise a previously unrecognised area to consider given the overlap of symptoms (particularly fatigue and depression) with other HIVrelated complaints.

Symptoms of hypothyroidism include increased sensitivity to cold, constipation, pale or dry skin, elevated blood cholesterol levels and unexplained weight (fluid) gain, heavier than normal menstrual periods and depression.

References:

6. Esnault et al – High prevalence of thyroid abnormalities in era of HAART. Abstract 16. Antiviral Therapy 2001; 6 (Supplement 4):12
7. Toma et al – High rate of thyroid autoimmunity and dysfunction in HIVinfected adults receiving HAART. Abstract 80. Antiviral Therapy 2001; 6 (Supplement 4):55.