Endocrine Abstracts

Introduction: To evaluate if improved thyroid status in patients with hypopituitarism would improve cardiovascular risk markers.

Patients and methods: A total of 85 hypopituitary patients (45 women) with GH deficiency; 7 had isolated GH deficiency, 25, 16 and 22 patients had 1, 2 and 3 additional deficits respectively. Fifteen patients had panhypopituitarism. Biochemical and body composition assessment was performed at baseline (when patients were GH naïve), and at follow-up (median 4.7 years (3.0–5.5) after initiation of GH replacement). Patients were divided into TSH sufficient (TSHsuff) (not on levothyroxine and free T₄ >12 (n=23)), and TSH deficient (TSHdef), that were further divided into tertiles according to baseline free T₄.

Results: Baseline free T₄ was negatively associated to BMI (P=0.003) and total fat mass (P=0.01). TSHdef patients with lowest tertile free T₄ had higher total (P=0.01) and LDL cholesterol (P=0.05) and triglycerides (P<0.01) compared to TSHsuff patients, also after adjustment for gender, age, BMI and IGF1. At follow-up 9 patients initially defined as TSHsuff had initiated levothyroxine treatment. 53 and 28% of patients with free T₄ from the low and median tertiles respectively, received an increased levothyroxine dose compared to baseline, whereas 40% of patients with free T₄ from the median/high tertile groups had had a dose reduction. None recovered from TSHdef. Free T₄ at follow-up was not significantly correlated to body-composition or cholesterol variables, nor were there any group differences comparing patients in the four groups according to TSH and free T₄. Delta free T₄ (follow-up−baseline) was negatively correlated to delta total cholesterol (r=−0.23; P=0.06) and LDL cholesterol (r=−0.30; P=0.01) and remained so after adjustment for the change in IGF1 (P=0.02).

Conclusion: After ~5 years of GH replacement also the secondary hypothyroidism was better adjusted with an improvement of the lipids of a higher magnitude than seen after GH replacement alone.