Endocrine Abstracts

There are a number of symptomatic patients with hypothyroidism who fail to normalise thyroid function (TFTs) despite large doses of thyroxine (LT4) replacement. Non-compliance is a common cause of treatment failure even in patients who strongly deny this. To avoid unnecessary and prolonged investigations for other causes we advocate a simple protocol to manage this problem. Patients are observed taking 1000 mcg of LT4 at 09.00 hrs, and have hourly Free T4 and TSH levels measured for 6 hours. Following this they attend the endocrine day unit weekly for 5 weeks to take observed treatment of 1000 mcg LT4 and repeat Free T4 and TSH levels.

We report the results of 5 patients (all female; 4 autoimmune hypothyroidism, 1 hypothyroid following surgery and I¹³¹) mean (range) age 43.2 yrs(33–60) included in this protocol. All denied poor compliance with medication. They had been on LT4 12.2 yrs(8–23) and were taking 240 mcg(125–300) at 2.8 mcg/Kg (1.9–3.4). All had symptomatic hypothyroidism [TSH 72 miu/L (9.5–187), FT4 10.6 pmol/L (1.3–16.2) normal ranges 0.2–6 and 10–25 respectively].

Results: After observed ingestion of 1000 mcg LT4 patients’ TSH fell by 26% (from 49.8 miu/L to 41.7 miu/L) and the FT4 increased by 105% (from 14.2 pmol/L to 25.2 pmol/L). During the weekly-observed thyroxine therapy TSH normalised in all subjects (1.7 miu/L, 0.1–3.8) and the FT4 increased by 69% (18.3 pmol/L, 14.5–28.6).

In all 5 five patients non-compliance was confirmed as the cause for persistent biochemical and symptomatic hypothyroidism. All subjects TFTs improved with weekly directly observed therapy. 4 subjects have chosen to continue to weekly-observed therapy (1000 mg –1600 mg weekly) either at the endocrine day unit or at their GP. This simple protocol confirmed non-compliance with LT4 medication and has avoided the need for multiple investigations in patients who deny poor compliance.