Review of a thyrotoxicosis shared-care scheme: treatment choice and outcomes

T. Howlett; V. Kieffer; C. Robinson; I. Peat; M. Kong; H. Gleeson; M. Levy

Since 1994, after initial outpatient review (OPD) for thyrotoxicosis, we have minimised OPD attendance and provided shared-care advice to primary care physicians on thyroid function tests (TFT) and anti-thyroid drug (ATD) and levothyroxine (T₄) dose titration using our electronic patient record (EPR). Using EPR data we analysed treatment (Rx) choice, effectiveness and outcomes, classifying patients as autoimmune (+ve TPO or other Graves’ features), nodular, mixed or other (no recorded features of either).

Results: 2696 patients (13–94 years; 77%♀), 55 079 TFTs (median 18, max 97/patient), 13 840 patient-years observation (median 4.1 y, max 17.4 y), median 2.9 y from last OPD. Rx choice was patient-driven after appropriate information was given: overall 90% had ATD (84% carbimazole; 11% PTU; median first course 1.50 y; mean # courses 1.6, median 1), 21% radioiodine (RAI) and 7% thyroidectomy. Rx and outcomes are summarised in table. RAI was used more often in nodular disease, and fewer patients became hypothyroid, but many cases of every aetiology chose to continue ATD as an alternative. ‘Long-term’ ATD (stated strategy or actual use >1000d) was used in 20% and ongoing in 12%; longest ongoing Rx was 24.8 y duration.

T₄ (tT₄ or fT₄)/TSH/Both were normal in 92/59/55% of 55,079 TFTs reported. Control was best in patients on no Rx (94/66/63%) compared to patients on T₄ alone (95/58/55%) or ATD (90/54/50%). Control on long-term ATD (92/65/60%) was better than shorter-term courses (89/51/47%) but best control was observed in the minority of TFTs on a block and replace regime (95/63/61%). Control was not better in TFTs taken after RAI: 91/51/48% overall; 86/49/43% on no Rx; 95/56/53% when on T₄ Rx.

Conclusions: Thyrotoxicosis can be effectively monitored by a specialist clinic using EPR whilst minimising the need for patient attendance in hospital. Good control of T₄ was observed but achieving a normal TSH is more challenging. Long term use of ATD is a valid patient treatment choice which achieves TFT control better than RAI in our hands.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

**Table 1**
		Anti-thyroid drugs			Radioactive iodine				Latest F/U
	Cases	% Rx	Courses	Long-term	% Rx	% Hypo	Days^a	Thyroidectomy	On ATD	On T₄
Autoimmune	1137	93%	1.8	21%	18%	79%	302	8%	32%	22%
Nodular	318	79%	1.3	27%	40%	34%	712	12%	36%	17%
Mixed	107	91%	1.7	28%	31%	67%	444	17%	24%	35%
Other	1134	89%	1.5	15%	18%	74%	197	4%	30%	20%
^aMean days from RAI to hypothyroidism.

Endocrine Abstracts

P1654