Introduction Thyrotoxicosis, acute and chronic liver injuries and to a lesser extent, hypothyroidism are well-recognised side effects of amiodarone. It is therefore recommended that patients who take amiodarone should have thyroid function (TFT) and liver function (LFT) tested at six monthly intervals. The aim of this audit is to assess the frequency of thyroid and liver function testing carried out by the Supportive Heart Unit in Beaumont Hospital on their patients taking amiodarone.

Methods A retrospective review of the case notes of all patients on amiodarone seen in the Supportive Heart Unit between December 2015 and April 2016 was undertaken. Blood results for these patients were reviewed to ascertain the frequency with which TFTs and LFTs were checked. Only patients who had been on amiodarone for more than one year were included. Only bloods taken on an outpatient basis were considered. Where patients had more than the required number of tests per year, notes were reviewed to ascertain the reason for the increased frequency of testing. These were then categorised as appropriately or inappropriately increased frequency of testing.

Results A total of 40 suitable patients attended the Heart Support Unit between December 2015 and April 2016. The indication for amiodarone was rhythm control of atrial fibrillation in 67.5% and management of ventricular arrhythmias in 32.5%. The mean number of TFTs over the monitoring period was 3.775 (SD 1.69) per patient. 29 patients (72.5%) had more than 2 sets of TFTs taken in the last year. Of these, 10 (25% of total) were deemed to have no clinical reason for the increased frequency of testing and therefore were inappropriate. 9 patients (22.5%) had the recommended number (2) of TFTs in the last year. 2 patients (5%) had only one TFT check during the monitoring period. The mean number of LFTs during the monitoring period was 5.35 (SD 1.35) per patient. 4 patients (10%) had the appropriate number of LFT checks (2) in the last year. 36 patients (90%) had more than the recommended two LFT checks. 19 of these (47.5% of total) had no clinical reason for the increased frequency of testing and therefore were inappropriate. 1 patient (2.5%) had less than 2 LFT checks during the monitoring period.

Conclusions Our results show that most patients are having both their LFTs and TFTs checked a minimum of twice per year. Only two patients did not have the desired number of TFTs in the last year and one did not have the desired number of LFTs. This demonstrates that there is good knowledge among the Heart Support Unit nurses regarding the need for close monitoring of these parameters in patients taking amiodarone. Our results also demonstrate that there is a potential cost saving to be made from patients who are having excessive TFT and LFT testing. Our plan is to alter the standard patient form in the Heart Support Unit to include a reminder to check TFTs and LFTs at the desired frequency and re-audit in June 2017.