Endocrine Abstracts

Introduction: Clinical practice guidelines advocate testing the aldosterone-renin ratio (ARR) in specific circumstances only. Tests should be taken following abstinence from drugs associated with false results. We aimed to determine the appropriateness of testing locally and any associated wasted healthcare costs.

Methods: We retrospectively evaluated ARR requests taken July-October 2019 and July-October 2021 in Swansea Bay University Health Board to determine the indication, review of interfering medication and test outcome. We used clinical letters and request forms to determine these data.

Results: Sixty-three patients were included with a mean age 52.3 years and 34 (54.0%) were male. Endocrinology was the commonest requesting team (33.3%) followed by cardiology and general practice (15.9%). Indications for testing included adrenal adenoma plus hypertension (20.6%), hypertension with hypokalaemia (14.3%), hypertension aged <40 years (25.4%), resistant hypertension (4.8%) and 34.9% of requests were inappropriate. Table 1 summarises inappropriate testing by specialty. Twelve patients required medication to be held, evidenced in 3 (25.0%) patients. Three (4.8%) patients had a significantly high ARR, with 1 patient undergoing adrenalectomy and two patients managed medically for adrenal hyperplasia. In total 50.8% tests were either not indicated or taken without holding interfering medications, resulting in an estimated excess cost of £3,040 over 8-months (estimated annual cost £4,560).

Conclusions: Most ARR tests taken locally were for either an inappropriate indication or incorrectly carried out, resulting in significant excess laboratory costs. A third of endocrinology ARR testing was inappropriate, typically in those with adrenal adenoma without hypertension. Proposed changes to local requesting methods should improve ARR test requesting in future.