SAT-418 Investigating the Clinical Appropriateness of Inpatient Short Synacthen Testing in a Tertiary Hospital

Abstract L. Tan: None. V. Ramadoss: None. A.E. Teo: None. K. Lazarus: None. K. Meeran: None. D. Deepak: None. L. Ong: None. C. Khoo: None. P. Eng: None. Background: Adrenal insufficiency (AI) is a life-threatening condition that needs early recognition and treatment. Symptoms of AI can be non-specific which overlap with other disease conditions. The Short Synacthen test (SST) evaluates adrenal function, which despite its relative ease of administration, has led to increased healthcare cost due to the rising cost of Synacthen® (tetracoscactide). Thus, appropriate patient selection is needed to optimise SST testing and mitigate healthcare costs associated with unnecessary testing and inappropriate steroid replacement. This study aims to determine the indications of inpatient SSTs and its concordance with SSTs outcomes in clinical practice. Method: We conducted a retrospective cohort study of all inpatient SSTs performed between 28th February 2022 and 28th February 2023 at our institution. Relevant clinical information was collected from patients’ electronic patient records. An SST test was considered appropriate if there were symptoms suggestive of AI, and inappropriate if no clear indication was provided or the patient’s clinical history and presenting features did not support the need for SST. Results: A total of 485 SSTs were conducted in 457 patients (Median age 67yrs). The common indications for SST were postural hypotension (36.70%), of which 89.9% were symptomatic and 10.1% were asymptomatic. Other indications included hyponatremia (17.1%), hypotension (16.3%) and previous or current exogenous glucocorticoid (GC) use (8.1%). In patients presenting with hyponatremia, initial median sodium level was 127nmol/L (IQR 124nmol/L- 130nmol/L) and only 6.0% had symptoms suggestive of AI. Among patients with hypotension, 41.7% had only a transient episode of low blood pressure whereas 27.9% had ongoing infection and only 30.4% had persistent low blood pressure suggestive of AI. 4.5% of patients had subjective feelings of giddiness with no documented postural blood pressure changes and 5.6% of SST had no clear clinical indications. In patients receiving exogenous/current GCs, 4/39 (10.3%) were symptomatic with blood pressure changes. Taken together, 236/485 (49%) of the SSTs were performed in patients who did not have features suggestive of AI. In both the clinically appropriate and clinically inappropriate groups, only 34% and 35% of SSTs performed were abnormal. Conclusion: We advocate judicious patient selection for SST testing to avoid inappropriate use of SST. However, our study showed that pre-test clinical symptoms or examination findings could not reliably predict SST outcomes across our cohort. This highlights the extent of challenge associated with early diagnosis of AI and the need for alternative clinical and biochemical strategies for accurate diagnosis of AI. Saturday, June 1, 2024