Appropriateness of adrenocorticotropic hormone stimulation test for critically ill patients.

BACKGROUND In earlier work, it was shown that patients with septic shock who also have adrenal insufficiency experience a benefit in terms of lower mortality rates with hydrocortisone supplementation. As such, the adrenocorticotropic hormone (ACTH) stimulation test has been used frequently to identify these patients. However, recent evidence has suggested that the identification and treatment of adrenal insufficiency in patients with septic shock does not reduce mortality. These results call into question the utility of the ACTH stimulation test in this patient population. OBJECTIVES To determine the indications for ordering the ACTH stimulation test for critically ill patients at a tertiary care hospital and to classify the indications as either appropriate (e.g., primary adrenal insufficiency or medication-induced suppression of the hypothalamus-pituitary-adrenal axis) or inappropriate (e.g., patients with septic shock, prior etomidate exposure, or absence of steroid use). METHODS A retrospective analysis of health care records was conducted for all patients who had been admitted to the intensive care unit and who had undergone an ACTH stimulation test during 2007. For each patient, the indication for the test was identified and classified as appropriate or inappropriate. RESULTS A total of 35 ACTH stimulation tests were performed during the study period, of which 8 (23%) were classified as having an appropriate indication and 27 (77%) as having an inappropriate indication. Of the tests with an inappropriate indication, 15 (56%) were ordered for patients with septic shock. However, the number of ACTH tests ordered for this indication declined as the year progressed. CONCLUSIONS The ACTH stimulation test was often used inappropriately for patients with septic shock. Over time, there appeared to be a trend away from use of this test in this patient population, perhaps reflecting increasing awareness of the lack of benefit.