Response to the high-dose corticotrophin stimulation test depends on plasma adrenocotropin hormone levels in septic shock

Purpose The use of the high-dose corticotrophin stimulation test (HDCST) as a guide to use low-dose steroid therapy in septic shock is controversial. The adrenocotropin hormone (ACTH) constitutes the immediate stimuli to produce cortisol. We evaluated the correlation of the response to the HDCST with plasma ACTH levels in patients with septic shock. Methods This is a retrospective review of 102 patients with septic shock in which adrenal function was evaluated using the HDCST and plasma ACTH levels were measured. Patients with a δ cortisol of 9 μg/dL or less were considered as nonresponders or with subnormal response. The association between plasma ACTH levels and the response to the HDCST was investigated. Results Sixty-four patients (62.7%) had a subnormal response. Plasma ACTH levels were higher in patients with subnormal response (19.8 [11.7-31.4] vs 10.0 [7.0-21.2] pg/mL; P = .002). Patients in the highest quartile of plasma ACTH had lower δ cortisol (P = .014) and higher percentage of subnormal response (P = .005). The optimal cutoff point of plasma ACTH level with fewest false classifications was 10 pg/mL (sensitivity, 0.83 [95% confidence interval, 074-0.90] and specificity, 0.50 [95% confidence interval, 0.74-0.90]). Conclusion Patients with septic shock with higher plasma ACTH values presented a subnormal response to the HDCST. The number of patients who failed to the HDCST was higher as plasma ACTH increased.