A 3-Level Prognostic Classification in Septic Shock Based on Cortisol Levels and Cortisol Response to Corticotropin

CONTEXT The hypothalamic-pituitary-adrenal axis is a major determinant of the host response to stress. The relationship between its activation and patient outcome is not known. OBJECTIVE To evaluate the prognostic value of cortisol levels and a short corticotropin stimulation test in patients with septic shock. DESIGN AND SETTING Prospective inception cohort study conducted between October 1991 and September 1995 in 2 teaching hospital adult intensive care units in France. PARTICIPANTS A total of 189 consecutive patients who met clinical criteria for septic shock. INTERVENTION A short corticotropin stimulation test was performed in all patients by intravenously injecting 0.25 mg of tetracosactrin; blood samples were taken immediately before the test (T0) and 30 (T30) and 60 (T60) minutes afterward. MAIN OUTCOME MEASURES Twenty-eight–day mortality as a function of variables collected at the onset of septic shock, including cortisol levels before the corticotropin test and the cortisol response to corticotropin (Δmax, defined as the difference between T0 and the highest value between T30 and T60). RESULTS The 28-day mortality was 58% (95% confidence interval [CI], 51%-65%) and median time to death was 17 days (95% CI, 14-27 days). In multivariate analysis, independent predictors of death (P≤.001 for all) were McCabe score greater than 0, organ system failure score greater than 2, arterial lactate level greater than 2.8 mmol/L, ratio of PaO2 to fraction of inspired oxygen no more than 160 mm Hg, cortisol level at T0 greater than 34 µg/dL and Δmax no more than 9 µg/dL. Three groups of patient prognoses were identified: good (cortisol level at T0 ≤34 µg/dL and Δmax >9 µg/dL; 28-day mortality rate, 26%), intermediate (cortisol level at T0 34 µg/dL and Δmax ≤9 µg/dL or cortisol level at T0 >34 µg/dL and Δmax >9 µg/dL; 28-day mortality rate, 67%), and poor (cortisol level at T0 >34 µg/dL and Δmax ≤9 µg/dL; 28-day mortality rate, 82%). CONCLUSION Our data suggest that a short corticotropin test has a good prognostic value and could be helpful in identifying patients with septic shock at high risk for death.