Changes in serum cortisol levels during community-acquired pneumonia: the influence of dexamethasone

In community-acquired pneumonia (CAP), the cortisol level on admission can be a useful biomarker for prognosis. Serial cortisol measurements during the clinical course of disease and their association with disease outcome have never been reported. Furthermore, the time to recovery of the hypothalamic-pituitary-adrenal axis after a short course of dexamethasone during infection is unclear. We analyzed data from 270 hospitalized patients with CAP. Total serum cortisol was measured on presentation, day 1, 2, 4, and on control visit (day 30). Intensive care unit (ICU) admission and mortality were assessed. Additionally, to study the influence of dexamethasone on the kinetics of the cortisol response, we analyzed serial cortisol values of 43 patients treated with a four-day regimen of dexamethasone 5 mg. During hospital stay, 26/270 patients (9.6%) were admitted to the ICU and 15/270 patients (5.6%) died. Compared to patients with an uneventful recovery, cortisol on presentation was significantly higher in patients with an adverse outcome (360 μg/L, IQR 209-597 vs. 238 μg/L, IQR 151-374) (p:0.01), and also remained significantly higher throughout the course of disease. Dexamethasone treatment resulted in nearly complete suppression of the endogenous cortisol production after the first dose, but cortisol production was fully recovered on control visit. In conclusion, we showed that an adverse outcome of CAP was associated with persisting higher total serum cortisol throughout the course of disease. Delta-cortisol could be another meaningful biomarker in CAP. Next, our data indicate that a four-day dexamethasone regimen during CAP does not lead to prolonged secondary adrenal insufficiency.