Cortisol levels are associated with mortality risk in hemodialysis patients

Background: End-stage renal disease (ESRD) conveys high mortality risk by complex mechanisms not fully elucidated but possibly linked to hormonal abnormalities, including cortisol. Whereas a high serum cortisol level has recently been linked with increased mortality in the general population, there is scarce information on the clinical associates and prognostic value of cortisol levels in ESRD. Patients and methods: Prospective study of prevalent hemodialysis patients (n = 75), mostly non-diabetic (76%), where cortisol levels were assessed and patients were afterwards followed for a median of 20 (interquartile range (IQR) 8 - 31) months. Results: Cortisol levels were negatively correlated with plasma sodium (Rho = -0.26. p < 0.025) and positively correlated with C-reactive protein (CRP; Rho = 0.26, p = 0.027). The association with CRP remained independent of multiple confounders. Baseline cortisol levels of those who died were higher than of those who survived (19.8 +/- 6.9 vs. 15.3 +/- 5.7 mcg/dL, p = 0.0083). Kaplan-Meier analysis showed that patients with cortisol levels within the highest tertile (>= 18 mcg/dL) were at increased risk of death. Cortisol was associated with risk of death both in crude and adjusted Cox proportional hazards models (HR 1.09 (1.021 - 1.167) p = 0.011; and 1.16 (1.027 - 1.309), p = 0.01, respectively)). Conclusions: High serum concentrations of cortisol were associated with a state of inflammation and independently identified a subgroup of chronic hemodialysis patients at a high mortality risk.