High evening salivary cortisol is an independent predictor of increased mortality risk in patients with systolic heart failure

AimsSerum cortisol independently predicts mortality risk in patients with systolic heart failure. Salivary cortisol may provide advantages as it better reflects the biologically active free compound. Furthermore, sampling is non-invasive and may easily be performed in outpatients. We comparatively evaluated associations of morning (MSC) vs. evening salivary cortisol (ESC) and all-cause mortality risk.Methods and resultsMSC (8 am) and ESC (9 pm) were determined in 229 patients with heart failure participating in the Interdisciplinary Network for Heart Failure program (66 ± 13 years; 21% female; 37% New York Heart Association (NYHA) class III/IV, median left ventricular ejection fraction 33%). The association of cortisol with mortality risk was determined by univariate and Cox multivariable regression analyses adjusting for age, sex, NYHA class, and N-terminal pro-hormone B-type natriuretic peptide. Compared to ESC, MSC was significantly higher and exhibited a higher variance: median 0.59 ng/ml (interquartile range 0.41-0.93) vs. 0.25 ng/ml (0.15-0.48), p < 0.001. During 18 months of follow-up, 25 (11%) patients died. In univariate and multivariable models mortality risk was not increased in the highest MSC quartile: crude hazard ratio (HR) 1.81 (95% confidence interval 0.79-4.14, p = 0.160), adjusted HR 1.26 (0.51-3.13, p = 0.616). However, patients in the highest ESC quartile had a significantly increased mortality risk, suggesting that associations of high ESC and increased mortality were independent of disease severity: crude HR 3.33 (1.50-7.42, p = 0.003), adjusted HR 2.49 (1.01-6.14, p = 0.047). ESC alone proved the best predictor of mortality.ConclusionHigh ESC but not MSC levels independently predict increased mortality risk in heart failure.