Serum melatonin levels are associated with mortality in severe septic patients

Melatonin in septic patients has been scarcely explored and only in studies of small sample size (maximum 20 patients). Thus, the objective of this study was to determine whether serum melatonin levels are associated with severity, oxidant and inflammatory state, and mortality in a large series of septic patients.

A prospective, observational, multicenter study was performed in 6 Spanish intensive care units with 201 severe septic patients. Serum levels of melatonin were measured at moment of severe sepsis diagnosis. The end point was 30-day mortality.

Non-surviving patients (n = 71) showed higher serum melatonin levels (P < .001) than survivors (n = 130). Multiple logistic regression analysis showed that serum melatonin levels were associated with 30-day mortality (odds ratio, 1.022; 95% confidence interval, 1.001-1.043; P = .04), controlling for serum tumor necrosis factor-α levels, serum interleukin 6 levels and age. Serum melatonin levels were positively associated with serum levels of malondialdehyde as biomarker of oxidative stress, interleukin-6 and lactate, and with SOFA score.

The novel finding of our study was that serum melatonin levels are associated with mortality in septic patients.