Urinary biomarker of oxidative stress correlating with outcome in critically septic patients

Objective: To determine whether urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), an in vivo parameter of oxidative stress, is correlated with the outcome of critically septic patients. Design and setting: Clinical outcome study in an adult medical intensive care unit (ICU). Patients:85 consecutive septic patients (59 men, 26 women). Measurements and results: Patient characteristics and the clinical course were examined. Urinary 8-OHdG was analyzed using isotope-dilution liquid chromatography with tandem mass spectrometry (LC/MS/MS). ICU mortality was 25.9% (22/85) and hospital mortality 38.8% (33/85). Survivors' APACHE II scores on days 1 and 3 and the difference between them differed significantly from those of nonsurvivors (day 1, 21.0 +/- 7.1 vs. 25.9 +/- 8.0; day 3, 15.0 +/- 5.8 vs. 23.2 +/- 8.3; difference, 6.0 +/- 5.5 vs. 1.7 +/- 6.6). Urinary 8-OHdG was significantly lower in survivors than in nonsurvivors on day 1 (1.8 +/- 2.4 vs. 3.0 +/- 2.4). The area under receiver operating characteristic curve analysis for the association between day 1 urinary 8-OHdG and ICU mortality was 0.71. The comparison performed upon discharge from hospital revealed similar results. Conclusions: This is a preliminary study. Excretion of urinary 8-OHdG, as measured using isotope-dilution LC/MS/MS, and the APACHE II score were correlated with the outcome of critically septic patients in medical ICU.