Total Antioxidant Capacity and C-Reactive Protein Levels in Patients with Community-Acquired Pneumonia

Aims: The aim of this study was to evaluate the oxidative stress measured by serum total antioxidant capacity(TAC) and malondialdehyde (MDA) in patients with community-acquired pneumonia (CAP), and to evaluate their possible correlation with the serum C-reactive protein (CRP) and pneumonia severity index (PSI).Materials and Methods: The PSI, chest X-ray (CXR) scores, and the serum TAC, MDA, and CRP levels were determined in 67 CAP patients on admission and compared to 45 healthy controls.Results: In the whole study population, the TAC level was inversely correlated with CRP levels and WBC counts (r=-0.648, P=0.0001; r=-0.626, P=0.0001, respectively). Lower TAC and higher MDA levels were found in CAP patients compared with those of controls (P = 0.0001, P = 0.029). Although the mean serum MDA and TAC levels were similar between the groups of PSI class I-III (n=45) and PSI class IV-V (n=22), the radiological scores (2.36±1.23 vs 3.19±1.17) and CRP levels (138.67 ± 63.86 vs 177.14 ± 56.43) were significantly higher in the latter group (P = 0.010 and P=0.005, respectively).Conclusions: Single measurement of serum MDA or TAC levels in CAP patients, in contrast to CRP level measurement, does not seem to predict the severity of disease.