Background: Biomarkers are useful for diagnosing infection and sepsis in adults, but data are limited in elderly patients. Furthermore, clinical symptoms of infection in elderly patients are usually atypical or unclear. We aimed to assess the usefulness of PCT, CRP, and WBC in distinguishing elderly patients infected with sepsis from infected without sepsis and those with no-infection. We also aimed to find a cut-off value for diagnosing sepsis and infection without sepsis in elderly critically ill patients.
Methods: In this single-center and prospective observational study, patients older than 65 years were enrolled. Serum levels of PCT, CRP, and WBC were measured within 24 h. Patients were allocated into sepsis (S), infected without sepsis (IWS), and noinfection (NI) groups. Data were analyzed with Mann-Whitney U test and Kruskal-Wallis test.
Results: We analyzed 188 patients with a mean age of 77.05 ± 7.4 in the study; 95 (50.5%) of them were women. Sixty-four (34%) of whom were classified as IWS, 29 (15%) as S, and 95 (50.5%) as NI group. There were significant differences in the PCT, CRP levels between the IWS and NI, S and NI (p < 0.001, p < 0.001, p < 0.001, p < 0.01, respectively). The PCT levels were significantly different when the NI group was compared to IWS (p < 0.001) and S (p < 0.001) groups. The CRP levels were also different when the NI group was compared to both IWS (p < 0.001) and S (p < 0.001). The PCT cut-off values were 0.485 μ/L and 1.245 μg/L for the discrimination of patients with IWS and S, respectively. The cut-off values of CRP level were 59.45 mg/L and 57.50 mg/L for infected without sepsis and sepsis, respectively.
Discussion: PCT was found to be a more valuable marker than CRP and WBC for the discrimination of elderly patients with infected without sepsis and sepsis.
Keywords: Aged; C-reactive protein; infections; procalcitonin; sepsis.