The value of C-reactive protein in infection diagnosis and prognosis in elderly patients

The aim of this study was to determine the value of C-reactive protein level in the diagnosis and prognosis of infection in elderly patients.

This prospective study included inpatients in the palliative care unit during the 1-year period between January 2016 and January 2017. Patients' demographic data, Acute Physiology and Chronic Health Evaluation score, and Charlson Comorbidity Index were recorded.

A total of 233 patients were included in the study. A total of 199 instances of infection were diagnosed in 175 of those patients; 75.3% of the infections were detected at admission and 24.7% during hospitalization. At a cut-off value of 4.82, CRP value had 81.0% specificity and 75.4% sensitivity in the diagnosis of infection. Among the patients with infection, there was no difference between those who died and those who survived in terms of baseline CRP level, but a significant difference emerged in CRP level at 48 and 96 h. Factors which were found to significantly reduce survival time were the presence of chronic kidney disease, chronic obstructive pulmonary disease, hypoxia and tachycardia at admission, APACHE-II score over 20.5, initial albumin level below 2.44 g/dL, and serum CRP clearance rates of less than 11% at 48 h and 20% at 96 h.

In elderly patients with infection, the initial CRP value alone does not have prognostic value, but changes observed in serial CRP measurement are a valid indicator of prognosis.