Reliability of serum procalcitonin concentration for the diagnosis of sepsis in elderly patient with chronic kidney disease

Background and aims. Sepsis is complicated by high mortality in hospitalized patients. Procalcitonin (PCT) is a validated tool in the diagnosis of sepsis in both adults and aged patients. Several studies demonstrated the reliability of PCT in adults with chronic kidney disease (CKD), but this has not been studied in the geriatric population. Thus, we aimed at evaluating the reliability of PCT in a group of elderly patients with CKD. Methods. 382 subjects (mean age, 78.9 years) were consecutively enrolled and stratified in two groups at the time of the admission based on the absence or presence of CKD, defined as estimated Glomerular Filtration Rate (e-GFR) less than 60 ml/min/1.73 m2. These two groups were further divided according to the presence (SEPSIS/NO CKD, n = 41; SEPSIS/CKD, n = 45) or absence of sepsis (NO SEPSIS/NO CKD, n = 147; NO SEPSIS/ CKD, n = 149), and the serum PCT was analyzed. Results. PCT was highly sensitive and specific in patients presenting with sepsis and no CKD. The mean serum PCT concentration in the group SEPSIS/CKD was significantly higher than in NO SEPSIS/CKD (21.00 [5.83 to 97.00] ng/ml vs 0.90 [0.24 to 1.32] ng/ml, p < 0.001). However, the PCT threshold value was 1.7 ng/ml (sensitivity 91.1%, specificity 88.6%) as compared with the currently used threshold value of 0.5 ng/ml (sensitivity 93.3%, specificity 30.2% in our population study). Conclusions. Our study confirms the diagnostic reliability of PCT for the diagnosis of sepsis in elderly patients with CKD. Nevertheless, we suggest to apply a cut-off of 1.7 ng/ml in this population.