ABSTRACT

Scleroderma/Systemic Sclerosis (SSc) is characterized by progressive fibrosis. SSc related interstitial lung disease (SSc-ILD) is a major cause of mortality and morbidity among SSc patients. Procalcitonin (PCT) is used for diagnosis and follow up bacterial infections and sepsis. Bacterial pneumonia is an important situation that should be considered in the differential diagnosis of lung diseases. In this study, we aimed to investigate the diagnostic value of serum PCT between in patients with SSc-ILD and bacterial pneumonia.

One-hundred and fifty-one SSc patients were retrospectively evaluated. Of these, 27 patients with SSc-ILD whose PCT levels checked, and 18 patients diagnosed with bacterial pneumonia were included to the study.

Twenty-seven (23 female, four male) patients with a mean age of 49.3±13.5 and a mean duration of disease 9.9±5.9 years were evaluated in the SSK-ILD group. There were 17 (two female, 15 male) patients with a mean age of 75.2±14.6 in pneumonia group. PCT level was higher in pneumonia group than in SSK-ILD group (8.1±15 and 0.1±0.4, p<0.001, respectively). PCT level was higher than 0.12 ng/mL in four of SSK-ILD (14.8%) and 15 of pneumonia patients (88.2%) (p<0.001). Similarly, one patient (3.7%) in SSK-İAH group had a PCT level that was higher than 0.5 ng/mL, whereas nine patients (52.9%) in pneumonia group (p<0.001). Receiver operating characteristic analyses showed good sensitivity and specificity with a 0.16 ng/mL PCT level to predict discrimination between SSc-ILD and pneumonia (AUC=0.96, 95% Confidence interval=0.91-1.0, p<0.001).

This study showed that high serum PCT levels induce infection rather than SSc-ILD and it could be used in differential diagnosis of SSc-ILD and pneumonia.

Keywords: Systemic Sclerosis, Scleroderma, Interstitial Lung Disease, Acute Phase Reactants, Procalcitonin