Procalcitonin predicts the severity of cystic fibrosis pulmonary exacerbations and readmissions in adult patients: a prospective cohort study

Patients with cystic fibrosis (CF) experience multiple pulmonary exacerbations throughout their lifetime, resulting in repeated antibiotic exposure and hospital admissions. Reliable diagnostic markers to guide antibiotic treatment in patients with CF, however, are lacking. Given that the CF airway is characterized by persistent and frequent bacterial infection, our goal was to determine if procalcitonin (PCT) could be used as a severity and prognostic marker of CF exacerbation. We enrolled 40 participants at the time of diagnosis of CF pulmonary exacerbation. Inclusion criteria: age ≥19 years with exacerbation requiring antibiotics as determined by the treating physician. Exclusion criteria: antibiotics initiated more than 48 hours prior to enrollment, and pregnancy. Blood samples were collected on enrollment day and after 7–10 days of treatment. Of the 40 patients enrolled, 23 (57.5%) had detectable levels of PCT (≥0.05 ng/mL). PCT levels were significantly associated with pulmonary exacerbation scores (p=0.01) and per cent decrease in forced expiratory volume in 1 second (FEV1) (p=0.01) compared with the best in the last 12 months. Those who had worsening PCT during treatment had less improvement in FEV1 (p=0.001) and were more likely to be readmitted to the hospital sooner (p