C-Reactive Protein Changes in Adult and Pediatric People With Cystic Fibrosis During Treatment of Pulmonary Exacerbations.

Objective: Although studies have examined changes in C-reactive protein (CRP) during pulmonary exacerbations (PEX) in people with cystic fibrosis (PwCF), few have evaluated CRP profiles across age groups. Here, we characterize age-related CRP responses to PEX treatment.

Methods: We measured CRP concentrations at the beginning and end of intravenous (IV) antibiotic therapy for PEX in 100 pediatric and 147 adult PwCF at 10 US CF Centers. We examined relationships between CRP and age, lung function, severity of PEX symptoms, and time to next PEX.

Results: CRP measured at initiation of IV antibiotic treatment for PEX was higher in adults than children, median 8 mg/L (IQR 4, 32) versus 5 mg/L (IQR 2, 10), respectively (p < 0.001). There was a significant correlation between the initial CRP and drop in lung from baseline to the beginning of IV antibiotics in adults and children. Adjusted CRP dropped in response to PEX treatment more commonly in adults than in children (70% vs. 48%, respectively). The range of treatment responses was greater in adults, in those with higher symptom scores, and in those with more advanced lung disease. In adults elevated CRP at the end of treatment was also associated with incomplete recovery of lung function. CRP at the start of IV antibiotics was inversely related to time until the next PEX.

Conclusion: In children and adults with CF, CRP is increased at the initiation of IV antibiotic therapy for PEX and declines with treatment. The response is more pronounced in highly symptomatic adults with advanced lung disease.