Pulmonary exacerbations in adult patients with cystic fibrosis associated with positive viral PCR

Abstract

Introduction: Studies show the prevalence of respiratory viruses in patients (pts) with cystic fibrosis (CF) and increased respiratory symptoms ranges from 13% to 52% and infection is associated with increased morbidity. Given the recent H1N1 pandemic we investigate the clinical impact of positive virus isolates in adult CF pts with an exacerbation. Method: We routinely undertake throat swabs for viral PCR in all pts starting i.v antibiotics (abx). A retrospective analysis of all pts receiving i.v abx for an exacerbation between 01/12/08 and 01/12/09 was undertaken. Pts with positive viral PCR were compared to negative controls. Exclusion criteria included pregnancy, transplant and continuous I.V. therapy. Results: A total of 42 pts (median age 26.5) had positive viral PCR (overall prevalence 9.5%), with 7 having H1N1. Negative PCR occured in 440 IV courses (189 pts). The 1st course of treatment for each patient was used as a control. Positive PCR was associated with a significantly worse baseline lung function and weight with a higher proportion of pts on enteral feed. The viral group had a higher CRP (p< 0.05), wcc (p< 0.05) and neutrophil count (p< 0.05) at the start of treatment. Viral infection was associated with a greater drop in FEV1 between pre exacerbation baseline and end of treatment in comparison to controls.