C-reactive protein as a biomarker of response to inhaled corticosteroids among patients with COPD

C-reactive protein (CRP) is an important biomarker in systemic inflammation in COPD; reports have suggested inhaled corticosteroids (ICS) attenuate CRP levels. We evaluated the risk of moderate-to-severe exacerbations, severe exacerbations and all-cause mortality among patients with COPD currently exposed to Inhaled corticosteroids (ICS) stratified by CRP levels compared to never ICS users with low CRP levels.

We included subjects age 40 or more who had a diagnosis of COPD from January 1, 2005 to January 31, 2014 from the UK Clinical Practice Research Datalink (CPRD). ICS exposure was determined time-dependently, as current, recent, past or never users. We evaluated the risk of moderate-to-severe exacerbations, severe exacerbations and all-cause mortality among ICS users stratified by CRP levels.

17,722 subjects diagnosed with COPD met the inclusion criteria. Among current or never ICS with elevated CRP levels we found, no significantly reduced risk of moderate-to-severe or severe exacerbations. For patients currently exposed ICS with CRP levels ≥8 mg/L there was no reduced risk of moderate-to-severe exacerbations (adjusted hazard ratio [adj. HR] 0.99; 95% confidence interval [CI] 0.76-1.31) or severe exacerbations (adj.HR 1.52; 95% CI 0.71-3.27). However, we found an increased risk of all-cause mortality among COPD patients with CRP levels ≥8 mg/L irrespective of ICS exposure.

We did not find a reduced risk of moderate and/or severe COPD exacerbations among COPD patients with varying CRP levels currently exposed to ICS. However, low-grade systemic inflammation was associated with all-cause mortality among COPD patients.