Value of C-reactive protein measurements in exacerbations of chronic obstructive pulmonary disease

AbstractC-reactive protein (CRP) has been shown to be a useful and sensitive indicator of pyogenic infections in many clinical situations, including acute pneumonia and infective pulmonary exacerbations in cystic fibrosis patients. Exacerbations of COPD are often, but not always, associated with demonstrable infection. The value of CRP measurement in this situation has not been assessed.We have evaluated CRP measurement in 50 patients [age 71 ± 8 (sd) years] who were admitted to hospital with clinical evidence of exacerbation [PaO2=7·3 ± 1·3 (sd) kPa, baseline FEV1=0·8 ± 0·4 (sd) 1]. These patients all had serial measurement of CRP [polarizing immunofluorescence (Abbot, TDx)], peripheral white cell count (WCC), body temperature, peak expiratory flow rate, Karnofsky performance status and chest X-ray, in addition to serial sputum bacteriological analysis carried out in a specialized laboratory.CRP was elevated ( > 10 mg 1−1) in all patients (n=29) with proven infection [103 ± 98 (sd) mg 1−1]. Levels were markedly elevated in patients infected with Streptococcus pneumoniae (mean 156 mg 1−1); there was also a rapid fall in the CRP with therapy. WCC fell with therapy, giving a correlation with CRP level (r=0·44, P