Delayed resolution of inflammatory response compared with clinical recovery in patients with acute exacerbations of chronic obstructive pulmonary disease

Background and objective: The temporal profile of inflammatory markers during acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and their relationship to clinical response are not well characterized. The aim was to assess the changes in levels of inflammatory markers in AECOPD and correlate these with clinical and laboratory indices of recovery. Methods: Serum levels of C-reactive protein (CRP), interleukin (IL)-6 and fibrinogen were measured in patients with AECOPD within 24 h of hospitalization and pre-discharge (stable state). Results: Ninety-seven patients were evaluated (79 males; mean (SD) age, 61.4 (10.3) years). Eighty eight (90.7%) were current or former smokers, with a median consumption of 15 (075) packs/year. The median duration of COPD was 8 (225) years. Forty-six patients (56.9%) required mechanical ventilation for a median of 5 days (134) while in hospital. The median duration of hospital stay was 13 days (177). At reassessment before planned discharge, the levels of dyspnoea, leucocyte counts, erythrocyte sedimentation rate, creatinine, partial pressure of oxygen, and albumin normalized. The levels of CRP, IL-6 and fibrinogen reduced significantly but did not reach the normal range. Changes in IL-6 and fibrinogen levels correlated significantly with the acute physiologic assessment and chronic health evaluation II score, smoking history, blood pressure and leucocyte counts. Baseline IL-6 and fibrinogen levels significantly predicted a prolonged duration of mechanical ventilation. Conclusions: During AECOPD, the inflammatory response lags behind clinical and biochemical improvement. Fibrinogen and IL-6 are potentially useful markers for monitoring clinical response following an acute episode.