Clinical judgement of airway inflammation versus sputum cell counts in patients with asthma

The inflammatory component of asthma is usually assessed indirectly by symp toms and spirometry, these may be inaccurate. It can now he assessed direct ly and reliably by the examination of sputum cell counts. There is no infor mation on how clinical assessment of the presence and type of airway inflam mation compares with actual measurements. In this single-centre observational study, sputum was collected from 76 con secutive adults with asthma attending a tertiary chest clinic after their p hysicians had recorded the expected cell counts in sputum. The authors exam ined the extent of agreement between clinical judgement of sputum cell coun ts and actual counts in asthmatic patients (Cohen's Kappa) and the possible predictors of agreement (multiple logistic regression). Sixty-seven of the 76 sputum samples were suitable for analysis, Agreement between expected and actual cell counts occurred in 30/67 patients, The ove rall agreement for the different cell types was poor (estimated kappa=0.14, 95% confidence interval (CI)=0.02, 0.26). The experience of the physician in using sputum cell counts in clinical practice, steroid requirement at th e time of assessment, and control of asthma as assessed by the physician or by the patient could not predict the chances of agreement or disagreement. Unaware of the sputum results, the physicians often changed treatment in a way that seemed inappropriate for the cell counts present. There is poor agreement between clinical judgement of the presence and type of airway inflammation in asthmatic patients and sputum cell counts. The i mpact of sputum examination on the outcomes of anti-inflammatory treatment now needs investigation.