Asthma control, quality of life and successful sputum induction

Induced sputum is widely used in clinical practice and scientific studies. This technique has become enormously useful in assessment of airway inflammation. However, some asthmatics are unable to expectorate sputum of sufficient quality and quantity necessary for further processing, therefore not providing reliable results. This research study aimed to examine whether asthma control and asthma quality of life influence the results of sputum induction.

Fourty-seven adult subjects, current non-smokers with symptomatic asthma, were studied. All participants underwent clinical assessment, skin prick testing, spirometry and sputum induction. Before sputum induction, subjects were asked to fill in the Mini Asthma Quality of Life Questionnaire (MiniAQLQ) and Asthma Control Questionnaire (ACQ).

Twenty-nine (62%) subjects produced sputum eligible for processing. This group had a significantly lower ACQ score (0.83 ±0.65 vs. 1.37 ±0.77; p = 0.02), higher MiniAQLQ total score (5.67 ±0.99 vs. 4.86 ±1.07; p = 0.011), higher MiniAQLQ symptoms domain score (5.54 ±1.13 vs. 4.63 ±1.24; p = 0.013) and higher MiniAQLQ activity limitations domain score (6.08 ±0.92 vs. 5.07 ±1.37; p= 0.014). The noted differences between groups of patients were not only statistically but were clinically important.

The study results suggest that successful sputum induction may be expected in patients with better asthma control and better quality of life.