PURPOSE OF THE STUDY.
The primary goal of asthma management is control. This can be assessed by history, physical examination, and measurement of lung function. There are multiple methods to measure control. The purpose of this study was to describe agreement among different measures of asthma control in children.
Atopic children ages 4 to 11 with chronic asthma attending routine follow-up examinations. Asthma was defined as chronic cough or wheezing responsive to bronchodilator. Atopy was defined as a positive skin prick test and symptoms consistent with allergic rhinitis. Patients were on inhaled corticosteroids for asthma and nasal steroids for allergic rhinitis. They had to be able to perform spirometry and not be on oral steroids.
Observations were made in a 4-step sequence: (1) exhaled nitric oxide fraction (FeNO) measurement with a portable NIOX MINO (Aerocrine Inc, Morrisville, NC; ≤35 ppb = controlled, >35 ppb = uncontrolled); (2) spirometry (forced expiratory volume in 1 second ≥80%, forced expiratory flow, midexpiratory phase ≥60%, peak expiratory flow rate ≥80% and forced expiratory volume in 1 second/forced vital capacity ≥80% = controlled); (3) childhood Asthma Control Test (cACT) (<19 = uncontrolled); and (4) clinical assessment by a pediatrician without knowledge of preceding results.
A total of 71 children (mean age 8.4 years; 46 boys and 25 girls) completed the study. The mean FeNO is uncontrolled asthma and was 37 ppb vs 15 ppb in controlled asthma (P < .005) but with considerable overlap. Comparison of individual spirometric indices revealed some correlation, but of the unrelated comparisons, those that agreed with each other most often (69%) were clinical assessment by the pediatrician and the cACT. Worst agreement was noted for FeNO and cACT (49.3%).
Overall this study revealed significant disagreement among many of the common methods used to assess asthma control.
Asthma control is the key to successful management, and assessment of control is recommended in all major guidelines. It is nice to have different measures to choose from but disheartening to see the lack of agreement between tests. Previous studies have also shown a lack of agreement between many of these measures. The authors speculate that taking the individual patient’s asthma phenotype into consideration may be the key and that a combination of physician assessment and objective testing will be required. We continue to wait for the perfect test or combination of tests.
- Copyright © 2013 by the American Academy of Pediatrics