Exhaled and Systemic Biomarkers to Aid the Diagnosis of Bronchial Asthma in Elite Water Sports Athletes

Abstract

Purpose: Our aim was to evaluate the accuracy of a combined airway inflammatory biomarker assessment in diagnosing asthma in elite water sports athletes.

Methods: Members of the Hungarian Olympic and Junior Swim Team and elite athletes from other aquatic disciplines were assessed for asthma by objective lung function measurements, and blood eosinophil count (BEC), serum total immunoglobulin E (IgE), fractional exhaled nitric oxide (F ENO ) measurements, and skin prick testing were performed. A scoring system from BEC, F ENO , serum IgE, and skin test positivity was constructed by dichotomizing the variables and assigning a score of 1 if the variable is elevated. These scores were summed to produce a final composite score ranging from 0 to 4.

Results: A total of 48 participants were enrolled (age 21 ± 4 yr, 42% male), of which 22 were diagnosed with asthma. Serum total IgE and F ENO levels were higher in asthmatic individuals (68 [27-176] vs 24 [1-43], P = 0.01; 20 [17-26] vs 15 [11-22], P = 0.02), and positive prick test was also more frequent (55% vs 8%, P < 0.01). Asthmatic participants had higher composite variable scores (2 [1-3] vs 1 [0-1], P = 0.02). Receiver operating characteristic analysis showed that total IgE, F ENO , and composite variable were suitablefor identifying asthmatic participants (area under the curve = 0.72, P = 0.01; 0.70, P = 0.02, and 0.69, P = 0.03). A composite score of >2 reached a specificity of 96.2%, a sensitivity of 36.4%, and a likelihood ratio of 9.5. Logistic regression model revealed a strong association between the composite variable and the asthma diagnosis (OR = 2.71, 95% confidence interval = 1.17-6.23, P = 0.02).

Conclusions: Our data highlight the diagnostic value of combined assessment of Th2-type inflammation in elite water sports athletes. The proposed scoring system may be helpful in ruling in asthma in this population upon clinical suspicion.

FIGURE 1

Flow chart of patient selection.

FIGURE 2

Levels of F_ENO (A), IgE (B), and BEC (C) in nonasthmatic and asthmatic participants.

FIGURE 3

ROC curves of BEC, blood eosinophil percentage, total IgE concentration, and F_ENO to predict asthma diagnosis.