Comparison of diagnostic validity of mannitol and methacholine challenges and relationship to clinical status and airway inflammation in steroid-naïve asthmatic patients.
OBJECTIVE
The purpose of this study was to demonstrate and compare the diagnostic validity of two bronchial challenges and to investigate their correlation with patient clinical status, atopy and inflammation markers.


METHODS
Eighty-eight patients, 47 women and 41 men, mean age 38.56 ± 16.73 years who presented with asthma related symptoms and were not on any anti-asthma medication, were challenged with mannitol and methacholine on separate days. Medical history regarding asthmatic symptoms, physical examination, skin prick tests and FeNO levels were also assessed. The clinical diagnosis of asthma was based on bronchodilator reversibility test.


RESULTS
Sixty-seven patients were diagnosed with asthma and 21 without asthma. Both methacholine (P < 0.014) and mannitol (P < 0.000) challenges were significant in diagnosing asthma. The positive/negative predictive value was 93.33%/41.86% for methacholine, 97.72%/45.45% for mannitol and 97.05%/45.45%. for both methods assessed together. Worthy of note that 22% of asthmatics had both tests negative. There was a negative correlation between PC20 of methacholine and the FeNO level P < 0.001, and positive with the PD15 of mannitol P < 0.001 and the pre-test FEV1% pred P < 0.005, whereas PD15 of mannitol was negatively correlated with the FeNO level P < 0.001. Furthermore, dyspnea was the only asthmatic symptom associated with FeNO level P < 0.035 and the positivity of mannitol P < 0.014 and methacholine P < 0.04.


CONCLUSIONS
Both challenge tests were equivalent in diagnosing asthma. Nevertheless, specificity appeared to be slightly higher in mannitol challenge.
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Konstantinos
K
Porpodis
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Kalliopi
K
Domvri
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Theodoros
T
Kontakiotis
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Evangelia
E
Fouka
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Eirini
E
Kontakioti
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Konstantinos
K
Zarogoulidis
a Department of Pulmonary Medicine , Aristotle University of Thessaloniki , Thessaloniki , Greece.
Despina
D
Papakosta
D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000276:immunology; D001985:Bronchial Provocation Tests / Q000379:methods*; D016085:Bronchoconstrictor Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001993:Bronchodilator Agents / Q000494:pharmacology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology; D018836:Inflammation Mediators / Q000276:immunology; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000494:pharmacology*; D016210:Methacholine Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012882:Skin Tests
D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents; D018836:Inflammation Mediators; D016210:Methacholine Chloride; D009569:Nitric Oxide; D008353:Mannitol
Airway inflammation; mannitol; methacholine; validity