Complementary roles of capsaicin cough sensitivity test and induced sputum test to methacholine bronchial provocation test in predicting response to inhaled corticosteroids in patients with chronic nonproductive cough.
BACKGROUND
The capsaicin cough sensitivity test (CCST), methacholine bronchial provocation test (MBPT), and induced sputum test (IST) are widely used in the clinical evaluation of chronic nonproductive cough. However, little is known about their roles in predicting response to inhaled corticosteroids (ICSs) in patients with chronic nonproductive cough.


OBJECTIVE
To test the hypothesis that the CCST and IST play complementary roles to the MBPT for predicting the response to ICS treatment in patients with chronic nonproductive cough.


METHODS
A total of 43 patients with chronic nonproductive cough who showed isolated capsaicin cough hypersensitivity (CCST group) and 55 patients with chronic nonproductive cough who had methacholine airway hyperresponsiveness (MBPT group) were enrolled. These patients underwent the IST followed by treatment with ICSs for 4 weeks. Measurement of symptom improvement was recorded by the visual analog scale.


RESULTS
The response rates to ICS treatment in the CCST and MBPT groups were similar (74.5% vs 86.0%; P = .21). Only the neutrophil count in the IST group was significantly different in responders and nonresponders after the ICS treatments (P = .005 for the CCST group and P = .006 for the MBPT group). Interestingly, the absence of sputum neutrophilia used as a criterion for subgroup analysis increased response rates in the patients with either methacholine airway hyperresponsiveness or capsaicin cough hypersensitivity.


CONCLUSIONS
In the present study, we demonstrate that CCST and IST play complementary roles to MBPT. By combining the results of these tests, we are able to identify more patients with chronic nonproductive cough and treat patients more successfully with ICSs by improving the response rate to ICS treatment.
Park
Heung-Woo
HW
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
Kim
Sang-Hoon
SH
Chang
Yoon-Seok
YS
Lee
Byung-Jae
BJ
Min
Kyung-Up
KU
Kim
You-Young
YY
Cho
Sang-Heon
SH
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D018712:Analgesics, Non-Narcotic; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D002211:Capsaicin; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis* / Q000188:drug therapy*; D003948:Diagnostic Techniques, Respiratory System; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D013183:Sputum / Q000166:cytology
D000305:Adrenal Cortex Hormones; D018712:Analgesics, Non-Narcotic; D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D002211:Capsaicin