Laurie Slovarp1, Jane E Reynolds2, Emma Bozarth-Dailey2, Sarah Popp2, Sarah Campbell2, Paige Morkrid2. 1. School of Speech, Language, Hearing, & Occupational Sciences, University of Montana, 32 Campus Dr., Missoula, MT, USA. Electronic address: laurie.slovarp@umontana.edu. 2. School of Speech, Language, Hearing, & Occupational Sciences, University of Montana, 32 Campus Dr., Missoula, MT, USA.
Abstract
BACKGROUND: The purpose of this study was to determine feasibility of treating refractory chronic cough (RCC) with progressive doses of capsaicin paired with cough suppression. METHODS: In this sham-controlled, parallel RCT, 14 adults with RCC were randomly assigned to either behavioral cough suppression therapy (BCST) plus 6 treatment sessions involving exposure to nebulized capsaicin in progressively larger concentrations while actively suppressing cough (n = 8), or BCST plus 6 sessions of exposure to a single subthreshold dose of capsaicin (sham; n = 6). The Leicester Cough Questionnaire (LCQ) was the primary outcome measure. Urge-to-cough (UTC) testing, measuring both UTC and cough frequency, served as secondary outcome measures. Data was analyzed with mixed effects linear regression and follow-up contrasts. RESULTS: Results on all measures favored the treatment group; however, there was only strong evidence of a difference in treatment effect on cough frequency during UTC testing. Mean change in LCQ at 3-weeks post treatment was 2.95 and 1.75 (p = .23), in the treatment and sham groups, respectively. Cough frequency during UTC testing reduced by 97% and 56% (p < .0001) at three weeks post, respectively. Within-group comparisons revealed strong evidence of change in the treatment group (p < .001) and moderate evidence of a change in the sham group (p = .08) in LCQ. CONCLUSIONS: Conclusions from this study are limited due to the very small sample size; however, the study provides feasibility and proof-of-concept evidence to support further investigation of treating RCC with repeated exposure to nebulized capsaicin paired with BCST.
BACKGROUND: The purpose of this study was to determine feasibility of treating refractory chronic cough (RCC) with progressive doses of capsaicin paired with cough suppression. METHODS: In this sham-controlled, parallel RCT, 14 adults with RCC were randomly assigned to either behavioral cough suppression therapy (BCST) plus 6 treatment sessions involving exposure to nebulized capsaicin in progressively larger concentrations while actively suppressing cough (n = 8), or BCST plus 6 sessions of exposure to a single subthreshold dose of capsaicin (sham; n = 6). The Leicester Cough Questionnaire (LCQ) was the primary outcome measure. Urge-to-cough (UTC) testing, measuring both UTC and cough frequency, served as secondary outcome measures. Data was analyzed with mixed effects linear regression and follow-up contrasts. RESULTS: Results on all measures favored the treatment group; however, there was only strong evidence of a difference in treatment effect on cough frequency during UTC testing. Mean change in LCQ at 3-weeks post treatment was 2.95 and 1.75 (p = .23), in the treatment and sham groups, respectively. Cough frequency during UTC testing reduced by 97% and 56% (p < .0001) at three weeks post, respectively. Within-group comparisons revealed strong evidence of change in the treatment group (p < .001) and moderate evidence of a change in the sham group (p = .08) in LCQ. CONCLUSIONS: Conclusions from this study are limited due to the very small sample size; however, the study provides feasibility and proof-of-concept evidence to support further investigation of treating RCC with repeated exposure to nebulized capsaicin paired with BCST.
Authors: H M Blom; J B Van Rijswijk; I M Garrelds; P G Mulder; T Timmermans; R Gerth van Wijk Journal: Clin Exp Allergy Date: 1997-07 Impact factor: 5.018
Authors: L P McGarvey; L G Heaney; J T Lawson; B T Johnston; C M Scally; M Ennis; D R Shepherd; J MacMahon Journal: Thorax Date: 1998-09 Impact factor: 9.139