Table 2.
Cough Responses to Tussive Agents in Airway Diseases Compared with Healthy Control Subjects
| Healthy Control Subjects | Healthy Smokers | COPD | Asthma | Chronic Cough | P Value | |
|---|---|---|---|---|---|---|
| Capsaicin, μM | ||||||
| logC5 | 3.75 (±2.06) | 3.37 (±1.24) | 2.52 (±1.54)* | 2.82 (±1.99) | 1.63 (±0.81)* | 0.001 |
| logC2 | 2.12 (±1.59) | 2.02 (±1.11) | 1.48 (±1.07) | 1.57 (±1.06) | 1.22 (±0.92) | 0.091 |
| logC1 | 2.01 (±1.38) | 1.81 (±1.31) | 1.25 (±0.90)* | 1.36 (±0.78)* | 1.11 (±0.90)* | 0.035 |
| Citric acid, M | ||||||
| logC5 | 0.37 (±1.40) | −0.54 (±1.16) | −1.01 (±1.99) | −1.33 (±1.77)* | −1.98 (±1.30)* | 0.002 |
| logC2 | −1.98 (±0.98) | −2.14 (±1.35) | −1.79 (±1.49) | −2.35 (±1.13) | −3.09 (±0.50)* | 0.014 |
| logC1 | 2.13 (±1.01) | −2.45 (±1.28) | −1.84 (±1.53) | −2.45 (±1.11) | −3.09 (±0.50)* | 0.028 |
| PGE2, μg/ml | ||||||
| logC5 | 3.83 (±3.81) | 6.23 (±3.21)* | 7.50 (±2.04)* | 3.88 (±3.50) | 2.67 (±2.61) | <0.001 |
| logC2 | 1.82 (±2.23) | 3.87 (±3.20)* | 3.49 (±3.46) | 2.62 (±2.89) | 1.44 (±1.55) | 0.027 |
| logC1 | 1.42 (±1.85) | 3.25 (±2.90)* | 3.40 (±3.34)* | 1.76 (±2.07) | 1.34 (±1.59) | 0.013 |
Definition of abbreviations: COPD = chronic obstructive pulmonary disease; PGE2 = prostaglandin E2.
Concentrations of tussive agents causing at least five coughs (C5), at least two coughs (C2), and at least one cough (C1). The lower the C5, C2, or C1, the greater the sensitivity of the cough reflex. Data are mean ± SD. P values <0.05 are shown in bold.
*
Significant differences compared with healthy control group (P < 0.05) based on analysis of variance.