Table 6. Management of chronic cough in respiratory disease.
| Disease | Intervention | Study | Outcome |
|---|---|---|---|
| Asthma | Gefapixant | RCT (n=732), comorbid asthma in 41% (16) | Improved objective CFreq, cough severity VAS and LCQ |
| Tiotropium | Noncontrolled study of asthma with CC on LABA/ICS (n=17) (66) | Improved cough severity VAS, LCQ and ACT with no change to FEV1. CRS reduced when VAS reduced ≥15 mm |
|
| LTRAs: Zafirlukast and Montelukast | 2 RCTs (n=8 and 14) and an observational study (n=14) (91-93) | Improved cough severity VAS, objective CFreq, and CRS with no change to FEV1 | |
| Mepolizumab | Observational study (n=11) (94) | 24 h objective CFreq improved from baseline of 172 to 71 at 6 months |
|
| Azithromycin | RCT, post-hoc analysis of patients with asthma (n=7) (95) | LCQ and cough severity (VAS) improved compared to placebo; difference 6.19, P<0.01, and −3.1, P<0.01, respectively | |
| COPD | Smoking cessation | Observational study (n=68) (1) | Current smokers had worse objective CFreq, cough severity VAS and LCQ compared to COPD ex-smokers |
| Pulmonary rehabilitation | Observational study in consecutive COPD (n=49) (67) | Significant improvement in LCQ and CASA-Q | |
| Azithromycin | RCT of COPD with chronic bronchitis (n=84) (69) | Treatment conferred benefit to LCQ (difference 1.3, P=0.01) | |
| Codeine | RCT of COPD with cough (n=21) (96) | No benefit to cough severity VAS, objective CFreq or CRS | |
| Bronchiectasis | BHPT | Observational study of stable bronchiectasis (n=53) (73) | Cough severity VAS and LCQ improved |
| Twice daily chest physiotherapy | RCT of stable bronchiectasis (n=20) (74) | Improved LCQ | |
| Atorvastatin | RCT of stable bronchiectasis colonised with Pseudomonas aeruginosa (n=27) (97) | No change in LCQ, improvement in SGRQ | |
| Atorvastatin | RCT of stable bronchiectasis (n=82) (98) | Improved LCQ | |
| ILD | Thalidomide | Cross-over study in IPF (n=98) (99) | Improved cough severity VAS, CQLQ and SGRQ. High rates of adverse events |
| Cyclophosphamide and mycophenolate | Post-hoc analysis of trials SLS1 (n=158) and SLS2 (n=142) in SSc-ILD (43,44) | Both improved self-reported cough | |
| Omeprazole | RCT in IPF (n=45) (77) | No effect on objective CFreq or LCQ | |
| Oral prednisolone | Uncontrolled trial in IPF (n=6) (89) | Improved CRS and cough severity VAS | |
| Azithromycin | RCT cross-over trial in IPF (n=25) (100) | No benefit in LCQ, cough severity VAS, or objective CFreq | |
| Nebulised sodium cromoglycate | Phase 2b RCT in IPF (n=108) (101) | Despite promising phase 2a results, gave no benefit in LCQ, cough severity VAS, or objective CFreq | |
| Pirfenidone | Observational study in IPF (n=43) (102) | Improved cough severity VAS, LCQ and objective CFreq | |
| Gefapixant | Cross-over RCT in IPF (n=51) (103) | No effect on cough severity VAS, CQLQ and objective CFreq. Cough severity diary scores improved with treatment | |
| Sarcoidosis | Azithromycin | Noncontrolled, open-label trial (n=21) (78) | Reduced objective CFreq, cough severity (VAS) and LCQ |
| Inhaled corticosteroid | 3 RCTs in sarcoidosis (n=21, 29 and 44) (104-106) | No benefit to reported cough | |
| Nebulised VIP | Open phase 2 study (n=20) (107) | Improved self-reported cough and reduced bronchoalveolar TNF-α |
RCT, randomised controlled trial; CFreq, cough frequency; VAS, visual analogue scale; LCQ, Leicester Cough Questionnaire; CC, chronic cough; LABA/ICS, long-acting beta agonist/inhaled corticosteroid; ACT, asthma control test; FEV1, forced expiratory volume in one second; CRS, cough reflex sensitivity; LTRA, leukotriene receptor antagonists; COPD, chronic obstructive pulmonary disease; CASA-Q, Cough and Sputum Assessment Questionnaire; BHPT, bronchopulmonary hygiene physical therapy; SGRQ, St. George’s respiratory questionnaire; IPF, idiopathic pulmonary fibrosis; CQLQ, Cough Quality of Life Questionnaire; SLS, scleroderma lung study; SSc, systemic sclerosis; ILD, interstitial lung disease; VIP, vasoactive intestinal peptide; TNF-α, tumour necrosis factor α.