#329 Coughing up the evidence: Bronchodilators or inhaled steroids for post-infectious cough

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- Differences statistically significant unless noted.
- ICS versus placebo:
- Four systematic reviews of treatments for persistent cough (4-9 RCTs, 335-750 patients): Interpretation limited by inclusion of RCTs with acute (<3 weeks)1,2 and chronic (>8 weeks)2,3 cough, and multiple drug classes.4
- Most useful systematic review2 (2 RCTs, 163 patients), mostly subacute cough (3-8 weeks):
- ICS 0.42 (standard mean difference) better than placebo. In clinical terms, placebo improved cough scores at ~2 weeks by ~50-56% and ICS improves ~2-13% more.
- Largest RCT5 (133 patients) also reported:
- Additional outcomes (days off work, nocturnal awakenings, adverse effects): No difference.
- Proportion of non-smokers with >50% cough improvement: 81% versus 54% (placebo), number needed to treat (NNT)=4.
- No improvement among smokers.
- Limitations: Not all patients had post-infectious cough; study industry funded.
- Bronchodilators versus placebo:
- One RCT6 of 92 patients (cough duration 3-4 weeks): Combination of nebulized salbutamol/ipratropium versus placebo.
- Proportion with ongoing cough at day 10: 37% versus 69% placebo, NNT=3.
- No difference at day 20 (both >80% resolved).
- Limitations: Small studies; non-validated cough scores; multiple outcomes.
- One RCT6 of 92 patients (cough duration 3-4 weeks): Combination of nebulized salbutamol/ipratropium versus placebo.
- Most useful systematic review2 (2 RCTs, 163 patients), mostly subacute cough (3-8 weeks):
- Four systematic reviews of treatments for persistent cough (4-9 RCTs, 335-750 patients): Interpretation limited by inclusion of RCTs with acute (<3 weeks)1,2 and chronic (>8 weeks)2,3 cough, and multiple drug classes.4
- Post-infectious cough is a cough persisting 3-8 weeks after an acute respiratory illness.7
- One RCT8 compared beclomethasone and placebo in 72 patients with prolonged acute cough (10 days-3 weeks), so likely not true post-infectious (subacute) cough.
- ICS improved 3 of 6 outcomes over placebo on device-measured cough, but no difference in patient-reported symptoms.
- Guidelines suggest considering a trial of inhaled ipratropium or, if refractory, inhaled corticosteroids.9
- RCTs above did not include patients with COVID-19.