- Design
- Prospective, randomised (2:1), sham-controlled device trial
- Population
- 203 patients with COPD and chronic bronchitis
- Primary outcome
- Change in SGRQ and CAT at 12 months; safety
- Effect
- SGRQ −5.9 (−11.6 to −0.2); CAT −3.4 (−5.8 to −1.0); pneumothorax 3.6% per treatment
SPRAY-CB, in the American Journal of Respiratory and Critical Care Medicine (21 September), randomised 203 patients with COPD and chronic bronchitis 2:1 to two bronchoscopies with mucus clearance plus metered liquid-nitrogen cryospray to the airways, or the same bronchoscopies without it. The idea is to destroy abnormal mucus-producing epithelium so healthier epithelium regenerates.
At 12 months, cryospray improved St George's Respiratory Questionnaire scores by 5.9 points more than sham (95% CI −11.6 to −0.2) and COPD Assessment Test scores by 3.4 points (−5.8 to −1.0). Any exacerbation was about equally common (70.6% vs 67.2%); severe exacerbations were numerically fewer (21.3% vs 26.9%). Pneumothorax occurred after 3.6% of treatments. Six deaths occurred with cryospray and two with sham, none judged device-related.
The SGRQ gain sits close to the 4-point minimal important difference, and its confidence interval nearly touches zero. This is a promising option for patients whose main problem is sputum, but not yet one to refer for routinely.
- Optimise inhaled therapy, airway clearance and smoking cessation first
- Consider roflumilast or macrolides in frequent exacerbators with chronic bronchitis where appropriate
- Refer to trial centres for patients with persistent productive cough despite this
- Discuss pneumothorax risk explicitly if cryospray is considered
Why it matters
Chronic bronchitis has few targeted treatments, and this is the first sham-controlled device trial to show a symptom benefit.
Don't overread it
The quality-of-life gain is near the minimal important difference, and the exacerbation reduction was not shown to be significant.
The statistics, in plain English
The SGRQ difference of −5.9 has an interval from −11.6 to −0.2, so the true benefit could be anywhere from large to barely noticeable. The difference in severe exacerbations was not reported as significant, so it should not be counted as a benefit yet.
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