COPD: oral mucolytics reduce exacerbations and days of illness

Clinical bottom line (level 1a)

  1. Patients with chronic bronchitis who take oral mucolytics regulalry compared with placebo are less likely to develop exacerbations (NNT = 5 at 2-12 months) and complain of adverse effects (NNT = 26 at 2-12 months) .
  2. Patients on mucolytics have fewer days of illness (roughly 7 fewer a year) and fewer days on antibiotics (roughly 6 fewer a year).
Poole and Black: BMJ 2001; 322 : 1271-1274
Expires May 2004

The study

Systematic review of all randomised controlled trials of
  • Patients: COPD
  • Intervention: oral mucolytics: n-acetylcysteine, s-carboxymethylcysteine, bromhexine, ambroxol, sobrerol, cithiolone, letosteine, n-isobutyrylcysteine, myrtol and iodinated glycerol compared with placebo
  • Outcome: number of exacerbations, days of illness, days on antibiotics

Articles found in all languages using Cochrane Airways Group register (including Medline, Embase, CINAHL, hand-searching of 20 respiratory journals and meeting abstracts), to August 1999 (search terms: detailed in text )

Selection criteria: by 2 independent reviewers with disagreement resolved by consensus
Appraisal criteria: using concealment allocation, blinding and follow-up
Articles excluded if:
  • aged < 20
  • asthma or cystic fibrosis
  • inhaled mucolytics, combinations with antibiotics or bronchodilators, deoxyribonucleases or proteases
23 RCTs found: 21 on patients with chronic bronchitis, 2 on patients with COPD
Studies were not found to be heterogeneous.

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
free from exacerbations 2-12 months 744/1769
(42.1%)		 2.22
(1.93 to 2.54) 		5
(4 to 6)
adverse effects 2-12 months 444/2014
(22.0%)		 0.79
(0.67 to 0.93) 		26
(16 to 82)

  • mucolytics v. placebo: weighted mean difference in days of illness per month: 0.56 days (95% CI: 0.35 to 0.77)
  • mucolytics v. placebo: weighted mean difference in days on antibiotics per month: 0.53 (95% CI: 0.31 to 0.76)

Comments

  1. No study reported the effects on hospital admissions.

Citation

  1. Poole PJ, and Black PN: oral mucolytic drugs for exacerbations of chronic obstructive pulmonary disease: systematic review. BMJ 2001; 322 : 1271-1274
Search Terms: from ACP Journal Club
Contributor: Chris Ball, May 2002
Reviewer:

Clinical Question.
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Intervention or Exposure
Outcome