Research

Improved outcomes in patients with chronic obstructive pulmonary disease treated with salmeterol compared with placebo/usual therapy: results of a meta-analysis

Robert A Stockley¹ , Philip J Whitehead² and Michael K Williams²

¹  Queen Elizabeth Hospital, Birmingham, UK

²  GlaxoSmithKline, Greenford Road, Greenford, Middlesex UB6 OHE, UK

author email corresponding author email

Respiratory Research 2006, 7:147doi:10.1186/1465-9921-7-147

Published:	29 December 2006

Abstract

Background

Several studies have demonstrated that long-acting β₂-agonists such as salmeterol are beneficial in chronic obstructive pulmonary disease (COPD). A meta-analysis was therefore conducted to review studies in COPD to provide pooled estimates of the effect of salmeterol 50 mcg taken twice daily in addition to usual therapy on several clinically relevant endpoints, when compared with placebo/usual therapy.

Methods

An extensive search of literature and clinical trial databases was conducted using the terms salmeterol, COPD, chronic, obstructive, bronchitis and emphysema. Nine randomized, double-blind, parallel-group, placebo-controlled trials of ≥12 week duration with salmeterol 50 mcg bid treatment in COPD were included (>3500 patients), with a further 14 trials excluded due to study design or reporting timelines. All patients were included, and a sub-group of subjects (84%) with poorly reversible COPD were considered separately. Statistical testing was carried out at the 5% level, except for interaction testing which was carried out at the 10% level.

Results

Patients treated with salmeterol over 12 months were less likely to withdraw early from the studies (19% patients compared with 25% on their current usual therapy, p < 0.001), less likely to suffer a moderate/severe exacerbation (34% compared with 39%, p < 0.0001) and had a greater increase in average FEV₁ (73 mL difference vs placebo/usual therapy, p < 0.0001). Similar differences were found at 3 and 6 months. At all time points, more patients experienced an improvement in health status and also a greater change with salmeterol than with placebo/usual therapy (p < 0.002). There was no evidence of tachyphylaxis to salmeterol over 12 months.

Conclusion

The meta-analysis confirmed clinically and statistically significant, sustained and consistent superiority of salmeterol 50 mcg bid over placebo/usual therapy on a broad range of outcome measures.