Table 1

Study characteristics

CharacteristicNumber of studies* (n=208)Percentage of studies
Year of publication
 1989–199431.4
 1995–1999157.2
 2000–20043516.8
 2005–20096832.7
 2010–20148741.8
Geographic region
 Europe7234.6
 Multicontinent4421.2
 North America3617.3
 Multicountry (not specified)2411.5
 Asia209.6
 Not reported94.3
 Africa10.5
 Australia10.5
 South America10.5
Setting
 Single centre3215.4
 Multicentre15273.1
 Not reported2411.5
Duration of follow-up†
 0 to ≤64521.6
 >6 to ≤125225
 >12 to ≤243516.8
 >24 to ≤48199.1
 >48 to ≤723918.8
 >72 to ≤9621
 >96 to ≤12062.9
 >120 weeks94.3
 Not reported10.5
Outcomes examined: frequency‡
 Efficacy—exacerbations11253.8
 Efficacy—mortality9545.7
 Harm—cardiovascular-related mortality4622.1
 Harm—pneumonia5426.0
 Harm—arrhythmia3215.4
  • *Includes unpublished data.

  • †Duration is in weeks unless otherwise noted.

  • ‡Multiple interventions and outcomes reported per study.