Summary of findings for the main comparison. Tiotropium versus placebo for chronic obstructive pulmonary disease.
| Tiotropium versus placebo for chronic obstructive pulmonary disease | ||||||
|
Patient or population: people with COPD who have smoked for ≥ 10 pack‐years
Settings: community
Intervention: tiotropium Comparison: placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo | Tiotropium | |||||
|
Quality of life (SGRQ) Scale 0 to 100, where 100 represents worst possible health status and 0 indicates best possible health status Follow‐up: 3 to 48 months |
See comment | See comment | MD ‐2.89 (‐3.35 to ‐2.44) | 13,034 (9 studies) | ⊕⊕⊕⊕ high | Several studies did not report results for individual treatment groups and reported MD between the groups only. The accepted threshold for a clinically significant difference is ‐4 units |
| Number of patients with a clinically significant improvement (≥ 4 units) in quality of life (SGRQ) Follow‐up: 3 to 48 months | 389 per 1000 | 492 per 1000 (468 to 517) |
OR 1.52 (1.38 to 1.68) |
11,672 (9 studies) | ⊕⊕⊕⊕ high | |
| Number of patients with a clinically significant worsening (≥ 4 units) in quality of life (SGRQ) Follow‐up: 3 to 48 months | 348 per 1000 | 257 per 1000 (239 to 277) |
OR 0.65 (0.59 to 0.72) |
11,672 (9 studies) | ⊕⊕⊕⊕ high | |
| Number of patients with one or more exacerbations Follow‐up: 3 to 48 months | 442 per 1000 | 382 per 1000 (357 to 408) | OR 0.78 (0.70 to 0.87) | 23,309 (22 studies) | ⊕⊕⊕⊕ high1 | |
| Number of patients with one or more exacerbations requiring hospitalisation Follow‐up: 3 to 48 months | 131 per 1000 | 113 per 1000 (98 to 131) | OR 0.85 (0.72 to 1.00) | 22,852 (21 studies) | ⊕⊕⊕⊖ moderate2 | |
| Number of patients with one or more hospitalisations for any cause Follow‐up: 3 to 48 months | 234 per 1000 | 234 per 1000 (212 to 257) | OR 1.00 (0.88 to 1.13) | 20,963 (19 studies) | ⊕⊕⊕⊖ moderate2 | |
| Mortality Follow‐up: 3 to 48 months | 49 per 1000 | 48 per 1000 (43 to 54) | OR 0.98 (0.86 to 1.11) | 23,309 (22 studies) | ⊕⊕⊕⊖ moderate2 | |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; MD: Mean difference; RD: Risk difference; OR: Odds ratio; SGRQ: St George's Respiratory Questionnaire | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1 Although there was moderate unexplained heterogeneity between the study results (I2 = 51%), this was deemed not to affect the direction of the effect or have a large effect on the size of the effect.
2 The number of participants and/or events were low, leading to wide CIs and imprecision in the result.