The review identified 22 studies involving 23,309 participants. 19 studies use the dry powder inhaler while 3 used the soft mist inhaler. The studies were between three months and four years in duration and compared active treatment to placebo.
Based on evaluation of data from the St George's Respiratory Questionnaire (SGRQ) there was a statistically significant improvement in quality of life (mean difference -2.89; 95% CI -3.35 to -2.44), more patients had a clinically significant improvement in quality of life (odds ratio 1.52; 95% CI 1.38 to 1.68) and fewer had a clinically significant deterioration (OR 0.65; 95% CI 0.59 to 0.72).
Tiotropium treatment also resulted in significantly fewer exacerbations (OR 0.78; 95% CI 0.70 to 0.87) corresponding to an NNT of 16 when compared to placebo to prevent one exacerbation in a year. Hospital admissions for exacerbations were also reduced but all-cause hospital admissions remained the same.
All-cause mortality was similar between the placebo and active treatment groups until the two inhaler devices were analysed individually. Treatment with the dry powder device resulted in fewer deaths (non-significant) compared with placebo (Peto OR 0.92; 95% CI 0.80 to 1.05) but treatment with the soft mist inhaler resulted in significantly more deaths (Peto OR 1.47; 95% CI 1.04 to 2.08).
The authors conclude that, "tiotropium improves patients' quality of life, and reduces the risk of exacerbations, including exacerbations leading to hospitalisation". They also advise caution in using the soft mist inhaler.
Action: The findings of this analysis are in keeping with the advice in the current NICE guideline for COPD. As suggested previously, it may be prudent to reserve use of the soft mist inhaler to patients who cannot operate or tolerate the dry powder device.
Thanks to Kevin Ashworth for spotting this article