Tiotropium 18 mcg daily has proven superior to ipratropium bromide 36 mcg qid for multiple outcomes in trials of up to one year duration. However, it is assumed that short-term negative fluctuations in clinical status do not occur during the period immediately following the switch from ipratropium to tiotropioum. The purpose of this post-hoc analysis was to investigate potential changes in clinical status when treatment was switched from ipratropium to tiotropium in patients with COPD.
From previously reported one-year clinical trials (tiotropium vs. ipratropium), we conducted a post-hoc analysis of all patients receiving ipratropium prior to randomization. At randomization, these patients either continued with blinded ipratropium or were switched to blinded tiotropium. We compared the outcomes over the first 4 weeks on variables that would be indicative of clinical improvement or deterioration. Variables included the percent of patients with a mean weekly change in AM PEFR of ≥5% or ≥10%, or a mean weekly change in albuterol use of ≥1 puff/day, and the mean weekly percent of patients who had an exacerbation of COPD. The outcomes were defined by the relative risk (RR) (i.e., % in tiotropium group divided by % in ipratropium group).
There were 332 patients from the entire cohort (n=535) who were receiving ipratropium prior to randomization. The mean age of the cohort was 65 years; 85% were men. Mean baseline FEV1 was 1.14 L (41% predicted). The RR for increases or decreases in AM PEFR and albuterol use are displayed in the tableAM PEFRAlbuterol (puffs/day)Increase ≥5%Decrease ≥5%Increase ≥10%Decrease ≥10%Increase ≥1Decrease ≥1Week 11.600.631.520.421.001.17Week 21.900.501.760.610.721.31Week 31.780.461.950.260.631.41Week 41.770.381.640.400.831.38below. The cumulative RR of an exacerbation of COPD over weeks 1, 2, 3 and 4 were 1.32, 0.86, 0.69 and 0.74, respectively.
In this post-hoc analysis, patients switched to tiotropium from ipratropium were more likely to have improvements in these short-term clinical outcomes than if they had remained on ipratropium.
Conversion to tiotropium can be accomplished with the reasonable expectation of a prompt improvement in the clinical outcomes of COPD.
S. Kesten, Boehringer Ingelheim