The study found no causal link between anticholinergic inhalers and CVD, but an association. The justification for the study came from the finding of a previous meta-analysis reported by the FDA which found that tiotropium was associated with an increased risk of stroke.
No association was found with stroke in the new study by Singh et al but, instead, a different set of associations was reported.
In our view, the Singh study has several methodological problems including double counting patients, comparing tiotropium to both active treatments and placebos and failing to account for increased drop-outs in the placebo arms as this resulted in a smaller risk of adverse events.
The findings of an increased risk of cardiovascular events are interesting, and merit further consideration, but are not a reason to change prescribing. The results of the UPLIFT study to be released this month may clarify the safety profile of tiotropium.
We believe Dr Yoon's comments in your article are completely inappropriate. GPs should not change the way they prescribe anticholinergic inhalers on the basis of this single study unless advised by independent bodies. There is no clinical rationale to prescribe anticholinergics for short-term use - they are to treat symptoms and prevent exacerbations of a long-term progressive condition.
Long-term benefits of anticholinergic inhalers have been demonstrated and are reported in UK national and all international guidelines. Dr Yoon's recommendations to GPs on the basis of his single study will cause unnecessary distress to patients and confusion to clinicians.
GPs should allow time for the findings to be considered in the light of other scientific data and reach a calm objective conclusion before they change their prescribing habits.
Professor David Price, professor of primary care respiratory medicine, Aberdeen University; Dr Rupert Jones, GP in Plymouth; Dr Dermot Ryan, GP in Loughborough; Dr Mike Thomas, GP in Gloucestershire; Dr Daryl Freeman, GP in Norfolk; Dr John Haughney, GP in Scotland.