Why do we test chronic obstructive pulmonary disease (COPD) patients for bronchodilator responsiveness (besides getting to charging a few extra bucks for it)?
If I am reading this article right, the answer is, there's no good reason. Consider this:
- Bronchodilator responsiveness (BDR) or the lack thereof does not distinguish COPD from asthma.
- Bronchodilator repsonsiveness can come and go on different visits by the same patient (38-52% intra-individual variability).
- There is no consensus on the standardization of testing (which drug, dose, definition of response) or the interpretability of the results in COPD patients.
- The absence of a BDR does not mean a patient won't get a good benefit from bronchodilator therapy (especially long-acting). In clinical trials, those with bronchodilator repsonses did get a greater increase in lung function than those without a BDR, but those without a BDR had stat.significant improvements in dyspnea and quality of life with bronchodilator therapy compared to placebo. So you should never withhold bronchodilator therapy based on the lack of a response on testing. Guidelines argue against checking BDR for this purpose.
The main thing I took from this well-written article by Hanania et al was that checking bronchodilator response in COPD patients only has a downside: it can spur you to wrongly deny or discourage bronchodilator therapy.
So ... is there any good reason to check for a bronchodilator response in someone with COPD, ever (outside of a clinical trial or research registry)?
Hanania NA et al. Bronchodilator Reversibility in COPD. CHEST 2011;140(4):1055-1063.