Exercise treadmill testing was used to compare risk factors for coronary artery disease among those who use and who do not use pulmonary medication.
Background
In the general population, the exercise treadmill testing variables of lower resting heart rate, higher peak heart rate, and greater fitness have favorable prognosis for mortality. Patients with obstructive lung disease have increased mortality risk. Furthermore, some pulmonary medications (ie, beta2-agonists) can influence heart rate. We determined whether exercise treadmill test parameters carry the same prognostic value in patients who are using versus not using pulmonary medications.
Methods
We analyzed data on 69,855 patients (mean age, 55 years) who completed a clinically indicated exercise treadmill test. Patients were defined as having “lung disease” if they were taking medications routinely used to treat obstructive lung disease (n = 6145, 9%). International Classification of Diseases, 9th Revision codes regarding the type of lung disease were not available. Multivariate-adjusted Cox models were used to determine the risk of mortality, major adverse cardiac events, and myocardial infarction over a mean of 11 years follow-up.
Results
Higher resting heart rate was associated with increased mortality risk, and higher peak heart rate and fitness were associated with decreased risk. No significant interaction for lung disease status was seen for the heart rate variables, but a slightly stronger protective effect was observed for higher fitness among patients with lung disease (P interaction = .032). The results were similar for major adverse cardiac events and myocardial infarction.
Conclusions
Heart rate parameters achieved on exercise treadmill tests are equally prognostic among patients using versus not using pulmonary medications. Higher fitness was associated with improved clinical outcomes for both; however, the relative benefit of fitness on survival was even greater in patients using pulmonary medications compared with those not using them.
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-Tolulope Adesiyun, MD, Di Zhao, PhD, Michael J. Blaha, MD, MPH, Clinton A. Brawner, PhD, Steven J. Keteyian, PhD, Jonathan K. Ehrman, PhD, Mouaz H. Al-Mallah, MD, MPH, Erin D. Michos, MD, MHS
This article originally appeared in the April 2016 issue of The American Journal of Medicine.
