Dear Editor,

We read with great interest the article by Schanen[1] et al. - Asthma and incident cardiovascular disease in which the authors have shown an association between multivariate adjusted Hazard ratio and incident stroke, but, not with Coronary heart disease in both model 1 and 2. One of the most important risk factors for coronary heart disease in asthmatics identified so far is the use of inhaled short-acting and long acting beta 2 agonists.[2]

More recently a meta analysis conducted by Shelley et al.[3] reported that for trials lasting from 3 days to 1 year, ß2-agonist treatment significantly increased the risk for a cardiovascular event (relative risk [RR], 2.54; 95% CI, 1.59 to 4.05) compared to placebo. Similar findings of increased risk of unstable angina, myocardial infarction associated with inhaled beta- agonists were also reported by Au et al.[4,5] It would have had tremendous clinical application if the authors had studied the association between inhaled beta 2 agonist and incident coronary heart disease in ever asthmatics.

Also studies have shown that rapid decline of FEV1 is an independent risk factor for coronary heart disease.[6] Since this was a prospective cohort study, it would be useful if the authors also analysed the association between decline of FEV1 /Low quartiles of FEV1 and incident coronary heart disease.

References

1. JG Schanen et al: Asthma and incident cardiovascular disease: the Atherosclerosis Risk in Communities Study. Thorax. 2005 Aug;60(8):633-8.

2. Suissa et al. Patterns of increasing beta-agonist use and the risk of fatal or near-fatal asthma Eur Respir J 1994; 7: 1602-1609.

3. Shelley R. Salpeter, Thomas M. Ormiston, and Edwin E. Salpeter Cardiovascular Effects of ß-Agonists in Patients With Asthma and COPD: A Meta-Analysis Chest, Jun 2004; 125: 2309 - 2321.

4. Au, DH, Curtis, JR, McDonell, MB, et al. Association between inhaled beta-agonists and the risk of unstable angina and myocardial infarction. Chest 2002;121,846-851.

5. Au, DH, Lemaitre, RN, Curtis, JR, et al. The risk of myocardial infarction associated with inhaled beta-adrenoceptor agonists. Am J Respir Crit Care Med 2000;161,827-830.

6. Tockman MS et al. A new risk factor for coronary heart disease mortality. Am J Respir Crit Care Med 1995;151:390-398.