Do statins improve outcomes in patients with asthma on inhaled corticosteroid therapy? A retrospective cohort analysis

OBJECTIVES Animal studies and clinical trials have examined the potential benefits of statins in asthma management with contradictory results. The objective of this study was to determine if asthma patients on concurrent statins are less likely to have asthma-related hospitalisations. DESIGN A retrospective cohort study using Mississippi Medicaid data for 2002-2004. PARTICIPANTS Asthma patients ≥18 years were identified using the ICD9 code 493.xx from 1 July 2002 through 31 December 2003. The index date for an exposed subject was any date within the identification period, 180 days prior to which the subject had at least one inhaled corticosteroid prescription and at least an 80% adherence rate to statins. Asthma patients on inhaled corticosteroids, but not on statins, were selected as the unexposed population. The two groups were matched and followed for 1 year beginning the index date. MAIN OUTCOMES MEASURES Patient outcomes in terms of hospitalisations and ER visits were compared using conditional logistic regression. RESULTS After matching, there were 479 exposed subjects and 958 corresponding unexposed subjects. The odds of asthma-related hospitalisation and/or emergency room (ER) visits for asthma patients on concurrent statins were almost half the odds for patients not on statins (OR=0.55; 95% CI (0.37 to 0.84); p=0.0059). Similarly, the odds of asthma-related ER visits were significantly lower for patients on statins (OR=0.48; 95% CI (0.28 to 0.82); p=0.0069). CONCLUSION The findings suggest beneficial effects of statins in asthma management. Further prospective investigations are required to provide more conclusive evidence.