One-quarter of severe asthma attacks could be prevented if patients consistently took their medication as prescribed, U.S. researchers found. Lead author Dr. Keoki Williams, associate director of Henry Ford\'s Center for Health Policy and Health Service Research in Detroit, said inhaled corticosteroid medication is the most effective treatment for controlling symptoms and preventing asthma attacks. Working from the theory that inhaled corticosteroid medication use changes with the episodic nature of asthma, Williams and his team measured changes in medication use over time among 298 patients. Patients were tracked an average of two years and study participants had 435 asthma attacks during the study period. \"Our findings demonstrated a relationship between medication adherence and asthma events in a manner that accounts for the changing patterns of inhaler use over time,\" Williams said in a statement. \"We found that every 25 percent increase in inhaled corticosteroid medication adherence was associated with an 11 percent decrease in asthma attacks,\" Williams said. \"But most importantly, we found that causal use of these medications is not enough, especially among patients whose asthma is not controlled. Patients must use their asthma controller medication as prescribed if they want to have the best chance of preventing serious asthma attacks.\"The findings were published online in The Journal of Allergy and Clinical Immunology.