A review of the records of more than 63,000 Asthma patients shows that only one in four avoided having at least one uncontrolled asthma episode over a 3-year period, researchers report.

The study “emphasizes the unpredictable nature of asthma,” said Dr. David A. Stempel. “Asthma may require continued monitoring and treatment, even when the disease is perceived to be stable, to prevent future exacerbations.”

In the Journal of Allergy and Clinical Immunology, Dr. Stempel of Infomed Northwest and the University of Washington, Seattle, and colleagues note that “the goal of asthma therapy is to maintain control,” avoiding symptoms and exacerbations.

To investigate how well this is achieved, the researchers studied information from a nationally representative database of pharmacy and medical claims from a number of managed care health plans.

The researchers identified 63,324 patients who were undergoing treatment with at least one asthma drug and had received 36 months of continuous insurance coverage.

Patients were defined as controlled if they had few claims for short-acting beta2 agonists (which are classified as rescue medications), no claims for oral corticosteroids (which would indicate that inhaled steroids were not sufficient), and no asthma-related emergency room visits or hospitalizations.

During the first year, 39,095 patients (57 percent) had controlled asthma. However, over the 3-year period as many as 14 percent with controlled asthma had uncontrolled asthma in any given quarter.

Overall, 46,227 (73 percent) “met the criteria for uncontrolled asthma at least once during the 3-year period,” the researchers report. By the end of that period “a minority of the population (27 percent) was consistently identified as having controlled asthma.”

Patients “continue to be at risk for asthma symptoms, as well as Asthma exacerbations,” whether or not their disease seems to be under control, the researchers conclude.

SOURCE: Journal of Allergy and Clinical Immunology, May 2005.