Led by Dr. Gene Colice of Washington Hospital Center, Washington, D.C., the researchers used a large insurance database to analyze costs associated with persistent asthma. Patients were classified as having persistent asthma if they suffered from asthma attacks at least twice weekly (among other criteria). The analysis included nearly 3,000 patients with persistent asthma, including employees and dependents covered by insurance plans at 17 U.S. companies.
Direct medical costs for patients with persistent asthma averaged about $6,500 per year, compared to just over $2,000 for patients without asthma. Thus, direct costs for a patient with persistent asthma were $4,500 higher than for nonasthma patients.
Data on 443 employees with persistent asthma also showed high indirect costs—costs from disability and missed work days. On average, annual indirect costs were $924 higher for workers with persistent asthma. The differences in direct and indirect costs remained significant after statistical adjustment for other factors.
Further analysis compared costs for workers with mild, moderate, and severe persistent asthma. Costs were highest for patients with severe persistent asthma who have continual asthma symptoms causing significant limitations in physical activity.
Surprisingly, there was no significant difference in costs between patients with moderate persistent asthma, who have asthma attacks at least twice weekly; and those with moderate persistent asthma, who have daily attacks. This probably reflected the low rate of treatment with inhaled steroids—the most effective medications for controlling asthma—by patients in the mild group. Less than 10 percent of patients with mild persistent asthma used inhaled steroids on a daily basis, compared to 80 percent or more of those with moderate to severe persistent asthma.
Asthma is a common chronic disease in adults as well as children. Asthma-related medical costs have been estimated at $12.7 billion per year in the United States. However, few studies of asthma costs have used data from insurance claims databases, which provide a more realistic reflection of costs.
"Persistent asthma is an expensive chronic condition for both third-party payers and employers," Dr. Colice and colleagues conclude. Direct medical costs are substantially higher than for employees and dependents without asthma. Since factors such as reduced productivity weren't included, the study probably underestimates the true impact on indirect costs. The researchers highlight the potential for health and economic benefits by increasing use of regular inhaled steroid therapy among patients with mild persistent asthma.