National trends in ambulatory asthma treatment, 1997-2009

Despite reductions in morbidity and mortality and changes in guidelines, little is known regarding changes in asthma treatment patterns.

To examine national trends in the office-based treatment of asthma between 1997 and 2009.

We used the National Ambulatory Care Survey (NAMCS) and the National Disease and Therapeutic Index™ (NDTI), nationally representative audits of office-based physicians, to examine patients diagnosed with asthma less than 50 years of age.

Visits where asthma was diagnosed and use of six therapeutic classes (short-acting β(2) agonists [SABA], long-acting β(2) -agonists [LABA], inhaled steroids, antileukotrienes, anticholinergics, and xanthines).

Estimates from NAMCS indicated modest increases in the number of annual asthma visits from 9.9 million [M] in 1997 to 10.3M during 2008; estimates from the NDTI suggested more gradual continuous increases from 8.7M in 1997 to 12.6M during 2009. NAMCS estimates indicated declines in use of SABAs (from 80% of treatment visits in 1997 to 71% in 2008), increased inhaled steroid use (24% in 1997 to 33% in 2008), increased use of fixed dose LABA/steroid combinations (0% in 1997 to 19% in 2008), and increased leukotriene use (9% in 1997 to 24% in 2008). The ratio of controller to total asthma medication use increased from 0.5 (1997) to a peak of 0.7 (2004). In 2008, anticholinergics, xanthines, and LABA use without concomitant steroids accounted for fewer than 4% of all treatment visits. Estimates from NDTI corroborated these trends.

Changes in office-based treatment, including increased inhaled steroid use and increased combined steroid/long-acting β(2)-agonist use coincide with reductions in asthma morbidity and mortality that have been demonstrated over the same period. Xanthines, anticholinergics, and increasingly, LABA without concomitant steroid use, account for a very small fraction of all asthma treatments.