National trends in ambulatory asthma treatment, 1997-2009

Abstract

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

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

Participants and design: 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.

Measurements: 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).

Results: 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.

Conclusions: 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.

Figure 1

Total treatment visits for asthma among individuals less than 50 years of age, United States, 1997–2009 (NDTI and NAMCS). Treated visits represent office based physician visits in which one or more treatments were newly prescribed, renewed, or mentioned as therapy. Sources: IMS Health’s National Disease and Therapeutic Index, 1997–2009; National Ambulatory Medical Care Survey, 1997–2008.

Figure 2

a. Trends in use of inhaled steroids, long-acting β2-agonists, and steroid/ β2-agonist combination therapy (NAMCS). “Long-acting β₂-agonist/steroids" depicts both fixed dose combinations and concurrent use of separate therapies. b. Trends in use of inhaled steroids, long-acting β2-agonists, and steroid/β2-agonist combination therapy (NDTI). “Long-acting β₂-agonist/steroids" depicts both fixed dose combinations and concurrent use of separate therapies.