Overall, we can feel a sense of accomplishment in reducing asthma mortality and hospitalizations due to asthma in the United States. Measurement of asthma prevalence changed with the redesign of the National Health Interview Survey (NHIS) in 1997 . There was a rapid increase from 1980 to 1996 of asthma 12-month period prevalence by an average of 3.8% per year. After the redesign, the most comparable measure, current asthma prevalence, was introduced in 2001 and still demonstrates increasing prevalence, although at a lower rate, an average of 1.4% per year. The growing proportion of the U.S population with current asthma, 8.2% (24.6 million people) in 2009, presents a continuing challenge to adapt and improve effective prevention and disease management strategies.
Asthma prevalence in the United States, 1980–2009
Coupled to this observation of increasing prevalence of asthma is the current estimate of substantial costs related to asthma. Barnett and Nurmagambetov (42
) evaluated data from the Medical Expenditure Panel Survey and reported that over the years 2002–2007, the incremental cost of asthma was $3,259 per person per year. For 2007, the total incremental cost of asthma to society was $59 billion, with productivity losses due to morbidity accounting for $3.8 billion and productivity losses due to mortality accounting for $2.1 billion.
Reductions in both asthma hospitalization and death rates have occurred over the past decade despite the challenge of increasing prevalence . However, racial disparities in hospitalization and mortality remain a challenge. Asthma hospitalization rates among the black population remain consistently higher than among the white population . In 2008, hospitalization rates were 3.6 times as high among black versus white populations, the largest disparity during the period shown from 1980 to 2008.
Figure 2a. Asthma hospitalizations per 10,000 population, United States, 1980–2008
Figure 3a. Asthma hospitalizations per 10,000 population, by race, United States, 1980–2008
While asthma death rates among the black population are also much higher, the relative disparity has decreased from a high of 3.1 times higher death rates among black compared to whites in 2004 to 2.8 in 2007 . These striking disparities post a challenge for implementing effective asthma control measures among disparate populations with likely different needs and obstacles.
Although less dramatic, gender disparities also exist. In 2008, asthma hospitalizations were 1.5 times higher among females than males . The rise in asthma death rates in the 1980s was disproportionately borne among females with relative disparities reaching 1.4 times higher rates among females compared to males, a difference that has persisted despite declining death rates during the last decade .
Figure 4a. Asthma hospitalizations per 10,000 population, by sex, United States, 1980–2008
Although this information has not been quantified in full publications, clinicians have recognized a reduction in the number of patients receiving oral glucocorticoid therapy as part of the maintenance schedule. This has significantly reduced the number of patients suffering the consequences of adverse effects of systemic steroid therapy including osteoporosis, cataracts, and growth suppression. This observation has been particularly remarkable for children and has changed the spectrum of the disease. This has been largely attributed to the introduction of new medications, organization of treatment into guidelines, and better systems of management.
Currently, there is a focus on asthma control and emerging interest in prevention, initially on preventing symptoms and then moving towards preventing progression. However, available research and surveillance show a continued underutilization of evidence-based management strategies to control asthma and thus there is room for improvement. This is an important step for addressing disparities in health care. National data exists for persons with asthma who report receiving components of self-management education and show that only a low to moderate percentage have received the basic elements of asthma education  (43
Percent of people with current asthma* reporting receipt of self-management education, National Health Interview Survey, 2008
Steps have been taken to achieve better monitoring systems for asthma including new tools such as electronic medical records and health care provider surveillance systems. This level of systematic monitoring also has practice level implications that strive to improve quality of care by tracking outcomes.
Along with the changes in practice management, the concept of personalized medicine has also emerged and early indicators suggest that this could significantly advance asthma management since there are variable responses to asthma treatment. While clinicians readily use a personalized approach to selecting a medication, dose and delivery system to relieve and prevent asthma symptoms, they do not currently use patient characteristics, biomarkers, and genetics to select and adjust treatment. Generally, treatment is still based most often on symptom presentation. Even basic tools, such as spirometry, are not readily incorporated in assessing asthma control, monitoring the course of asthma, and adjusting therapy accordingly. While spirometry is incorporated in asthma care conducted by most subspecialists, it has not been readily adapted in the course of asthma management in primary care.
There are several other interesting trends that will impact asthma management in the near future. There are increasing public health concerns regarding the impact of the environment on respiratory health and measures are being taken to institute control procedures and alert the public to hazards, for example publication of pollen counts and to incorporate asthma friendly environmental policies into public housing as well as school structure and rehabilitation. Current targets have been set to reduce hospitalizations and urgent care utilization by developing a systematic approach to managing chronic diseases including asthma by health care providers. The concept of a medical home has been introduced in order to help coordinate medical care, self-management education, and programs to link families to the services they need to support the treatment plan.
Unfortunately, there are no new asthma medications on the horizon. However, observations have been made regarding the beneficial effects of medications that were not directly approved for asthma management, including vitamin D and tiotropium (44
). Steps are also being taken to obtain better insight on the origins of asthma, the natural history of asthma, the relationship of genetics to the risk of developing asthma and to the variations in response to treatment, and identification of easily measured biomarkers that can be used to predict response to medications and monitor disease activity.
In summary, we are now at a crossroads in asthma care. We have recognized some remarkable accomplishments in reducing asthma mortality and morbidity and closing some gaps in health disparities with the introduction of new medications and management systems. The availability of new tools to monitor disease activity, including biomarkers and epigenetic markers, along with information technology systems to monitor asthma control hold some promise in identifying gaps in disease management and should prompt the evolution of new strategies and new treatments to further reduce disease burden.