The National Center for Health Statistics released the latest data brief analyzing trends in asthma prevalence, health care utilization and mortality in the US from 2001-2010.

Most of the news is not good:

• Prevalence rates of asthma have reached 8.4 percent, the highest ever recorded in the US.
• Rates of emergency department visits and hospitalizations remained stable.

but mortality – which was highest among those 65 and older – did decline over the period.

The CDC’s Air Pollution and Respiratory Health Branch has also posted a new graphical overview of “Asthma’s Impact on the Nation”

“The information in this release is a stark reminder that asthma continues to be major public health concern with a large financial impact on families, the nation and our health care system,” Christopher Portier, director of CDC’s National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry, said in an agency news release.

Portier also highlighted the lack of asthma action plans among the majority of children and adults with asthma, and encouraged those with asthma to work with their doctors to take control of this disease.

A new article by Swedish researchers highlights the extent to which the results of epidemiological studies can be influenced by the choice of methodology. The researchers tested whether subtle differences – including questionnaire layout and wording – had a measurable impact on prevalence and risk estimates of asthma.

Their report, published in the Clinical Respiratory Journal, describes how questions with different set-up or differences in wording resulted in significantly different prevalence and risk estimates. In particular, the use of follow-up questions that excluded subjects answering no to the initial question, resulted in 2.9-6.7 percent-units lower prevalence.

These kinds of findings highlight some of the underestimated complexities of chronic disease epidemiology. But they also underscore how little attention developers of mobile and wireless health tools have put into understanding and incorporating previous research on the implications of different methodologies into their applications. Reports like these should motivate us to save ourselves a lot of unnecessary originality and admonish us to greater care and reflection in our work.

I had the fortune to meet Jim Crow during my first year as a postdoc on campus and remember well listening to him step us through connections between genetics and population health with energy and agility. At one point, I ordered a used copy of Crow’s Notes, which was out of print by then, but am embarrassed to say that I never made it through much of the book. Time to pull it off the shelf today and reflect on his striking and inspiring career as scientist and mentor.

These summaries highlight key statistical data, such as prevalence and health care use in adults and children, as well as data on patient education and medication use from the Asthma Call-Back Survey.

Great to have these standardized briefs collected in one place. The obvious next step: Make the data underlying these PDFs readily available.

CDC – Asthma – National Asthma Control Program State Profiles

A new report from a large interview study suggests that worldwide, few children and adolescents achieve control of their asthma and experience frequent symptoms. A significant portion (11 percent) reported mild asthma attacks at least weekly, while 35 percent required oral corticosteroids or hospitalization at least annually.

The team interviewed 1,284 parents of children with asthma in six countries (Canada, Greece, Hungary, the Netherlands, South Africa and the UK) and 943 of the children themselves. The results highlight the impact of frequent morbidity on daily life: Asthma restricted the child’s activities in 39 percent of families and caused 70 percent to change their lifestyle. The article was published in the European Respiratory Journal.

One reason for the significant morbidity may be parental misperception of asthma control. Parents in the study tended to underestimate the severity of their child’s asthma while overestimating the level of control. While 73 percent of parents described their child’s asthma as mild or intermittent, 40 percent of children/adolescents had C-ACT scores ≤19, indicating inadequate control. In addition, even fewer (14.7%) achieved complete control as defined by the more stringent Global Initiative for Asthma (GINA) guidelines.

Parent misperception of control in childhood/adolescent asthma: the Room to Breathe survey

W.D. Carroll, J Wildhaber and PLP Brand

Our Q&A – about Asthmapolis and the potential of mobile technology to improve the quality of care and public health – is published in their Quality Matters newsletter this month. Read more »

In addition, the newsletter has another article on apps for health care quality improvement that is well worth reading.

Providers have proven eager adopters of health care “apps,” the software applications used on cell phones and other mobile devices to perform specific tasks, such as charting data points or aggregating information. Apps can be easily integrated into providers’ workflow, delivering information when and where they need it. Disease management apps, in particular, can improve communication between patients and providers and promote adherence to recommended care. Still, for apps to achieve their potential, they will need to be factored into reimbursement models and meet clear clinical needs. Read more »

A new report, and accompanying website, released today by the International Union Against Tuberculosis and Lung Disease (The Union) and the International Study of Asthma and Allergies in Childhood (ISAAC) highlights the issues surrounding asthma in the global context.

The report, authored by some of the leading asthma experts around the world, is described as an atlas of known “causes and triggers of the disease, the global prevalence, the progress being made and the significant challenges today and for the future.”

I expect to be posting more as I read through the report, but the key findings highlighted by the press release are the following:

• ISAAC data show that asthma in children is increasing in low- and middle-income countries, where it is more severe than in high-income countries.
• The World Health Survey found an 8.2% prevalence of diagnosed asthma among adults in low-income countries and 9.4% in the richest countries. Middle-income countries had the lowest prevalence at 5.2%.
• Smoking and secondhand smoke are two of the strongest risk factors — and triggers — for asthma.
• Although asthma is frequently thought of as an allergic disease, this does not apply to all cases, and the non-allergic mechanisms need to be the focus of more research.
• Surveys around the world found asthma treatment falling short, with few patients consistently using the inhaled corticosteroids that effectively manage the disease.  For example, the Asthma in America survey found only 26.2% of patients with persistent asthma used these medicines.
• While many countries now have asthma management guidelines, many health workers do not know how to diagnose or treat asthma and health systems are not organised to handle this type of long-term, chronic disease.
• A 2011 Union survey of the pricing, affordability and availability of essential asthma medicines in 50 countries found dramatic variations. For example, one generic Beclometasone 100µg inhaler in a private pharmacy cost the equivalent of nearly 14 days’ wages — and a patient with severe asthma requires about 16 of these inhalers per year.
• The Asthma Drug Facility established by The Union has been able to bring down the cost of treating a patient with severe asthma to approximately US$ 40 per year.
• When people do not have access to ongoing care, they often end up in emergency rooms and hospitals — a costly and unnecessarily disruptive process for all involved.
• Although economic data are unavailable for almost all low-income countries, a 2009 systematic review found annual national costs (in 2008 US dollars) ranging from $8,256 million in the United States to $4,430 million in Germany.
• Success stories from five high- and low-income countries that have implemented asthma management activities show that well-managed asthma saves money – and enables people to get on with their active lives. For example, in Finland, the mortality, number of hospital days and disability due to asthma fell 70–90% between 1994 and 2010 and a conservative estimate of the savings was $300 million in 2007 alone.

Obviously the economic data on costs in the US needs to be updated. A recent CDC report calculated direct economic costs nearly six times higher. Nevertheless the main message remains valid. There is an urgent need to overcome the frustrating gap between what we should be able to do, and what we’ve so far been able to accomplish. As articulated by Nils Billo, Executive Director of The Union:

The tools to treat asthma are already available – there is no reason to delay. Moreover, when asthma is not diagnosed, not treated or poorly managed, and when people can not access or afford treatment, they regularly end up having to miss school or work, they are unable to contribute fully to their families, communities and societies, they may require expensive emergency care, and everyone loses.  The obstacles to well-managed asthma can be overcome.  Asthma is a public health problem that can – and should be addressed now.

Our goal was to investigate whether alternative statistical methods (quantile regression) might better illustrate the effects of educational achievement (as a proxy for SES) across the entire distribution of lung function in a population, and to understand variability across racial/ethnic groups. In addition, we wanted to understand how sample selection criteria used to generate reference equations for normal lung function might alter estimates of the effect of socioeconomic status.

The resulting paper, Understanding Socioeconomic and Racial Differences in Adult Lung Function, has just been published in the current (September 2011) issue of the American Journal of Respiratory and Critical Care Medicine, along with an editorial (FEV1 in the Suburbs) authored by Peter Wagner of the Univ of California San Diego. The Univ of Wisconsin School of Medicine and Public Health has also issued a press release, with the following great quote from John about sample selection:

Seemingly subtle issues in how samples are constructed and data are analyzed ultimately have important implications for how we understand the roles of race and socioeconomic status as determinants of respiratory health.