Surveillance for Asthma: Measuring a Moving Target David M. Mannino Air Pollution and Respiratory Health Branch Centers for Disease Control and Prevention

Why do surveillance for asthma? Define magnitude of the problem –Enable public health planning Follow trends in magnitude of the problem over time –Evaluate the effectiveness of interventions

Issues for asthma surveillance How is asthma defined? What questions need to be answered? –How many people have asthma? –How severe is asthma? –How well managed is asthma?

Asthma A disease characterized by wide variations over short periods of time in resistance to flow in intrapulmonary airways, and manifest by recurrent attacks of cough or wheeze separated by symptom free intervals. The airflow obstruction and clinical symptoms are largely or completely reversed by treatment with bronchodilator drugs or steroids - Godfrey, 1985

CSTE case definition for asthma Different definitions depending on source of data –patient interview –administrative data –interview plus laboratory findings Confirmed, Probable, Suspected classification Available at

Prevalent Asthma in Surveys is based on…. Person (or proxy) reporting (hopefully accurately) of Physician (or health care provider) diagnosis of asthma that was (hopefully accurately) made based on the (hopefully accurate) report of symptoms by the person (or proxy) who (hopefully accurately) recognized these symptoms.

Problems in Defining Asthma CENTERS FOR DISEASE CONTROL AND PREVENTION

Problems in Defining Asthma 8 to 11 year olds in New South Wales, Australia Salome et al, % 7% Symptoms 34% Asthma 13% Airways Hyperresponsiveness 18% 17% 5% 7% 5% CENTERS FOR DISEASE CONTROL AND PREVENTION

From Turner-Warwick’s Respiratory Disease, 1989

Acute Reversibility in Clinic Patients with COPD or Asthma Personal Communication, F Hansen N= 1095 COPD and 491 Asthma COPD Asthma

Per 1,000 population. Race-, sex- and age-adjusted to 2000 U.S. population Asthma prevalence during the preceding 12 months Episode of asthma or asthma attack during the preceding 12 months Lifetime Asthma Asthma Prevalence in US,

Restricted Activity Days Attributable to Asthma From NHIS, 1995

Per 1,000 population. Race-, sex- and age-adjusted to 2000 U.S. population Physician Office and Hospital Outpatient Visits for Asthma, United States, Includes hospital outpatient visits from 1992 forward

Per 10,000 population. Race-, sex- and age-adjusted to 2000 U.S. population Emergency Department Visits for Asthma, United States,

Per 10,000 population. Age-adjusted to 2000 U.S. population Hospitalizations for Asthma, United States,

Per 1,000,000 population. Race-, sex- and age-adjusted to 2000 U.S. population Asthma Deaths, United States International Classification of Disease, 9 th Revision International Classification of Disease, 10 th Revision

Asthma in BRFSS 1996-present: State added questions 1999: Two optional questions –Have you ever been told you have asthma? –Do you still have asthma? : Two questions in Core : Optional module for asthma severity in adults and asthma prevalence in children

Asthma Surveillance Measuring Asthma Prevalence and Severity in Children –Lara Akinbami Asthma in Adults- What you need to know –Deborah Rose Update on the National Asthma Survey –Jeanne Moorman