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Last Edited: 9/29/2010

Asthma Surveillance

There are many ways to measure asthma.  Asthma is a complex disease that has a range of severity and symptoms. Because there is no single way to diagnose asthma and people experience asthma differently, measuring asthma in the population is difficult.

It is important to know how many people have asthma (known as prevalence), as well as understand the symptoms and the severity of their asthma. The effort to keep track of asthma in the population is called asthma surveillance.

The Asthma Surveillance Pyramid

The Asthma Surveillance Pyramid (see image below) is a model developed by the Centers for Disease Control and Prevention (CDC) to describe the spectrum of asthma indicators, or ways to measure the asthma burden.

  • The pyramid sits on a base (1) that represents asthma prevalence, or all people with asthma
    • Within this group, the severity and symptoms of asthma can be very different
    • Some individuals may not even know they have asthma
  • Each level of the pyramid represents an indicator of asthma (2-6)
    • The lower levels of the pyramid indicate less severe asthma, which affects a greater proportion of people with asthma
    • Each successively higher level in the pyramid represents increasingly severe asthma, affecting a smaller proportion of people with asthma
  • Outside the pyramid are quality of life, cost, pharmacy, and triggers (7-10)
    • These are four factors that impact or are impacted by asthma

asthma surveillance pyramid

To get a complete picture of asthma in California, we must look at all the asthma indicators depicted on the pyramid. This is a challenge because data are not readily available for all the indicators.


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Indicators of asthma

For more information on how each asthma indicator is measured and where the data is from, click on the indicator name below.


1. Asthma Prevalence refers to all the people with asthma in a population during a period of time. Severity refers to the range of symptoms that people with asthma can experience.


2. Scheduled Office Visits represent people who have access to a physician, indicating their asthma may be controlled.


3. Unscheduled Office Visits represent people who have access to a physician, but who may be experiencing severe symptoms.


4. Emergency Department /Urgent Care Visits represent people with asthma who end up at the emergency department (ED) or utilize urgent care services for treatment of asthma symptoms. This may be because they have been unable to manage their asthma properly or they lack access to a primary health care provider.


5. Hospitalizations represent people with severe asthma who end up being hospitalized for their asthma. Like ED visits, asthma hospitalizations suggest that the individual may not have been able to manage his or her asthma properly. Asthma hospitalizations are often preventable and are very serious and costly.


6. Mortality represents people who die from their asthma. Like asthma hospitalizations and ED visits, most asthma deaths can be prevented with proper management and quality health care.


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Factors that may impact or be impacted by asthma

7. Quality of Life- When a person’s asthma is not properly managed or treated, their quality of life can be greatly impacted. This may include activity limitations, school/work absenteeism, and general health status.


8. Cost- There are many direct and indirect costs associated with asthma. These may include health care utilization costs, such as hospitalizations or ED visits (direct), and missed days at work costs (indirect) .


9. Pharmacy- Asthma can be managed and treated by having access to and properly using medication.


10. Triggers- An asthma trigger is an element that makes existing asthma worse or brings about an asthma attack. Each person with asthma may be susceptible to different types of triggers.


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Barriers to measuring asthma

The data for the indicators on the asthma surveillance pyramid are not always available or simple to obtain.

  • They often come from different data sources and are collected for different reasons
    • For example, health care providers are not required to report asthma-related office visits to the State. Hospital data are collected for the purposes of tracking health care quality, rather than for public health surveillance
  • Where data from hospitals or health care providers do not exist, telephone-administered surveys are often used to gather information
    • However, telephone surveys are limited by what the respondent can or can’t recall

Learn more about how indicators are measured and who collects the data.


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