The asthma predictive index (API) is a widely-used test doctors use to predict whether a child under 3 years old may develop persistent asthma before they turn 13. Research suggests it’s better at predicting which children may not develop asthma.

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The API is a diagnostic tool that helps doctors predict which children may be at high risk of developing asthma, a chronic lung condition. Asthma involves inflammation and narrowing of the airways in your lungs.

Despite being the most common chronic condition among children worldwide, diagnosing asthma in young children who have yet to develop clear symptoms can be challenging. Scientists introduced the API in 2000 to aid this process, and doctors have used it widely since.

This article explores everything you need to know about the API, including its purpose, criteria, accuracy, and more.

The API aims to help doctors predict the likelihood of a child developing persistent asthma during ages 6 to 13. It’s specifically intended for use in children under 3 years old with wheezing episodes.

Wheezing in very young children is typically due to viral infections. The API may help doctors distinguish whether wheezing could be due to early asthma.

Early identification can enable your child’s pediatrician to diagnose asthma sooner. This may lead to better management of the condition and reduce the severity and frequency of asthma symptoms.

The API uses a set of criteria to identify children who may be at risk of developing persistent asthma. These criteria include major and minor decisive factors.

If your child has had more than three wheezing episodes in the past year, their risk of developing persistent asthma after 5 years old may be higher if they meet one of the major criteria or two of the minor criteria.

The major criteria involve the child having a parent with asthma or the child receiving an atopic dermatitis (eczema) diagnosis.

The minor criteria involve the child:

Scientists measure the accuracy of the API by looking at its sensitivity and specificity.

Sensitivity refers to the proportion of children the API correctly identifies as having asthma. Specificity refers to the API’s ability to correctly identify children who don’t have asthma.

According to a 2019 study in Korea, the API has a specificity of 82%, accurately identifying children unlikely to develop asthma about 4 out of 5 times. But its sensitivity is lower — around 72% — meaning that it may not identify all children who may go on to develop asthma.

While doctors can use the API to predict the likelihood of a child developing persistent asthma, other factors may also play a role. So, it’s important to use the API alongside other diagnostic tools.

The pediatric asthma risk score (PARS) is another tool doctors use to predict the likelihood of a child developing asthma. But its approach is different from the API.

The API looks at clinical criteria like wheezing and atopy (a genetic predisposition to allergies) to predict the likelihood of developing asthma. In contrast, the PARS considers various risk factors, including family history, eczema, and respiratory infections.

The API and PARS also provide different results. The API gives either a “yes” or “no” regarding the likelihood of developing asthma. The PARS provides a risk percentage ranging from 3% to 79%.

Studies suggest that while the API is best at predicting who may not develop asthma, the PARS might be better at predicting who may develop asthma. A 2019 research review suggested that the PARS has 11% better sensitivity than the API. It’s especially helpful for predicting which children may have mild to moderate asthma.

Other risk factors for childhood asthma include experiencing:

American Indians, Native Alaskans, and people of Black communities may often have a higher risk. Boys may also have a higher risk of developing childhood asthma than girls.

It’s important to note that the stress of enduring racism, discrimination, and racist systems may play a part in these inequities in healthcare beyond the above factors.

Consider taking the following steps if your child has a positive API result to help manage their risk and prevent the onset of symptoms:

  • Monitor your child’s symptoms: While your child may not have asthma symptoms yet, it’s important to monitor them for any signs of wheezing, coughing, or shortness of breath.
  • Avoid triggers: Environmental triggers such as smoke, pollution, and allergens can exacerbate asthma symptoms.
  • Consider medications: Your child’s doctor may recommend medications like inhaled corticosteroids to help reduce inflammation in the airways and prevent the onset of asthma symptoms.
  • Follow up with your doctor: Regular follow-up appointments with your child’s doctor can help to track any changes in their symptoms.

Doctors use the API to predict the likelihood of a child developing persistent asthma. The API considers a child’s history of wheezing and the presence of risk factors for asthma, such as a family history.

A positive API result means your child may have a higher risk of developing asthma. The API is more accurate in predicting children who may not develop asthma.

In either case, if your young child experiences frequent wheezing, their doctor may recommend additional testing and treatment to help manage their risk and prevent the onset of symptoms.