Modified Asthma Predictive Index (mAPI)

mAPI explained

The modified asthma predictive index can help determine whether respiratory and allergic criteria present in pediatric patients aged three or younger are linked to likelihood of acute asthma at school age.

The only exclusion of the model is that the index cannot be applied in children with less than four episodes of wheezing per year, which is the compulsory criteria.

The other major and minor criteria are presented below:

■ API major criteria:

- Family history (parent) with asthma;

- Patient diagnosed with eczema (atopic dermatitis);

- Diagnosed sensitivity to allergens in the air (demonstrated through positive skin prick tests or blood tests to a series of allergens such as dust mites, molds, weeds etc.).

■ API minor criteria:

- Wheezing present apart from colds;

- Greater than 4% blood eosinophils;

- Diagnosed food allergies (i.e. milk, eggs, peanuts).

In order for the index to be validated (likelihood of asthma diagnosis at school age) the four or more wheezing episodes per year criteria must be checked AND at least one major OR at least two minor criteria to be met.

The table below presents the sensitivity and specificity values for predictions in patients aged 3 at assessment date, as extracted from the study group:

The main limitation of the model relies in the fact that its predictive capacity depends on the prevalence of asthma in the general population.

Predicting asthma

It is important to delineate between normal wheezing presence in the first year of life (in 40% of children) and subsequent 30% recurrent wheezing in children at the age of 6.

Predictor indices such as API or mAPI provide information about future diagnosis and there are quite similar in terms of criteria used.

At a glance, the most important change that occurs in the mAPI is the addition of another minor criteria, that concerns the presence of diagnosed food allergies.

However, there are several other differences, from criteria to prediction specificities. The following table compares the two models:

Currently, API is the preferred version when an asthma index is required in a longitudinal study. Further studies are also trying to find ways in which the indices can be employed in pharmaco-clinical methods that prevent asthma.

References

1. Chang TS, Lemanske RF, Guilbert TW, Gern JE, Coen MH, Evans MD, Gangnon RE, Page CD, Jackson DJ. Evaluation of the Modified Asthma Predictive Index in High-Risk Preschool Children. J Allergy Clin Immunol Pract. 2013; 1(2): 10.1016.

2. Guilbert TW, Morgan WJ, Zeiger RS, Mauger DT, Boehmer SJ, Szefler SJ, Bacharier LB, Lemanske RF Jr, Strunk RC, Allen DB, Bloomberg GR, Heldt G, Krawiec M, Larsen G, Liu AH, Chinchilli VM, Sorkness CA, Taussig LM, Martinez FD. Long-term inhaled corticosteroids in preschool children at high risk for asthma. N Engl J Med. 2006; 354(19):1985-97.

3. Castro-Rodríguez JA, Holberg CJ, Wright AL, Martinez FD. A clinical index to define risk of asthma in young children with recurrent wheezing. Am J Respir Crit Care Med. 2000; 162(4 Pt 1):1403-6.