Helpful diagnostic tool: Modified Asthma Predictive Index increases future asthma probability from 30% to 90%

This study aimed to confirm the predictive ability of the modified Asthma Predictive Index (mAPI). The current version of mAPI requires 4 wheezing episodes for a positive test. The authors tested a modification of the index with a 2-wheezing episode requirement (m2API).



Modified Asthma Predictive Index (API) (click to enlarge the image).

Modified Asthma Predictive Index (API) is calculated in children under the age of 3 with ALL of the following:

- 4 wheezing exacerbations in past year
- with one physician-confirmed episode
- plus one major criteria OR 2 minor criteria

Major criteria - one of the following: parental history (mother who had childhood asthma only, father with exercise-induced asthma); physician-diagnosed atopic eczema; allergic sensitization to one aeroallergen.

Minor criteria - two of the following: allergic sensitization to milk, eggs, or peanuts (positive skin or blood test sufficient); wheezing unrelated to respiratory illness (ie, cold);
blood eosinophilia 4% of total white blood cell (WBC) count.

This study included 289 children with a family history of allergy and/or asthma who were evaluated for asthma at age 6, 8, and 11 years with the use of characteristics collected during the first 3 years of life.

For the mAPI and m2API, school-age asthma prediction improved from 1 to 3 years of age. The mAPI had high predictive value after a positive test for asthma development at years 6, 8, and 11. Lowering the number of wheezing episodes to 2 (m2API) lowered the predictive value.

Posttest probabilities for a positive mAPI was 72% and 90% in unselected and high-risk populations, respectively.

In a high-risk cohort, a positive mAPI greatly increased future asthma probability (eg, 30% pretest probability to 90% posttest probability). The mAPI helps decision making in assessing future asthma risk for preschool-age children.

References:

Evaluation of the Modified Asthma Predictive Index in High-Risk Preschool Children. Chang TS, Lemanske RF Jr, Guilbert TW, Gern JE, Coen MH, Evans MD, Gangnon RE, Page CD, Jackson DJ. J Allergy Clin Immunol Pract. 2013 Mar 1;1(2). doi: 10.1016/j.jaip.2012.10.008.
http://www.ncbi.nlm.nih.gov/pubmed/24187656