Exploratory factor analysis of a score for grading the severity of bronchial obstruction evaluated in children younger than 3 years old, Chile, 2015.

INTRODUCTION

The modified Tal's score has been used in Chile to determine the severity of bronchial obstruction. Its validity has been reported already; however, its structure as a scale to significantly quantify the severity of bronchial obstruction has not been analyzed.

OBJETIVE: To identify the relationship pattern among the score's items and the severity of bronchial obstruction in a sample of children younger than 3 years seen in two health care centers in the province of Concepción, Chile.

METHOD: Exploratory factor analysis. Nonrandom, voluntary selection of participants younger than 36 months, August-November 2015. Participants were assessed independently and subsequently by a physician and a physical therapist. The following measurements were applied: central tendency, exploratory factor analysis, subgroups of participants younger and older than 6 months, and internal consistency.

RESULTS

A total of 204 measurements were done in 102 children. With a 39% explained variance, items incline towards to two different concepts: one factor groups respiratory rate, wheezing, and retractions, and the other determines only cyanosis, with a Cronbach's alpha of 0.5. Once cyanosis is removed from the analysis, the original one-factor matrix sample shows a 38% total explained variance and a 0.62 internal consistency.

CONCLUSIONS

Based on its items, the score's structure does not fit adequately to this sample. Cyanosis appears as a dissociated item within the structure. Once the model is adjusted to only 3 items, the stability of Chronbach's alpha as a measure of internal consistency increases but at an objectionable value, which will undoubtedly vary once it is applied to a different sample.