Development and validation of a questionnaire to identify patients with sleep apnea in Mexican population: Mexican questionnaire to identify sleep apnea

Abstract

Purpose: To develop and validate a questionnaire to identify patients with obstructive sleep apnea (OSA) in Mexican population.

Methods: We performed a cross-sectional study to develop and validate an instrument in Spanish language, consistent in an 18-item questionnaire. We enrolled patients seen from July 2008 to August 2009. We evaluated the internal consistency with the Kuder Richardson coefficient, a value greater than 0.70 was considered a good index correlation. Sensitivity, specificity, and positive and negative predictive factor was obtained with standard methods by comparison with polysomnographic results. Validity of Mexican questionnaire at baseline and follow-up was assessed using Pearson correlations coefficient.

Results: We enrolled 100 patients. The initial pool comprised 25 items, four items were considered confusing and they were omitted; then, a preliminary questionnaire comprising 21 items was obtained, and three items were removed by presenting a response rate lesser than 90%, yielding a total of 18 items for the final questionnaire. This evaluation was performed stratifying in groups related to severity of illness. Snoring was the question with the greatest sensitivity to detect OSA; and obesity class I was the criteria with greatest specificity to detect OSA.

Conclusion: The screening tool proposed in this study has the advantages of being quick, inexpensive, easy to apply and reproducible, and the result has reliability with acceptable sensitivity; this is a symptom-based questionnaire with good predictive ability and it will avoid unnecessary sleep studies in the subjects who are not at high risk for having OSA.