Performance of commonly used respiratory questionnaire items in a cohort of infants born preterm

BACKGROUND Items from respiratory questionnaires validated in older children are often used in research studies of preterm infants, although they have not been validated in this population. We aimed to assess both test-retest reliability and convergent validity of a group of commonly used respiratory questionnaire items in a cohort of preterm infants. METHODS The health status of 300 preterm infants was assessed by telephone questionnaire as part of a prospective cohort study. The questionnaire items analyzed in this study included six commonly used respiratory questions. The questionnaire responses used in this analysis were from the telephone follow-up in this cohort at six months of age adjusted for prematurity. A repeat interview one to two weeks after this interview was performed in a subset of subjects to assess test-retest reliability. The convergent validity of the respiratory items was also assessed by calculating the associations among the responses to the respiratory questions. RESULTS A total of 43 infants were singletons that met the criteria for test-retest reliability analysis. All of the respiratory questions demonstrated fair to strong test-retest reliability. Among 206 respondents, respiratory questionnaire items also demonstrated strong convergent validity, in that caretakers reporting wheezing or whistling in the chest were significantly more likely to also report other respiratory events. CONCLUSIONS This selection of standard respiratory questionnaire items performed well for research purposes in this population.