Risk factors for wheezing and allergy in preschool children (PSC) after admission for acute bronchiolitis

Abstract

Introduction: Acute bronchiolitis (AB) is associated to later development of wheezing (W) and allergic sensitisation, but risk factors remain controversial. This study aimed to test the hypothesis that clinical background and features of the acute episode influences outcomes.

Methods: A cross-sectional study was performed in 71 out of 340 infants< 2 year-old admitted for AB (Oct/02-Apr/04) in a terciary teaching hospital. We conducted structured interviews, spirometry and skin-prick tests (SPT) to common inhalant allergens to 4-6 year-old and looked for demographic and clinical risk factors (male gender, born season, prematurity, exposure to smoke, nursery,older siblings, pets, family history of allergy, no breast feeding) and for the acute episode [RSV, age <6 weeks, severity] (length of hospital stay ≥6 days and time on oxygen ≥4 days)] and use of steroids. Main outcomes were any episode of W and persistent wheezing (PW).

Results: W occurred in 50 (70%) of children, but only 19 (39%) referred PW. We found no differences between groups, except for steroid treatment at acute episode [W 6 (12%)/not W 8 (38%)] that was associated with a 4,5 risk reduction of wheezing (adjusted OR [IC] 0,22 [0,065–0,76]),but not for PW. PW was associated with positive SPT [PW 7 (39%); no PW 3 (10%)], adjusted OR [IC] 3,7 [1,4–10,2].

Conclusion: This study shows a high prevalence of wheezing in PSC after AB in infancy associated with atopy. The use of steroids seemed protective.We found no influence from family history of allergy, RSV infection or severity at the acute episode. These data suggests caution on using established risk factors for prognosis after an episode of BA.