[Clinico-epidemiological study of acute bronchiolitis objective]

To determine the incidence of hospital admissions for bronchiolitis in our environment, to analyze the importance of neonatal malformations as a risk factor for hospitalization for bronchiolitis and to establish the variables available on admission that are associated with a worse evolution.

Descriptive study of admissions for bronchiolitis in a sample of the general population and in children with severe neonatal malformations. Descriptive and analytical study of the clinical characteristics available on admission for bronchiolitis that predict a worse evolution. Sixty-one children born at the Medina del Campo Hospital in Spain were studied. All the children were diagnosed according to McConnochie's criteria and classified into three groups according to evolution (mild, moderate and severe).

The annual cumulative incidence of admissions due to bronchiolitis was 1.79 % (95 % CI, 1.37-2.30). This incidence was higher in children with a history of severe neonatal malformations (13.11 %) than in those without malformations (1.59 %) (RR 5 8.26; CI 95 %, 4.10-16.02). Children with severe bronchiolitis were younger (p 5 0.0056; median 1.0, quartiles 1.0-2.75) than those with moderate bronchiolitis (median 5.0; quartiles 2.0-8.0) or mild bronchiolitis (median 5.5; quartiles 3.25-9.0). Using the group with mild bronchiolitis as reference, diminished appetite (OR 5 4.08; 95 % CI, 1.10-16.80), vomiting (OR 5 4.22; 95 % CI, 1.14-25.30) and prolonged expiration (OR 5 5.35, 95 % CI, 1.14-24.30) were associated with moderate-severe evolution. Using the mild-moderate group as reference, vomiting (p 5 0.004), crepitant rales (p 5 0.002), decreased ventilation (p, 0.001) and radiological consolidations (p 5 0.017) were associated with severe evolution.

The incidence of hospital admission for bronchiolitis in our environment was similar to data reported from other countries. Variables available at admission predicting a worse evolution were age lower than 3 months, vomiting, diminished appetite, prolonged expiration, crepitant rales, decreased ventilation and radiological consolidations. Severe neonatal malformations were an important risk factor for hospital admission due to bronchiolitis.