Determination of predictive risk factors for severe bronchiolitis

Objective: Acute bronchiolitis is a common lower respiratory tract disease especially in children under two years of age. A number of factors have been identified that cause the disease to become widespread, clinically severe, and increase the rate of hospitalization. The aim of this study was to determine the predictive personal, familial and environmental risk factors for the development of severe bronchiolitis in patients with acute bronchiolitis who had no previous chronic disease. Materials and methods: In this prospective study, 440 children aged between 1-24 months, who were hospitalized the diagnosis of acute bronchiolitis, were examined between February 1, 2018 and February 28, 2019. The patient's history, such as gender, age, body weight, week of birth, mode of delivery, diet and history of wheezing, familial factors such as asthma, history of smoking and parental education, environmental factors such as residential place, home type, warming pattern and number of people living at home, physical examination findings, laboratory data, degree of bronchiolitis and need for oxygenation were recorded. Results: Of the total patients, 277 (63%) were male and 163 (37%) were female. Of these, 85 were considered as severe bronchiolitis and 355 as mild to moderate bronchiolitis. There was a statistically significant difference (p<0,05) among the severe bronchiolitis group and the mild-moderate bronchiolitis group based on the weight-for-age z-score, the history of bronchiolitis, the mother's active smoking history, the father's education level, the only child of the family, the number of people living at home, the decrease in nutrition, the onset of complaints the time between symptoms and worsening of symptoms, subcostal retraction, cyanosis, oxygen saturation, oxygenation requirement and length of hospital stay. The hemoglobin, lymphocyte amount and capillary pH values in the severe bronchiolitis group were lower than the mild to moderate bronchiolitis group, on the other hand, absolute neutrophil amount, C-reactive protein and capillary pCO2 values were higher in the severe bronchiolitis group (p<0,05). Weight-for-age z-score was -0,87 ± 1,54 (-4,28 – 4,78) in severe bronchiolitis group and -0,30 ± 1,16 (-4,91 – 3,07) in the mild-moderate bronchiolitis group (p<0,001). The mean time interval between the beginning of complaints and admission was 4,04 ± 2,11 (1-10) days in the severe bronchiolitis group and 4,90 ± 3,15 (1-20) days in the mild-moderate bronchiolitis group (p=0,017). The mean number of bronchiolitis attacks was 1,59 ± 1,02 (1-5) in the severe bronchiolitis group and it was 1,34 ± 0,64 (1-4) in the mild-moderate bronchiolitis group (p=0,004). The mean Hb value was 10,83 ± 1,47 g/dL in the severe bronchiolitis group and 11,19 ± 1,21 g/dL in the mild-moderate bronchiolitis group (p=0,021). According to the results of logistic regression analysis, it was determined that the low weight-for-age z-score was increased 0,56 times of the risk of severe bronchiolitis development (CI: 0,409 - 0,760), the short duration between the beginning of complaints and admission was 0,62 times (CI: 0,519 - 0,735), the frequent history of bronchiolitis status was increased 1,81 times (CI: 1,135-2,968) and low hemoglobin levels was increased 0,72 times (CI: 0,537 – 0,969). Conclusion: In this study, low weight-for-age z-score, short duration between the beginning of complaints and admission, high number of previous attacks, and low hemoglobin levels were determined as independent parameters of severe bronchiolitis development. Key words: Bronchiolitis, Infant, Risk factors, Severity degree