Predictors of prognosis in children under six years of age with recurrent croup: a retrospective cohort study

Croup is a common cause of upper respiratory tract obstruction in young children. Although most cases resolve spontaneously, some children experience recurrent attacks. Identifying prognostic factors that determine the risk of recurrence in children with recurrent croup may help optimize follow-up and treatment strategies. We aimed to investigate the clinical, demographic, and laboratory characteristics of children under six years of age with recurrent croup and to identify independent predictors of disease recurrence during a 6- and 12-month follow-up period. We conducted a retrospective cohort study of 69 children (<6 years) diagnosed with recurrent croup at a single tertiary pediatric pulmonology and allergy–immunology center. Eligible subjects (≥2 clinician-documented episodes within 12 months) presented between October 2020 and October 2023 and had at least 12 months of follow-up. We gathered information from medical records about the children's background, health details, laboratory results, and treatments. Binary logistic regression was used to identify independent predictors of croup recurrence within the first 6 and 12 months. The mean age was 4.4±1.5 years, and 67% (n=46) were male. Within 6 months, 40.6% of cases experienced at least one recurrent attack, and 11.6% experienced a croup attack between 6 and 12 months. For 6-month recurrence, a family history of atopy (OR: 7.50, 95% CI: 1.96–28.68; p=0.003) and a higher number of croup attacks before follow-up (OR: 1.43, 95% CI: 1.06–1.92; p=0.020) were independent predictors, but age and cough trigger were not significant. For 12-month recurrence, family history of atopy (OR: 9.11, 95% CI: 1.12–74.00; p=0.039) and the number of attacks prior to follow-up (OR: 1.66, 95% CI: 1.08–2.54; p=0.020) were significant, while advanced age emerged as a protective factor (OR: 0.48, 95% CI: 0.24–0.95; p=0.035). In a small, clinically selected subgroup, flexible optical bronchoscopy and thoracic CT angiography identified airway compression and laryngeal findings possibly consistent with reflux-related irritation. In young children with recurrent croup, a family history of atopy and the number of prior croup episodes were independently associated with a higher probability of further recurrences during 6- and 12-month follow-up. These easily available clinical factors may help identify children who warrant closer follow-up, but validated risk thresholds and diagnostic pathways require prospective external validation.