Health outcomes and drug utilisation in children with Noonan syndrome: a European cohort study.

Background: Noonan Syndrome (NS) is a rare multisystemic disorder with heterogeneous phenotypic manifestations. The aim of this study was to analyse rates of survival, hospitalisation, surgeries and prescriptions in children born with NS in the first 10 years of life.

Methods: This is a multi-centre population-based cohort study. Data on 175 liveborn children diagnosed with NS from 11 EUROCAT congenital anomaly registries were linked to healthcare databases. Each registry applied a common data model to standardise data and run common syntax scripts to produce aggregated results which were pooled using random effects meta-analyses.

Results: Mortality rates were high in the first year of life with 5.4% (95%CI 1.5%-10.1%) of children dying before the age of 1 year with a further 2% dying up to age 5. In the first year, 87.9% (95%CI 75.3%-94.3%) of children were hospitalized and the median Length Of hospital Stay (LOS) was 15.3 days (95%CI 9.3-21.2). After the first year, the proportion of children hospitalized remained higher than 70%, but the LOS decreased to 1.3 days per year. In the first 5 years, 65.2% of children underwent a median of two surgical procedures. The median age at first surgery was 29 weeks. The proportion of children with an antibiotic prescription increased from 53.6% at age 1 to 62.4% yearly until 4 years of age.

Conclusions: Children with NS have high mortality and morbidity not only in the first year of life but also up to five years of age. This study evaluated the health burden of NS and provided information for clinicians, health-care providers and families.