The significant impact of meconium ileus on clinical outcomes among Brazilian individuals with cystic fibrosis-a retrospective analysis of a patient registry.

Background: Meconium ileus (MI) is one of the earliest manifestations of cystic fibrosis (CF), affecting 15-20% of individuals. The impact of MI on health outcomes has yet to be elucidated and may vary based on the amount of health care resources. The aim of this study was to investigate the clinical impact of MI on outcomes among Brazilian CF individuals using data from the Brazilian Cystic Fibrosis Patient Registry. Methods: This retrospective cohort study included data from individuals with CF from 53 reference centres in Brazil. Data from individuals with a history of MI during the neonatal period were compared to those of the non-MI individuals. Demographic data, genotype, lung function, nutritional data, microbiological data and survival data were compared between groups. The impact of MI on lung function and anthropometric outcomes was evaluated using mixed effects models after adjusting for age. Individual survival data were analyzed by Kaplan-Meier curves, log-rank tests and Cox proportional hazards models. Findings: Among the 5128 individuals included in the registry, 369 (7·2%) were diagnosed with MI at birth. The occurrence of MI was associated with an earlier diagnosis of CF but a lower mean Z score for weight (-0·32, 95% CI -0·46 to -0·18, p < 0·0001) and height (-0·28 95% CI -0·40 to -0·15, p < 0·0001). Lung function was significantly lower among those affected by MI (reduction of -4·3% 95% CI -8·0 to -0·5, p = 0·028) up to the age of 18 years. A greater prevalence of Interpretation: CF individuals affected by MI had more severe and earlier declines in lung function, slower rates of weight and height gain, and lower survival rates. These findings underscore the importance of early identification and tailored management strategies for this high-risk subgroup. Funding: None.