Background: There is limited data on the adult repair of pectus excavatum (PE). Existing literature is largely limited to single institution experiences and suggests that adults undergoing modified Nuss repair may have worse outcomes than pediatric and adolescent patients. Using a representative national database, this analysis is the first to describe trends in demographics, outcomes, charges, and facility volume for adults undergoing modified Nuss procedure.Methods: Because of a coding change associated with ICD-10, a retrospective cohort analysis using the National Inpatient Sample (NIS) for patients 12 or older undergoing modified Nuss repair between 2016-2018 was possible. Pearson's χ 2 and Student's t-tests were utilized to compare patient, clinical, and hospital characteristics. Complications were sub-classified into major and minor categories. Facilities performing greater than the mean number of operations were categorized as high-volume.Results: Of 360 patients, 79.2% were male. There was near gender parity for patients over 30 undergoing repair (55.2% male, 44.8% female). In all age cohorts, patients were predominantly Caucasian. Rates of any postoperative complication differed by age (12-17 years: 30.6%; 18-29 years: 45.2%; 30+ years: 62.1%; P<0.01); older patients had higher rates of all but two subclasses of complication.