Using the pediatric health information system to study rare congenital pediatric surgical diseases: Development of a cohort of esophageal atresia patients

Background/Purpose Administrative databases include large multi-institutional cohorts of patients with rare congenital anomalies that can potentially be used to characterize these diseases and study variations in practice and outcomes. The purpose of this study was to develop a methodology to accurately identify a cohort of patients with a rare disease (esophageal atresia and tracheoesophageal fistula, EA/TEF) in the Pediatric Health Information System (PHIS) database. Methods Patients with EA/TEF treated from 2001 to 2010 were identified by chart review at two institutions and then located within the PHIS database to find ICD-9-CM coding patterns unique to EA/TEF. Subsequently, a step-wise search strategy for PHIS was developed to identify patients with EA/TEF: this included searching the ICD-9-CM diagnosis code for congenital EA/TEF; adding the ICD-9-CM code for acquired TEF; limiting age to ≤ 30 days; and adding at least one of a number of specified ICD-9-CM procedure codes. The PHIS search results were subsequently validated by chart review at each institution. Results The institutional chart reviews identified 207 patients with EA/TEF. The most refined PHIS search strategy identified 221 patients. The positive predictive value of the search increased incrementally from 65% with using only the correct ICD-9 code to 96% with the full methodology. A cohort of 2977 patients with EA/TEF is identified when this search strategy is applied to the entire PHIS database. Conclusion Administrative databases such as PHIS can be utilized to identify cohorts of patients with rare congenital anomalies; however, cohort development requires a systematic search strategy and validation process to ensure correct identification of patients.