Perinatal & Pediatric
Development of a Pregnancy Cohort in Commercial Insurance Claims Data: Evaluation of Inpatient Versus Apparent Outpatient Deliveries Jacob C. Kahrs* Jacob C. Kahrs Katelin B. Nickel Michael Durkin Sascha Dublin Sarah Osmundson Dustin Stwalley Mollie E. Wood Elizabeth Suarez Anne M. Butler
In studies using insurance claims data for perinatal research, pregnancies are often identified by an observed pregnancy outcome (e.g. live or still birth). Some studies have stricter inclusion criteria for pregnancies with only outpatient delivery claims, with the rationale that outpatient claims may be less reliable.
In a US commercial insurance database (2006-2021), we identified potential pregnancies by the presence of delivery claims from a provider and/or facility. We classified deliveries as inpatient (claim date during inpatient admission) and apparent outpatient (no inpatient admission on claim date). We identified possible confirmatory evidence for each pregnancy including: (1) provider and facility delivery diagnosis and/or procedure code, (2) delivery diagnosis and delivery procedure code, (3) delivery revenue codes, (4) gestational age codes, (5) prenatal care codes, (6) linkage to infant claim, (7) infant birthdate within 1 month of the delivery date. We quantified the proportion of deliveries with confirmatory evidence by delivery setting. Among deliveries with ≥1 piece of confirmatory evidence, we compared characteristics of patients by delivery setting.
Overall, 4.9% of deliveries appeared to be outpatient. A larger proportion of apparent outpatient deliveries (5.7%) vs inpatient (0.1%) did not have confirmatory evidence. Confirmatory evidence (5) was most common (99.7% inpatient, 91.3% apparent outpatient). (4) was the least common evidence for inpatient deliveries (37.3%) and (1) was the least common for apparent outpatient deliveries (12.4%). Confirmed deliveries classified as inpatient occurred among patients who were older and more clinically complex, defined by more pregnancy complications, chronic diseases and prescription medication use.
The vast majority of inpatient and apparent outpatient deliveries had confirmatory evidence. Patient characteristics differed by delivery setting, which has implications for generalizing future study results.