Prenatal syphilis screening rates measured using medicaid claims and electronic medical records

To prevent congenital syphilis, the Centers for Disease Control and Prevention and professional organizations recommend universal prenatal syphilis screening. State-level or larger-scale evaluations of adherence to these guidelines have relied on administrative data. We measured prenatal syphilis screening rates in Indiana women with prenatal Medicaid coverage and also used electronic medical records to examine the completeness of syphilis screening claims in Medicaid administrative data.

In statewide Indiana Medicaid claims data, diagnosis and procedure codes were used to identify women who delivered an infant between October 1, 1998, and September 30, 2002. Claims for prenatal (that is, during the 40 weeks before and including the delivery date) syphilis screens, including the "obstetric panel" of tests, and for prenatal visits were extracted. A subset of the study population received prenatal care in a large public hospital and its affiliated clinics served by an electronic medical records system. For these women, claims data were compared with laboratory reports.

Among 74,188 women with one delivery in Medicaid claims data, 60% had at least 1 prenatal syphilis screening claim, and 15% had 2 or more. Women with continuous Medicaid enrollment during pregnancy or with at least one prenatal visit claim had higher rates. Among the 3960 women for whom Medicaid claims and laboratory data were available, 49.8% had at least one prenatal syphilis screen in Medicaid claims, but 99.3% had at least one laboratory report of a syphilis screen.

Measurements made using Medicaid administrative data appear to substantially underestimate true prenatal syphilis screening rates.