Medicaid Accountable Care Organization Implementation and Perinatal Claims Documentation of Social Risk Factors

Abstract

Importance: Addressing social risk factors (eg, food insecurity) during the perinatal period has the potential to improve pregnancy-related outcomes. While social risk factor diagnosis codes (ie, International Statistical Classification of Diseases, Tenth Revision, Z codes) were introduced in 2016, adoption in claims has been slow. In 2018, Massachusetts' Medicaid program implemented an accountable care organization (ACO) model, including a requirement that all ACOs screen for social risks.

Objective: To assess claims documentation of Z codes in the perinatal period for Medicaid enrollees and evaluate changes in documentation following implementation of Massachusetts' Medicaid ACO program.

Design, setting, and participants: This cross-sectional study used the Massachusetts All-Payer Claims Database to identify all Medicaid-enrolled live deliveries between January 31, 2016, and December 31, 2020, among people 18 years or older. A difference-in-differences (DiD) approach was used to compare Z code documentation before (2016-2017) vs after (2018-2020) ACO implementation for Medicaid ACO vs non-ACO deliveries. Data were analyzed between August 23, 2024, and January 27, 2025.

Exposures: Attribution to a Medicaid ACO (vs non-ACO), determined based on whether an enrollee's primary care physician participated in an ACO.

Main outcomes and measures: The primary outcome was claims documentation of any Z code, measured separately for the prenatal period, 60 days post partum, 12 months post partum, and the full perinatal period. Secondary outcomes included documentation of specific Z codes (eg, housing, food insecurity).

Results: The study sample included 79 293 deliveries (mean [SD] age of Medicaid-enrolled pregnant people, 28.2 [5.7] years), of which 69 535 (87.7%) were in a Medicaid ACO. Among all Medicaid deliveries from 2016 to 2020, 4.45% had claims documentation of a Z code in the prenatal period; 1.14%, within 60 days post partum; and 3.31%, within 12 months post partum. Within the prenatal period, Medicaid ACO implementation was associated with statistically significant increases in documentation of any Z code (DiD, 1.09 [95% CI, 0.38-1.80] percentage points [PP]), housing or economic circumstances codes (DiD, 1.52 [95% CI, 1.07-1.97] PP), and food insecurity codes (DiD, 0.58 [95% CI, 0.42-0.73] PP). The Medicaid ACO was associated with few changes in Z code documentation in the postpartum period.

Conclusions and relevance: In this cross-sectional study of Medicaid-enrolled live births in Massachusetts, ACO implementation was associated with increased claims documentation of Z codes during the perinatal period, driven by increases in the prenatal period. While Z code documentation remains low, implementation of care delivery models that incentivize screening and documentation of social risk factors among Medicaid enrollees may help to identify the care needs of pregnant and postpartum people.

Figure.. Changes in Claims Documentation of Any Social Risk Factor by Enrollment in a Massachusetts Medicaid Accountable Care Organization (ACO)

Graphs present unadjusted quarterly averages. SDOH indicates social determinants of health. The vertical line represents the first quarter of ACO implementation in Massachusetts (2018-Q1).