Changes in documentation of social risk factor diagnosis codes: comparison of Medicaid Accountable Care Organization model types

This is the authors' abstract. We don't add key points for this paper.

Introduction Identifying social risk factors during the perinatal period may improve pregnancy-related outcomes. In 2018, the Massachusetts Medicaid program implemented an accountable care organization (ACO)—which required social risk factor screening—under 2 ACO model types: Model A (health system/Medicaid managed care plan partnership model) and Model B (primary care practice model). Methods Using the 2016-2020 Massachusetts All Payer Claims Database and a difference-in-differences (DiD) design, we compared changes in any social risk factor documentation (ie, ICD-10 Z-codes) for Medicaid-enrolled deliveries in non-ACOs vs ACO Model A vs Model B, measured separately for the prenatal period, 60 days postpartum, 12 months postpartum, and the perinatal period. Secondary outcomes included documentation of specific Z-codes related to homelessness and food insecurity. Results Both Model A (DiD = 1.03 percentage points [PP], P < .001) and Model B (DiD = 0.65 PP, P < .001) were associated with significant increases in Z-code documentation of food insecurity in the perinatal period. Model B was associated with a significant increase in Z-code documentation of homelessness in the perinatal period (DiD = 1.10 PP, P < .001) but not Model A. Conclusion Massachusetts' Medicaid ACO was associated with modest increases in Z-code documentation during the perinatal period, with some variation by ACO model type.