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

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.