Medicaid ACOs Associated With Persistent Insurance-Based Disparities in Routine Pediatric Asthma Visit Rates

In the US, nearly 6 million children have asthma and over one-third are insured by Medicaid. Although there are 23 state Medicaid programs that have experimented with implementing accountable care organizations (ACO), there is little information about the effects of ACO on long-standing insurance-based disparities within the pediatric asthma care space and outcomes. Authors of a study published in JAMA Pediatrics evaluated associations of Massachusetts Medicaid ACO implementation with changes in 2 common pediatric asthma quality measures and emergency department (ED) visits and/or hospitalizations for asthma.

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For this cross-sectional study, Massachusetts All Payer Claims Database data from January 1, 2014 to December 31, 2020 was used. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology reporting guidelines, as well as fully reported Medicaid beneficiaries and private insurance plans with optional reporting by self-insured employer plans.

Additionally, the investigators included child-year observations for January 1, 2015 to December 31, 2020 for children aged 2 to 17 years with 12 months of primary Medicaid or private insurance and Massachusetts residence. The investigators identified child-years with asthma for children who met at least 1 of the following criteria: 1 or more inpatient or observation hospital stay or ED visit with an asthma diagnosis (using the diagnosis codes from either International Classification of Diseases, Ninth Revision or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision); 2 or more outpatient visits with an asthma diagnosis; or at least 1 outpatient visit with an asthma diagnosis and at least 1 asthma medication.

The findings demonstrated that among the 376,509 child-years for 174,467 children, approximately 71.27% child-years (n = 268,338) were Medicaid insured, and those with Medicaid were significantly more likely to have persistent asthma, higher comorbidity risk scores, and were younger than those who had private insurance. Additionally, each child contributed a mean of 2.16 child-year observations. The investigators also observed substantial differences in unadjusted outcomes between the 2 groups, with lower rates of any routine asthma visit, lower rates of asthma medication ratio (AMR) greater than 0.5, and higher rates of any ED or hospital use among child-years insured with Medicaid compared with privately insured child-years.

Further, the rates of any routine asthma visit were lower among those with Medicaid (66.9%) compared with private insurance (74.1%) during the pre-period. The investigators also observed an insignificant decrease of 0.4 pp (95% CI, −1.4 to 0.6 pp) in the change in the rate of any routine visit from pre-ACO implementation to post-ACO implementation for those with Medicaid compared with those with private insurance. For patients with persistent asthma, increases in the proportion with AMR greater than 0.5 from the pre-period to post-period for those with Medicaid compared with those who had private insurance (3.7 pp; 95% CI, 2.0-5.4 pp), and there were absolute declines in both groups from pre-implementation to post-implementation, with larger declines present among those with private insurance.

In addition, any ED or hospital use for asthma was higher among those with Medicaid (27.2%) compared with those privately insured (19.0%) during the pre-period. The estimate showed that the change in any ED or hospital use between the pre-ACO and post-ACO implementation periods was about 2.1 pp higher (95% CI, 1.2-3.0 pp) for those who had Medicaid compared to private insurance, which was an approximate 8% relative increase form the pre-period Medicaid rate. The investigators noted that this was driven by changes in use of any ED visit, with no changes in hospitalizations. There was also a statistically significant increase in the change in any ED visit from pre-period to post-period for those with Medicaid compared with those with private insurance (DiD, 2.3 pp; 95% CI, 1.4-3.2 pp). There were no differences in the change in hospitalizations from pre-ACO to post-ACO implementation between the 2 insurance groups, according to the authors.

Study limitations included the lack of generalizability, potential ACO start-up issues were reflected in results because the first 3 years of Medicaid ACO contracts were included, and self-insured employers were no longer required to report their data starting in 2016. The authors also noted that claims data may not provide a clear picture of asthma control and care delivery, and pre-period trends for the treatment and control groups were not parallel. The investigators suggested that additional research that includes mixed-methods research is needed for a stronger assessment of ACO effects on the quality of care, outcomes, and disparities within pediatric asthma.

REFERENCE

Geissler KH, Shieh M, Ash AS, Lindenauer PK, Krishnan JA, Goff SL. Medicaid Accountable Care Organizations and Disparities in Pediatric Asthma Care. JAMA Pediatr. Published online September 30, 2024. doi:10.1001/jamapediatrics.2024.3935