Fragmented ambulatory care and subsequent emergency department visits and hospital admissions among Medicaid beneficiaries.

OBJECTIVES: Results of previous studies of Medicare beneficiaries have shown that more fragmented ambulatory care is associated with more emergency department (ED) visits and hospital admissions. Whether this observation is generalizable to Medicaid beneficiaries is unknown. STUDY DESIGN: We conducted a 3-year retrospective cohort study in the 7-county Hudson Valley region of New York. We included 19,330 adult Medicaid beneficiaries who were continuously enrolled, were attributed to a primary care provider, and had 4 or more ambulatory visits in the baseline year. METHODS: We measured fragmentation using a modified Bice-Boxerman Index. Cox proportional hazards models were used to determine associations between fragmentation score and ED visits or, separately, hospital admissions, adjusting for age, gender, and chronic conditions. RESULTS: The average beneficiary had 15 ambulatory visits in the baseline year, spread across 5 providers, with the most frequently seen provider accounting for 48% of the visits. One-fourth of the sample had more than 20 ambulatory visits and more than 7 providers, with the most frequently seen provider accounting for fewer than 33% of visits. For every 0.1-point increase in fragmentation score, the adjusted hazard of an ED visit over 2 years of follow-up increased by 1.7% (95% CI, 0.5%-2.9%). Having more fragmented care was not associated with a change in the hazard of a hospital admission. CONCLUSIONS: Among Medicaid beneficiaries, having more fragmented care was associated with a modest increase in the hazard of an ED visit, independent of chronic conditions. Fragmented ambulatory care may be modifiable and may represent a novel target for improvement.