Abstract
BACKGROUND: The magnitude of the relationship between ambulatory care fragmentation and subsequent total health care costs is unclear. OBJECTIVE: To determine the association between ambulatory care fragmentation and total health care costs. RESEARCH DESIGN: Longitudinal analysis of 15 years of data (2004-2018) from the national Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, linked to Medicare fee-for-service claims. SUBJECTS: A total of 13,680 Medicare beneficiaries who are 65 years and older. MEASURES: We measured ambulatory care fragmentation in each calendar year, defining high fragmentation as a reversed Bice-Boxerman Index ≥0.85 and low as <0.85. We used generalized linear models to determine the association between ambulatory care fragmentation in 1 year and total Medicare expenditures (costs) in the following year, adjusting for baseline demographic and clinical characteristics, a time-varying comorbidity index, and accounting for geographic variation in reimbursement and inflation. RESULTS: The average participant was 70.9 years old; approximately half (53%) were women. One-fourth (26%) of participants had high fragmentation in the first year of observation. Those participants had a median of 9 visits to 6 providers, with the most frequently seen provider accounting for 29% of visits. By contrast, participants with low fragmentation had a median of 8 visits to 3 providers, with the most frequently seen provider accounting for 50% of visits. High fragmentation was associated with $1085 more in total adjusted costs per person per year (95% CI $713 to $1457) than low fragmentation. CONCLUSIONS: Highly fragmented ambulatory care in 1 year is independently associated with higher total costs the following year.