ObjectivesThe COMPASS (COMprehensive Post-Acute Stroke Services) pragmatic trial cluster-randomized 40 hospitals in North Carolina to the COMPASS transitional care (TC) postacute care intervention or usual care. We estimated the difference in healthcare expenditures postdischarge for patients enrolled in the COMPASS-TC model of care compared with usual care. MethodsWe linked data for patients with stroke or transient ischemic attack enrolled in the COMPASS trial with administrative claims from Medicare fee-for-service (n = 2262), Medicaid (n = 341), and a large private insurer (n = 234). The primary outcome was 90-day total expenditures, analyzed separately by payer. Secondary outcomes were total expenditures 30- and 365-days postdischarge and, among Medicare beneficiaries, expenditures by point of service. In addition to intent-to-treat analysis, we conducted a per-protocol analysis to compare Medicare patients who received the intervention with those who did not, using randomization status as an instrumental variable. ResultsWe found no statistically significant difference in total 90-day postacute expenditures between intervention and usual care; the results were consistent across payers. Medicare beneficiaries enrolled in the COMPASS intervention arm had higher 90-day hospital readmission expenditures ($682, 95% CI $60-$1305), 30-day emergency department expenditures ($132, 95% CI $13-$252), and 30-day ambulatory care expenditures ($67, 95% CI $38-$96) compared with usual care. The per-protocol analysis did not yield a significant difference in 90-day postacute care expenditures for Medicare COMPASS patients. ConclusionsThe COMPASS-TC model did not significantly change patients’ total healthcare expenditures for up to 1 year postdischarge.