OBJECTIVES: Patients using opioids chronically may be especially costly to Accountable Care Organizations (ACOs) and their hospitals, partly because medication portfolios of these patients may be suboptimal. To better understand these patients, we leveraged hospital and claims data for patient level continuum of care analyses, focusing on chronically prescribed short-acting opioids without baseline long-acting opioids.  METHODS:  Using linked data from the Premier hospital database and Optum commercial claims, we selected patients chronically taking opioid pain medications who presented to an emergency department (ED) from 2006-2010. We focused on the subset who exclusively took short-acting opioid analgesics, comparing those using Schedule C-II opioids to patients using only C-III opioids. We analyzed total inpatient and outpatient costs at intervals within the 90-day period following the ED visit. We used Medicare reimbursement for medical services and patient copays for medications. Bootstrap analyses with 1000 replications were performed adjusting for primary diagnoses plus 28 comorbid conditions. RESULTS:  We identified 5,240 chronic opioid patients receiving exclusively short-acting C-II (SAC-2) opioids and 1,587 using only short-acting C-III (SAC-3) opioids. Within 72 hours of the ED visit, adjusted and unadjusted costs were higher for SAC-2 versus SAC-3 patients ($2,411±4,023 vs. $2,354±3,461; p<0.05). At 30, 45, 60, and 90 days, respectively, mean costs were higher for SAC-2 patients compared to SAC-3 patients ($5,694±9,201 vs. $4,561±8,069, $7,244±11,580 vs. $5,500±9,640, $8,678±13,601 vs. $6,369±11,120, and $11,571±17,400 vs. $7,938±13,736; all p<0.05).  Adjusted mean differences were $48, $731*, $1,152*, $1,586*, and $2,457* (*p<0.05) at 72 hours, 30 days, 45, 60, and 90 days. CONCLUSIONS:  Total costs of care were higher for patients receiving only SAC-2 opioid analgesics than for patients receiving only SAC-3 opioids. This was consistent at all analyzed intervals of time within the 90 days following an ED visit. Further analyses of patients having other opioid medication portfolios may be warranted.