Abstract
BACKGROUND: Infusion therapy, used to administer medications for multiple chronic diseases, can be performed in hospital outpatient departments (HOPDs), patients' homes, ambulatory infusion centers, and physicians' offices. The site for administering infusion therapy can impact the cost of care. However, there is limited evidence on quality associated with the site of care (SOC). OBJECTIVE: To assess how patient utilization, cost, and adherence outcomes differ between infusions administered in HOPDs compared with alternative SOCs (ambulatory infusion centers, patients' homes, and physicians' offices). METHODS: This retrospective cohort study used administrative claims data to construct a sample of infusions administered in January 2022 to December 2023 to commercially insured adults across the United States, with infusions occurring in all 50 states and Washington, District of Columbia. These included 23 infusion agents used to treat 7 chronic conditions. To assess outcomes across SOCs, infusions in HOPDs were 1:1 matched to infusions in alternative SOCs using a combination of exact matching and propensity score matching on the infusion agent, treated disease, infusion sequence number, state of residence, patient demographics, baseline health status, and baseline medical utilization. Infusions were excluded when an HOPD was deemed medically necessary. Using logistic and Poisson regressions, outcomes were observed in two separate postinfusion time frames, including the infusion date: 1-day postinfusion and 7-day postinfusion. Outcomes included all-cause cost and utilization across inpatient, emergency department (ED), outpatient, and pharmacy services; mild adverse events; and severe adverse events. Using linear regressions, infusion therapy adherence outcomes were observed within 12 months of an index infusion for a subset of the study sample treated with 8 infusion agents. RESULTS: Of 52,760 infusions among 18,988 patients, within 1-day postinfusion, patients administered infusions in HOPDs had no significant differences in ED and inpatient utilization and costs compared with alternative SOCs. However, outpatient costs were 41.9% higher (P < 0.01) among patients treated in an HOPD compared with those treated in alternative SOCs. There were no significant differences in serious or mild adverse events between the two groups. Within 7 days postinfusion, outcomes were similar, except HOPD-treated patients had 8.6% lower odds of filling any prescription at a pharmacy (P < 0.01) and 45.2% higher odds of having an inpatient admission (P < 0.05). Among the 410 patients analyzed for infusion adherence, there were no significant differences in adherence outcomes 12 months after the index infusion. CONCLUSIONS: Patients receiving infusions in HOPDs have higher outpatient costs without a reduction in adverse events, inpatient admissions, or ED visits or an increase in infusion therapy adherence compared with SOCs, indicating that SOCs offer similar quality outcomes at lower costs.