Costs of outpatient parenteral antimicrobial therapy (OPAT) administered by Hospital at Home units in Spain.

The aim of this study was to assess the direct healthcare costs of outpatient parenteral antimicrobial therapy (OPAT) administered by Hospital at Home (HaH) units in Spain. An observational, multicentre, economic evaluation of retrospective cohorts was conducted. Patients were treated at home by the HaH units of three Spanish hospitals between January 2012 and December 2013. From the cost accounting of HaH OPAT (staff, pharmacy, transportation, diagnostic tests and structural), the cost of each outpatient course was obtained following a top-down strategy based on the use of resources. Costs associated with inpatient stay, if any, were estimated based on length of stay and ICD-9-CM diagnosis. There were 1324 HaH episodes in 1190 patients (median age 70 years). The median (interquartile range) stay at home was 10 days (7-15 days). Of the OPAT episodes, 91.5% resulted in cure or improvement on completion of intravenous therapy. The mean total cost of each infectious episode was €6707 [95% confidence interval (CI) €6189-7406]. The mean cost per OPAT episode was €1356 (95% CI €1247-1560), mainly distributed between healthcare staff costs (46%) and pharmacy costs (39%). The mean cost of inpatient hospitalisation of an infectious episode was €4357 (95% CI €3947-4977). The cost per day of inpatient hospitalisation was €519, whilst the cost per day of OPAT was €98, meaning a saving of 81%. This study shows that OPAT administered by HaH units resulted in lower costs compared with inpatient care in Spain.