The history and evolution of outpatient parenteral antibiotic therapy (OPAT).

Outpatient parenteral antibiotic therapy (OPAT) is now a widely accepted and safe therapeutic option for carefully selected patients. Benefits include cost savings and improved patient satisfaction; risks include failure to adhere to care, unexpected changes in the underlying infection, and adverse drug and intravenous access events. We report on our 40-year experience with OPAT in a single healthcare system in the USA and highlight OPAT developments in several countries. We compared data on patients treated in our programme over two time periods: Period 1 from 1978 to 1990; and Period 2, calendar year 2014. In Period 2 paediatric patients were excluded. Between Periods 1 and 2, changes included an almost three-fold increase in the number of patients treated per year (80 vs. 229), treatment of more patients with severe orthopaedic-related infections (20% vs. 38%), a marked increase in the use of peripherally inserted central catheters to administer antibiotics (20% vs. 98%), a shorter duration of inpatient stay and a longer duration of OPAT (13 days vs. 24 days). Other changes in Period 2 included treatment of 20% of patients without antecedent hospitalisation, and use of carbapenems rather than cephalosporins as the most frequently administered agents. OPAT was safe, with rehospitalisation rates of 6% and 1% in Periods 1 and 2, respectively. We recommend increased access to structured OPAT teams and the development of standard definitions and criteria for important outcome measures (e.g. clinical 'cure' and unplanned hospital re-admissions). These steps are critical for patient safety and financial stewardship of resources.