Developed initially in the manufacturing industry, indicators are increasingly used in hospitals to monitor organisational performance or patient management.¹ Clinical indicators are specifically designed to measure the quality and safety of patient care. They are increasingly used in perioperative medicine to drive improvement initiatives or assess the overall quality of care provided.

Clinical indicators can measure structure, process, or outcome-related aspects of perioperative care.  Structure indicators measure organisational composition and resource utilisation.  Some examples include staffing levels, equipment, and access to facilities. Process indicators measure the way care is delivered. Outcome indicators measure patient-related results of care. They occupy a prominent position in perioperative care as the nature of clinical practice and its improvement largely relies on measures of outcome. For example, only after the demonstration that hospital-acquired infections are reduced with preoperative administration of antibiotics within 60 min can this administration become an evidenced-based patient quality improvement recommendation. As such, an increasingly larger number of outcome indicators have been developed to guide quality improvement initiatives in anaesthesia and perioperative medicine⁹ where they are used as direct measures of the quality and safety of care provided. They can also be used in clinical trials as primary or secondary endpoints of interventions to improve patient-related quality and safety of care within the perioperative setting.

Because there is limited academic interest in clinical indicators and their use as outcome measures, there is a significant lack of standardised definitions for this type of endpoints. For instance, according to the Australian Council on Healthcare Standards (ACHS), an unplanned admission to the ICU, a popular and validated outcome indicator is ‘an unplanned admission to the Intensive Care Unit within 24 hours of a procedure with an anaesthetist in attendance’, whereas for the Anaesthesia Quality Institute (USA), it is defined as ‘an unplanned admission to the intensive care unit within 48 hours of induction’. In addition, only a limited number of indicators have undergone a formal validation process, resulting in the use of poorly defined and validated measures of outcomes.

There is a need to identify and provide clearly defined, reliable, and validated clinical outcome indicators that can be used as endpoints in both perioperative clinical trials and health services research assessing quality and safety improvement initiatives. The Standardised Endpoints in Perioperative Medicine (StEP) initiative is an international collaboration with the aim of identifying a set of endpoints supported by expert guidance and international consensus for use in perioperative medicine trials. The current study describes the results of a systematic literature review and Delphi process to identify important outcome clinical indicators.

Patient-centred outcomes are increasingly used in perioperative clinical trials. The Standardised Endpoints in Perioperative Medicine (StEP) initiative aims to define which measures should be used in future research to facilitate comparison between studies and to enable robust evidence synthesis.