Clinical outcome measure

An outcome measured in clinical practice, e.g. survival or surgical complications such as anastomotic leak, including the specific measurement variable (e.g. systolic blood pressure), analysis metric (e.g. change from baseline, final value, time to event), method of aggregation (e.g. median, proportion) and timepoint [58].

Patient reported outcome (PRO)

An outcome reported directly by the patient themselves without interpretation from an observer [59]. Examples include assessments of health status and quality of life (e.g. physical ability, symptom severity). PROs are typically recorded in a self-completed questionnaire.

Patient-reported outcome measure

A measure of a PRO including domain (e.g. anxiety), specific measurement tool (e.g. name of questionnaire) and other levels of specification required for clinical outcomes (analysis metric and method of aggregation) [60].

Hospital/process-related outcome

A metric related to the organisation or individual involved in the patients’ care rather than the effect of the intervention on the patient’s health, e.g. length of hospital stay or number of tests conducted.

Resource use measure

A metric to quantify the cost of care, including direct financial expenses as well as staff time.

Surrogate outcome

A measure that is not of direct practical importance but is believed to reflect an outcome that is important; often a physiological or biochemical marker that can be relatively quickly and easily measured, and that is taken as being predictive of an important clinical outcome [3].

Composite outcome

An outcome that consists of two or more component outcomes [5].

Primary outcome

The outcome of greatest importance [3].

Secondary outcome

An outcome used to evaluate additional effects of the intervention deemed a priori as being less important than the primary outcomes [3].

Explanatory outcome

Outcomes that are measured to provide additional information about an intervention, but may be without an a priori hypothesis.