Measures of clinical effectiveness typically reflect outcomes that are important to patients, such as:

  • symptoms and events related to the disease (morbidity), or
  • patient survival mortality.

Sometimes, outcomes – such as a heart attack, or a malignant growth (cancer) or death – can be identified and measured using a clinical definition by someone other than the patient. However, there is increasing awareness that treatments should not just be clinically effective and economically appropriate, but should also be acceptable and indeed desirable to patients. Clinical effectiveness measures cannot tell us how a patient feels, or what they want to achieve with a treatment. Measuring this element of acceptability requires patient-based evidence that includes measures of well-being.

PROs have become steadily more important across the spectrum of healthcare and life sciences. Patient-centred models of care are integrating shared decision-making and PROs at the point of care; comparative effectiveness research (and HTA) seeks to include patients as participatory stakeholders; and industry is expanding its involvement with patients and patient groups as part of the medicines development process and safety monitoring. Additionally, pharmacovigilance legislation from regulatory authorities in the EU and the USA calls for the inclusion of patient-reported information in benefitrisk assessment of pharmaceutical products.

To this end, an increasing focus has been placed on the development of patient-reported outcomes (PROs), which are based on a patient’s perception of a disease and its treatment. The  European Medicines Agency (EMA) defines PROs as ’Any outcome evaluated directly by the patient himself and based on patient’s perception of a disease and its treatment(s) is called patient-reported outcome (PRO)’. The term PRO is proposed as an umbrella term to cover both single dimension and multi-dimension measures of symptoms, health-related quality of life (HRQL), health status, adherence to treatment, satisfaction with treatment, etc.

Patient-reported outcome measures (PROMs) are the tools used to measure and collect data on PROs. The term PROs is becoming increasingly synonymous with "patient reported outcome measures" (PROMs).