Development of Patient Reported Outcome Measures (PROM)

Development of Patient Reported Outcome Measures (PROM)


The benefits, importance and relevance of Patient Reported Outcomes (PROs) have already been discussed in a previous article. We highlighted the benefits of PROs for precision medicine, for randomised controlled trials (RCTs) and for the marketing authorisation of medicines. > Read the full article here!

Today, we want to look at this topic from a different angle and answer the question of who actually creates the questionnaires that ask for subjective patient responses. How are PROMs checked for validity, i.e., the accuracy of the match between the measurement result and the measurement construct, and reliability, i.e., the error-free measurement so that the measurements also match the population? Are there any international standards for PROMs?

To answer these questions, we start at the beginning, with the manufacturers of PROMs. In the following, we will first introduce the two most important players in the industry.

What exactly is the ICHOM initiative?

In the book “Redefining Health Care”, 2006 the authors Michael E. Porter and Elisabeth O. Teisberg introduced the concept of value-based health care. This means that health care should be oriented in such a way that it creates “value” for patients. Value is defined as the outcome of health divided by the costs spent on it.[1] The value calculation also includes, for instance, patient-reported outcomes. Ultimately, healthcare is to be focused on the value and the composition of the endpoint categories.[2] Up to now, healthcare has only paid attention to the endpoint categories mortality, i.e., the number of deaths from a certain disease per 1,000 people per year, and morbidity, i.e., the number of people who fall ill in a population per year.[2] Based on their own conviction that PROs in particular have a great additional benefit for healthcare, Porter and Teisberg, together with the Boston Consulting Group, founded the ICHOM in 2012 to collect these PROs.

ICHOM – that stands for International Consortium for Health Outcome Measurements, based in Boston, USA, develops the necessary tools to measure Patient Reported Outcomes together with patients, physicians and other industry experts. These are standardised questionnaires, so-called standard sets, which patients fill out themselves, depending on the target group and disease.[3,4] These standard sets are then used to measure subjective endpoints of therapies on the patients’ perceived quality of life. The result is then comparable in the same target group or among patients with the same disease.

What does ICHOM do?

The task of ICHOM is to firstly operationalise these questionnaires, i.e., to transform certain constructs, such as physical or mental well-being, into individual questions, i.e., items, and secondly to standardise them, i.e., to make them comparable. In addition, the ICHOM’s tasks include the definition of standard values for the individual constructs in order to be able to use them as reference values.[4] The non-profit organisation works together with researchers from different fields, patients, doctors, medical professionals and other experts in order to use the latest medical findings to develop the sets. This ensures that the standard sets are always up to date and of continuously high quality.[5]


In summary, the international comparability of patient self-assessment among the individual disease and target groups, along the entire treatment chain, is the central task of the ICHOM. Currently, the ICHOM offers 30 evaluated and standardised free sets covering the most important clinical syndromes.[4]

What is the PROMIS initiative?

In 2002, when the director of the National Institutes of Health (NHI) commissioned a roadmap for medical research in the 21st century over many meetings, the idea of leveraging patient-reported outcomes of chronic diseases as a new way to conduct medical research was developed.[6] Two years later, the PROMIS group was formed to turn this very idea into reality. PROMIS stands for Patient Reported Outcome Measurement Information System. This international research initiative, just like ICHOM, develops internationally standardised measurement systems for examining patient-reported outcomes.[7] The difference is that the PROMIS questionnaires are applicable to all patients, with or without disease or ongoing therapy. This means that these outcomes of evaluating physical, mental or social health are comparable among all individuals. Unlike the ICHOM sets, the PROMIS questionnaires do not depend on whether a person has an illness or what illness they have in order to obtain comparable results.[1]

National divisions of PROMIS

The international PROMIS initiative is divided into national units. In Germany, for example, there is PROMIS Germany, based at the Charité Berlin. These national units translate the individual questionnaires so that they remain internationally comparable. In addition, PROMIS Germany takes care of the validation of the sets. This means that PROMIS Germany makes sure that the questionnaires really measure the construct they are supposed to measure.

Benefits and importance of the work of PROMIS and ICHOM

In general, there is a high level of scientific interest in the PROMIS items. In the first half of 2021 alone, almost 100 studies were published that either used the PROMIS items to evaluate therapy outcomes or tested the PROMIS system for validity and confirmed its usefulness. It is important to develop such instruments because in the past a wide variety of measurement methods were developed in different medical fields, including the ICHOM sets, which measure the same characteristic but do not necessarily provide comparable results due to their disease-specific orientation. This means that physical functioning, for example, could be asked differently in the questionnaire set for one clinical picture than for another. On the one hand, this creates redundancies in the questionnaire and low comparability between patients with different clinical patterns. In addition, the quality of the different questionnaires was often very different. Today, it is recommended to use disease-unspecific items, such as those of the PROMIS, instead of disease-specific items, such as those of the ICHOM. In order to support clinical diagnostics in addition to gold standard studies (RCTs), standardised, disease-unspecific measurement systems developed by research initiatives such as the PROMIS are needed.


Self-reported patient outcomes collected by the two initiatives are enabling ever more individualised, precise therapy management, prognosis and screening. These measured outcomes have already become increasingly relevant in medical research and therapy evaluation in recent years. For example, the assessment of the benefit of the endpoint “quality of life” has been firmly anchored as a subjective endpoint in therapy evaluations for several years.[4] Thus, we at XO Life also consider PROs to be a useful instrument to help medicine develop even more precisely, patient-oriented and value-oriented in the future.


[1] Terwee C.B., Zuidgeest M., Vonkeman H.E, Cella D., Haverman L., Noorda L.D. (n.d.). Common patient-reported outcomes across ICHOM Standard Sets – the potential contribution of PROMIS.

[2] Harvard Business School. (n.d.) International Consortium for Health Outcome Measurement.

[3] IQWiG. (2020) Konzepte zur Generierung versorgungsnaher Daten und deren Auswertung zum Zwecke der Nutzenbewertung von Arzneimitteln nach § 35a SGB V. 

[4] Deutsches Ärzteblatt. (2020). Rehabilitation: Messbarer Patientennutzen als Ziel.

[5] ICHOM. (n.d.). About Us.

[6] Cella D. et al. (2007). The Patient-Reported Outcomes Measurement Information System (PROMIS).

[7] PROMIS. (n.d.). Hintergrund.

[8] PROMIS. (n.d.). Publications by Year.

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