Core outcome measurement set

How to measure?

Outcome measurement instruments

The next step towards uniform outcome reporting was determining how to measure the core domains, i.e. developing a core outcome measurement set (COMS). This project involved an appraisal and the validation of existing instruments1,2, and the development of a new disease-specific instrument: the OVAMA questionnaire.

Patient-reported outcome measures

Existing instruments

Four patient-reported core domain categories were determined: 1. anatomy (appearance), 2. symptoms, 3. quality of life, and 4. satisfaction.

A systematic review of outcome measurement instruments in vascular malformations yielded no validated patient-reported outcome measures (PROMs) for all core domain categories.1

To correctly evaluate treatment outcome, outcome measurement instruments are needed that are able to detect changes in the outcomes before and after treatment, which means that the measurement instruments must be responsive to change (longitudinal validation).

It is generally advised to measure ‘universal’ domains (such as the core domains falling under ‘quality of life’) with generic instruments. In the following studies, we therefore assessed if four widely used generic PROMs were responsive to changes in quality of life in both adults (SF-36, Skindex-292) and children (PedsQL, CDLQI: submitted) with vascular malformations. Unfortunately, all four PROMs seemed not responsive to changes in quality of life.

No PROMs exist for measuring vascular malformation appearance, symptoms, and satisfaction.

PROMIS and the OVAMA questionnaire

For the more universal domains falling under quality of life, we are currently (longitudinally) validating the generic PROMIS (Patient-Reported Outcomes Measurement Information System) scales. This includes the scales ‘pain interference’, ‘depression’, ‘anxiety’, ‘ability to participate in social roles and activities’, ‘mobility’ and ‘upper extremity functioning’. These scales are already thoroughly tested in large populations, available for both adults and children and in multiple languages, and can be administered as short forms or computer adaptive tests.

For the more disease-specific domains, we have developed the ‘OVAMA questionnaire’. This comprises of the following scales: ‘general symptoms’, ‘appearance’, ‘head and neck symptoms’ and ‘satisfaction with outcomes and treatment strategy’. The head and neck symptoms scale is only intended for patients in which the head and neck region is affected. In prospective studies, the satisfaction scale needs only to be completed at follow-up.

Clinician-reported outcome measures

Three clinician-reported core outcome domains were determined: 1. anatomy (appearance), 2. signs, and 3. adverse events.

Existing instruments

A systematic review of outcome measurement instruments in vascular malformations yielded no validated clinician-reported outcome measures for all core domain categories.1 A clinician-reported appearance scale will be developed, as well as concise checklists for clinical signs and adverse events.


1. Horbach SER, Rongen APM, Elbers RG, van der Horst CMAM, Prinsen CAC, Spuls PI, OVAMA Steering Group. Outcome measurement instruments for peripheral vascular malformations and an assessment of the measurement properties: a systematic review. Qual Life Res 2019.

2. Lokhorst MM, Horbach SER, Waner M, O TM, van der Vleuten CJM, Mokkink LB, van der Horst CMAM, Spuls PI. Responsiveness of quality of life measures in patients with peripheral vascular malformations: the OVAMA project. Br J Dermatol 2019.