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Outcome measures for vascular malformations (OVAMA)


peripheral vascular malformations


Peripheral vascular malformations are congenital anomalies of the vascular or lymphatic system, often visible as a mass other in colour and texture than normal skin. The lesions are classified according vessel type and flow speed. Distinguished are the high-flow arteriovenous malformations (AVM), the low-flow capillary (CM), venous (VM) and lymphatic malformations (LM), and combined lesions. Symptoms experienced by patients vary by type and localization, and include disfigurement, pain, bleeding, functional impairment, thrombotic complications and an overall poorer quality of life as compared to the general population. There is great heterogeneity in outcome reporting in the clinical research on peripheral vascular malformations. Without harmonization of outcome measures, treatments cannot be properly compared. This hampers the development of evidence-based treatment guidelines, which are urgently needed for these challenging congenital conditions. The mission of the Outcome measures for VAscular MAlformations (OVAMA) project is to uniform outcome reporting in clinical research.

Scope of the intended COS

  • Study types: all clinical research
  • Global scope: adults and children


Development of a core outcome set, comprised of a core domain set and a core outcome measurement set. For the core domain set: a systematic review on outcome domains, e-Delphi study, consensus meetings. For the core outcome measurement set: a systematic review on outcome measurement instruments, appraisal of existing outcome measurement instruments, development of disease-specific questionnaire for the patient-reported outcome domains for which instruments are lacking (OVAMA questionnaire), consensus meetings.

Involvement of stakeholders

Patients, parents of patients, researchers, clinicians.

Current status

Core domain set: finished. Core outcome measurement set: disease-specific patient-reported outcome measure is developed and awaits first field-test. Four quality of life questionnaires have been evaluated and were found to not be responsive to change. New evaluation with PROMIS scales for measuring quality of life will start alongside first field-test of disease-specific questionnaire.



Involved Countries

The Netherlands, Belgium, Australia, New Zealand, United States, United Kingdom.

Date of updates

  • 09/12/2019


  • Max Lokhorst

Project team members

  • Sophie Horbach
  • Chantal van der Horst
  • Phyllis Spuls
  • Swee Tan
  • Francine Blei
  • Carine van der Vleuten
  • Ilona Frieden
  • Gresham Richter
  • Tobian Muir
  • Tony Penington
  • Laurence Boon

Responsible member of Methods group (as assigned by CS-COUSIN)

  • Kim Thomas


Published references

  1. Horbach, S. E. R., Rongen, A. P. M., Elbers, R. G., van der Horst, C., Prinsen, C. A. C., Spuls, P. I., & Collaborators, O. c. g. (2019). Outcome measurement instruments for peripheral vascular malformations and an assessment of the measurement properties: a systematic review. Qual Life Res
  2. Horbach, S. E. R., van der Horst, C., Blei, F., van der Vleuten, C. J. M., Frieden, I. J., Richter, G. T., . . . Group, O. C. (2018). Development of an international core outcome set for peripheral vascular malformations: the OVAMA project. Br J Dermatol, 178(2), 473-481
  3. Lokhorst, M. M., Horbach, S. E. R., van der Horst, C., Spuls, P. I., & Group, O. S. (2019). Finalizing the international core domain set for peripheral vascular malformations: the OVAMA project. Br J Dermatol, 181(5), 1076-1078
  4. Lokhorst, M. M., Horbach, S. E. R., Waner, M., O, T. M., van der Vleuten, C. J. M., Mokkink, L. B., . . . Spuls, P. I. (2019). Responsiveness of quality of life measures in patients with peripheral vascular malformations: the OVAMA project. Br J Dermatol