Qualitative study of patients with venous malformations: symptom experiences and content validity of patient-reported outcome measures.

Purpose: To determine important symptoms and functional effects of venous malformations (VMs) to assess the content validity of commonly used patient-reported outcome (PRO) measures for use with VM patients.

Methods: This cross-sectional, qualitative study involved cognitive interviews with participants with VM aged ≥ 14 years. From February to June 2016, 11 participants (8 female) with a mean (± standard deviation) age of 31 ± 15 years were recruited from three clinical sites. The following subgroups were evaluated: 5 adults (aged ≥ 18) with trunk/extremity VMs; 3 adolescents (aged 14-17) with trunk/extremity VMs; and 3 adults with head/neck VMs. We evaluated the content validity of the Worst Pain Numeric Rating Scale (NRS), Patient-Reported Outcomes Measurement Information System (PROMIS®) Pain Interference 8-item short form, and PROMIS Physical Function 8-item short form.

Results: The most common participant-reported VM symptoms were swelling (n = 10), skin discoloration (n = 8), acute episodic pain (n = 8), chronic pain (n = 7), numbness (n = 7), and tingling/burning (n = 6). Participants reported that VMs affected their physical function (n = 10), appearance (n = 10), relationships/social activities (n = 7), and emotional health (n = 3). The Worst Pain NRS and PROMIS Pain Interference measures were relevant to all participants' VM experience. Only adults with head/neck VMs found the PROMIS Physical Function measure to be irrelevant. The assessed PRO measures did not address several symptoms commonly reported by VM patients (swelling, skin discoloration, numbness, and appearance).

Conclusion: These results suggest that several VM symptoms are not assessed fully by commonly used PRO measures, and that the relevance of functional limitation questions may vary by VM location.