Qualitative concept elicitation and cognitive debriefing interviews of symptoms, impacts and selected customized PROMIS Short Forms: a study in patients with axial spondyloarthritis.

Background: Sleep disturbance, pain, and fatigue are key symptoms/impacts of axial spondyloarthritis (axSpA). Three customized Patient-Reported Outcomes Measurement Information System (PROMIS) Short Forms (Sleep Disturbance, Pain Interference, and Fatigue) have been proposed for use in axSpA to assess these key disease concepts. This study was designed to further understand the patient experience of axSpA and evaluate the content validity of the three customized PROMIS Short Forms to support their use in axSpA clinical trials.

Methods: Non-interventional, cross-sectional, qualitative (concept elicitation [CE] and cognitive debriefing [CD]) study. Participants took part in 90-min telephone interviews. The CE section used open-ended questions to elicit information about axSpA symptoms and impacts. The CD section involved a 'think-aloud' exercise where participants read out each instruction, item, and response option for the customized PROMIS Short Forms and shared their feedback. Participants also discussed the relevance of the items, response options and recall period. Verbatim interview transcripts were subject to thematic and content analysis.

Results: In total, there were 28 participants (non-radiographic axSpA, n = 12; ankylosing spondylitis, n = 16), from the US (n = 20) and Germany (n = 8). Mean age was 52.8 years, and 57% were male; mean time since diagnosis was 9.5 years. The CE section identified 12 distinct symptoms that characterized axSpA: pain, sleep problems, fatigue/tiredness, stiffness, swelling, vision/eye issues, restricted body movements, headache/migraine, spasms, change in posture/stature, balance/coordination problems, and numbness. Pain, sleep problems, and fatigue/tiredness were experienced by ≥ 90% of participants, occurring simultaneously and exacerbating one another. Participants reported axSpA impacted their lives across six domains of health-related quality of life (HRQoL): physical functioning (100%), emotional wellbeing (89%), work/volunteering (79%), social functioning (75%), activities of daily living (61%) and cognitive functioning (54%). Impacts were most frequently associated with pain, stiffness, and fatigue. CD showed the PROMIS instruments were conceptually comprehensive and well understood, with all items relevant to ≥ 50% of participants.

Conclusions: Pain, sleep problems and fatigue are pivotal symptoms of axSpA and associated with HRQoL impacts. These results were used to update a conceptual model of axSpA which was originally developed based on a targeted literature review. Interpretability and content validity of the customized PROMIS Short Forms were confirmed, with each deemed to adequately assess key impacts associated with axSpA, making them suitable for use in axSpA clinical trials.