The Hidradenitis Suppurativa Symptom and Impact Diary: Development and psychometric evaluation of a novel set of patient-reported outcomes for hidradenitis suppurativa.

BACKGROUND

Hidradenitis suppurativa (HS) is associated with a substantial disease burden. Given the complex nature of HS-related symptoms, patient-reported outcome (PRO) measures are important to ensure that the patient experience is captured when evaluating the efficacy of treatments in clinical trials.

OBJECTIVES

To develop the Hidradenitis Suppurativa Symptom and Impact Diary (HSSID©), a novel PRO measure for use in clinical trials to assess the symptoms and impacts of HS in adult patients, and to validate its psychometric properties.

METHODS

The development phase involved patients with HS and clinicians with HS expertise and included three sequential stages: (i) concept elicitation interviews (n = 8); (ii) item development; and (iii) cognitive debriefing interviews (n = 12). The psychometric properties of the HSSID were evaluated using data from a subset of patients participating in the SUNSHINE (NCT03713619) and SUNRISE (NCT03713632) trials, and included assessments of reliability, validity and ability to detect change. Anchor-based methods to estimate meaningful change thresholds were explored.

RESULTS

The HSSID comprises 11 items; 5 relate to HS symptoms (lesion-related pain, lesion-related itching, lesion drainage, odour and physical fatigue) and 6 to HS impacts (ability to walk, ability to move [other than walking], sleep disturbance, time spent with other people, negative impact on emotions and ability to complete work). Patients found the HSSID items easy to understand and reported no difficulties recalling symptoms/impacts experienced in the previous 24 h. Overall, 478 patients from SUNSHINE and SUNRISE were included in the psychometric evaluation phase. Good association with low redundancy was observed among HSSID items with moderate (> 0.30) to strong (> 0.50) inter-diary item correlations among symptoms and impact items, and across groups. Test-retest reliability estimates in stable subsets were high across SUNSHINE and SUNRISE, ranging from 0.78 to 0.96. Construct validity analysis confirmed that each HSSID item correlated with ≥ 1 targeted support variable. HSSID item scores demonstrated satisfactory responsiveness to detect change; however, anchor-based meaningful change thresholds could be established for the worst lesion-related pain item only.

CONCLUSIONS

The HSSID appropriately assesses the symptoms and impacts of HS in adults. HSSID items demonstrated generally robust psychometric properties.