Highlights
- Of 15 unique HS-specific patient-reported outcome measures (PROMs) evaluated, only 7 currently meet the COSMIN criteria for recommendation based on content validity and psychometric evidence.
- The 17-item Hidradenitis Suppurativa Quality of Life (HiSQOL-17) demonstrated the most robust internal consistency (pooled Cronbach α = 0.94) and strong construct validity.
- Significant research gaps remain, particularly the total absence of studies evaluating measurement error for any HS-specific instrument.
- Current evidence supports a shift from generic dermatology tools to disease-specific instruments to better capture the unique psychosocial and physical burden of HS.
Background
Hidradenitis suppurativa (HS) is a chronic, debilitating inflammatory skin condition characterized by recurrent, painful nodules, abscesses, and draining tunnels in intertriginous areas. Beyond its physical manifestations, HS is associated with a profound psychosocial burden, including high rates of depression, social isolation, and work disability. As the therapeutic landscape for HS expands with the introduction of novel biologics and small molecules, the need for accurate, sensitive, and validated Patient-Reported Outcome Measures (PROMs) has become paramount.
Historically, clinical trials for HS have relied heavily on physician-assessed outcomes (such as HiSCR) or generic dermatology instruments like the Dermatology Life Quality Index (DLQI). However, generic tools often fail to capture the specific nuances of HS, such as the impact of drainage, odor, and site-specific pain. The Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) framework provides a rigorous methodology for evaluating the quality of PROMs, ensuring that the instruments used in clinical research and practice are both reliable and valid for the target population.
Key Content
Landscape and Classification of HS PROMs
The systematic review identified 26 studies involving 5,811 patients, which collectively described 15 unique HS-specific PROMs. These instruments were categorized into three primary domains:
- Health-Related Quality of Life (HRQoL): 10 instruments (e.g., HiSQOL, HSQoL-24).
- Symptom-Specific: 4 instruments focused on pain, drainage, or itch.
- Treatment Benefit: 1 instrument specifically assessing patient-perceived benefit from therapy.
This categorization reflects a maturing field that is moving toward multi-dimensional assessment of the patient experience.
The COSMIN Framework and Methodological Quality
The study employed the COSMIN checklist to appraise the risk of bias and the GRADE approach to assess the quality of evidence. A critical finding was that while 14 of the 15 PROMs achieved sufficient content validity—the most important measurement property according to COSMIN—only 8 instruments met the highest standards for rigorous developmental methodology. This suggests that while researchers are identifying the right domains to measure, the statistical and structural validation of these instruments is frequently inconsistent.
Meta-Analysis of the HiSQOL-17
The 17-item Hidradenitis Suppurativa Quality of Life (HiSQOL-17) emerged as a high-performing instrument. The random-effects meta-analysis revealed:
- Internal Consistency: A pooled Cronbach α of 0.94 (I2 = 81.3%), indicating excellent reliability among items.
- Construct Validity: Strong correlations with existing measures, with a pooled Pearson r of 0.84 and a pooled Spearman r of 0.88.
These findings solidify HiSQOL-17 as a premier tool for capturing the multidimensional impact of HS in both clinical trials and longitudinal patient monitoring.
Evidence Synthesis for Other PROMs
Beyond the HiSQOL-17, the evidence for other instruments was mixed. Test-retest reliability was found to be sufficient in 9 PROMs, providing confidence in their stability over time in the absence of clinical change. Responsiveness—the ability of an instrument to detect clinically meaningful change—was rated sufficient in only 5 instruments. Notably, many instruments were rated as “indeterminate” for internal consistency because the studies failed to provide adequate evidence for unidimensionality (the proof that the instrument measures a single underlying construct).
Critical Gaps: Measurement Error
A striking discovery in this systematic review was the absolute lack of data regarding measurement error for any of the 15 PROMs. Measurement error is essential for calculating the Minimal Clinically Important Difference (MCID). Without these data, it remains difficult for clinicians and researchers to definitively state whether a change in a PROM score represents a true clinical improvement or merely statistical noise.
Expert Commentary
The shift toward HS-specific PROMs represents a critical evolution in dermatological research. From a mechanistic perspective, the high psychosocial burden of HS is driven not only by cutaneous inflammation but also by the systemic cytokine profile (e.g., TNF-α, IL-17) which may directly affect neuro-psychological well-being. Therefore, a PROM that captures both physical symptoms and emotional state is more likely to reflect the true biological and clinical status of the patient.
The recommendation of 7 specific PROMs by Tarafdar et al. provides a much-needed roadmap for trialists. However, the prevalence of “indeterminate” ratings for many instruments highlights a systemic issue in instrument development: the frequent neglect of structural validity and measurement error. Future studies must prioritize these psychometric properties to ensure that the instruments can be used effectively for health technology assessments and regulatory approvals. Furthermore, the high heterogeneity observed in the meta-analysis (I2 > 70%) suggests that the performance of these PROMs may vary significantly across different patient cohorts (e.g., varying Hurley stages or geographic regions), necessitating further cross-cultural validation.
Conclusion
This systematic review and meta-analysis identifies the HiSQOL-17 and six other instruments as meeting the threshold for recommended use in HS clinical practice and research. While content validity is strong across the field, there is an urgent need for more rigorous validation of structural integrity and measurement error. For clinicians, adopting recommended HS-specific PROMs like the HiSQOL-17 can significantly enhance the precision of treatment monitoring and ensure that the therapeutic goals align with the patient’s lived experience. Future research should focus on refining these tools to establish clear MCID thresholds, facilitating their use in value-based healthcare models.
References
- Tarafdar N, Varambally M, Karimi N, Akuffo-Addo E, Ingram JR, Piguet V. Hidradenitis Suppurativa Patient-Reported Outcome Measures: A Systematic Review and Meta-Analysis. JAMA Dermatol. 2026 Jan 28:e255644. doi: 10.1001/jamadermatol.2025.5644. PMID: 41604180.
- Prinsen CA, Mokkink LB, Bouter LM, et al. COSMIN guideline for systematic reviews of patient-reported outcome measures. Qual Life Res. 2018;27(5):1147-1157. PMID: 29435801.
- Ingram JR. The importance of patient-reported outcomes in hidradenitis suppurativa. Br J Dermatol. 2017;177(6):1475-1476. PMID: 29265431.