Comparing maximum and average numerical rating scale pain scores in hidradenitis suppurativa

Pain is the most impactful and burdensome symptom of hidradenitis suppurativa (HS) and profoundly affects patients' quality of life. There is variation in how trials measure HS pain, with some reporting maximum and others reporting average 7-day pain. It remains unknown whether there is a difference between these measures and which is more strongly associated with quality of life in HS. This is a retrospective cross-sectional study of 257 adults with HS who received care in an HS Specialty Clinic from January 2019 to August 2021. Patients self-reported their average pain and maximum pain severity in the past 7 days measured on a numerical rating scale (0-10). The absolute difference between patient-reported average and maximum pain was calculated and assessed for statistical differences using a paired t-test. Multivariable linear regression was used to assess the correlation between the average versus maximum pain score with Skindex-16 quality of life (QoL) score. The maximum pain scores were significantly higher than the average, with a mean absolute difference of 0.83 points (95% CI: 0.74, 0.92) (p < 0.0001). The association between Skindex-16 QoL and average pain was not significantly different from Skindex-16 QoL correlation with maximum pain severity (p = 0.52). This study highlights a small but statistically significant difference in HS patients' maximum and average 7-day pain severities. Both maximum and average 7-day score correlated with skin-related QoL, suggesting equipoise as outcome measures for clinical HS studies.