Pain scores may indicate treatment response in patients with pyoderma gangrenosum

Key takeaways:

• A minimal important difference of 7-day pain scores was a 2-point improvement on an 11-point scale.
• A 2-point improvement may indicate a patient is responding to treatment.

Pain as a patient-reported outcome measure during the treatment of pyoderma gangrenosum may indicate whether a patient is responding to treatment, according to a research letter published in JAMA Dermatology.

“Pain is a major determinant of quality of life in patients with pyoderma gangrenosum, and pain relief may be an early sign of healing even before ulcer reepithelization,” Katherine M. Erickson, MD, of the departments of dermatology at Oregon Health & Science University and New York Medical College, and colleagues wrote. “As a commonly and easily assessed symptom, pain is a candidate for a patient-reported outcome measure.”

In this study, Erickson and colleagues set out to establish a minimal important difference (MID) to define patient improvements in pain and further indicate a treatment response for clinicians.

The survey study used data from the Pyoderma Gangrenosum Study registry at Oregon Health & Science University between June 2021 and June 2022. A total of 43 patients (mean age, 55 years; 77% women) with a mean of 30 weeks between their first and most recent follow-up assessments were included in the analysis.

Patient Global Assessment (PGA) score was used as the study’s anchor, and to ensure this anchor correlated with pain, the authors calculated a Spearman correlation coefficient (r) using a cutoff of 0.3 or higher.

According to the results, patients initially reported a pain score of 4 (interquartile range, 2-7) based on the 11-point numeric rating scale (NRS). During the study, 32 patients were prescribed oral pain medications, of which 19 reported no improvement vs. 13 with improvement.

Pain correlated with PGA score (r = 0.61), with a 1-point improvement in global score being associated with an approximately 2-point improvement on an NRS for pain.

The sensitivity and specificity for a threshold of 2-point improvement on an NRS being linked to improvement in PGA was 0.74 and 0.84, respectively.

“A MID of 7-day pain scores for pyoderma gangrenosum was a 2-point improvement on an NRS,” the authors wrote. “Improvement of 2 or more points in pain may be an indication that a patient is responding to treatment.”

The authors also noted that while 5-point global scales are most commonly used, they may lack the ability to detect the smallest improvements in pain compared with the 11-point scale used in the study.