Pruritus self-assessment tool valid in moderate to severe psoriasis
MedWire News: A simple patient-reported pruritus assessment tool is reliable and reflects treatment-related improvements in patients with moderate to severe psoriasis, research shows.
The tool is a 6-point rating scale, with 0 representing no itching and 5 representing severe itching.
Alice Gottlieb (Tufts Medical Center, Washington, Boston, Massachusetts, USA) and colleagues tested the tool in patients participating in three randomized controlled trials of etanercept.
The pruritus assessment tool was validated in the population of one study (n=583), 79% of whom had scores of at least 3 points on the scale. During 12 weeks of treatment, scores among patients taking etanercept fell by up to 2 points. In contrast, changes in scores among those taking placebo remained close to 0, indicating good test-retest reliability.
The team reports that the tool appeared responsive according to three different statistical methods.
In the other two studies (n=652 and 618), pruritus scores also improved among patients receiving active, but not placebo, treatment. Patients receiving active treatment recorded statistically significant improvements in pruritus scores after just 2 weeks, the researchers note in the Journal of the American Academy of Dermatology.
Patients who achieved at least a 50% improvement in their Psoriasis Area and Severity Index (PASI) scores reported an average 2.2-point improvement in their pruritus scores. Gottlieb et al therefore consider a 2.2-point change to represent a clinically significant improvement in pruritus.
The correlation between PASI scores and pruritus scores became stronger over time, with low to moderate correlations at weeks 2 and 4 and moderate to substantial correlations at weeks 8 and 12.
"The pruritus assessment tool described here could be a simple and effective tool to assess pruritus in community clinics, where time available for individual consultation is limited," concludes the team.
"Further studies to validate this instrument for use in individual patients are warranted."
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By Eleanor McDermid