Impact of efalizumab on psoriasis-specific patient-reported outcomes: results from three randomized, placebo-controlled clinical trials of moderate to severe plaque psoriasis

Journal of Drugs in Dermatology,  Jan-Feb, 2004  by Alan Menter,  Mark Kosinski,  Brian W. Bresnahan,  Kim A. Papp,  John E. Ware

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the PSA-S scale, which measures the burdensomeness or troublesomeness of psoriasis symptoms on patients; complete PSA-F results available from authors upon request.

In all three trials, the DLQI, PSA, and Itch scale were administered to patients prior to obtaining physician assessments for measures such as PASI at baseline (pre-treatment) and at 12 weeks, the end of the first treatment phase. These assessments were also conducted at 24 weeks, after the 12-week treatment extension period. Patient-reported outcome data have been analyzed for the three individual trials and at the aggregate level with the three trials combined. The current paper briefly presents the individual study results for these outcomes in the Discussion section to demonstrate consistency; however, primary focus is placed on the aggregate analyses.

Disease Burden

The disease burden of moderate to severe psoriasis from the patient's perspective was evaluated by examining the responses to individual questions from the DLQI and PSA-S measures. For each question from the DLQI and PSA-S, there are 4 response options. The response options for the DLQI questions include "not at all," "a little," "a lot," and "very much." The response options of the PSA-S questions include "not at all," "a little," "somewhat," and "a great deal." Dichotomous variables were derived for each DLQI and PSA-S question. Specifically, the response options "not at all" and "a little" were combined into one category, and the response options "a lot" and "very much" were combined into another category on each DLQI question. Likewise, the response options "not at all" and "a little" were combined into one category and the response options "somewhat" and "a great deal" were combined into another category for each PSA-S question. Disease burden (i.e., DRQL and symptom burden) was evaluated by comparing the percentage of patients that responded "a lot" or "very much" on each DLQI question, and by comparing the percentage of patients that responded "somewhat" or "a great deal" on each PSA-S question. All patients with baseline data on each measure were included in the burden analysis.

Impact of Treatment on DRQL and Psoriasis Symptoms

The impact of treatment on DRQL and psoriasis symptom measures was evaluated in four ways among patients with complete DRQL data at baseline and week 12. The proportion of patients with complete data was relatively high for both treatment and placebo groups (greater than 90%) and was similar between groups (Table 1).

Mean changes in DLQI, PSA-S, and Itch scale scores from baseline to week 12 were compared between the active treatment and placebo groups using analyses of covariance (ANCOVA). A separate ANCOVA model was run for each patient-reported outcome measure. Each ANCOVA model included a variable for treatment and the baseline values for the patient-reported outcome scale.