Evaluation of Quality of Life, Efficacy, and Tolerance of Duac® Gel Compared to Differin® Gel in the Treatment of Acne

Skindex-29 is a self-administered QoL questionnaire comprised of 29 items scored on a 5-point scale (0=never, 1=rarely, 2=sometimes, 3=often, 4=all the time) covering 3 domains: emotional (10 items), symptomatic (7 items), and functional (12 items), with domain scores ranging from 0 to 40, 28, and 48, respectively. Lower scores = better QoL. A Global Score (range 0-100) was derived by multiplying the sum of the points for all 29 items by a constant (0.862). Change from Baseline was calculated as the value at Week 2 minus the value at Baseline (Week 0).

Skindex-29 is a self-administered QoL questionnaire comprised of 29 items scored on a 5-point scale (0=never, 1=rarely, 2=sometimes, 3=often, 4=all the time) covering 3 domains: emotional (10 items), symptomatic (7 items), and functional (12 items), with domain scores ranging from 0 to 40, 28, and 48, respectively. Lower scores = better QoL. A Global Score (range 0-100) was derived by multiplying the sum of the points for all 29 items by a constant (0.862). Change from Baseline was calculated as the value at Week 2 minus the value at Baseline (Week 0).

Lesions were counted on the entire face (defined as the area from the upper part of the jaw to the lower part of the hairline), excluding maculae and non-inflammatory lesions located on the nose or chin. Inflammatory lesions included papules, pustules, nodules, and cysts. Non-inflammatory lesions included closed comedones (whiteheads) and open comedones (blackheads). The total lesion count was calculated as the sum of inflammatory and non-inflammatory lesions. Change from Baseline was calculated as the values at Weeks 1, 2, 4, 8, and 12 minus the value at Baseline (Week 0).

Lesions were counted on the entire face (defined as the area from the upper part of the jaw to the lower part of the hairline), excluding maculae and non-inflammatory lesions located on the nose or chin. Inflammatory lesions (IL) included papules, pustules, nodules, and cysts. Non-inflammatory lesions (NIL) included closed comedones (whiteheads) and open comedones (blackheads). Total lesion count was calculated as the sum of IL and NIL. Percent change from Baseline was calculated as the values at Weeks 1, 2, 4, 8, and 12 minus the value at Baseline divided by Baseline value * 100.

Analyses were performed to determine whether there was a correlation between the total lesion count and either the global or subdomain Skindex-29 questionnaire scores. Correlations between the Skindex-29 questionnaire scores and total lesion count from Baseline to Week 2 were assessed using Spearman's correlation coefficients, which ranges from -1 to 1. A score of 0 denotes no correlation, a score approaching 1 denotes correlation, and a score approaching -1 denotes inverse correlation.

Global change in acne improvement was assessed by the investigator on a 7-point scale: 1=greatly worsened, 2=significantly worsened, 3=slightly worsened, 4=no change, 5=slightly improved, 6=significantly improved, or 7=greatly improved. Global change at the indicated week was assessed in terms of change from the previous week. Change at Week 2, for example, was an assessment of change from Week 1.

Participants self-evaluated their acne improvement on a 3-point scale: 1=worsened, 2=no changes, and 3=improved.

The acne grade on the participant's face was assessed by the investigator using the LRAG, a photographic scale allowing for the assessment of the clinical status for acne severity for the face, back, and chest. It consists of a 12-grade scale (1, least severe; 12, most severe) for inflammatory visible lesions (les.). For non-inflammatory les., this scale comprises 3 photos of les. of increasing severity (grades 1-3). The scale provides a qualitative assessment of superficial/visible les. and provides consistency and inter-/intra-rater reliability. Grading was performed prior to les. counting.

Tolerance symptoms of peeling (flaking), erythema (redness of skin), and dryness were evaluated at each visit by the investigator. Possible scores were: 0=absent, 1=mild intermittent, 2=mild persistent, 3=moderate intermittent, 4=moderate persistent, 5=severe intermittent, and 6=severe persistent.

Tolerance symptoms of itching and burning were evaluated at each visit by participants. Possible scores were: 0=absent, 1=mild intermittent, 2=mild persistent, 3=moderate intermittent, 4=moderate persistent, 5=severe intermittent, and 6=severe persistent.

Participants were evaluated for overall tolerance to study drug by the investigator at the end of the study (Week 12 or Early Termination). Participants were given the tolerance grades of poor, fair, good, or excellent.