Efficacy and Safety of Stabilised Hydrogen Peroxide Cream (Crystacide) in Mild-to-Moderate Acne Vulgaris: A Randomised, Controlled Trial Versus Benzoyl Peroxide Gel

Massimo Milani, Andrea Bigardi, Marco Zavattarelli


Curr Med Res Opin. 2003;19(2) 

In This Article

Statistical Methods and Study Outcomes

The sample size was calculated on the basis of published data,[8] which indicated that with BP a reduction of 55% in TL could be expected. We hypothesised that with HPS a similar (i.e. 55 ± 5%) reduction in TL could be observed after 8-week treatment. With a power of 95% and a type I error of 0.05, a total of 54 patients had to be recruited in the trial. The Fisher exact test, the Mann-Whitney test and the paired t-test were used, when appropriate, to compare clinical study variables. Values are presented as mean ± SD. A p value of < 0.05 was considered significant.

The study endpoints were: (1) to evaluate the reduction in mean inflammatory (IL), non-inflammatory (NIL) and total (TL = IL+NIL) acneic lesions counts in comparison with baseline; (2) to assess the cutaneous tolerance, evaluating erythema, dryness and burning sensations using a 0-3 qualitative score (score 0 = poor tolerability; score 3 = very good tolerability) (Tolerability Score: TS). Spontaneously reported adverse events were recorded at each scheduled visit. The efficacy and tolerability evaluations were performed on an intention-to-treat basis.


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