Statistical analysis
REGRESSION
Based on internal data collected by Ceva Santé Animale in France and the USA, and analyzing absolute change of Index score between 0 and 14 days, probabilities of success (to have a significant p-value for the product with a regression model) were calculated with simulated databases to estimate the number of cases required. Considering the worst case, the probability of having a significant product effect was 90% with 1000 cats.Data was analyzed using SAS v9.4 (SAS Institute) and R software (v4.2.2). The level of significance was set at p<0.05. Undesirable scratching was assessed through three components: the Frequency of the behaviour, the Intensity of the behaviour and the Index Score that represents a global evaluation of the behaviour. The Global Index Score was calculated by multiplying the Frequency by the Intensity of the undesirable scratching behaviour. Due to the randomization process any difference at Baseline must have occurred by chance, so it is not appropriate to report the results of significance tests comparing the two groups at baseline [For quantitative parameters, the number of animals, the mean and standard deviation were calculated. For qualitative parameters, Frequency distributions and number of animals were detailed.For scratching Frequency, since the data are ordinal, medians were presented and a Wilcoxon test was performed. A cumulative Link model for ordinal regression was also performed to determine the probabilities of being in each scratching Frequency category according to days and product group. To limit the number categories, we regrouped them two by two for this analysis (Never (0 per week) / once or twice a week (1 or 2 per week) / every two days and almost every day (3 to 6 per week) / every day and more (7 and more per week)). The Frequency at baseline, treatment group, day and interaction between day and treatment were added to the model.A chi-squared test was used to compare the percentage of cats with more or less than 50% reduction of scratching for Frequency, Intensity and Global Index Score.For both Intensity and Global Index Score, the same analyses were performed: as these two parameters followed a normal distribution, their change from baseline was analyzed using a longitudinal mixed model with repeated measures (MIXED procedure of SAS). Visit day, baseline value and treatment group were fixed effects. Cat age, lifestyle, presence of behavior problem, emotional health, time spent at home, other pets at home, owner’s family situation (see 