Zylkene data set

This data set has been originally published in:

C. Beata, J. Cordel, N. Marlois (2007). Effect of alpha-casozepine (Zylkene) on Anxiety in Cats, Journal of Veterinary Behavior: Clinical Applications in Research, Vol. 2., Issue 2, pp. 40-46.

The putative effects of a tryptic bovine αs1-casein hydrolysate on anxious disorders in cats was investigated. This product is known as alpha-casozepine and patented under the name of Zylkene (Ingredia, Arras, France). Within veterinary practices, 34 cats were recruited by certified behaviorist surgeons. This 56-day trial against placebo showed the statistically positive effect of this product in the management of anxious disorders such as social phobias in cats. Global score, as well as different items (fear of strangers, contact with familiars, general fears, fear-related aggressions, autonomic disorders), were all significantly improved by the use of this natural decapeptide.

Below we show a snapshot of the data set:

Note that in the MonolixSuite the output categories must be coded as integers. In that cases, observation is a score between 1 and 25. The definition of the columns is the following:

We can see on the following figure the evolution of all SCORE with respect to time. We see that, when the time increases, the number of cats with a higher score increases too.

To see the impact of the treatment, we can split by the covariate TRT and see what is the difference between the two groups as on the following figure (placebo on the left and treatment on the right). We see that the treatment seems efficient as the SCORE is better with the treatment

We can do the same with the GENDER categorical covariate, we can create two groups the female (associating F and NeuteredF) and the male (NeutredM). On the contrary to the treatment, the GENDER does not seem to impact the SCORE.