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A clinical practice for detecting the phases of Herpes Zoster.

A clinical practice for detecting the phases of Herpes Zoster.

Dimitris Karlis

* Athens University of Economics and Business, Department of Statistics (www.stat-athens.aueb.gr )* Frontier Science Foundation Hellas (www.frontier-science.gr )

11 Apr 2019

Very often in clinical research we start with an assumption that the hazard rate of patients is constant across time but in real life it is more likely to vary over different intervals giving rise to the developed statistical modelling, called piecewise survival modelling. The proposed research focuses on patients who suffer from Herpes Zoster. Herpes Zoster, or Shingles, is an infection caused by the reactivation of the latent Varicella-Zoster virus, which is the same virus that causes chickenpox. Herpes Zoster is known as a disease for which there are distinct phases of pain (Zoster-Associated Pain). The purpose of the research is to consider such piecewise survival models to analyse data where the outcome variable is the time until the complete cessation of Zoster-Associated Pain (ZAP). The term “piecewise” denotes the implementation of different hazard function for each distinct phase of the disease. One of the major problems in the piecewise models is to determine the points of change, the so called change points, of the hazard rate. From the practical point of view, this can provide very important information as it may reflect changes in the progress of the disease. The main goal of the proposed research is to develop methods, based on the piecewise models, capable of detecting the significant changes in the hazard rate, or instantaneous rate of occurrence of the event of interest (i.e. complete cessation of ZAP), over time and defining the transition times where the disease passes to the next stage and characterize ZAP. The contribution of the proposed research is focused on:a) developing new and more flexible piecewise models which take into account patient-level data (covariates), called piecewise Weibull models,b) developing numerical approaches for fitting such models to data in order to identify the change points,c) answering to the clinical question; "When acute becomes postherpetic neuralgia pain?",d) developing proper testing procedures for testing certain hypotheses about the treatments' efficiency, ande) applying and comparing the new methodology to the existing ones using the Herpes Zoster data as in previous published papers.Hence access to the related data are very useful for the application of such flexible types of statistical models and the demonstration of the developed algorithms and methods. Moreover, this will be a statistical exercise for comparing the models with respect to which one fits best on the data and provides us faster with more accurate results. Simultaneously, the application of the new and potentially better technique for defining the distinct phases of herpes zoster will be a very useful tool in medicine helping patients to receive the most proper treatments. Last but not least, this research will also contribute in developing further the related bibliography.

[{ "PostingID": 5037, "Title": "GSK-123-005", "Description": "An International, Double-Blind, Controlled Trial Comparing Oral Acyclovir to Oral Valaciclovir for the Treatment of Herpes Zoster in Immunocompetent Patients 50 Years of Age or Older" },{ "PostingID": 5038, "Title": "GSK-123-006", "Description": "A multicenter, double-blind, placebo-controlled trial evaluating oral 256U87 for the treatment of herpes zoster in immunocompetent patients less than 50 years old" }]

Statistical Analysis Plan