Statistical analysis
uremic pruritis
Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. (Armonk, NY: IBM Corp). Categorical data were represented as numbers and percentages. Chi-square test was applied to investigate the association between the categorical variables. For continuous data, they were tested for normality by the Shapiro–Wilk test. Distributed data were expressed as mean and standard deviation. Student t-test was used to compare two groups for normally distributed quantitative variables while Paired t-test was used to compare between two periods. On the other hand, Mann Whitney test was used to compare two groups for abnormally distributed quantitative variables. Significance of the obtained results was judged at the 5% level. Sample size was calculated using Power Analysis and Sample Size Software (PASS 2020) “NCSS, LLC. Kaysville, Utah, USA, ncss.com/software/pass”. A minimal total hypothesized sample size of 60 eligible hemodialysis patients (30 per group) was needed to assess the effect of sertraline on uremic pruritis in patients undergoing regular HD; taking into consideration 5% level of significance, effect size of 30% and 80% power using Chi Square-test.