Statistical analysis
’, ’ pain, pain
REGRESSION, COMPLICATIONS
Descriptive statistics and 95% confidence intervals (CIs) were calculated for the pain levels in different groups and subgroups. An independent-samples t-test was used to compare the main groups with each other in terms of their pain and age. Furthermore, a 3-way analysis of covariance (ANCOVA) was used to assess the simultaneous effects of the independent variables (lidocaine incorporation, the brand of botulinum toxin, and participants’ age and sex) on postinjection pain. Age was a continuous variable recorded as an integer number; it was without any grouping and with a unit of change of 1 year. A Pearson correlation coefficient and a partial correlation coefficient were used to examine the correlation between patients’ age (continuous) and their pain levels. Since the correlations were significant, descriptive statistics and 95% CIs were calculated for patients’ pain in different decades of life (as discrete age groups). As well, a histogram was drawn to show the distribution of patients’ ages. For the assessment of the effects of the same 4 independent variables on each of the 2-week post-injection complications, a point-biserial correlation coefficient, a Fisher, and a multiple binary logistic regression were used. Again, the variable “age” was an integer continuous variable without grouping. However, since its role became significant in some complications, the incidences of complications in different life decades (as discrete groups) were summarized as well. The level of significance was set at 0.05.
