Statistical methods
REGRESSION, REGRESSION
The sample size was calculated using the following equation:Considering the type one error of 0.05, type 2 error of 0.20, and All the statistical analyses were performed using SPSS software version 24.0 (IBM, Chicago, Illinois, USA). Data are shown as mean ± standard deviation or median (IQR) for quantitative variables and frequency (percentage) for qualitative ones. The Kolmogorov–Smirnov test was used to assess the normality of data distribution. According to normality test results, the independent sample T-test or Mann–Whitney test was used to compare the mean outcome quantities between the two study groups. The Chi-Square test or Fisher exact test were also used to compare qualitative factors between the two groups. Serum variables, 24-h urine analysis, and supersaturation changes were compared between groups using a univariate general linear model (GLM) with generalized estimating equations (GEE) approach. Finally, multivariable GEE analysis was performed to assess the 24-h urinary calcium changes by adjusting confounding variables. Regression coefficient (β) were reported along with 95% confidence interval. The β (regression coefficient) signifies how much the mean of a dependent variable (for example the level of serum parathyroid hormone) changes when the participants received loading vitamin D repletion therapy (50,000 IU cholecalciferol/oral/weekly) compared with the maintenance vitamin D repletion protocol (2000 IU cholecalciferol/oral/daily). A p- value < 0.05 was considered statistically significant.