Statistical analysis
anaemia, fatigue
ANAEMIA, ADVERSE EVENTS, HYPOPHOSPHATEMIA
Sample size was determined based on the primary hypothesis that IV iron is superior to oral iron for avoiding anaemia. It was assumed that 95% of the IV iron group and 82.5% of the oral iron group would be non-anaemic (Hb ≥ 11.0 g/dL at all follow-up visits). Using a significance level of 5%, and setting the power to 80%, 100 participants in each treatment group were required to detect a difference between IV iron and oral iron.Statistical analyses were performed using SASEfficacy analyses were conducted on all randomised participants (i.e., the intention-to-treat analysis set). Based on Kaplan–Meier statistics using scheduled follow-up visits, the proportion of women who were non-anaemic was assessed and continuously multiplied at follow-up visits (i.e., the product-limit survival estimates). The cumulative proportion at the last study visit (i.e., 18 weeks after treatment initiation) reflected the primary endpoint (i.e., avoidance of anaemia throughout follow-up) and was compared between the treatment groups as risk difference with 95% confidence intervals (CIs). Women who were anaemic and/or who received prohibited medication during follow-up (iron formulations other than the trial drugs, erythropoiesis-stimulating agents, or RBC transfusion) were set to failures. Women censored at the final, 18-week visit included those who remained non-anaemic, were lost to follow-up, withdrew consent to participate, or lacked a Hb measurement at this visit. Because additional IV iron was only offered to participants with Hb < 11.0 g/dL, (i.e., those who failed to meet the primary endpoint) only the initial treatment allocated at baseline had an impact on the primary analysis. Least squares mean changes (referred to as mean change hereafter) in haematological parameters, fatigue, and QoL from baseline to each follow-up visit were analysed in the intention-to-treat analysis set using a restricted maximum likelihood-based mixed model for repeated measures (MMRM) approach. Observed data were included for all women and, for women without follow-up measurements, the change from baseline was set to 0 at the first follow-up visit. The model included treatment, week, treatment-by-week interaction and stratum as factors, with baseline value and baseline value-by-week interaction as covariates. Compliance data were summarised with descriptive statistics.Safety analyses were conducted on all women who received treatment (i.e., the safety analysis set). Incidences of adverse events that were related to, or possibly related to, trial treatment, hypophosphatemia, and of discontinuations due to intolerance of, or a lack of response to, trial treatment were compared between the treatment groups using Fisher’s exact test. Biochemical safety parameters were assessed using the same maximum likelihood-based MMRM used for analyses of haematological parameters.Baseline demographics and clinical characteristics, and obstetric and perinatal outcomes were summarised using descriptive statistics and compared between the treatment groups (post-hoc) using Fisher’s exact test for categorical data and two-sample 