Handling of missing data
Fatigue
Questionnaire-based variables to be analysed are the KDQoL SF1.3, the EQ-5D-5 L, Chalder Fatigue Questionnaire, the WSAS, GPAQ, PAM-13 and the PHQ4. The number (%) with complete data will be reported. Where questionnaire-specific guidance is available for the treatment of missing items in the construction of scales, this will be used. Where such guidance is not available, the following guideline will be followed, i.e., scales will be pro-rated for an individual if 20% or fewer items are missing. For example, in a scale with ten items, prorating will be applied to individuals with one or two items missing. The average value for the eight or nine complete items will be calculated for that individual and used to replace the missing values. The scale score will be calculated based on the complete values and these replacements.We expect baseline MCS KDQoL SF1.3 questionnaire data to be nearly complete, if not fully complete. It is unlikely that excluding any participants with missing baseline data will bias treatment effect estimates or lead to much loss of precision, if any, and so a complete case analysis will be undertaken in such a scenario [86]. If there is some missing data for the primary outcome of MCS KDQoL SF1.3 questionnaire at 12 weeks, several strategies will be considered. If missingness is below 5%, and missingness is not thought to be isolated to a particular clinically relevant subgroup, then a complete-case analysis (CCA) will be performed [