Table 1 General reporting guidelines for missing data

STROBE Guideline

i State the amount of missing data for per variable and analysis step

ii Provide reasons for missing data

iii Indicate the number of individuals excluded due to missing data

iv Describe method used to handle missing data

v State the assumptions made for missing data analysis

vi Perform sensitivity analysis to examine robustness of findings

Sterne et al (for multiple imputation)

i Compare differences between individuals with and without missing data

ii Indicate number of imputed datasets

iii State the variables included in the imputation model

iv Describe how non-normally distributed and categorical variables were handled

v Evaluate multiple imputation analysis