Table 4.

Summary of results for reporting and analysing for missing data

	Main analysis	DS1	DS2
N	211	131	115
Reporting of the no of missing data of covariates of interest	36 (17%)	22 (17%)	20 (17%)
Reporting of the method to handle missing data	63 (30%)	39 (30%)	36 (31%)
Handling of missing data*
Complete case	31 (15%)	18 (14%)	16 (14%)
Multiple imputation	21 (10%)	13 (9%)	12 (10%)
Last observation carried forward	7 (3%)	4 (3%)	4 (3%)
Supplementary category	2 (1%)	2 (2%)	2 (2%)
Other	5 (3%)	3 (2%)	3 (3%)

DS1: Dataset 1 includes only studies where the comparison of at least two treatments was the main exposure of interest (head to head studies).

DS2: Dataset 2 includes only studies from DS1, which had no other outcome than effectiveness.

*Sum of the methods may be greater than the numbers of studies as some studies used several methods.