Table 3.

Summary of results for reporting and analysing for follow-up information and handling of attrition

	Main analysis	DS1	DS2
N	211	131	115
Reporting of patients lost to follow-up	69 (33%)	47 (36%)	44 (38%)
Reporting of patients lost to follow-up by treatment	30 (14%)	26 (20%)	24 (21%)
Reporting of patients changing/stopping treatment	101 (48%)	75 (57%)	64 (56%)
Reporting of reasons for treatment discontinuation	62 (29%)	47 (36%)	41 (36%)
Handling of attrition in the analysis (in studies with outcome other than retention)	44/177 (25%)	31/106 (29%)	28/95 (29%)
Method to handle attrition (when acknowledged)*
Non-responder imputation	27/44 (62%)	22/31 (71%)	20/28 (72%)
Complete case	8/44 (18%)	5/31 (16%)	5/28 (18%)
Last observation carried forward	8/44 (18%)	4/31 (12%)	2/28 (7%)
Other	8/44 (18%)	7/31 (23%)	6/28 (21%)

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.