4. Actual and estimated treatment withdrawal rates (percentage): adults.

Trial	Year	Study location	Maintanence period (weeks)	Levetiracetam dose (mg)	Actual withdrawal rate	Withdrawal rate fitted with trial	Withdrawal rate fitted with year of publication	Withdrawal rate fitted with year of publication and length of maintenance period
Shorvon 2000	2000	2	12	Placebo	13.4	14.2	13.2	15.0
				1000	11.3
				2000	17.9
Cereghino & Cramer 2000	2000	4	14	Placebo	6.3	8.8	13.2	8.8
				1000	12.2
				3000	7.9
Ben‐Menachem 2000	2000	2	12	Placebo	14.3	16.4	13.2	15.0
				3000	17.7
Tsai 2006	2006	1	12	Placebo	2.1	4.3	4.3	8.8
				2000	6.4
Zhou 2008	2008	1	12	Placebo	21.4	14.3	14.3	7.3
				3000	7.1
Wu 2009	2009	1	12	Placebo	8.7	6.3	6.9	6.6
				3000	3.9
Peltola 2009	2009	3	12	Placebo	8.9	9.5	6.9	6.6
				1000	10.1
Xiao 2009	2009	1	12	Placebo	3.6	1.8	6.9	6.6
				3000	3.9
Note: Study location: 1) = China/Taiwan region; 2) Europe region; 3) Multiregional (Europe, South America, Africa, Asia); 4) USA region