Placencia 1993

Methods	Randomised parallel group study conducted in the context of existing community health care in a rural highland area of a developing country (Ecuador)
Participants	Participants with a history of at least 2 afebrile seizures and no previous AED treatment in the 4 weeks preceding the study were eligible Number randomised: PB = 97, CBZ = 95 133 participants (69%) with partial epilepsy 67 (35%) male participants Mean age (range): PB = 28.6 (2 to 68 years), CBZ = 29.2 (2 to 68 years) Study duration: 12 months Range of follow‐up: 0 to 53.4 months
Interventions	Monotherapy with PB or CBZ. Minimum maintenance doses by age groups: 2 to 5 years: PB: 15 mg/day, CBZ: 150 mg/day; 6 to 10 years: PB: 30 mg/day, CBZ: 300 mg/day; 11 to 15 years: PB: 45 mg/day, CBZ: 500 mg/day; > 16 PB: 60 mg/day, CBZ: 600 mg/day. Doses gradually increased Doses achieved not stated
Outcomes	Proportion seizure‐free at 3‐, 6‐, and 12‐month follow‐ups Proportion seizure‐free, with more than 50% seizure reduction and no change in seizure frequency in 6‐ to 12‐month follow‐up period Incidence of adverse effects
Notes	We received IPD for all outcomes used in this review. Results in the published paper were given for 139 participants who completed 6 months' follow‐up, but we received IPD for all 192 participants randomised.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants randomised with random number list, no information provided on method of generating random list.
Allocation concealment (selection bias)	High risk	Allocation concealed used sealed opaque envelopes but method not used for all participants (information provided by study author).
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No information provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition rates reported, all randomised participants analysed from IPD provided².
Selective reporting (reporting bias)	Low risk	All outcomes were reported or calculated with the IPD provided².
Other bias	High risk	Inconsistencies between number and reasons of withdrawals between the data and the published paper which could not be resolved by the authors (see Sensitivity analysis).

AED: antiepileptic drug CBZ: carbamazepine IPD: individual participant data IQ: intelligence quotient ITT: intention‐to‐treat PB: phenobarbitone WISC‐R scale: the Wechsler Intelligence Scale for Children

²For studies for which we received IPD (Banu 2007; de Silva 1996; Heller 1995; Mattson 1985; Ogunrin 2005; Placencia 1993), attrition and reporting bias were reduced as we requested attrition rates and unpublished outcome data.