Backonja 1998.

Methods	Multicentre, randomised, double‐blind, placebo‐controlled, parallel groups, not enriched, LOCF Titration to maximum tolerated dose or 3600 mg daily over 4 weeks, then stable dose for 4 weeks (8 weeks in total)
Participants	PDN. Pain duration > 3 months before treatment, PI ≥ 40/100 at randomisation N = 165 Mean age 53 years, 40% women Initial mean pain score 6.4/10
Interventions	Gabapentin 3600 mg daily (max), n = 84 Placebo, n = 81 Medication for diabetes control remained stable during study. Paracetamol (max 3 g daily) allowed
Outcomes	PGIC much or moderately improved ≥ 50% reduction in pain (CTR) PGIC much improved (CTR) PGIC moderately or much improved (CTR) Adverse events Withdrawals
Notes	Oxford Quality Score: R = 2, DB = 2, W = 1, Total = 5 Parke‐Davies/Pfizer sponsored
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random code
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	"supplied in identical capsules in blinded fashion". "All participants were supplied with an equal number of capsules".
Incomplete outcome data (attrition bias) Efficacy	Unclear risk	LOCF imputation
Size Efficacy	Unclear risk	50‐200 participants per treatment arm (81, 84)