Simpson 2008.

Study characteristics
Methods	RCT, DB, multicentre, parallel groups, single application, 12‐week duration. Patches applied to both feet, up to maximum 1000 cm2 Oral pain medication continued without change. No topical analgesics During application participants allowed oral oxycodone solution (1 mg/mL) or equivalent, after application allowed hydrocodone/paracetamol (5/500 mg) for ≤ 7 days Pain assessed daily (average pain for last 24 hours). PGIC assessed at 12 weeks. Clinic visits at 4, 8, 12 weeks
Participants	HIV‐associated distal sensory polyneuropathy with ≥ 2 months' moderate to severe pain in both feet N = 307 M = 286, F = 21 Mean age: 48 years (range 29 to 74) Baseline pain: 30 mm to 90 mm (mean ~ 60 mm)
Interventions	(1) Capsaicin patch 8% 30 min, n = 72 (2) Capsaicin patch 8% 60 min, n = 78 (3) Capsaicin patch 8% 90 min, n = 75 (4) Control patch, n = 82 Topical local anaesthetic applied for 60 min, then patch applied for 30, 60, or 90 min Control patch contained 0.04% capsaicin to mimic AEs
Outcomes	PI: 11‐point numeric pain rating scale (responder: ≥ 30% reduction from baseline) PGIC: 7‐point scale (responder: much and very much improved) AEs Withdrawals
Notes	Oxford Quality Score: R1, DB1, W1. Total = 3/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Low risk	Control patch contained a low concentration of capsaicin to mimic local skin reaction of active treatment. Although it does not say "identical" or use similar wording, we judged this to be low risk
Incomplete outcome data (attrition bias) All outcomes	Low risk	BOCF or 'no improvement' imputed for missing values for dichotomous data analyses
Size	Unclear risk	50 to 200 participants per treatment arm