Shigematsu 2010.

Methods	Study design: stated as randomised, placebo‐controlled, double‐blind Multicentre trial (30 centres), randomisation 2:1 Recruitment: February 2004 ‐ June 2007 (Japan)
Participants	People with critical limb ischaemia (Rutherford 4 and 5) who were not eligible for revascularisation (N randomised = 46, 44 treated, 40 analyseda) Age (mean): 72 years (HGF), 72 years (placebo) Sex (N males/females): 21/6 (78%/22%, HGF), 7/6 (54%/46%, placebo) Severity: Rutherford 4/5: 16/11 (59%/41%, HGF), 8/5 (62%/38%, placebo)
Interventions	HGF plasmid (Collategene, beperminogene perplasmid) 2 × 4 mg HGF plasmid (days 0, 28); n randomised and treated = 29, 27 analyseda 2 × placebo (days 0, 28); n randomised and treated = 15, 13 analyseda All administered via 8 intramuscular injections of 3 mL
Outcomes	Improvement in rest pain or ulcer size at week 12 (primary) Improvement in ulcer size up to week 12 Improvement in rest pain up to week 12 Limb salvage during the 12‐week period ABI up to week 12 Quality of life at week 12 Safety during the study period
Notes	aBased on interim analysis which was carried out (according to the study protocol) when the number of participants evaluated for efficacy reached 40
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomly allocated by the central registration centre
Allocation concealment (selection bias)	Low risk	Central randomisation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The study medication was administered in a blinded manner
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Outcome measurement is not likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) Subjective outcomes	Unclear risk	Blinding procedure described only for administration of medication
Incomplete outcome data (attrition bias) Death	Low risk	No missing data
Incomplete outcome data (attrition bias) Limb amputation	Low risk	No missing data
Incomplete outcome data (attrition bias) Ulceration	High risk	Results only for subgroup of participants (40%) with ulcer at baseline
Incomplete outcome data (attrition bias) Rest pain	High risk	Results only for subgroup of participants (60%) without ulcer at baseline
Incomplete outcome data (attrition bias) Walking ability	Unclear risk	Study did not address this outcome
Incomplete outcome data (attrition bias) Haemodynamic measures	Unclear risk	Data for up to 20% of all treated participants
Incomplete outcome data (attrition bias) Adverse events /severe complications	Low risk	No missing data
Selective reporting (reporting bias)	Low risk	The study protocol is not available, but reporting bias is not expected
Other bias	Low risk	The study appears to be free of other sources of bias