Lohr 1977.

Methods	Study design: cross‐over RCT Duration of study: not reported Duration of follow‐up: 12 months
Participants	Country: USA Setting: single centre Girls with at least 3 culture‐proven episodes of bacteriuria in the previous year; no evidence of parenchymal damage or gross structural abnormality requiring surgery Number: 18 Mean age (range): 6.4 years (3 to 13 years) VUR: 1 Previously undergone urinary tract surgery for urethral dilatation: 4 Exclusion criteria: G6PD deficiency
Interventions	Treatment group Nitrofurantoin 50 mg/d for children > 20 kg 25 mg/d for children < 20 kg Control group Placebo tablets matched to both tablet sizes Cross‐over Antibiotic or placebo for 6 months then crossed over to alternate for 6 further months
Outcomes	Number of repeat symptomatic and asymptomatic infections/group
Notes	Funding source: "Supported in part by a grant from Eaton Laboratories"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study was described as randomised, method of randomisation was not reported
Allocation concealment (selection bias)	Low risk	States the code was unknown to investigators
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Matching placebo used so couldn't tell which drug the child was taking
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No missing data apparent
Selective reporting (reporting bias)	Unclear risk	Single outcome of bacteriuria, appears to have included symptomatic and asymptomatic events
Other bias	Unclear risk	Methodology details poorly reported