Singh 1995.

Methods	Randomised clinical trial
Participants	Country: USA Period of recruitment: not stated Number randomised: 60 Postrandomisation dropouts: 0 (0%) Revised sample size: 60 Mean age (years): 45 Females: not stated Presence of other features of decompensation (hepatorenal syndrome, hepatic encephalopathy, or variceal bleeding): not stated Ascites with low protein: not stated Primary prophylaxis: 47 (78.3%) Alcohol‐related cirrhosis: 24 (40.0%) Viral‐related cirrhosis: 31 (51.7%) Autoimmune disease‐related cirrhosis (e.g. PSC, PBC, AIH): not stated Other causes for cirrhosis: 5 (8.3%) Treated for ascites in addition to antibiotics (e.g. albumin or diuretics): not stated Exclusion criteria: allergy to sulfonamides renal failure active infections
Interventions	Participants randomly assigned to 2 groups. Group 1: sulfamethoxazole + trimethoprim (n = 30) Further details: sulfamethoxazole 160 mg + trimethoprim 800 mg daily (duration not stated, but probably until follow‐up) Group 2: no active intervention (n = 30) Further details: no treatment
Outcomes	Outcomes reported: all‐cause mortality; number of any adverse events per participant; proportion with spontaneous bacterial peritonitis (as per definition). Follow‐up (months): 3
Notes	Attempted to contact authors in November 2018, but received no replies.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: information not available
Allocation concealment (selection bias)	Unclear risk	Comment: information not available
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: information not available
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: information not available
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no postrandomisation dropouts
Selective reporting (reporting bias)	Low risk	Comment: protocol not available, but authors reported mortality and adverse events adequately.
Other bias	Low risk	Comment: no other bias noted