Kim 2013b.

Methods	Study design: parallel, 2‐arm RCT Time frame: November 2010 to June 2011 Duration of follow‐up: 4 months
Participants	Setting: single centre Country: Korea Inclusion criteria: biopsy‐proven IgAN; aged ≥ 18 and < 70 years; SCr ≤1.5 mg/dL or eGFR ≥ 45 mL/min/1.73 m2, UACR ≥ 0.3 and < 3.0 g/g creatinine, and BP < 130/80 mmHg during the 3‐month period before randomisation Number (analysed/randomised): treatment group (20/20); control group (20/20) Mean age ± SD (years): treatment group (36.9 ± 11.4); control group (40.1 ± 12.8) Sex (M/F): treatment group (6/14); control group (6/20) Exclusion criteria: ≥ 20% variations of BP, urinary albumin, SCr during 3 months before randomisation, or with potassium sparing diuretics, corticosteroid, immunosuppressive medication, omega‐3 fatty acid, or two or more medications of renin angiotensin system blocker (RAS blocker), pregnancy, secondary IgAN
Interventions	Treatment group Tacrolimus: 0.1 mg/kg/day administered in two divided doses and titrated to maintain trough concentrations at 5 to 10 ng/mL. If concentration ≥ 15 ng/mL the tacrolimus was stopped for 2 weeks. After 8 weeks of randomisation, the dose of tacrolimus was reduced to 0.05 mg/kg/day or to half of the decided dose to maintain the trough level in 5 to 10 ng/mL at the 8‐week visit and continued this up to 16 weeks after randomisation Control group Placebo Co‐interventions Not reported
Outcomes	Percentage change (from the trial phase to the observational phase) of time‐averaged proteinuria (TA‐proteinuria; g/g creatinine) eGFR Complete remission Doubling of SCr Adverse events
Notes	Trials registration identification number: NCT01224028 This study was designed and supported by Astellas Pharma Korea
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation
Allocation concealment (selection bias)	Unclear risk	Conducted by the independent statistical committee (independent from the researcher (doctors, nurses, and pharmacists related to this study) and patients))
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blinded study
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding of outcome assessment not specifically reported. Key outcomes were objective laboratory measures and were unlikely to be affected by any knowledge of treatment allocation. Reporting of adverse events may have been influenced by knowledge of treatment allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	2/20 participants assigned to tacrolimus did not complete study. 1/20 participants assigned to control did not complete study
Selective reporting (reporting bias)	High risk	The reported study outcomes matched the outcomes reported in the published study protocol (published with the study). Key outcomes expected for this type of study (death (any cause), ESKD, change in GFR, infection) were not reported
Other bias	Low risk	The study appeared to be free from other sources of bias