Masutani 2016.

Methods	Study design: parallel, 2‐arm RCT Time frame: November 2006 to April 2010 Duration of follow‐up: 25 months
Participants	Setting: multicentre (number of sites not reported) Country: Japan Inclusion criteria: biopsy‐proven primary IgAN, aged 15–59 years, and with a previously reported glomerular score of 5 or higher determined by scoring method Number (analysed/randomised): treatment group (20/20); control group (20/20) Mean age ± SD (years): treatment group (43.8 ± 10.8); control group (36.4 ± 12.9) Sex (M/F): treatment group (11/9); control group (11/9) Exclusion criteria: secondary IgAN caused by lupus nephritis, purpura nephritis (IgA vasculitis), rheumatoid arthritis, viral hepatitis, or liver cirrhosis; previous treatment with corticosteroids, mizoribine or other immunosuppressants; DM; viral hepatitis; malignant tumour; pregnancy; active infectious disease; white blood cell count < 3000/µL; and known allergy to the study medication
Interventions	Treatment group Prednisolone: 500 mg IV methylprednisolone for 3 days in weeks 1 and 2, followed by 30 mg/day oral prednisolone for 2 weeks. The prednisolone dose was then reduced by 2.5 to 5.0 mg for 12 months until 5 mg/day which was the maintenance dose for 13 months Mizoribine: started at 150 mg/day when the daily dose of prednisolone was 20 mg, and continued for 24 month. Blood levels of mizoribine were measured at 2 or 4 weeks after initial administration, and the concentration level after 3 h (C3 level) confirmed was within the range of 1.0 to 5.0 µg/mL Control group Prednisolone: 500 mg IV methylprednisolone for 3 days in weeks 1 and 2, followed by 30 mg/day oral prednisolone for 2 weeks. The prednisolone dose was then reduced by 2.5 to 5.0 mg for 12 months until 5 mg/day which was the maintenance dose for 13 months Co‐interventions RAS inhibitors were used when BP > 130/80 mmHg Tonsillectomy offered as optional treatment
Outcomes	Reduction of urinary protein defined as ≥ 50% decrease Doubling of SCr or 50% decline in eGFR BP Adverse events
Notes	This study was funded by The Kidney Foundation, Japan
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information to permit judgement
Allocation concealment (selection bias)	Unclear risk	Patients were allocated using a minimisation method in which stratifying factors were UPCR ≥ 2.0 g/g Cr), serum Cr levels (≥ 1.2 mg/dL for males and ≥ 1.0 mg/dL for females), and adding tonsillectomy
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label 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. However, reporting of adverse events may have been influenced by knowledge of treatment allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	3/20 participants allocated to mizoribine and prednisolone did not complete follow‐up; 2/20 participants allocated to prednisolone did not complete follow up. However, "Although 5 patients did not complete study medication because of the side effects, retracted consent or deviation from the tapering schedule, no patient was lost to follow‐up, and we could perform ITT analyses."
Selective reporting (reporting bias)	High risk	Key outcomes expected for this type of study (death (any cause), infection, ESKD) were not reported
Other bias	High risk	Imbalance at baseline in age, BP, and eGFR