Pozzi 1999.

Methods	Study design: parallel, 2‐arm RCT Duration of study: July 1987 to September 1995 Duration of follow‐up: 6 years
Participants	Setting: multicentre (7) Country: Italy Inclusion criteria: aged 15 to 69 years; biopsy‐proven IgAN; proteinuria 1.0 to 3.5 g/day for at least 3 months, and SCr ≤ 133 mol/L Number (analysed/randomised): treatment group (not reported/43); control group (not reported/43) Mean age, range (years): treatment group (38, 26 to 45); control group (40, 29 to 51) Sex (M/F): not reported Exclusion criteria: treatment with steroids or cytotoxic drugs during the previous 3 years; pregnancy; HSP nephritis; systemic lupus nephritis; diabetes; neoplasia; active peptic‐ulcer disease, viral hepatitis; other infections
Interventions	Treatment group Methylprednisolone: 1g IV for 3 days, repeated at 2 and 4 months Prednisone 0.5 mg/kg/day on alternating days for 6 months Control group No treatment Co‐interventions Both groups of patients were administered diuretics, antihypertensive drugs and antiplatelet agents as needed. ACEi were allowed for the treatment of hypertension
Outcomes	ESKD SCr CrCl Urinary protein excretion Adverse events
Notes	Funding: not reported Trials registration identification number: not applicable
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Centralised table of random numbers
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
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	High risk	All patients in the steroid group completed the 6 months of therapy; high dropout in both groups after this period
Selective reporting (reporting bias)	Low risk	Data for outcomes such as death (any cause), and infection were not reported. All other outcomes that would be expected for this type of study were reported
Other bias	High risk	Four patients in the control group received steroids as rescue therapy