Messa 1999.

Methods	Study design: open‐label, parallel RCT Duration of study: not reported Duration of follow‐up: 6 months
Participants	Country: Italy Setting: Inclusion criteria: kidney transplant recipients Number: treatment group (12); control group (16) Mean age ± SD (years): not reported Sex (M/F): not reported Exclusion criteria: not reported
Interventions	Treatment group Calcitriol: 0.008 µg/kg/d Control group No treatment Co‐interventions Calcium supplementation
Outcomes	Vitamin D levels Serum PTH Ionised calcium Lumbar spine and femoral neck BMD Kidney function
Notes	Abstract publication only, no full‐text publication identified Funding source: not reported Trial registration: not applicable as published before end of 2005
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	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not reported ‐ unlikely to be blinded as different interventions
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Selective reporting (reporting bias)	High risk	Patient‐centred outcomes not reported
Other bias	Unclear risk	Insufficient information to permit judgement