Haidinger 2010

Methods	Study design: phase 2 RCT Study duration: March 2009 to July 2012 Study follow‐up period: 16 weeks; 3 months of treatment, and data reported at 3 months
Participants	Country: Austria Setting: single centre outpatient clinic, Department of Nephrology and Dialysis from Vienna General Hospital/Medical University of Vienna Patients with NODAT, transplant vintage > six months; stable graft function (no clinically meaningful change in kidney function within the last three months) and informed consent. Number: treatment group (16); control group (16) Mean age ± SD (years): treatment group (64.25 ± 27); control group (63 ± 8.4) Sex: (M/F): treatment group (10/6); control group (14/2) Exclusion criteria: prior history of T1DM or T2DM; pregnancy; severe kidney impairment with eGFR ≤ 30 mL/min/1.73 m2; severe liver impairment with AST and ALT 3x upper limit of normal
Interventions	Treatment group Vildagliptin: 50 mg orally/d for 3 months Control group Placebo Baseline immunosuppression TAC or CSA, MMF or MPA or AZA, and prednisolone Co‐interventions None
Outcomes	Primary outcomes Transplant or graft survival: reported on correspondence to be no difference between groups HbA1c FBG Kidney function markers including creatinine, eGFR, albuminuria Systolic and diastolic BP Lipids (HDL, LDL, triglyceride) Body weight: weight reported on correspondence; BMI reported Secondary outcomes All‐cause mortality: reported on correspondence Macrovascular events (cardiovascular death, non‐fatal MI, non‐fatal stroke): cardiovascular events reported on correspondence Microvascular events (new or worsening kidney disease, or retinopathy): not reported Safety/adverse events (including hypoglycaemia)
Notes	Groups were well matched for nearly all baseline characteristics including gender, age, BMI (28.4 ± 4.5 versus 27.9 ± 6 kg/m2, P = 0.78), HbA1c (6.7 ± 0.73% versus 6.7 ± 0.82%, P = 0.95), eGFR (58.3 ± 16.3 versus. 53.6 ± 14.4 mL/min/1.73 m2, P = 0.40), time since transplantation (69.9 ± 63.9 versus 51.4 ± 47.2 months, P = 0.38) and prednisolone dose (3.6 ± 1.8 versus 4.1 ± 2.6 mg/d, P = 0.52). However, use of MPA (8 participants in the intervention versus 4 in the control arm, P = 0.02) and MMF (7 participants in the intervention versus 2 in the control arm, P = 0.049) at baseline was significantly different Conflict of interest: none declared Contact with authors: authors contacted
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	On correspondence, randomisation was reported to be performed by the pharmaceutical department via a computer randomisation program
Allocation concealment (selection bias)	Low risk	On correspondence, allocation concealment and blinding was reported to be maintained until the end of the study
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding was done at the local pharmacy; study was also double blind and a placebo pill was used
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low dropout rate, with 1/33 not completing the study
Selective reporting (reporting bias)	Low risk	The main prespecified primary and secondary outcomes of interest were reported
Other bias	Low risk	Funding source: Medical University of Vienna, Austria