Prophylactic hydration to protect renal function from intravascular iodinated contrast material in patients at high risk of contrast-induced nephropathy (AMACING): a prospective, randomised, phase 3, controlled, open-label, non-inferiority trial

Summary Background Intravenous saline is recommended in clinical practice guidelines as the cornerstone for preventing contrast-induced nephropathy in patients with compromised renal function. However, clinical-effectiveness and cost-effectiveness of this prophylactic hydration treatment in protecting renal function has not been adequately studied in the population targeted by the guidelines, against a group receiving no prophylaxis. This was the aim of the AMACING trial. Methods AMACING is a prospective, randomised, phase 3, parallel-group, open-label, non-inferiority trial of patients at risk of contrast-induced nephropathy according to current guidelines. High-risk patients (with an estimated glomerular filtration rate [eGFR] of 30–59 mL per min/1·73 m2 ) aged 18 years and older, undergoing an elective procedure requiring iodinated contrast material administration at Maastricht University Medical Centre, the Netherlands, were randomly assigned (1:1) to receive intravenous 0·9% NaCl or no prophylaxis. We excluded patients with eGFR lower than 30 mL per min/1·73 m2 , previous dialysis, or no referral for intravenous hydration. Randomisation was stratified by predefined risk factors. The primary outcome was incidence of contrast-induced nephropathy, defined as an increase in serum creatinine from baseline of more than 25% or 44 μmol/L within 2–6 days of contrast exposure, and cost-effectiveness of no prophylaxis compared with intravenous hydration in the prevention of contrast-induced nephropathy. We measured serum creatinine immediately before, 2–6 days, and 26–35 days after contrast-material exposure. Laboratory personnel were masked to treatment allocation. Adverse events and use of resources were systematically recorded. The non-inferiority margin was set at 2·1%. Both intention-to-treat and per-protocol analyses were done. This trial is registered with ClinicalTrials.gov , number NCT02106234. Findings Between June 17, 2014, and July 17, 2016, 660 consecutive patients were randomly assigned to receive no prophylaxis (n=332) or intravenous hydration (n=328). 2–6 day serum creatinine was available for 307 (92%) of 332 patients in the no prophylaxis group and 296 (90%) of 328 patients in the intravenous hydration group. Contrast-induced nephropathy was recorded in eight (2·6%) of 307 non-hydrated patients and in eight (2·7%) of 296 hydrated patients. The absolute difference (no hydration vs hydration) was −0·10% (one-sided 95% CI −2·25 to 2·06; one-tailed