Presurgical IV iron does not PREVENTT post-surgical mortality in anaemic patients

An intravenous (IV) iron infusion before major open abdominal surgery does not reduce the risk of post-surgical mortality or need for blood transfusion in anaemic patients, according to the UK-based PREVENTT* trial.

“The primary results of our trial show no evidence of clinical benefit in giving IV iron preoperatively to patients undergoing major abdominal surgery and provide the highest quality of evidence to date, with sufficient statistical power to make strong inferences about effectiveness,” said the researchers.

Participants in this multicentre, double-blind study were 487 adults (median age 66 years, 55 percent female) with anaemia (haemoglobin [Hb] <130 g/L and <120 g/L in men and women, respectively) scheduled for major open elective abdominal surgery. They were randomized 1:1 to receive a single IV dose of iron (1,000 mg ferric carboxymaltose in 100 mL saline; intervention) or placebo (100 mL saline) 10–42 days pre-surgery.

The most common surgical procedures were upper gastrointestinal (34 percent), gynaecological (30 percent), and colorectal (15 percent) surgery.

Baseline Hb levels were comparable between groups (111.2 and 111.0 g/dL in the intervention and placebo groups, respectively), and by time of surgery, had increased with the intervention (mean difference 4.7 g/dL). More patients in the intervention than placebo group had anaemia corrected (21 percent vs 10 percent; risk ratio [RR], 2.06). Hb concentration was increased in the intervention vs placebo groups at 8 weeks (mean difference 10.7 g/dL) and 6 months (mean difference 7.3 g/dL) post-treatment.

The risk of the composite outcome of blood transfusion or death between randomization and 30 days post-surgery was comparable between patients who received IV iron and placebo (29 percent vs 28 percent; RR, 1.03, 95 percent confidence interval [CI], 0.78–1.37; p=0.84). [Lancet 2020;doi:10.1016/S0140-6736(20)31539-7]

The number of blood transfusion episodes from randomization to 30 days post-surgery also did not differ between the IV iron and placebo groups (n=105 vs 111; rate ratio, 0.98, 95 percent CI, 0.68–1.43; p=0.93).

The findings were similar at 6 months post-surgery (blood transfusion or death: RR, 0.99; number of blood transfusion episodes: rate ratio, 0.92).

Transfusion rate at 30 days (300 units of blood/blood products between randomization and 30 days post-surgery, excluding large blood transfusions) was also similar between intervention and placebo recipients (rate ratio, 0.98), as was significant post-surgery complications (9 percent vs 11 percent; RR, 0.89).

Patients in both groups were hospitalized for a median 9 days, and duration of intensive care unit stay did not differ between the intervention and placebo groups (median 2 vs 1 days). Health-related quality of life at 8 weeks and 6 months post-surgery was also similar between groups.

Post-surgical hospital readmission for complications at 8 weeks was reduced in the intervention vs placebo group (13 percent vs 22 percent; RR, 0.61). All-cause mortality was comparable between groups at 30 days (1 percent in each group) and 6 months (5 percent vs 4 percent).

The reduction in hospital readmission rates warrants further study, said the researchers. “Clinically, this finding raises the possibility that postoperative IV iron, before discharge from the hospital, might be effective at boosting Hb levels in surgical patients during their recovery period,” they said. However, post- vs pre-surgical iron infusions were unlikely to have altered mortality or transfusion rates.

“International treatment guidelines recommend that patients undergoing surgery with an expected blood loss of ≥500 mL should be screened for anaemia at least 2 weeks before surgery, with a recommendation that anaemia should be treated with IV iron,” said the researchers.

“The evidence base now suggests that current guidance on preoperative iron therapy … should be revised … preoperative iron therapy is not recommended in major elective surgery patients with anaemia,” they said.