The association between iron deficiency and outcomes: a secondary analysis of the intravenous iron therapy to treat iron deficiency anaemia in patients undergoing major abdominal surgery (PREVENTT) trial

In the intravenous iron therapy to treat iron deficiency anaemia in patients undergoing major abdominal surgery (PREVENTT) trial, the use of intravenous iron did not reduce the need for blood transfusion or reduce patient complications or length of hospital stay. As part of the trial protocol, serum was collected at randomisation and on the day of surgery. These samples were analysed in a central laboratory for markers of iron deficiency. We performed a secondary analysis to explore the potential interactions between pre-operative markers of iron deficiency and intervention status on the trial outcome measures. Absolute iron deficiency was defined as ferritin <30 μg.l^-1 ; functional iron deficiency as ferritin 30-100 μg.l^-1 or transferrin saturation < 20%; and the remainder as non-iron deficient. Interactions were estimated using generalised linear models that included different subgroup indicators of baseline iron status. Co-primary endpoints were blood transfusion or death and number of blood transfusions, from randomisation to 30 days postoperatively. Secondary endpoints included peri-operative change in haemoglobin, postoperative complications and length of hospital stay. Most patients had iron deficiency (369/452 [82%]) at randomisation; one-third had absolute iron deficiency (144/452 [32%]) and half had functional iron deficiency (225/452 [50%]). The change in pre-operative haemoglobin with intravenous iron compared with placebo was greatest in patients with absolute iron deficiency, mean difference 8.9 g.l^-1 , 95%CI 5.3-12.5; moderate in functional iron deficiency, mean difference 2.8 g.l^-1 , 95%CI -0.1 to 5.7; and with little change seen in those patients who were non-iron deficient. Subgroup analyses did not suggest that intravenous iron compared with placebo reduced the likelihood of death or blood transfusion at 30 days differentially across subgroups according to baseline ferritin (p = 0.33 for interaction), transferrin saturation (p = 0.13) or in combination (p = 0.45), or for the number of blood transfusions (p = 0.06, 0.29, and 0.39, respectively). There was no beneficial effect of the use of intravenous iron compared with placebo, regardless of the metrics to diagnose iron deficiency, on postoperative complications or length of hospital stay.

The need to screen for anemia in exercising women

ABSTRACT

Anemia is common, affecting 1 in 3 women in their lifetime. Despite high prevalence rates, awareness is poor. This is relevant for women undertaking sport as anemia can lead to reduced physical performance. There is no current screening program for testing of anemia for exercising women. Therefore, the objective of the present study was to assess a simple screening tool to predict anemia in exercising women.Cross sectional survey study.National fitness festival.Three hundred exercising women.Screening methodology (Female Health Questionnaire and a haemoglobin concentration measurement).The Female Health Questionnaire inquired about; previous iron status, menstrual blood loss, diet, and motherhood. Participants were asked to self-report any symptoms of iron deficiency, including; brain fog, palpitations, shortness of breath, restless legs, hair loss, and pica. Results were compared to fingerprick haemoglobin levels with anemia defined as [Hb] < 120 g/L.Average age was 31.21years (s.d.7.72), average [Hb] was 131.76 g/L (s.d.11.5) and 36 (12%) had anemia. A history of iron deficiency was reported by 127 (43.49%), 127 (43.49%) reported heavy menstrual bleeding (HMB), 75 were vegetarian (18%) or vegan (8%) and 33 were mothers (11%). In total 80 reported taking time off work (total 1612 days). Women with anemia more commonly reported HMB (58.33% vs. 41.57%, P = .04), and those with HMB were more likely to report days off (39.37% vs. 18.18%, P < .001).Anemia was common in exercising women, particularly those with HMB. A simple screening tool for HMB and finger prick haemoglobin testing for anemia is recommended in women undertaking exercise.

Preoperative intravenous iron for anaemia in elective major open abdominal surgery: the PREVENTT RCT

BACKGROUND

Anaemia affects 30-50% of patients before they undergo major surgery. Preoperative anaemia is associated with increased need for blood transfusion, postoperative complications and worse patient outcomes after surgery. International guidelines support the use of intravenous iron to correct anaemia in patients before surgery. However, the use of preoperative intravenous iron for patient benefit has not been assessed in the setting of a formal clinical trial.

OBJECTIVES

To assess if intravenous iron given to patients with anaemia before major abdominal surgery is beneficial by reducing transfusion rates, postoperative complications, hospital stay and re-admission to hospital, and improving quality of life outcomes.

DESIGN

A multicentre, double-blinded, randomised, controlled, Phase III clinical trial, with 1 : 1 randomisation comparing placebo (normal saline) with intravenous iron (intravenous ferric carboxymaltose 1000 mg). Randomisation and treatment allocation were by a secure web-based service.

SETTING

The study was conducted across 46 hospitals in England, Scotland and Wales between September 2013 and September 2018.

PARTICIPANTS

Patients aged > 18 years, undergoing elective major open abdominal surgery, with anaemia [Hb level of > 90 g/l and < 120 g/l (female patients) and < 130 g/l (male patients)] who could undergo randomisation and treatment 10-42 days before their operation.

INTERVENTION

Double-blinded study comparing placebo of normal saline with 1000 mg of ferric carboxymaltose administered 10-42 days prior to surgery.

MAIN OUTCOME MEASURES

Co-primary end points were risk of blood transfusion or death at 30 days postoperatively, and rate of blood transfusions at 30 days post operation.

RESULTS

A total of 487 patients were randomised (243 given placebo and 244 given intravenous iron), of whom 474 completed the trial and provided data for the analysis of the co-primary end points. The use of intravenous iron increased preoperative Hb levels (mean difference 4.7 g/l, 95% confidence interval 2.7 to 6.8 g/l; p < 0.0001), but had no effect compared with placebo on risk of blood transfusion or death (risk ratio 1.03, 95% confidence interval 0.78 to 1.37; p = 0.84; absolute risk difference +0.8%, 95% confidence interval -7.3% to 9.0%), or rates of blood transfusion (rate ratio 0.98, 95% confidence interval 0.68 to 1.43; p = 0.93; absolute rate difference 0.00, 95% confidence interval -0.14 to 0.15). There was no difference in postoperative complications or hospital stay. The intravenous iron group had higher Hb levels at the 8-week follow-up (difference in mean 10.7 g/l, 95% confidence interval 7.8 to 13.7 g/l; p < 0.0001). There were a total of 71 re-admissions to hospital for postoperative complications in the placebo group, compared with 38 re-admissions in the intravenous iron group (rate ratio 0.54, 95% confidence interval 0.34 to 0.85; p = 0.009). There were no differences between the groups in terms of mortality (two per group at 30 days post operation) or in any of the prespecified safety end points or serious adverse events.

CONCLUSIONS

In patients with anaemia prior to elective major abdominal surgery, there was no benefit from giving intravenous iron before the operation.

FUTURE WORK

The impact of iron repletion on recovery from postoperative anaemia, and the association with reduced re-admission to hospital for complications, should be investigated.

LIMITATIONS

In the preoperative intravenous iron to treat anaemia in major surgery (PREVENTT) trial, all patients included had anaemia and only 20% had their anaemia corrected before surgery. The definition and causality of iron deficiency in this setting is not clear.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN67322816 and ClinicalTrials.gov NCT01692418.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25 No. 11. See the NIHR Journals Library website for further project information.

Preoperative intravenous iron to treat anaemia before major abdominal surgery (PREVENTT): a randomised, double-blind, controlled trial

BACKGROUND

Preoperative anaemia affects a high proportion of patients undergoing major elective surgery and is associated with poor outcomes. We aimed to test the hypothesis that intravenous iron given to anaemic patients before major open elective abdominal surgery would correct anaemia, reduce the need for blood transfusions, and improve patient outcomes.

METHODS

In a double-blind, parallel-group randomised trial, we recruited adult participants identified with anaemia at preoperative hospital visits before elective major open abdominal surgery at 46 UK tertiary care centres. Anaemia was defined as haemoglobin less than 130 g/L for men and 120 g/L for women. We randomly allocated participants (1:1) via a secure web-based service to receive intravenous iron or placebo 10-42 days before surgery. Intravenous iron was administered as a single 1000 mg dose of ferric carboxymaltose in 100 mL normal saline, and placebo was 100 mL normal saline, both given as an infusion over 15 min. Unblinded study personnel prepared and administered the study drug; participants and other clinical and research staff were blinded to treatment allocation. Coprimary endpoints were risk of the composite outcome of blood transfusion or death, and number of blood transfusions from randomisation to 30 days postoperatively. The primary analysis included all randomly assigned patients with data available for the primary endpoints; safety analysis included all randomly assigned patients according to the treatment received. This study is registered, ISRCTN67322816, and is closed to new participants.

FINDINGS

Of 487 participants randomly assigned to placebo (n=243) or intravenous iron (n=244) between Jan 6, 2014, and Sept 28, 2018, complete data for the primary endpoints were available for 474 (97%) individuals. Death or blood transfusion occurred in 67 (28%) of the 237 patients in the placebo group and 69 (29%) of the 237 patients in the intravenous iron group (risk ratio 1·03, 95% CI 0·78-1·37; p=0·84). There were 111 blood transfusions in the placebo group and 105 in the intravenous iron group (rate ratio 0·98, 95% CI 0·68-1·43; p=0·93). There were no significant differences between the two groups for any of the prespecified safety endpoints.

INTERPRETATION

Preoperative intravenous iron was not superior to placebo to reduce need for blood transfusion when administered to patients with anaemia 10-42 days before elective major abdominal surgery.

FUNDING

UK National Institute of Health Research Health Technology Assessment Program.

Peri-operative blood management

Anaemia and allogeneic blood transfusions in surgical patients are associated with poor outcomes. Patient blood management (PBM) has been developed as an evidence-based clinical tool, by which clinicians can optimise anaemia, manage peri-operative bleeding, avoid unnecessary blood transfusion and improve patient outcome. This article aims to highlight the recent updates regarding evidence-based PBM in the perioperative period, following a thorough literature review involving original research articles, published guidelines and consensus documents discovered through an extensive PubMed and Medline search. PBM addresses three main pillars of the patient's journey through the pre-operative, intra-operative and post-operative periods. PBM encourages a restrictive approach to transfusion of blood products and promotes alternatives to blood transfusion to maximise clinical efficacy while minimising risks. Anaemia has been identified as an independent risk factor for poor outcomes. PBM highlights the importance of treating anaemia in the pre-operative period. Major elective surgery may be postponed until anaemia is corrected preoperatively. The intra-operative approach to PBM is a collaborative effort between the anaesthesia, surgery and transfusion laboratory teams. Use of tranexamic acid, meticulous haemostasis and cell salvage techniques play an important role during the intra-operative management of surgical and traumatic haemorrhage. Point-of-care coagulation tests with visco-elastographic methods and haemoglobin measurement ensure that the transfusion prescription is tailored to a patient. In the post-operative period, PBM highlights the need for patients to be optimised before discharge from the hospital. Implementation of the PBM has been shown to have individual health as well as economic benefits.

Cardiopulmonary exercise testing for predicting postoperative morbidity in patients undergoing hepatic resection surgery

OBJECTIVES

Cardiopulmonary exercise testing (CPET) may predict which patients are at risk for adverse outcomes after major abdominal surgery. The primary aim of this study was to determine whether CPET variables are predicative of morbidity.

METHODS

High-risk patients undergoing elective, one-stage, open hepatic resection were preoperatively assessed using CPET. Morbidity, as defined by the Postoperative Morbidity Survey (POMS), was assessed on postoperative day 3.

RESULTS

A total of 104 patients underwent preoperative CPET and were included in the analysis. Of these, 73 patients (70.2%) experienced postoperative morbidity. Oxygen consumption at anaerobic threshold (V˙O2 at AT, ml/kg/min) was the only CPET predictor of postoperative morbidity on multivariable analysis, with an area under the curve (AUC) of 0.66 [95% confidence interval (CI) 0.55-0.76]. In patients requiring a major hepatic resection (three or more segments), a V˙O2 at AT of <10.2 ml/kg/min gave an AUC of 0.79 (95% CI 0.68-0.86) with 83.9% sensitivity and 52.0% specificity, 80.6% positive predictive value and 62.5% negative predictive value.

CONCLUSIONS

The application of a cut-off value for V˙O2 at AT of <10.2 ml/kg/min in patients undergoing major hepatic resection may be useful for predicting which patients will experience morbidity.