Lack of Cost-Effectiveness of Preoperative Erythropoiesis-Stimulating Agents and/or Iron Therapy in Anaemic, Elective Surgery Patients: A Systematic Review and Updated Analysis

Prognostic models for prediction of perioperative allogeneic red blood cell transfusion in adult cardiac surgery: A systematic review and meta-analysis

OBJECTIVES

Identifying cardiac surgical patients at risk of requiring red blood cell (RBC) transfusion is crucial for optimizing their outcome. We critically appraised prognostic models preoperatively predicting perioperative exposure to RBC transfusion in adult cardiac surgery and summarized model performance.

METHODS

Design: Systematic review and meta-analysis.

STUDY ELIGIBILITY CRITERIA

Studies developing and/or externally validating models preoperatively predicting perioperative RBC transfusion in adult cardiac surgery. Information sources MEDLINE, CENTRAL & CDSR, Embase, Transfusion Evidence Library, Web of Science, Scopus, ClinicalTrials.gov, and WHO ICTRP. Risk of bias and applicability: Quality of reporting was assessed with the Transparent Reporting of studies on prediction models for Individual Prognosis or Diagnosis adherence form, and risk of bias and applicability with the Prediction model Risk of Bias ASsessment Tool.

SYNTHESIS METHODS

Random-effects meta-analyses of concordance-statistics and total observed:expected ratios for models externally validated ≥5 times.

RESULTS

Nine model development, and 27 external validation studies were included. The average TRIPOD adherence score was 66.4% (range 44.1%-85.2%). All studies but 1 were rated high risk of bias. For TRUST and TRACK, the only models externally validated ≥5 times, summary c-statistics were 0.74 (95% CI: 0.65-0.84; 6 contributing studies) and 0.72 (95% CI: 0.68-0.75; 5 contributing studies) respectively, and summary total observed:expected ratios were 0.86 (95% CI: 0.71-1.05; 5 contributing studies) and 0.94 (95% CI: 0.74-1.19; 5 contributing studies), respectively. Considerable heterogeneity was observed in all meta-analyses.

DISCUSSION

Future high quality external validation and model updating studies which strictly adhere to reporting guidelines, are warranted.

Postoperative intravenous iron to treat iron-deficiency anaemia in patients undergoing cardiac surgery: a protocol for a pilot, multicentre, placebo-controlled randomized trial (the POAM trial)

Background

Iron-deficiency anaemia, occurring in 30-40% of patients undergoing cardiac surgery, is an independent risk factor for adverse outcomes. Our long-term goal is to assess if postoperative i.v. iron therapy improves clinical outcomes in patients with preoperative iron-deficiency anaemia undergoing cardiac surgery. Before conducting a definitive RCT, we first propose a multicentre pilot trial to establish the feasibility of the definitive trial.

Methods

This internal pilot, double-blinded, RCT will include three centres. Sixty adults with preoperative iron-deficiency anaemia undergoing non-emergency cardiac surgery will be randomised on postoperative day 2 or 3 to receive either blinded i.v. iron (1000 mg ferric derisomaltose) or placebo. Six weeks after surgery, patients who remain iron deficient will receive a second blinded dose of i.v. iron according to their assigned treatment arm. Patients will be followed for 12 months. Clinical practice will not be otherwise modified. For the pilot study, feasibility will be assessed through rates of enrolment, protocol deviations, and loss to follow up. For the definitive study, the primary outcome will be the number of days alive and out of hospital at 90 days after surgery.

Ethics and dissemination

The trial has been approved by the University Health Network Research Ethics Board (REB # 22-5685; approved by Clinical Trials Ontario funding on 22 December 2023) and will be conducted in accordance with the Declaration of Helsinki, Good Clinical Practices guidelines, and regulatory requirements.

Clinical trial registration

NCT06287619.

Evidence-Based Medicine: Principles and Values as Illustrated by the Case of Patient Blood Management

Evidence-based medicine is considered 1 of the 15 great inventions in medicine. It aims to remove bias in medical decision-making as much as possible through a rigorous process. In this article, the principles of evidence-based medicine are illustrated using the case of patient blood management (PBM). Acute or chronic bleeding, iron deficiency, and renal and oncological diseases may lead to preoperative anemia. To compensate for severe and life-threatening blood loss during surgery, doctors transfuse red blood cells (RBCs). PBM is an approach to take care of patients at risk for anemia, which includes detecting and treating anemia before surgery. Alternative interventions to treat preoperative anemia are the use of iron supplementation with or without erythro-stimulating agents (ESAs). The best available scientific evidence today indicates that preoperative intravenous (IV) or oral iron monotherapy may not be effective to reduce RBC utilization (low-certainty evidence). Preoperative IV iron supplementation in addition to ESAs is probably effective to reduce RBC utilization (moderate-certainty evidence), whereas oral iron supplementation in addition to ESAs may be effective to reduce RBC utilization (low-certainty evidence). The adverse events of preoperative oral/IV iron and/or ESAs and their impact on patient-important outcomes (morbidity, mortality, quality of life) remain unclear (very low-certainty evidence). Since PBM is a patient-centered approach, emphasis on monitoring and evaluation of patient-important outcomes in future research is urgently needed. Finally, the cost-effectiveness of preoperative oral/IV iron monotherapy is unproven, whereas preoperative oral/IV iron in addition to ESAs is extremely cost-ineffective.

Adverse events of iron and/or erythropoiesis-stimulating agent therapy in preoperatively anemic elective surgery patients: a systematic review

BACKGROUND

Iron supplementation and erythropoiesis-stimulating agent (ESA) administration represent the hallmark therapies in preoperative anemia treatment, as reflected in a set of evidence-based treatment recommendations made during the 2018 International Consensus Conference on Patient Blood Management. However, little is known about the safety of these therapies. This systematic review investigated the occurrence of adverse events (AEs) during or after treatment with iron and/or ESAs.

METHODS

Five databases (The Cochrane Library, MEDLINE, Embase, Transfusion Evidence Library, Web of Science) and two trial registries (ClinicalTrials.gov, WHO ICTRP) were searched until 23 May 2022. Randomized controlled trials (RCTs), cohort, and case-control studies investigating any AE during or after iron and/or ESA administration in adult elective surgery patients with preoperative anemia were eligible for inclusion and judged using the Cochrane Risk of Bias tools. The GRADE approach was used to assess the overall certainty of evidence.

RESULTS

Data from 26 RCTs and 16 cohort studies involving a total of 6062 patients were extracted, on 6 treatment comparisons: (1) intravenous (IV) versus oral iron, (2) IV iron versus usual care/no iron, (3) IV ferric carboxymaltose versus IV iron sucrose, (4) ESA+iron versus control (placebo and/or iron, no treatment), (5) ESA+IV iron versus ESA+oral iron, and (6) ESA+IV iron versus ESA+IV iron (different ESA dosing regimens). Most AE data concerned mortality/survival (n=24 studies), thromboembolic (n=22), infectious (n=20), cardiovascular (n=19) and gastrointestinal (n=14) AEs. Very low certainty evidence was assigned to all but one outcome category. This uncertainty results from both the low quantity and quality of AE data due to the high risk of bias caused by limitations in the study design, data collection, and reporting.

CONCLUSIONS

It remains unclear if ESA and/or iron therapy is associated with AEs in preoperatively anemic elective surgery patients. Future trial investigators should pay more attention to the systematic collection, measurement, documentation, and reporting of AE data.