Red Blood Cell Transfusion at a Hemoglobin Threshold of Seven g/dL in Critically Ill Patients: A Regression Discontinuity Study

Leading digit bias in hemoglobin thresholds for red cell transfusion

BACKGROUND

Leading digit bias is a heuristic whereby humans overemphasize the left-most digit when evaluating numbers (e.g., 9.99 vs. 10.00). The bias might affect the interpretation of hemoglobin results and influence red cell transfusion in hospitalized patients.

STUDY DESIGN AND METHODS

Adults who received a red cell transfusion while registered at the University Health Network (Toronto, Canada) between January 1, 2016 and January 1, 2022 (n = 6 years) were included. The primary analysis excluded apheresis, red cell disorders, radiology suites, and operating rooms. The primary comparison was a regression discontinuity analysis of transfusion occurrence above and below the hemoglobin threshold of 79 g/L (local units). Additional analyses tested other leading digit and control thresholds (71, 81, and 91 g/L). Secondary analyses explored temporal covariates and clinical subgroups.

RESULTS

A total of 211,872 red cell transfusions were identified over the study period (median pre-transfusion hemoglobin 76 g/L; interquartile range = 69-92 g/L), with 107,790 inpatient transfusions in the primary analysis. The 79 g/L threshold showed 815 fewer red cell units above the threshold (95% confidence interval [CI]: -1215 to -415). The 69 g/L threshold showed 2813 fewer transfused units (95% CI: -4407 to -1220), and 89 g/L showed 40 fewer units (95% CI: -408 to 328). The effect was accentuated during daytime, weekday, and May-June months, persisted in analyses including all transfusions, and was absent at control thresholds.

CONCLUSION

Leading digit bias might have a modest influence on the decision to transfuse red cells. The findings may inform practice guidelines and quasi-experimental study design in transfusion research.

Effectiveness of an Artificial Intelligence-Enabled Intervention for Detecting Clinical Deterioration

Importance

Inpatient clinical deterioration is associated with substantial morbidity and mortality but may be easily missed by clinicians. Early warning scores have been developed to alert clinicians to patients at high risk of clinical deterioration, but there is limited evidence for their effectiveness.

Objective

To evaluate the effectiveness of an artificial intelligence deterioration model-enabled intervention to reduce the risk of escalations in care among hospitalized patients using a study design that facilitates stronger causal inference.

Design, Setting, and Participants

This cohort study used a regression discontinuity design that controlled for confounding and was based on Epic Deterioration Index (EDI; Epic Systems Corporation) prediction model scores. Compared with other observational research, the regression discontinuity design facilitates causal analysis. Hospitalized adults were included from 4 general internal medicine units in 1 academic hospital from January 17, 2021, through November 16, 2022.

Exposure

An artificial intelligence deterioration model-enabled intervention, consisting of alerts based on an EDI score threshold with an associated collaborative workflow among nurses and physicians.

Main Outcomes and Measures

The primary outcome was escalations in care, including rapid response team activation, transfer to the intensive care unit, or cardiopulmonary arrest during hospitalization.

Results

During the study, 9938 patients were admitted to 1 of the 4 units, with 963 patients (median [IQR] age, 76.1 [64.2-86.2] years; 498 males [52.3%]) included within the primary regression discontinuity analysis. The median (IQR) Elixhauser Comorbidity Index score in the primary analysis cohort was 10 (0-24). The intervention was associated with a -10.4-percentage point (95% CI, -20.1 to -0.8 percentage points; P = .03) absolute risk reduction in the primary outcome for patients at the EDI score threshold. There was no evidence of a discontinuity in measured confounders at the EDI score threshold.

Conclusions and Relevance

Using a regression discontinuity design, this cohort study found that the implementation of an artificial intelligence deterioration model-enabled intervention was associated with a significantly decreased risk of escalations in care among inpatients. These results provide evidence for the effectiveness of this intervention and support its further expansion and testing in other care settings.

A novel measure to summarize blood transfusion practice during critical illness

BACKGROUND

Large-scale observational studies have summarized transfusion practice using traditional measures of central tendency (e.g., the mean hemoglobin concentration at the time of transfusion). However, the mean hemoglobin concentration fails to identify specific hemoglobin concentration thresholds that drive practice. In the following brief report, we propose a novel measure of "practice discontinuity" that identifies specific practice-defining hemoglobin thresholds.

STUDY DESIGN AND METHODS

We used the PINC AI Database (2016-2022) to identify adult patients admitted to an intensive care unit with at least one hemoglobin concentration measurement. For each day that hemoglobin was measured, we identified whether the patient received a red blood cell transfusion using hospital charge codes. We defined the "practice discontinuity" measure as the hemoglobin concentration at which there was the largest increase in transfusion use going from a higher to an incrementally lower hemoglobin concentration. We also calculated the mean and median pretransfusion hemoglobin concentrations.

RESULTS

We identified 1,298,367 patients and 4,905,839 patient-days for inclusion. RBC transfusion occurred in a total of 530,654 (10.8%) patient-days. The overall pre-transfusion mean and median hemoglobin concentrations were 8.4 and 8.0 g/dL, respectively. The practice discontinuity measure identified 7.0 g/dL as the hemoglobin concentration at which transfusion use increased the most, from 46.6% of patient-days at a concentration of 7.0 g/dL to 74.8% of patient-days at a concentration of 6.9 g/dL.

DISCUSSION

We propose that future studies of red blood cell transfusion practice consider inclusion of the practice discontinuity measure to more fully summarize clinical practice.

Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary

This multisociety commentary critically examines the Agency for Healthcare Research and Quality (AHRQ) final report and systematic review on long-term health outcomes in obstructive sleep apnea. The AHRQ report was commissioned by the Centers for Medicare & Medicaid Services and particularly focused on the long-term patient-centered outcomes of continuous positive airway pressure, the variability of sleep-disordered breathing metrics, and the validity of these metrics as surrogate outcomes. This commentary raises concerns regarding the AHRQ report conclusions and their potential implications for policy decisions. A major concern expressed in this commentary is that the AHRQ report inadequately acknowledges the benefits of continuous positive airway pressure for several established, long-term clinically important outcomes including excessive sleepiness, motor vehicle accidents, and blood pressure. While acknowledging the limited evidence for the long-term benefits of continuous positive airway pressure treatment, especially cardiovascular outcomes, as summarized by the AHRQ report, this commentary reviews the limitations of recent randomized controlled trials and nonrandomized controlled studies and the challenges of conducting future randomized controlled trials. A research agenda to address these challenges is proposed including study designs that may include both high quality randomized controlled trials and nonrandomized controlled studies. This commentary concludes by highlighting implications for the safety and quality of life for the millions of people living with obstructive sleep apnea if the AHRQ report alone was used by payers to limit coverage for the treatment of obstructive sleep apnea while not considering the totality of available evidence.

CITATION

Patil SP, Billings ME, Bourjeily G, et al. Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary. J Clin Sleep Med. 2024;20(1):135-149.

From Product to Patient-Transfusion and Patient Blood Management

This Viewpoint discusses how patient blood management can help curb the demand for blood products and reduce harm by determining who would most benefit from a blood transfusion.

Strategies to Assess the Effect of Continuous Positive Airway Pressure on Long-Term Clinically Important Outcomes among Patients with Symptomatic Obstructive Sleep Apnea: An Official American Thoracic Society Workshop Report

Continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA). Although CPAP improves symptoms (e.g., daytime sleepiness), there is a lack of high-quality evidence that CPAP prevents many long-term outcomes, including cognitive impairment, myocardial infarction, and stroke. Observational studies suggest that patients with symptoms may be particularly likely to experience these preventive benefits with CPAP, but ethical and practical concerns limited the participation of such patients in prior long-term randomized trials. As a result, there is uncertainty about the full benefits of CPAP, and resolving this uncertainty is a key priority for the field. This workshop assembled clinicians, researchers, ethicists, and patients to identify strategies to understand the causal effects of CPAP on long-term clinically important outcomes among patients with symptomatic OSA. Quasi-experimental designs can provide valuable information and are less time and resource intensive than trials. Under specific conditions and assumptions, quasi-experimental studies may be able to provide causal estimates of CPAP's effectiveness from generalizable observational cohorts. However, randomized trials represent the most reliable approach to understanding the causal effects of CPAP among patients with symptoms. Randomized trials of CPAP can ethically include patients with symptomatic OSA, as long as there is outcome-specific equipoise, adequate informed consent, and a plan to maximize safety while minimizing harm (e.g., monitoring for pathologic sleepiness). Furthermore, multiple strategies exist to ensure the generalizability and practicality of future randomized trials of CPAP. These strategies include reducing the burden of trial procedures, improving patient-centeredness, and engaging historically excluded and underserved populations.

Anaemia in the first week may be associated with long-term mortality among critically ill patients: propensity score-based analyses

BACKGROUND

Anaemia is highly prevalent in critically ill patients; however, the long-term effect on mortality remains unclear.

METHODS

We retrospectively included patients admitted to the medical intensive care units (ICUs) during 2015-2020 at the Taichung Veterans General Hospital. The primary outcome of interest was one-year mortality, and hazard ratios (HRs) with 95% confidence intervals (CIs) were determined to assess the association. We used propensity score matching (PSM) and propensity score matching methods, including inverse probability of treatment weighting (IPTW) as well as covariate balancing propensity score (CBPS), in the present study.

RESULTS

A total of 7,089 patients were eligible for analyses, and 45.0% (3,189/7,089) of them had anaemia, defined by mean levels of haemoglobin being less than 10 g/dL. The standardised difference of covariates in this study were lower than 0.20 after matching and weighting. The application of CBPS further reduced the imbalance among covariates. We demonstrated a similar association, and adjusted HRs in original, PSM, IPTW and CBPS populations were 1.345 (95% CI 1.227-1.474), 1.265 (95% CI 1.145-1.397), 1.276 (95% CI 1.142-1.427) and 1.260 (95% CI 1.125-1.411), respectively.

CONCLUSIONS

We used propensity score-based analyses to identify that anaemia within the first week was associated with increased one-year mortality in critically ill patients.

Evaluation of red blood cell transfusion threshold in the management of brain-dead organ donors

The disparity between the demand and supply of organs has necessitated an expansion of the criteria for organ donation. Consequently, numerous guidelines have been proposed for managing brain-dead organ donors (BDODs) to improve their organ function and the organ procurement rate. Therefore, we aimed to evaluate the previously recommended threshold for red blood cell transfusion in BDODs. Medical records of BDODs were retrospectively reviewed from January 2012 to December 2021. We enrolled BDODs who stayed for more than 24 hours at an hospital organ procurement organization. We analyzed their organ function and the rate of organ procurement according to the hemoglobin concentration. A total of 111 BDODs were enrolled and divided into the following 2 groups: hemoglobin (Hb) ≥ 10 g/dL (45.0 %) and Hb < 10 g/dL (55.0 %). There were no significant differences between the groups in the total bilirubin, creatinine, arterial blood lactate, and the rate of organ procurement. A correlation analysis did not reveal any association between the hemoglobin concentration and organ function of the BDODs. Hemoglobin concentration of 10 g/dL cannot be considered a threshold for red blood cell transfusion. Furthermore, organ function is not correlated with a hemoglobin concentration > 7 g/dL. Restrictive transfusion strategy is appropriate for BDOD management.