Abstract：
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.
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.
CONCLUSIONS: 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.
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.
CONCLUSIONS: 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.
摘要：
背景：领先数字偏差是一种启发式方法，即人类在评估数字时过分强调最左边的数字（例如，9.99vs.10.00).偏倚可能会影响血红蛋白结果的解释并影响住院患者的红细胞输注。
方法：在大学健康网络注册时接受红细胞输血的成年人（多伦多，加拿大）在2016年1月1日至2022年1月1日之间（n=6年）被包括在内。主要分析排除了单采血液成分,红细胞紊乱,放射科套房,和手术室。主要比较是对血红蛋白阈值79g/L（本地单位）以上和以下的输血发生的回归不连续性分析。其他分析测试了其他前导数字和对照阈值(71、81和91g/L)。次要分析探讨了时间协变量和临床亚组。
结果：在研究期间共发现211,872例红细胞输血（输血前血红蛋白中位数76g/L；四分位数范围=69-92g/L），在主要分析中使用107,790例住院输血。79g/L阈值显示高于阈值的815个红细胞单位(95%置信区间[CI]:-1215至-415)。69g/L阈值显示减少了2813个输注单位（95％CI：-4407至-1220），89克/升显示出少40个单位(95%CI:-408至328)。这种影响在白天得到了加强，工作日,5-6月,坚持在包括所有输血在内的分析中，并且在控制阈值时不存在。
结论：前导数字偏倚可能对输注红细胞的决定有适度的影响。这些发现可能为输血研究的实践指南和准实验研究设计提供信息。
方法：在大学健康网络注册时接受红细胞输血的成年人（多伦多，加拿大）在2016年1月1日至2022年1月1日之间（n=6年）被包括在内。主要分析排除了单采血液成分,红细胞紊乱,放射科套房,和手术室。主要比较是对血红蛋白阈值79g/L（本地单位）以上和以下的输血发生的回归不连续性分析。其他分析测试了其他前导数字和对照阈值(71、81和91g/L)。次要分析探讨了时间协变量和临床亚组。
结果：在研究期间共发现211,872例红细胞输血（输血前血红蛋白中位数76g/L；四分位数范围=69-92g/L），在主要分析中使用107,790例住院输血。79g/L阈值显示高于阈值的815个红细胞单位(95%置信区间[CI]:-1215至-415)。69g/L阈值显示减少了2813个输注单位（95％CI：-4407至-1220），89克/升显示出少40个单位(95%CI:-408至328)。这种影响在白天得到了加强，工作日,5-6月,坚持在包括所有输血在内的分析中，并且在控制阈值时不存在。
结论：前导数字偏倚可能对输注红细胞的决定有适度的影响。这些发现可能为输血研究的实践指南和准实验研究设计提供信息。
