Methodologic quality assessment of red blood cell transfusion guidelines and the evidence base of more restrictive transfusion thresholds.

BACKGROUND: Recent literature suggests that more restrictive red blood cell (RBC) transfusion practices are equivalent or better than more liberal transfusion practices. The methodologic quality of guidelines recommending more restrictive transfusion thresholds and their underlying scientific evidence is unclear. Therefore, we aimed to evaluate the quality of the development process of RBC transfusion guidelines and to investigate the underlying evidence of guidelines recommending a more restrictive hemoglobin (Hb) threshold.

STUDY DESIGN AND METHODS: Via systematic literature screening of relevant databases (NGC, GIN, Medline, and Embase), RBC transfusion guidelines recommending a more restrictive Hb level (<6, <7, or <8 g/dL) were included. Four assessors independently evaluated the methodologic quality by scoring the rigor of development domain (AGREE II checklist). The level of evidence served as a reference for the quality of the underlying evidence.

RESULTS: The methodologic quality of 13 RBC transfusion guidelines was variable (18%-72%) but highest for those developed by Advancing Transfusion and Cellular Therapies Worldwide (72%), the Task Force of Advanced Bleeding Care in Trauma (70%), and the Dutch Institute for Healthcare Improvement (61%). A Hb level of less than 7 g/dL (intensive care unit patients) or less than 8 g/dL (postoperative patients) were the only thresholds based on high-quality evidence. Only four of 32 recommendations had a high-quality evidence base.

CONCLUSION: Methodologic quality should be guaranteed in future RBC transfusion guideline development to ensure that the best available evidence is captured when recommending restrictive transfusion strategies. More high-quality trials are needed to provide a stronger scientific basis for RBC transfusion guidelines that recommend more restrictive transfusion thresholds.