Background: donor eligibility criteria are often determined at legal level and mostly based on the precautionary principle. The Belgian Red Cross Blood Service aims to support its blood donor eligibility criteria with solid evidence from systematic reviews (SRs), to guarantee the safety of both donor and recipient. Until now, we have conducted systematic reviews covering 15 of the 27 topics of our blood donor eligibility questionnaire, including 137 observational studies and resulting in low- to very low-certainty evidence. One of these topics is dental care, which is the 6th most common reason of donor deferral in Flanders, Belgium. Here, blood donors are deferred for 0 to 7 days after dental treatment dependent on the type of treatment.
Objectives: to give an overview of the scientific evidence concerning the risk of transfusion transmissible infections (TTIs) after dental care, and to describe how this supported current blood donor eligibility criteria.
Methods: we developed a systematic review according to the Cochrane method. We searched four databases: Medline, the Cochrane Library, Embase and Web of Science. We evaluated the certainty of evidence using the GRADE principle. We performed a meta-analysis to assess the association between dental treatment and TTI markers. Finally, the evidence was discussed by our operational Blood Services, in light of the current criteria for dental care.
Results: we included 22 studies investigating dental care as a risk factor for TTIs. Studies defined dental care as either dental treatment in general, or more specificly as dental cleaning or tooth extraction. A meta-analysis of 16 studies showed an increased risk of TTIs after dental care, however with large heterogeneity. Subgroup analysis revealed a significant increased risk of HBV after dental treatment. There was conflicting evidence concerning the risk of HCV. Three studies showed a significantly increased risk of HCV after tooth extraction. There is conflicting evidence concerning the risk of HBV or HCV after dental cleaning. One study could not demonstrate the risk of HIV after dental cleaning. All evidence is of very low certainty and results cannot be considered precise. After thorough consideration of the low-certainty evidence from this systematic review, our Blood Services decided there is no reason to change the current deferral criteria.
Conclusions: SRs are a useful tool to optimize our blood donor eligibility criteria, in order to lower the number of unnecessary deferrals, whilst ensuring the safety of both donors and recipients and securing an adequate blood supply.
Patient or healthcare consumer involvement: the priority of developing SRs to substantiate the medical questionnaire for donor eligibility is based on the top 30 of most common reasons of donor deferral in Belgium. Therefore our SRs fill evidence gaps identified by our consumers (i.e. blood donors).