Brierley, Rachel

Murphy, Gavin J

Pike, Katie

Reeves, Barney C

Rogers, Chris A

English

PubMed

Pike Katie

Brierley Rachel

Rogers Chris A

Murphy Gavin J

Reeves Barney C

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Trials

Adherence in a randomised controlled trial comparing liberal and restrictive red blood cell (RBC) transfusion protocols after cardiac surgery (TITRe2)

Pike, KE

Brierley, RCM

Rogers, CA

Murphy, GJ

Reeves, BC

Explore Bristol Research

Katie Pike

Rachel Brierley

Chris A Rogers

Gavin J Murphy

Barney C Reeves

Springer - Publisher Connector

ORAL PRESENTATION Open Access
Adherence in a randomised controlled trial
comparing liberal and restrictive red blood cell
(RBC) transfusion protocols after cardiac surgery
(TITRe2)
Katie Pike*, Rachel Brierley, Chris A Rogers, Gavin J Murphy, Barney C Reeves
From Clinical Trials Methodology Conference 2011
Bristol, UK. 4-5 October 2011
Objectives
The TITRe2 trial is comparing two haemoglobin (Hb)
thresholds for RBC transfusion after cardiac surgery,
Hb<9.0g/dl (liberal) vs. Hb<7.5g/dl (restrictive). Based
on historic data, and with complete adherence, transfu-
sion rates should be 100% in the liberal and 30% in the
restrictive group. Convergence of these rates due to
non-adherence severely threatens the power of the trial;
there is also concern about differential non-adherence,
with transfusion being delayed or withheld in the liberal
group when Hb remains close to the 9.0g/dl threshold.
Methods
In order to capture non-adherence, research staff collect
data describing:
• The lowest daily Hb;
• Date and time of each RBC transfusion and the pre-
ceding Hb measurement;
• Number of breaches of the allocated threshold
before a transfusion is prescribed.
These data allow non-adherence to the randomisation
and transfusion protocols to be detected:
• Failure to randomise when the 9.0g/dl threshold is
breached;
• Randomised >24 hours after first breaching Hb 9.0g/
dl threshold;
• Randomised without or before breaching Hb 9.0g/dl
threshold;
• After randomisation, transfusion given when allo-
cated threshold not breached (‘extra’), or transfusion
withheld when allocated threshold breached (‘withheld’);
Instances of extra and withheld transfusions are classi-
fied as mild, moderate or severe depending on their
likely influence on overall transfusion rates.
Results
56% of participants are being randomised; about 8% of
the remaining 44% consented participants breach the
9.0g/dl threshold but are not randomised. 3% of rando-
mised participants are randomised >24 hours after first
breaching, but none has been randomised without or
before breaching the 9.0g/dl threshold. 32% of partici-
pants have had ≥1 instance of non-adherence to the
transfusion protocol; in 6%, non-adherence was judged
severe (extra – transfused and patient did not breach at
any point post-randomisation; withheld – not transfused
and patient had no post-randomisation transfusions).
Site-specific rates of non-adherence are being fedback to
try to improve adherence. Rates of transfusion in the
liberal and restrictive groups are confidential to the
Data Monitoring and Ethics Committee (DMEC).
Conclusions
We believe that this is the first attempt to measure
withheld transfusions in trials of this kind. Data collec-
tion to do this is burdensome but satisfactory. The cur-
rent rates of transfusion in the liberal and restrictive
groups are, so far, judged by the DMEC to be consistent
with the sample size justification.
Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, UK
Pike et al. Trials 2011, 12(Suppl 1):A131
http://www.trialsjournal.com/content/12/S1/A131 TRIALS
© 2011 Pike et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
Published: 13 December 2011
doi:10.1186/1745-6215-12-S1-A131
Cite this article as: Pike et al.: Adherence in a randomised controlled
trial comparing liberal and restrictive red blood cell (RBC) transfusion
protocols after cardiac surgery (TITRe2). Trials 2011 12(Suppl 1):A131.
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Pike et al. Trials 2011, 12(Suppl 1):A131
http://www.trialsjournal.com/content/12/S1/A131
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Adherence in a randomised controlled trial comparing liberal and restrictive red blood cell (RBC) transfusion protocols after cardiac surgery (TITRe2)

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