The incidence of patients with operative hip fractures on
DOAC in this cohort was 9%, which is higher than earlier reports
reflective of increased adoption of guidelines advocating
a switch from warfarin to a DOAC. It is reasonable to conclude
that DOAC use will overtake that of warfarin, making the problem
of DOAC and emergent surgery more pressing in the future.
As the number of hip fracture patients on DOAC increases,
important differences in care delivery may be encountered.
Large cohort studies demonstrate that mortality in hip fracture
patients starts to rise after 24 hours from time to diagnosis to
surgical treatment. Pilot data from an ongoing multicenter
trial suggests that mortality can be decreased by even more
rapid surgery (within 6 hours of presentation).
is available for only one DOAC (dabigatran) currently, but was
not available at the time of this audit. While other antidotes will
eventually become available, an already vulnerable population
is exposed to increased risk of death due to hip fracture in the
meantime. Based on the Thrombosis Canada guidelines for
apixaban, 34% of this cohort would have “high bleeding risk”
surgery, requiring 3 days delay, while the remaining 66% had
“moderate bleeding risk” surgery, and could have been operated
after 2 days.
It is not clear at this time what the optimal balance
of risk of surgical delay versus risk of proceeding in the face of
active and irreversible anticoagulation is.
Selection of a minimum clinically important difference of
24 hours was influenced by the metrics already collected in the
local health region. The smallest unit recorded for length of stay
is a day. A clinically important effect size must be larger than
the normal ebb and flow of patients and operating room access.
Interestingly, unlike the Tran study,
capacity issues were not
a prominent problem in this cohort. While the data was not
corrected for non-medical or non-surgical delays, few patients
were affected by such delays. The vast majority of patients were
treated in a priority fashion as operating theatre access allowed.
This is a small prospective cohort study, but it has some
strengths. Because it was performed at a single site over a short
period of time, it avoids heterogeneity arising from different
operating theatre access and different practice patterns. There
was sufficient power to address our primary outcome, but
sweeping conclusions about our secondary outcomes are not
possible. Furthermore, this audit was not designed to examine
longer-term end-points such as complications, survival, or length
of stay between groups.
In summary, patients on DOAC faced clinically significant
delays to surgery in this prospective cohort. Nine percent of this
cohort was on a DOAC, a higher prevalence than prior reports.
Future work will need to relate the observed delays to patient
outcomes, as well as assessment of the economic impact of
these agents, especially in a time of health spending constraints.
Given that DOAC are here to stay, evidence-based guidelines
on management of these medications in a context in which
even a 2-day delay may adverse affect patient survival will be of
tremendous value to patients and their surgeons going forward.
Collaboration between internists, anesthetists and surgeons will
be vital to achieving this.
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