The DOAC-FRAIL trial is testing whether adjusting direct oral anticoagulant doses based on individual blood plasma levels improves safety in frail older patients, a group historically underrepresented in anticoagulation research. Results are pending, but the trial addresses a real problem: many frail older patients on standard DOAC doses have plasma concentrations outside therapeutic ranges.
This is not a completed study with results. Rather, it is a protocol paper describing the rationale and design of an ongoing international randomized controlled trial. The DOAC-FRAIL study represents an important research initiative, but no efficacy or safety data have been generated yet.
The core clinical problem the trial addresses is well-established: frail older patients face a precarious therapeutic balance. They require anticoagulation to prevent blood clots and stroke from conditions like atrial fibrillation, yet they are simultaneously at elevated risk for bleeding complications due to age-related changes in metabolism, polypharmacy, reduced organ function, and physiological frailty. Direct oral anticoagulants (DOACs) have become the standard-of-care replacement for warfarin in many patient populations because they maintain efficacy while reducing major bleeding risk. However, the evidence supporting their use specifically in frail older adults remains sparse.
Recent observational data cited in the protocol suggest that a substantial proportion of frail older patients have DOAC plasma concentrations outside the expected therapeutic window when receiving standard doses. This variability matters clinically. Plasma levels that are too low may fail to prevent thromboembolic events, while levels that are too high may increase bleeding risk. The DOAC-FRAIL investigators hypothesize that a single measurement-and-adjustment strategy, where DOAC doses are tailored based on individual peak plasma concentrations, could reduce the composite risk of both bleeding and thromboembolism compared with standard fixed dosing.
The trial design is pragmatic and inclusive. It enrolls frail older patients aged 70 years and older (Clinical Frailty Scale score greater than 3) across multiple international centers. Participants are randomized to either a measurement-and-adjustment arm (where DOAC therapy is adjusted based on peak plasma concentration results) or standard care. The primary outcome is the composite of clinically relevant non-major bleeding events and thromboembolic events over 2 years. Secondary outcomes examine feasibility, quality of life, cost-effectiveness, and mortality. The trial deliberately excludes patients with life expectancy under 3 months and those previously adjusted based on plasma levels, focusing on a population where treatment decisions remain genuinely uncertain.
If you or a family member is a frail older adult on a DOAC, this trial signals that current standard-dose anticoagulation is not optimized for everyone. The fact that researchers are investigating individualized dosing strategies suggests recognition within the clinical community that one-size-fits-all dosing may leave some patients either under-treated or over-treated.
However, conclusions should wait for results. This protocol paper does not yet provide evidence about whether plasma-guided dosing actually improves outcomes. The trial is ongoing, and completion is pending. In the meantime, the most evidence-based approach remains collaboration with your prescribing physician to monitor for signs of bleeding or clotting complications and to discuss whether any dose adjustments are warranted based on clinical judgment and any available pharmacokinetic data.
The design also highlights the importance of frailty-specific research. Frail older adults have historically been underrepresented in major anticoagulation trials, leaving a genuine evidence gap. This trial begins to address that gap.
| Parameter | Details |
|---|---|
| Study type | Randomized controlled trial (ongoing protocol) |
| Sample size | Not yet reported (recruitment ongoing) |
| Population | Frail older patients aged ≥70 years (Clinical Frailty Scale >3) on DOAC therapy |
| Intervention | Single-cycle measurement and adjustment of DOAC dose based on peak plasma concentration |
| Comparator | Standard care (fixed DOAC dosing) |
| Primary outcome | Composite of clinically relevant non-major bleeding and thromboembolic events over 2 years |
| Secondary outcomes | Feasibility, determinants of deviant plasma levels, quality of life, cost-effectiveness, all-cause mortality |
| Status | Ongoing; recruitment initiated; results expected after follow-up completion |
| Journal | Research and Practice in Thrombosis and Haemostasis |
| Registration | EU CT-2025-521362-10-00 |
Assessing the efficacy of a single-cycle measurement and adjustment strategy for direct oral anticoagulants in frail older patients: rationale and design of the DOAC-FRAIL randomized controlled trial. Research and Practice in Thrombosis and Haemostasis. PubMed: 42472242
ProtocolEngine provides general health information based on published research. This is not medical advice. Consult a healthcare professional before starting any supplement or health protocol.