EHA Library - The official digital education library of European Hematology Association (EHA)

ANTICOAGULATION IN THE OBESE - A PROSPECTIVE REGISTRY
Author(s): ,
Georgia McCaughan
Affiliations:
Department of Haematology,Westmead Hospital,Sydney,Australia;Sydney Medical School,Sydney,Australia
,
Helen Crowther
Affiliations:
Department of Haematology,Blacktown Hospital,Sydney,Australia;Department of Haematology,Westmead Hospital,Sydney,Australia
,
Leonardo Pasalic
Affiliations:
Haematology,NSW Health Pathology,Sydney,Australia;Haematology,ICPMR, Westmead Hospital,Sydney,Australia;Haematology,Westmead Hospital,Westmead,Australia;Sydney Centres for Thrombosis and Haemostasis,Sydney,Australia
,
Patricia Rebeiro
Affiliations:
Haematology,Blacktown Hospital,Sydney,Australia
Jennifer Curnow
Affiliations:
Department of Haematology,Westmead Hospital,Sydney,Australia;Sydney Centres for Thrombosis and Haemostasis,Sydney,Australia
(Abstract release date: 05/17/18) EHA Library. McCaughan G. 06/15/18; 215888; PF778
Georgia McCaughan
Georgia McCaughan
Contributions
Abstract

Abstract: PF778

Type: Poster Presentation

Presentation during EHA23: On Friday, June 15, 2018 from 17:30 - 19:00

Location: Poster area

Background
The optimal anticoagulation strategy in the obese remains unclear.  There is limited data to guide prescribing of low molecular weight heparin (LMWH) and direct oral anticoagulants (DOAC) in this population, particularly those with class III obesity (body mass index [BMI] ≥ 40kg/m2).

Aims
To examine anticoagulant prescribing patterns in the obese in Australia and New Zealand; determine the most appropriate dosing strategy for LMWH; determine whether obese patients achieve appropriate peak and trough DOAC drug levels and evaluate clinical efficacy and safety of these agents in the obese.

Methods
We are prospectively registering all patients with a BMI ≥ 35kg/m2 or weight > 120kg receiving anticoagulants at 5 study sites in Australia and New Zealand (with 5 further sites in the process of submitting or awaiting ethics approval).  Demographic data, weight, height, indication, anticoagulant choice, efficacy, adverse events and drug specific levels are being collected at registration and follow-up.

Results
As of abstract submission date we have recruited 21 patients at two sites with BMI ≥ 35kg/m2 with 3 sites commencing recruitment this month.  Median BMI was 43kg/m2 (range 39 - 80) and median weight was 132kg (range 108-229kg).  14/21 patients were female with a median age of 47 years (range 27-81).  Indication for anticoagulation was deep vein thrombosis (11), pulmonary embolus (7), superior mesenteric vein thrombosis (1), extensive superficial vein thrombosis (1) and atrial fibrillation (1).  Of those with venous thrombosis, 10/20 had a provoking factor and 7/20 had a prior history of DVT.  Initial anticoagulation was: rivaroxaban (8), apixaban (6), dabigatran (1), enoxaparin (6) with transition to warfarin for 4/6.  Of the four patients who received enoxaparin during the study period, 3 patients had a weight ≥ 200kg (BMI 70-80kg/m2) and required 0.65-0.75mg/kg to achieve therapeutic Anti-Xa. The final patient had a weight of 108kg (BMI 43.2kg/m2) and required a dose of 0.92mg/kg.  With regards to rivaroxaban 15mg twice daily, one peak level of 338ng/ml and three trough levels (< 25, 37 and 55ng/ml) were available.  There are no published ‘on therapy’ ranges for the rivaroxaban 15mg BD dose.  For the 20mg dose, peak levels (n = 4) ranged from 177-561 and median trough level (n = 5) was 31ng/ml (range 28-122).  3/4 peak levels and 5/5 trough levels fell within the 5th to 95th percentile of published ‘on therapy’ ranges.  For apixaban 5mg twice daily, median peak level (n = 4) was 112ng/ml (range 97-156) and median trough level (n = 5) was 40ng/ml (range 25-68).  All peak levels and trough levels fell within the 5th to 95th percentile of published ‘on therapy’ ranges.  2 patients were changed from rivaroxaban to apixaban, due to menorrhagia in one patient and an undetectable trough rivaroxaban level in another.  All patients that had progress imaging had radiological improvement and no patients had a symptomatic recurrent thrombotic event (median follow up 6 months).

Conclusion
There is limited data to guide prescribing of anticoagulation in the obese.  Published ‘on therapy’ ranges have not been validated with clinical outcomes and there is no data to guide dose adjustment on the basis of drug levels.  This makes interpreting the clinical significance of drug levels in the obese population difficult.  The measured drug levels within this cohort appear appropriate relative to published ‘on therapy ranges’ and reassuringly no patients had a recurrent thrombotic event.  Further data is required and we are now recruiting across multiple sites in Australia and New Zealand.

Session topic: 35. Thrombosis and vascular biology & translational Research

Keyword(s): Thrombosis, Anticoagulation, Obesity

Abstract: PF778

Type: Poster Presentation

Presentation during EHA23: On Friday, June 15, 2018 from 17:30 - 19:00

Location: Poster area

Background
The optimal anticoagulation strategy in the obese remains unclear.  There is limited data to guide prescribing of low molecular weight heparin (LMWH) and direct oral anticoagulants (DOAC) in this population, particularly those with class III obesity (body mass index [BMI] ≥ 40kg/m2).

Aims
To examine anticoagulant prescribing patterns in the obese in Australia and New Zealand; determine the most appropriate dosing strategy for LMWH; determine whether obese patients achieve appropriate peak and trough DOAC drug levels and evaluate clinical efficacy and safety of these agents in the obese.

Methods
We are prospectively registering all patients with a BMI ≥ 35kg/m2 or weight > 120kg receiving anticoagulants at 5 study sites in Australia and New Zealand (with 5 further sites in the process of submitting or awaiting ethics approval).  Demographic data, weight, height, indication, anticoagulant choice, efficacy, adverse events and drug specific levels are being collected at registration and follow-up.

Results
As of abstract submission date we have recruited 21 patients at two sites with BMI ≥ 35kg/m2 with 3 sites commencing recruitment this month.  Median BMI was 43kg/m2 (range 39 - 80) and median weight was 132kg (range 108-229kg).  14/21 patients were female with a median age of 47 years (range 27-81).  Indication for anticoagulation was deep vein thrombosis (11), pulmonary embolus (7), superior mesenteric vein thrombosis (1), extensive superficial vein thrombosis (1) and atrial fibrillation (1).  Of those with venous thrombosis, 10/20 had a provoking factor and 7/20 had a prior history of DVT.  Initial anticoagulation was: rivaroxaban (8), apixaban (6), dabigatran (1), enoxaparin (6) with transition to warfarin for 4/6.  Of the four patients who received enoxaparin during the study period, 3 patients had a weight ≥ 200kg (BMI 70-80kg/m2) and required 0.65-0.75mg/kg to achieve therapeutic Anti-Xa. The final patient had a weight of 108kg (BMI 43.2kg/m2) and required a dose of 0.92mg/kg.  With regards to rivaroxaban 15mg twice daily, one peak level of 338ng/ml and three trough levels (< 25, 37 and 55ng/ml) were available.  There are no published ‘on therapy’ ranges for the rivaroxaban 15mg BD dose.  For the 20mg dose, peak levels (n = 4) ranged from 177-561 and median trough level (n = 5) was 31ng/ml (range 28-122).  3/4 peak levels and 5/5 trough levels fell within the 5th to 95th percentile of published ‘on therapy’ ranges.  For apixaban 5mg twice daily, median peak level (n = 4) was 112ng/ml (range 97-156) and median trough level (n = 5) was 40ng/ml (range 25-68).  All peak levels and trough levels fell within the 5th to 95th percentile of published ‘on therapy’ ranges.  2 patients were changed from rivaroxaban to apixaban, due to menorrhagia in one patient and an undetectable trough rivaroxaban level in another.  All patients that had progress imaging had radiological improvement and no patients had a symptomatic recurrent thrombotic event (median follow up 6 months).

Conclusion
There is limited data to guide prescribing of anticoagulation in the obese.  Published ‘on therapy’ ranges have not been validated with clinical outcomes and there is no data to guide dose adjustment on the basis of drug levels.  This makes interpreting the clinical significance of drug levels in the obese population difficult.  The measured drug levels within this cohort appear appropriate relative to published ‘on therapy ranges’ and reassuringly no patients had a recurrent thrombotic event.  Further data is required and we are now recruiting across multiple sites in Australia and New Zealand.

Session topic: 35. Thrombosis and vascular biology & translational Research

Keyword(s): Thrombosis, Anticoagulation, Obesity

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