Oral Anticoagulants in the Real World: Bleeding Rates and Medical Costs Compared

April 03, 2012

April 2, 2012 (Chicago, Illinois) — Firsthand experience with the new oral anticoagulants, coupled with excitement over those yet to be widely in use, has inspired a range of studies examining real-world risk/benefits, as well as the potential costs of replacing warfarin with the new agents. In a poster session at last week's American College of Cardiology 2012 Scientific Sessions, investigators presented two separate experiences with dabigatran from different US centers--showing very different results--while others presented new cost analyses comparing different oral agents with warfarin.

One US report of patients switched to dabigatran showed a much higher rate of major bleeding than in the RE-LY trial, but a lower rate of dyspepsia, while a second report showed a lower rate of both major and minor bleeding compared with RE-LY trial.

In the first study, researchers led by Dr Valay Parikh (Staten Island University Hospital, NY) reviewed a database from a community anticoagulant clinic with 2200 patients. Of these, 89 had been switched from warfarin to dabigatran 150 mg. They compared data on these 89 patients with patients receiving dabigatran 150 mg in the RE-LY trial and found a far higher rate of major bleeding and lower rate of dyspepsia in the community patients compared with the clinical trial, despite their patients being younger and having a lower CHADS2 score.

Parikh commented: "This is just an observational study, so we don't know the details of each patient. Maybe there are some other factors that might bias the results, but I think we need more studies to identify patients with a high risk of bleeding."

Comparison of Dabigatran in Staten Island Community Patients With RE-LY

Outcome Community (%) RE-LY (%) p
Major bleeding 8.98 3.11 <0.01
Dyspepsia 6.74 11.3 0.05

In the second study, Dr Archana Rajdev (Danbury Hospital, CT) reported on a series of 188 patients who had been started on dabigatran at her hospital. Of these, 79% had been on prior warfarin. Their mean age was 72 (slightly higher than in RE-LY) and they had a higher CHADS2 score, so were at higher risk of stroke. Despite these factors, these patients had a lower risk of major bleeding than seen in the clinical trial.

Comparison of Dabigatran in Danbury Hospital Patients With RE-LY

Outcome Community (%) RE-LY (%)
Major bleeding 1.59 3.11
Minor bleeding 10.11 14.84
Intracranial bleed 0 0.3
Stroke 0 1.11

Rajdev concluded that her results were "very reassuring." She noted that two out of nine patients on the 75-mg dose of dabigatran had a bleed, and both these patients were on dronedarone. Noting that there is a warning about using dronedarone and dabigatran together, she added: "If patients are elderly or have a high creatinine, I would not add dabigatran onto dronedarone even at the 75-mg dose."

Asked why there was such a difference with the Staten Island experience, Rajdev suggested it might come down to the attitude of the prescribing doctor. "We were very cautious. We monitored everyone who might have fluctuating creatinine levels quite closely, with a blood test every three months. I think the drug is very safe as long as this is done."

Rivaroxaban Cost-Effective?

Another poster estimated the cost-effectiveness of rivaroxaban vs warfarin from the Medicare perspective. Using a cost of rivaroxaban of $205 per month and data from the ROCKET-AF trial, a group led by Dr Soyon Lee (University of Connecticut School of Pharmacy, Storrs) estimated total lifetime costs for a 65-year-old AF patient to be $94 456 on rivaroxaban vs $88 544 for warfarin. They calculated that rivaroxaban was associated with an additional 0.22 quality-adjusted life-years (QALY) over warfarin, giving an incremental cost-effectiveness ratio (ICER) of $26 873. ICERs below about $50 000 are considered cost-effective, Lee noted.

Reduction in Medical Costs

A second cost-related study suggested that use of any of the three new anticoagulants would be associated with a reduction in medical costs in terms of clinical and bleeding events. The researchers, led by Dr Steve Deitelzweig (Ochsner Clinical Foundation, New Orleans, LA), estimated the one-year US costs for treating clinical and bleeding events in AF patients, and, based on absolute risks determined for each event in the three main clinical trials with the new drugs, they calculated the medical costs associated with each of the new drugs and with warfarin. The analysis did not, however, include the cost of the drugs or monitoring expenses.

Their results suggested that apixaban would save the most in medical expenses, with dabigatran coming in second and rivaroxaban third.

Medical Costs ($/Patient-Year) With New Drugs vs Warfarin in AF Patients

Outcome Warfarin Dabigatran 150 mg Rivaroxaban Apixaban
Ischemic stroke 490 373 461 451
Hemorrhagic stroke 225 59 133 115
Systemic embolism 27 17 6 23
MI 292 371 237 257
Pulmonary embolism/deep venous thrombosis 13 21 11 10
Major bleed 998 1030 1106 715
Clinically relevant nonmajor bleed 25 23 26 17
Minor bleed 13 12 15 9
Total costs 2084 1905 1995 1599
Saving vs warfarin -- 179 89 485



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