Download Warfarin Efficacy in Cancer Patients on Long

Warfarin Efficacy
in Cancer Patients on
Long-term
Anticoagulation
Neha Doshi, PharmD Candidate
LeAnn B. Norris, PharmD, BCPS
P. Brandon Bookstaver, PharmD, BCPS
Julie Sease, PharmD, BCPS
Background
 “Patients with cancer are at high risk to develop venous
thromboembolisms, and they are also more likely to
develop complications from anticoagulant treatment”
 Presence of malignancy increases risk of VTE by a
factor of 4 to 6
▫ Up to 25% of patients with a malignancy will develop
thrombosis
▫ Cancer patients constitute 15-20% of patients diagnosed with
a VTE
Brose KMJ, et al. Curr Oncol 2008;15(1):S58-67.
Background
 Annual risk of recurrent VTE is 21-27%
 Annual risk of major bleeding is 12-13%
 Thromboembolic events = second leading cause of death
in cancer patients
Brose KMJ, et al. Curr Oncol 2008;15(1):S58-67.
2006 NCCN - Clinical Practice Guidelines in oncology-versus thromboembolic disease.
Rose AJ, et al. Soc Gen Int Med 2007;22:997-1002.
Primary Factors
 Various factors contribute to the increased risk of
thromboembolic and hemorrhagic events3
▫
▫
▫
▫
▫
Active cancer
Catheters
Prolonged bed rest
Chemotherapy
Hormone therapy
Lee AY, et al. Circulation 2003;107:117-21.
Objective
 Purpose
▫ Assess the effectiveness of warfarin in a population
of cancer patients
 Outcome
▫ Determine the proportion of time spent within INR
goal
▫ Assess the rate of thromboembolic and major
hemorrhagic events
Patient Selection
 Documented cancer diagnosis
 Active anticoagulation
▫ Any indication
▫ At least 6 months prior to diagnosis
▫ 1 year after diagnosis
Methods







Patient demographics
Primary indication for anticoagulation
Underlying comorbidities
Type of malignancy
Cancer treatment
INR values
Bleeding events
Time in Therapeutic Range
(TTR)
 Calculated for each patient, pre- and post- diagnosis
1.
2.
3.
4.
5.
If the patient was a new start, or restarted on warfarin, we excluded
values within the first 30 days of initiation due to bridging.
Given two INR values, we first calculated the time interval (days)
between the values.
Then, we took the difference of the two INR values and divided it by the
time interval to give us x1.
Then we took the point at which it became not therapeutic and
subtracted from last INR to give us x2.
Divide x1 by x2 and this gives the amount of days in therapeutic range
between the two INR values.
Rosendaal FR, et al. Thromb Haemostas 1993;69(3):236-9.
TTR - Calculation
Example
INR 2.5 on 1/01/07
Time interval: 9 days
INR 3.1 on 1/10/07
Difference of two INR’s: 3.1 – 2.5 = 1.24
Difference / Time interval: 1.24 / 9 = 0.06
Point at which INR is no longer therapeutic minus last INR:
3 – 2.5 = 0.5
0.5 / 0.06 = 8.3 days is TTR
Results
- Demographics Mean age, years
N=17
72.1
Gender
Total of 60
patients screened
17 met study
inclusion
Males
17
Females
0
Race
Caucasian
14
Non-Caucasian
3
Mean height, cm
179.8
Mean weight, kg
93.2
Mean body mass index, kg/m2
28.9
INR goal 2-3
17
fai
lur
e
Di
ab
ete
s
s
Me
llit
u
em
ia
Hy
pe
rli
pid
Hy
pe
r te
ns
ion
Ob
es
ity
He
ar
t
Sm
ok
er
Prevalence
Results
- Comorbidities -
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Results
- Type of Malignancies Bladder
Head/neck
Malignancy Type
Liver
Colon
Leukemia
Prostate
Lung
Skin
Bone
Breast
0%
5%
10%
15%
20%
Percent of Population
25%
30%
35%
Results
- Cancer Treatment -
Radiation
18%
Hormonal
18%
Chemotherapy
24%
Surgery
40%
Results
- TTR & Bleeding Events Comparison of Time in Therapeutic Range (TTR) and Bleeding Events
120%
100%
80%
29%
12%
60%
40%
66%
67%
Pre-cancer
Post-cancer
20%
0%
Bleeding
events
TTR
Limitations
 Short observation period
 Small population
 Isolated VA population (100% males)
Conclusions
 Chemotherapy was only group with better pre-cancer
TTR
 Post-cancer TTR was better than pre-cancer TTR
 Increased hospital visitations allowing for closer observation
and adjustment
 LMWH vs. warfarin
 LMWH superior in efficacy and convenience, fewer drug
interactions, and less hemorrhagic and thromboembolic events
 Guidelines indicate LMWH is first line for cancer patients
with primary or recurrent VTE
Warfarin Efficacy
in Cancer Patients on
Long-term
Anticoagulation
Neha Doshi, PharmD Candidate
LeAnn B. Norris, PharmD, BCPS
P. Brandon Bookstaver, PharmD, BCPS
Julie Sease, PharmD, BCPS