J Hematol

Journal of Hematology, ISSN 1927-1212 print, 1927-1220 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Hematol and Elmer Press Inc

Journal website http://www.thejh.org

Original Article

Volume 2, Number 2, October 2013, pages 55-63

Experience Always Wins the Day: Measure of Warfarin Anticoagulation Efficiency in the Internal Medicine Clinic

Figure 1. During the 2 weeks follow-up, when using linear interpolation, patient A remains in the therapeutic index (2.0 - 3.0) during 80% of the time (11.2 days) vs patient B who only remains 21% of the time (3 days). Comparatively when using the proportional method, both patients stay in the therapeutic index 67% of the time (2/3 values within 2.0 - 3.0).

**Table 1.** Causes of Exclusion From the Study (n = 110)
	Number of patients (n)
APLS: Antiphospholipid syndrome; HIT: Heparin-induced thrombocytopenia; INR: International normalized ratio; LWMH: Low weight molecular heparine.
Less than 3 INR values	25
Auricular fibrillation	17
Superficial venous thrombosis	11
Use of LWMH	11
Lack of data	10
Arterial embolic/thrombotic event/APLS	7
Outside the study period	5
Follow-up done by another service	3
No anticoagulation	3
Cerebrovascular event	3
Retinal thrombosis	3
Jugular venous thrombosis	2
Portal vein thrombosis	2
Digital ischemia	1
Sagital sinus thrombosis	1
Superior vena cava syndrome	1
Mesenteric vein thrombosis	1
Warfarin allergy	1
HIT	1
Surgical repair of patent foramen ovale	1
Not present at follow-up	1

Table 1. Causes of Exclusion From the Study (n = 110)

Number of patients (n)

APLS: Antiphospholipid syndrome; HIT: Heparin-induced thrombocytopenia; INR: International normalized ratio; LWMH: Low weight molecular heparine.

Less than 3 INR values

Auricular fibrillation

Superficial venous thrombosis

Use of LWMH

Lack of data

Arterial embolic/thrombotic event/APLS

Outside the study period

Follow-up done by another service

No anticoagulation

Cerebrovascular event

Retinal thrombosis

Jugular venous thrombosis

Portal vein thrombosis

Digital ischemia

Sagital sinus thrombosis

Superior vena cava syndrome

Mesenteric vein thrombosis

Warfarin allergy

HIT

Surgical repair of patent foramen ovale

Not present at follow-up

**Table 2.** Baseline Characteristics of Patients (n = 237)
	Total n (%)
All data are no. (%) of patients unless otherwise indicated; * Defined by a hemoglobin value < 120 for women and < 140 for men; ** Defined by an elevation any liver function test (LFT) at three times the upper normal limit.
Age mean (range)	61 (21 - 97)
Gender (male)	112 (47)
Weight mean in kg (range)	82.7 (44.4 - 185)
Excessive alcohol consumption	8 (3.4)
Chronic kidney disease - GFR < 60 mL/min	28 (11.8)
Hepathopathy*	6 (2.5)
Hypertension	96 (40.5)
Anemia**	88 (37.1)
Past medical history of bleeding	12 (5.0)
Concomitant use of antiplatelet drugs	22 (9.3)
Past history of stroke	9 (3.8)
Past history of DVT/PE	90 (38)
Active cancer	24 (10.1)

Table 2. Baseline Characteristics of Patients (n = 237)

Total n (%)

All data are no. (%) of patients unless otherwise indicated; * Defined by a hemoglobin value < 120 for women and < 140 for men; ** Defined by an elevation any liver function test (LFT) at three times the upper normal limit.

Age mean (range)

61 (21 - 97)

Gender (male)

112 (47)

Weight mean in kg (range)

82.7 (44.4 - 185)

Excessive alcohol consumption

8 (3.4)

Chronic kidney disease - GFR < 60 mL/min

28 (11.8)

Hepathopathy*

6 (2.5)

Hypertension

96 (40.5)

Anemia**

88 (37.1)

Past medical history of bleeding

12 (5.0)

Concomitant use of antiplatelet drugs

22 (9.3)

Past history of stroke

9 (3.8)

Past history of DVT/PE

90 (38)

Active cancer

24 (10.1)

**Table 3.** Median Proportion of Time at Target INR Data According to Patient’s Characteristics (n = 237)
	No of patients (n)	No of INR (n)	Median follow-up (days)	Median proportion of time at target INR 2.0 - 3.0 (%)	95% CI	P-value
All data are no. of patients unless otherwise indicated; * Defined by a Glomerular Function Rate (GFR) > 60 mL/min; ** Defined by a GFR < 60 mL/min; y.o: Years old.
Overall	237	2,553	250.5	68.9	63.1- 69.1	NA
Gender
Women	125	1423	229	65	47 -81
Men	112	1130	335	70	50 -86	0.153
Chronic kidney disease
No*	198	2,155	250.5	65	48 - 83
Yes**	28	398	356.5	80	72 - 90	0.048
Age
< 40 y.o	25	237	101	55	42 -83
40 - 60 y.o	111	1,198	249	66	48 -81
> 60 y.o	101	1,118	251	73	50 -87	0.186

Table 3. Median Proportion of Time at Target INR Data According to Patient’s Characteristics (n = 237)

No of patients (n)

No of INR (n)

Median follow-up (days)

Median proportion of time at target INR 2.0 - 3.0 (%)

95% CI

P-value

All data are no. of patients unless otherwise indicated; * Defined by a Glomerular Function Rate (GFR) > 60 mL/min; ** Defined by a GFR < 60 mL/min; y.o: Years old.

Overall

237

2,553

250.5

68.9

63.1- 69.1

Gender

Women

125

1423

229

47 -81

Men

112

1130

335

50 -86

0.153

Chronic kidney disease

No*

198

2,155

250.5

48 - 83

Yes**

398

356.5

72 - 90

0.048

Age

< 40 y.o

237

101

42 -83

40 - 60 y.o

111

1,198

249

48 -81

> 60 y.o

101

1,118

251

50 -87

0.186

**Table 4.** Thrombotic and Haemorrhagic Complications During Follow-Up (n = 17)
	Type of event	INR at complication	Intervention necessary
AcO: Anticoagulation; ATB: Antibiotics; ENT: Ear-nose-throat; FFP: Fresh frozen plasma; GI: Gastrointestinal; HD: Hemodynamic; IVCF: Inferior vena cava filter; OGD: Oesophageal-gastro-duodenoscopy; PE: Pulmonary embolism; PRBC: Packed red blood cell; UK: unknown.
Thrombotic event
F87	PE	2.1	None
Minor haemorrhagic event
F55	Macroscopic hematuria	2.9	Cystoscopy/ureteroscopy/pyelography
F57	Epistaxis	UK	None
M68	Hematochezia (anal fissure)	2.0	None
F49	Iron-deficiency anemia (menorrhagia)	UK	Intravenous iron repletion
F52	ENT bleeding	2.4	ENT consultation
F87	Epistaxis	UK	None
Major haemorrhagic event
F59	Lower GI bleeding	> 9	Transfusion/colonoscopy/AcO termination
F66	Upper GI bleeding (H. pylori gastritis)	4.1	Transfusion (1PRBC)/OGD/ATB/AcO termination
F79	Knee hemarthrosis	3.8	Vitamin K/surgical drainage/AcO suspension
M63	Upper GI bleeding (gastric cancer)	1.1	OGD/AcO termination
M66	Lower GI bleeding	UK	OGD/colonoscopy/arteriography/IVCF/AcO termination
F87	Thigh hematoma with HD instability	2.6	Transfusion (3PRBC)/AcO termination
M83	Lower GI bleeding (angiodysplasia)	2.7	Transfusion (2PRBC)/AcO termination
M64	Lower GI bleeding (angiodysplasia)	6.3	Transfusion (2PRBC and 3FFP)/AcO termination
F52	Lower GI bleeding (haemorrhoid)	1.4	Vitamin K/colonoscopy/AcO suspension
M77	Post-traumatic leg hematoma	4.1	Vitamin K/AcO termination at the patient demand

Table 4. Thrombotic and Haemorrhagic Complications During Follow-Up (n = 17)

Type of event

INR at complication

Intervention necessary

AcO: Anticoagulation; ATB: Antibiotics; ENT: Ear-nose-throat; FFP: Fresh frozen plasma; GI: Gastrointestinal; HD: Hemodynamic; IVCF: Inferior vena cava filter; OGD: Oesophageal-gastro-duodenoscopy; PE: Pulmonary embolism; PRBC: Packed red blood cell; UK: unknown.

Thrombotic event

F87

2.1

None

Minor haemorrhagic event

F55

Macroscopic hematuria

2.9

Cystoscopy/ureteroscopy/pyelography

F57

Epistaxis

None

M68

Hematochezia (anal fissure)

2.0

None

F49

Iron-deficiency anemia (menorrhagia)

Intravenous iron repletion

F52

ENT bleeding

2.4

ENT consultation

F87

Epistaxis

None

Major haemorrhagic event

F59

Lower GI bleeding

> 9

Transfusion/colonoscopy/AcO termination

F66

Upper GI bleeding (H. pylori gastritis)

4.1

Transfusion (1PRBC)/OGD/ATB/AcO termination

F79

Knee hemarthrosis

3.8

Vitamin K/surgical drainage/AcO suspension

M63

Upper GI bleeding (gastric cancer)

1.1

OGD/AcO termination

M66

Lower GI bleeding

OGD/colonoscopy/arteriography/IVCF/AcO termination

F87

Thigh hematoma with HD instability

2.6

Transfusion (3PRBC)/AcO termination

M83

Lower GI bleeding (angiodysplasia)

2.7

Transfusion (2PRBC)/AcO termination

M64

Lower GI bleeding (angiodysplasia)

6.3

Transfusion (2PRBC and 3FFP)/AcO termination

F52

Lower GI bleeding (haemorrhoid)

1.4

Vitamin K/colonoscopy/AcO suspension

M77

Post-traumatic leg hematoma

4.1

Vitamin K/AcO termination at the patient demand