PATAF (vs coumadin low dose) trial

PATAF (vs coumadin low dose) study, 1999	TRC2616
	download pdf: aspirin \| antithrombotics for atrial fibrillation

Treatments

Studied treatment	aspirin 300mg/d
Control treatment	coumarin low dose(target INR 1.1-1.6 )
Remarks	The PATAF trial includes 2 strata: -patients eligible for standard intensity coumarin:randomly assigned to standard anticoagulation(INR 2.5-3.5),very low intensity anticoagulation(INR 1.1-1.6) or aspirin(150mg/d). -patients ineligible for standard anticoagulation:randomly assigned to very low intensity anticoagulation(INR 1.1-1.6) or aspirin(150mg/d).

Patients

non rheumatic AF,recruited in general practice,with no established indication for anticoagulation.

Inclusion criteria

age >60;chronic or intermittent AF confirmed by ECG within the 2 past years;no established indication for coumarin

Exclusion criteria

General exclusion criteria:treatable cause of AF;previous stroke;rheumatic valvular disease,myocardial infarction or cardiovascular surgery in past year;cardiomyopathy(left ventricular ejection < 40%;chronic heart failure;cardiac aneurysm;history of systemic embolism;retinal infarction;coumarin use in the past 3 month;contra-indications for aspirin or coumarin;pacemaker;life expectancy < 2 years. Exclusion criteria for standard anticoagulation:age >78;retinopathy;ventricular or duodenal ulcer;history of gastro-intestinal or genito-urinary bleeding;diastolic blood pressure>105 mmHg or systolic pressure >185 mmHg or both.

Remarks

We took all patients who were given aspirin (strate 1+2) and all patients on low dose anticoagulation(strate 1+2).

Baseline characteristics

age(mean)	75.2
male(%)	44.9
systolic blood pressure(mean)	151.25
diastolic blood pressure(mean)	84.25
hypertension(%)	40.6
diabete mellitus(%)	16
prior myocardial infarction(%)	9
paroxysmal AF(%)	15.3
current smoker(%)	9.5
subgroup test	c

Method and design

Randomized effectives	319 / 279 (studied vs. control)
Design	Parallel groups
Blinding	Simple aveugle
Follow-up duration	2.7 years
Lost to follow-up	no lost to follow up
Geographic area	Netherlands
Hypothesis	non inferiority
Primary endpoint	stroke,systemic embolism,major haemorrhage and vascular death
Remarks	The study was carried out to show that aspirin is equivalent to warfarin, but the methodology used was inappropriate.The study team conducted an intention to treat analysis and assumed they could conclude to equivalence if no significant difference was found between treatments at the end of the study.But this hypothesis is wrong :if no difference has been found,no conclusion is possible,and particularly, equivalence can't be proven.
Withdrawals (T1/T0)	16.9% / 25.8%

Results

Endpoint Studied treat.
n/N Control treat.
n/N Graph RR [95% CI]

thrombo-embolic event (cerebral or systemic)

23 / 319
16 / 279
classic 1,26 [0,68;2,33]

stroke (fatal and non fatal)

22 / 319
18 / 279
1,07 [0,59;1,95]

ischemic stroke

17 / 319
15 / 279
0,99 [0,50;1,95]

All cause death

66 / 319
41 / 279
classic 1,41 [0,99;2,01]

Cardiovascular death

34 / 319
28 / 279
1,06 [0,66;1,71]

Fatal stroke

8 / 319
4 / 279
classic 1,75 [0,53;5,75]

TE event or ischemic stroke or systemic embolism

23 / 319
16 / 279
classic 1,26 [0,68;2,33] 0 2 1.0

Endpoint	Events (%)		Relative Risk	95% CI	Endpoint definition in the trial	Ref
Relative risks
Endpoint	Studied treat.	Control treat.	Relative Risk	95% CI	Endpoint definition in the trial	Ref
thrombo-embolic event (cerebral or systemic)	23 / 319 (7,2%)	16 / 279 (5,7%)	1,26	[0,68;2,33]
stroke (fatal and non fatal)	22 / 319 (6,9%)	18 / 279 (6,5%)	1,07	[0,59;1,95]	classified as ischemic or hemorrhagic according to computed tomography
ischemic stroke	17 / 319 (5,3%)	15 / 279 (5,4%)	0,99	[0,50;1,95]
All cause death	66 / 319 (20,7%)	41 / 279 (14,7%)	1,41	[0,99;2,01]
Cardiovascular death	34 / 319 (10,7%)	28 / 279 (10,0%)	1,06	[0,66;1,71]	within 4 weeks after stroke,systemic embolism,myocardial infarction,congestive heart failure or major bleeding or sudden death
Fatal stroke	8 / 319 (2,5%)	4 / 279 (1,4%)	1,75	[0,53;5,75]
TE event or ischemic stroke or systemic embolism	23 / 319 (7,2%)	16 / 279 (5,7%)	1,26	[0,68;2,33]	thrombo-embolic event, ischemic stroke or systemic embolism
The primary endpoint (if exists) appears in blod characters
Reference(s) used for data extraction: 0:

Endpoint	Events rate		Absolute risk reduction (ARR)
Absolute risk reduction (for a follow-up of 2.7 years)
Endpoint	Studied treat.	Control treat.	Absolute risk reduction (ARR)
thrombo-embolic event (cerebral or systemic)	7,21%	5,73%	1,5%
stroke (fatal and non fatal)	6,90%	6,45%	0,44%
ischemic stroke	5,33%	5,38%	-0,05%
All cause death	20,69%	14,70%	6,0%
Cardiovascular death	10,66%	10,04%	0,62%
Fatal stroke	2,51%	1,43%	1,1%
TE event or ischemic stroke or systemic embolism	7,21%	5,73%	1,5%

Meta-analysis of all similar trials:

antithrombotics in atrial fibrillation for primary prevention of thromboembolic events

Reference(s)

TrialResults-center ID	TRC2616
Trials register #	NA