Two-year outcomes of UK patients newly diagnosed with atrial fibrillation: findings from the prospective observational cohort study GARFIELD-AF

Patricia N Apenteng; Saverio Virdone; FD Richard Hobbs; A John Camm; Keith AA Fox; Karen S Pieper; Gloria Kayani; David Fitzmaurice

doi:10.3399/BJGP.2021.0548

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Figure 1.
a) Treatment at diagnosis by CHA₂DS₂-VASc score. b) Treatment at diagnosis by HAS-BLED score. AP = antiplatelet. DTI + AP = direct thrombin inhibitor and antiplatelet. FXa + AP = factor Xa inhibitor and antiplatelet. VKA + AP = vitamin K antagonist and antiplatelet.
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Figure 2.
a) Event rates according to CHA₂DS₂-VASc score. Includes only patients with available CHA₂DS₂-VASc scores (n = 3528). b) Event rates according to HAS-BLED scores. Includes only patients with available HAS-BLED scores (n = 2530). SE = systemic embolism.
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Figure 3.
Unadjusted and adjusted hazard ratios of OAC versus no OAC (reference) and corresponding 95% confidence intervals for selected outcomes at 2 years of follow-up in UK patients. Adjusted hazard ratios were obtained using an overlap-weighted Cox model. Variables included in the weighting scheme are: cohort enrolment, sex, age, ethnicity, type of AF, care setting specialty and location, congestive heart failure, acute coronary syndromes, vascular disease, carotid occlusive disease, prior stroke/transient ischaemic attack/SE, prior bleeding, venous thromboembolism, hypertension, hypercholesterolemia, diabetes, cirrhosis, moderate-to-severe chronic kidney disease, dementia, hyperthyroidism, hypothyroidism, current smoking, heavy alcohol consumption, body mass index, heart rate, systolic and diastolic blood pressure at diagnosis, and baseline antiplatelet use. AF = atrial fibrillation. OAC = oral anticoagulant. SE = systemic embolism.

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Atrial fibrillation (AF) increases the risk of stroke and death; anticoagulation reduces these risks at the cost of an increased risk of bleeding. There has been an increase in the proportion of patients with AF receiving anticoagulants, with patients receiving either vitamin K antagonists or direct-acting oral anticoagulants. Evidence on outcomes following the increase in the use of anticoagulant therapy in the UK is limited. In this study, the benefit of anticoagulation in this real-world cohort of patients with AF affirms recommendations in AF management guidelines. Addressing gaps in anticoagulation treatment for patients with AF may reduce AF-related stroke and death.

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Table 1.

Baseline characteristics of participants

Variable	Value	%
Age, years, median (Q1; Q3)	75.0 (69.0; 81.0)	—

Age, years, *n/N*
<65	471/3574	13.2
65–74	1178/3574	33.0
≥75	1925/3574	53.9

Sex, female, n/N	1522/3574	42.6

Ethnicity, White, n/N	3441/3483	98.8

Body mass index, median (Q1; Q3)	28.1 (25.0; 32.3)	—

Medical history, n/N
Congestive heart failure	274/3573	7.7
Coronary artery disease	678/3573	19.0
Acute coronary syndromes	363/3561	10.2
Carotid occlusive disease	52/3515	1.5
Prior stroke/TIA/systemic embolism	450/3551	12.7
Vascular disease^a	760/3551	21.4
History of bleeding	109/3560	3.1
Hypertension	2483/3564	69.7
Hypercholesterolemia	1318/3492	37.7
Diabetes mellitus	629/3573	17.6
Chronic kidney disease (grade ≥3)	896/3499	25.6
Cirrhosis	11/3527	0.3

CHA₂DS₂-VASc, median (Q1; Q3)	3.0 (2.0; 4.0)	—

CHA₂DS₂-VASc score categories, n/N
0	89/3528	2.5
1	289/3528	8.2
2	659/3528	18.7
3	972/3528	27.6
4	848/3528	24.0
5	398/3528	11.3
≥6	273/3528	7.7

HAS-BLED score, median (Q1; Q3)^b	2.0 (1.0; 2.0)	—

HAS-BLED score categories, n/N ^b
0	160/2530	6.3
1	941/2530	37.2
2	950/2530	37.5
3	391/2530	15.5
≥4	88/2530	3.5

Care setting at diagnosis, n/N
Cardiology	544/3573	15.2
Geriatrics	63/3573	1.8
Internal medicine	779/3573	21.8
Neurology	4/3573	0.1
Primary care/general practice	2183/3573	61.1

↵a Defined as peripheral artery disease and/or coronary artery disease.
↵b The risk factor ‘Labile INRs’ is not included in the HAS-BLED score as these data are not collected at baseline. As a result, the maximum HAS-BLED score at baseline is eight points (not nine). INR = international normalisation ratio. Q1 = quartile 1. Q3 = quartile 3. TIA = transient ischaemic attack.

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Table 2.

Baseline characteristics by anticoagulant treatment versus no anticoagulant treatment

Baseline characteristics	Baseline treatment		P-value^a

	No OAC (N= 1219)	OAC (N = 2342)
Sex, n (%)
Male	719 (59.0)	1324 (56.5)	0.161
Female	500 (41.0)	1018 (43.5)

Age, years, median (Q1; Q3)	75.0 (69.0; 82.0)	75.0 (69.0; 81.0)	0.353

Ethnicity, n (%)	1172	2298
White	1160 (99.0)	2268 (98.7)	0.659
Hispanic/Latino	2 (0.2)	8 (0.3)
Asian	3 (0.3)	10 (0.4)
African Caribbean/mixed/other	7 (0.6)	12 (0.5)

Body mass index, kg/m², median (Q1; Q3)	27.5 (24.6; 31.3)	28.4 (25.1; 32.7)	0.002

Systolic blood pressure, mmHg, median (Q1; Q3)	134.0 (121.0; 143.0)	132.0 (120.0; 140.0)	0.021

Diastolic blood pressure, mmHg, median (Q1; Q3)	79.0 (70.0; 84.0)	78.0 (70.0; 83.0)	0.127

Pulse, BPM, median (Q1; Q3)	82.0 (70.0; 102.0)	80.0 (70.0; 100.0)	0.033

Type of atrial fibrillation, n (%)
Permanent	379 (31.1)	852 (36.4)	<0.001
Persistent	65 (5.3)	209 (8.9)
Paroxysmal	257 (21.1)	392 (16.7)
New onset (unclassified)	517 (42.4)	889 (38.0)

Medical history, n (%)^b
Heart failure	70 (5.7)	201 (8.6)	0.003
Acute coronary syndromes	114 (9.4)	249 (10.7)	0.224
Vascular disease^c	251 (20.7)	504 (21.7)	0.521
Carotid occlusive disease	14 (1.2)	37 (1.6)	0.294
Venous thromboembolism	40 (3.3)	124 (5.3)	0.007
Prior stroke/TIA/systemic embolism	122 (10.1)	328 (14.1)	<0.001
Prior bleeding	69 (5.7)	40 (1.7)	<0.001
Hypertension	810 (66.6)	1664 (71.3)	0.004
Hypercholesterolaemia	429 (36.1)	883 (38.5)	0.172
Diabetes	161 (13.2)	464 (19.8)	<0.001
Cirrhosis	6 (0.5)	5 (0.2)	0.155
Moderate-to-severe CKD	308 (25.9)	585 (25.5)	0.774
Dementia	8 (0.7)	20 (0.9)	0.529

Heavy alcohol consumption, n (%)^b	68 (6.3)	58 (2.8)	<0.001

Current smoker, n (%)^b	87 (7.3)	155 (6.7)	0.554

Antiplatelet treatment, n (%)	742 (60.9)	447 (19.1)	<0.001

CHA₂DS₂-VASc score, median (Q1; Q3)	3.0 (2.0; 4.0)	3.0 (2.0; 4.0)	<0.001

HAS-BLED score, median (Q1; Q3)	2.0 (1.0; 3.0)	2.0 (1.0; 2.0)	<0.001

↵a P-values calculated using t-test or Wilcoxon-Mann-Whitney test for categorical variables and χ² test or Fisher exact test for categorical variables, as appropriate.
↵b Some patients have unavailable baseline characteristics information. Percentages are calculated among those with available information.
↵c Defined as peripheral artery disease and/or coronary artery disease.
d The risk factor ‘Labile INRs’ is not included in the HAS-BLED score as it was not collected at baseline. As a result, the maximum HAS-BLED score at baseline is eight points (not nine). BPM = beats per minute. CKD = chronic kidney disease. INR = international normalisation ratio. OAC = oral anticoagulant. TIA = transient ischaemic attack.

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Table 3.

Two-year event rates per 100 person–years in the GARFIELD-AF UK population by treatment at baseline

Treatment at baseline	All-cause mortality		Non-haemorrhagic stroke/systemic embolism		Major bleeding
Treatment at baseline	Events	Rate (95% CI)	Events	Rate (95% CI)	Events	Rate (95% CI)
OAC	172	3.89 (3.35 to 4.52)	46	1.05 (0.79 to 1.40)	55	1.26 (0.97 to 1.64)
No OAC	106	4.68 (3.87 to 5.66)	49	2.21 (1.67 to 2.92)	25	1.11 (0.75 to 1.65)
DOAC	52	3.98 (3.03 to 5.23)	13	1.00 (0.58 to 1.73)	10	0.77 (0.41 to 1.43)
VKA	120	3.85 (3.22 to 4.61)	33	1.07 (0.76 to 1.51)	45	1.46 (1.09 to 1.96)
OAC + antiplatelet	37	4.43 (3.21 to 6.11)	6	0.72 (0.32 to 1.61)	15	1.82 (1.10 to 3.02)
OAC only	135	3.77 (3.18 to 4.46)	40	1.13 (0.83 to 1.54)	40	1.13 (0.83 to 1.54)
Antiplatelet only	60	4.35 (3.37 to 5.60)	35	2.61 (1.87 to 3.63)	16	1.17 (0.72 to 1.91)
No OAC nor antiplatelet	46	5.19 (3.89 to 6.93)	14	1.60 (0.95 to 2.70)	9	1.02 (0.53 to 1.97)

DOAC = direct-acting oral anticoagulant. GARFIELD-AF = Global Anticoagulant in the FIELD — Atrial Fibrillation registry. OAC = oral anticoagulant. VKA = vitamin K antagonist.

Supplementary Data

SUPPLEMENTARY DATA

Supplementary material is not copyedited or typeset, and is published as supplied by the author(s). The author(s) retain(s) responsibility for its accuracy.