Biomarkers for predicting atrial fibrillation: An explorative sub-analysis of the randomised SCREEN-AF trial

Figures & data

Table 1. Characteristics of all patients included in the biomarker analysis (n = 291).

	All (n = 291)	Screening Group (n = 143)	Control Group (n = 148)
Age, mean ± SD	80 ± 3	80 ± 3	80 ± 3
Sex
Female	171 (59%)	82 (57%)	89 (60%)
Male	120 (41%)	61 (43%)	59 (40%)
Baseline BP, mean ± SD	145 ± 19 / 77 ± 9	144 ± 19 / 77 ± 9	146 ± 18 / 76 ±^1
BMI, mean ± SD	27.46 ± 3.88	27.53 ± 3.97^2	27.4 ± 3.79
CHA2DS2-VASc, mean ± SD	4 ± 1	4 ± 12	4 ± 1
Medical history
Diabetes	59 (20%)	29 (20%)	30 (20%)
Hyperlipidemia	128 (44%)	66 (46%)	62 (42%)
Coronary artery disease	65 (22%)	33 (23%)^2	32 (22%)
Myocardial infarction	25 (9%)	13 (9%)	12 (8%)
Congestive heart failure	20 (7%)	7 (5%)	13 (9%)
Severe aortic or mitral valve disease	1 (0.3%)	1 (0.7%)	0 (0%)
Cardiac surgery
Coronary Artery Bypass Grafting	17 (6%)	6 (4%)	11 (7%)
Valve Surgery	0 (0%)	0 (0%)	0 (0%)
Peripheral artery disease	25 (9%)	11 (8%)^2	14 (9%)
Chronic kidney disease	28 (10%)	15 (10%)	13 (9%)^3
Dialysis	0 (0%)	0 (0%)	0 (0%)
Sleep apnoea	23 (8%)	14 (10%)	9 (6%)
Ischaemic stroke/TIA/systemic embolism	37 (13%)	19 (13%)^2	18 (12%)
COPD	26 (9%)	11 (8%)	15 (10%)
Smoker
Current	16 (5%)	10 (7%)	6 (4%)
Past	105 (38%)	50 (38%)^4	55 (39%)^2
History of any palpitations in past year (patient self-report)	86 (30%)	41 (29%)	45 (30%)
Creatinine (mg/dl), mean ± SD	1.03 ± 0.33	1.02 ± 0.34	1.04 ± 0.33
Detected atrial fibrillation	8 (2.7%)	7 (4.9%)	1 (0.7%))

SD: standard deviation.^1-3Missing data: ¹n = 145 Control,²n = 142 Screening, ³n = 146 Control, ⁴n = 132 Screening.

Figure 1. Flow diagram SCREEN-AF sub-trial (*1 withdrew consent for biomarker analysis, 3 did not give consent for biomarker analysis, 6 blood samples not available).

Table 2. Biomarker levels in patients with and without AF.

	Patients with AF (n = 8)	Patients without AF (n = 283)	p-value*
BNP (ng/L), median (IQR)	78 (64.5-112)	41 (27-77)	0.0121
NT-pro BNP (ng/L), median (IQR)	273 (201.05-587.1)	186 (111.1-319)	0.0293
NT-ANP (nmol/L), median (IQR)	4.4 (3.7-7.3)	3.5 (2.6-4.68)	0.0270
MR-pro ANP (pmol/L), median (IQR)	164 (136.59-302.14)	125 (92.84-169.43)	0.0158
hsTnI (ng/L), median (IQR)	7.4 (4.15-16.2)	3.9 (3.1-5.9)	0.0129
CRP (mg/L), median (IQR)	2.8 (1.65-5.7)	1.9 (1.1-3.7)	0.1706

*Two-sided P-value comparing patients with and without AF.

Figure 2. ROC curves of different biomarkers to identify patients developing atrial fibrillation (patients included n = 291).

Table 3. Proportion of correctly classified patients according to the biomarker cut-off values for the 25%, 50% and 75% quantiles.

	25% - quantile	50% - quantile	75% - quantile	Highest specificity* (biomarker level)
BNP (ng/L),	28	42	81
Patients with AF	8/8 (100%)	8/8 (100%)	3/8 (37.5%)	60.29 % (50.1 ng/L)
Patients without AF	78/283 (27.56%)	147/136 (51.94%)	216/67 (76.33%)
NT-pro BNP (ng/L),	114.7	187.4	320.1
Patients with AF	8/8 (100%)	7/8 (87.5%)	3/8 (37.5%)	52.94 % (179 ng/L)
Patients without AF	73/210 (25.80%)	145/283 (51.24%)	214/283 (75.62%)
NT-ANP (nmol/L),	2.66	3.5	4.78
Patients with AF	8/8 (100%)	6/8 (75%)	4/8 (50%)	44.85 % (3.3 nmol/L)
Patients without AF	73/283 (25.8%)	144/283 (50.88%)	215/283 (75.97%)
MR-pro ANP (pmol/L),	94.97	126.02	169.96
Patients with AF	8/8 (100%)	7/8 (87.5%)	3/8 (37.5%)	45.59 % (120.47 nmol/L)
Patients without AF	73/283 (25.8%)	145/283 (51.24%)	214/283 (75.62%)
hsTnI (ng/L),	3.1	4.1	6.1
Patients with AF	8/8 (100%)	6/8 (75%)	5/8 (62.5%)	47.06 % (3.55 ng/L)
Patients without AF	107/283 (37.81%)	151/283 (53.36%)	219/283 (77.39%)
CRP (mg/L),	1.1	1.9	3.7
Patients with AF	8/8 (100%)	5/8 (62.5%)	3/8 (37.5%)	28.68 % (1.15 mg/L)
Patients without AF	77/283 (27.21%)	145/283 (51.24%)	214/283 (75.62%)

*Highest specificity (correctly identified patients without AF) while maintaining 100% sensitivity (correctly identify 8/8 patients with AF).