Patients’ time in therapeutic range on warfarin among atrial fibrillation patients in Warfarin Medication Therapy Adherence Clinic

Table 1 Baseline characteristics

Baseline characteristic	All patients, n = 420	TTR < 60%, n = 178	TTR ≥ 60%, n = 242
Age, yr
mean ± SD	65.7 ± 10.9	65.7 ± 10.8	65.7± 10.9
Median (IQR)	67 (15)	66 (14)	67 (15)
Male	227(54.0)	99 (55.6)	128 (52.9)
Female	193 (46.0)	79 (44.4)	114 (47.1)
Ethnicity
Malay	210 (50.0)	96 (53.9)	114 (47.1)
Chinese	179 (42.6)	64 (36.0)	115 (47.5)
Indian	26 (6.2)	16 (9.0)	10 (4.1)
Others	5 (1.2)	2 (1.1)	3 (1.2)
Comorbidities
Diabetes mellitus	170 (40.5)	85 (47.8)	85 (35.1)
Hypertension	291 (69.3)	128 (71.9)	163 (67.4)
Ischemic heart disease	90 (21.4)	48 (27.0)	42 (17.4)
Peripheral vascular disease	8 (1.9)	2 (1.1)	6 (2.5)
Stroke/transient ischemic attack	49 (11.7)	20 (11.2)	29 (12.0)
Deep vein thrombosis/pulmonary embolism	2 (0.5)	1 (0.6)	1 (0.4)
Heart failure	27 (6.4)	12 (6.7)	15 (6.2)
Chronic obstructive pulmonary disease/asthma	22 (5.2)	8 (4.5)	14 (5.8)
Chronic kidney disease	49 (11.7)	28 (15.7)	21 (8.7)
Dyslipidaemia	125 (29.8)	47 (26.4)	78 (32.2)
Chronic rheumatic heart disease	17 (4.0)	10 (5.6)	7 (2.9)
Liver disease	0 (0.0)	0 (0.0)	0 (0.0)
CHA2DS2-VASc score
Mean ± SD	2.6 ± 1.4	-	-
Median (IQR)	3 (1.0)	3 (2)	2(1)
Score 0-1	91 (21.7)	34 (19.1)	57 (23.6)
Score 2-4	297 (70.7)	125 (70.2)	172 (71.1)
Score ≥ 5	32 (7.6)	19 (10.7)	13 (5.4)
HAS-BLED score
Median (IQR)	2 (2.0)	3 (1.0)	2 (2.0)
Low bleeding risk (score ≤ 2)	257 (61.2)	83 (46.6)	174 (71.9)
High bleeding risk (score ≥ 3)	163 (38.8)	95 (53.4)	68 (28.1)

All values are reported as n (%) unless otherwise noted. IQR: Interquartile range; TTR: Time in therapeutic range; SD Standard deviation.

Table 2 Time in the therapeutic range of the study population

Variables	All patients, n = 420	TTR < 60%, n = 178	TTR ≥ 60%, n = 242
TTR
mean ± SD	60.6 ± 20.6	41.1 ± 14.7	75.0 ± 9.6
Median (IQR)	64 (27)	44 (22)	74 (14)
Good (≥ 60%)	242 (57.6)	-	-
Poor (< 60%)	178 (42.4)	-	-

SD: Standard deviation; TTR: Time in therapeutic range.

Table 3 Univariate and multivariate logistic regression analysis for predictors of poor time in therapeutic range < 60% among atrial fibrillation patients

Baseline characteristic	Univariate			Multivariate
				Model 11					Model 22
	OR	95%CI	P	aOR	95%CI		P		aOR	95%CI	P
Age	1.0	0.9-1.0	0.976
Ethnicity
Malay	1.0	Reference	-
Chinese	1.3	0.2-7.7	0.800
Indian	0.8	0.1-5.1	0.845
Others	2.4	0.3-16.9	0.380
Gender
Male	1.0	Reference	-
Female	0.9	0.6-1.3	0.580
Comorbidities
Diabetes mellitus	1.7	1.1-2.5	0.009	1.3		0.8-1.9		0.240
Hypertension	1.2	0.8-1.9	0.318
Ischemic heart disease	1.8	1.1-2.8	0.018	1.3		0.8-2.1		0.317
Peripheral vascular disease	0.4	0.1-2.2	0.328
Stroke/transient ischemic attack	0.9	0.5-1.7	0.814
Deep vein Thrombosis/pulmonary embolism	1.4	0.1-21.9	0.828
Heart failure	1.1	0.5-2.4	0.823						1.0	0.5-2.4	0.913
Chronic obstructive pulmonary disease/asthma	0.8	0.3-1.9	0.558
Chronic kidney disease	1.9	1.1-3.6	0.028	1.2		0.6-2.3		0.585	1.2	0.7-2.4	0.514
Dyslipidaemia	0.7	0.5-1.2	0.197
Chronic rheumatic heart disease	1.9	0.8-5.4	0.169
CHA2DS2-VASc score	1.4	0.9-2.1	0.060						0.9	0.6-1.4	0.629
HAS-BLED Score
Low bleeding risk (score ≤ 2)	1.0	Reference	-
High bleeding risk (score ≥ 3)	2.9	1.9-4.4	< 0.001	2.5		1.6-3.9		< 0.001	2.9	1.8-4.7	< 0.001

¹Model 1, adjusted to significant variables of the study populations.

²Model 2, adjusted to heart failure, chronic kidney disease, CHA2DS2-VASc score and HAS-BLED score. aOR: Adjusted odds ratio; CI: Confidence interval; TTR: Time in therapeutic range.