Study Population
427 AF patients who received anticoagulant therapy with warfarin or rivaroxaban were enrolled in the study. One group (216 participants) were treated with warfarin, the other group (211 participants) were treated with rivaroxaban. However, 40 participants were lost during the follow-up period: 22 in warfarin-treated group and 18 in rivaroxaban-treated group. The two group were comparable in age, gender, hypertension, diabetes mellitus, previous stroke, cardiac function, CHA2DS2-VASc score, and blood biochemical indexes et al. The results showed in Table 1.
Table 1
Baseline characteristics of study population
Characteristic | Warfarin (n = 194) | Rivaroxaban (n = 193) | P value |
Age (years) | 61.75 ± 9.83 | 64.90 ± 11.81 | 0.005 |
Men (%) | 107 (55.2%) | 112 (58.0%) | 0.568 |
Hypertension (%) | 68 (35.1%) | 95 (49.2%) | 0.005 |
Diabetes mellitus (%) | 30 (15.5%) | 40 (20.7%) | 0.179 |
Previous stroke/TIA (%) | 31 (16.0%) | 35 (18.1%) | 0.573 |
Heart failure (%) | 126 (64.9%) | 45 (23.3%) | < 0.001 |
Vascular disease (%) | 87 (44.8%) | 118 (61.1%) | 0.001 |
CHA2DS2-VASc score( mean) | 2.75 ± 1.44 | 2.90 ± 1.77 | 0.348 |
Smoker (%) | 52 (26.8%) | 35 (18.1%) | 0.041 |
Alcohol user (%) | 37 (19.1%) | 24 (12.4%) | 0.073 |
LDL-C (mmol/l) | 2.59 ± 0.85 | 2.33 ± 0.73 | 0.001 |
HDL-C (mmol/l) | 1.11 ± 0.32 | 1.09 ± 0.25 | 0.590 |
Total cholesterol (mmol/l) | 4.20 ± 1.03 | 3.98 ± 0.87 | 0.033 |
Triglyceride (mmol/l) | 1.55 ± 0.71 | 1.72 ± 1.16 | 0.089 |
Lipoprotein (a) (g/ l) | 1.12 ± 0.24 | 1.17 ± 0.26 | 0.062 |
Lipoprotein (b) (g/ l) | 0.90 ± 0.26 | 0.81 ± 0.23 | 0.001 |
Uric acid (µmol/l) | 393.31 ± 137.17 | 342.82 ± 122.61 | < 0.001 |
Crcl (ml/min) | 96.83 ± 46.51 | 90.49 ± 31.51 | 0.118 |
LAD (mm) | 45.98 ± 9.98 | 40.16 ± 6.38 | < 0.001 |
LVEF (%) | 55.34 ± 10.75 | 58.83 ± 8.20 | 0.001 |
Data are presented as mean ± standard deviation or proportions. TIA, transient ischemic attack; LDL-C, low-density lipoprotein cholesterol; HDL-C, high density lipoprotein cholesterol; Crcl, creatinine clearance; LAD, Left atrial diameter; LVEF, left ventricular ejection fraction. |
Adherence
Adherence rate was 59.3% in warfarin-treated group, which was lower than rivaroxaban-treated group (78.2%, P < 0.001). The adherence rate of moderate-risk stroke patients (score 2–3, 67.3%) was higher than patients with low or high-risk stroke in warfarin-treated group (score 0–1, 51.4% and score ≥ 4, 49.1%). The adherence rates were similar in rivaroxaban-treated patients with different CHA2DS2-VASc scores (score 0–1, 79.6%; score 2–3, 75.7%; score ≥ 4, 79.7%). There was lower adherence of warfarin-treated group than rivaroxaban-treated group with score 0–1 and score ≥ 4 (P < 0.01 for all comparisons). The results showed in Table 2.
Table 2
Adherence to warfarin and rivaroxaban
Characteristic | Warfarin (n = 194) | Rivaroxaban (n = 193) | P value |
All | 115 (59.3%) | 151 (78.2%) | < 0.001 |
CHA2DS2-VASc score 0 or 1 | 19 (51.4%) | 39 (79.6%) | 0.006 |
CHA2DS2-VASc score 2 or 3 | 70 (67.3%) | 53 (75.7%) | 0.232 |
CHA2DS2-VASc score ≥ 4 | 26 (49.1%) | 59 (79.7%) | < 0.001 |
CHA2DS2-VASc, risk based on the presence of congestive heart failure, hypertension, age ≥ 75 year, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category. |
Safety and Efficacy Outcomes
The safety and efficacy outcomes of two groups during the follow-up period were showed in Fig. 1. Bleeding events were more in warfarin-treated group (36, 18.6%) than rivaroxaban-treated group (29, 15.0%), but there was no statistical difference (Fig. 1A). There was 36 patients occurred bleeding in the warfarin group, which included hemorrhinia (12, 33.3%), fundus hemorrhage (4, 11.1%), gingival bleeding (16, 44.4%), and gastrointestinal bleeding (4, 11.1%) (Fig. 1C). There was 29 patients occurred bleeding in the rivaroxaban group, which included hemorrhinia (3, 10.3%), fundus hemorrhage (5, 17.2%), gingival bleeding (17, 58.6%), and gastrointestinal bleeding (4, 13.8%) (Fig. 1D). The cumulative incidence of IS events in the warfarin and rivaroxaban groups was 8.8% (17/194) and 6.7% (13/193), respectively (Fig. 1B). There was no statistical difference in the two treatment groups.
Risks of Bleeding and IS based on CHA2DS2-VASc Scores
To evaluate the safety and efficacy of warfarin versus rivaroxaban in AF patients at different CHA2DS2-VASc scores, we classified the AF patients to three groups: CHA2DS2-VASc score 0–1, score 2–3, and score ≥ 4, which have treated with warfarin or rivaroxaban. Bleeding events tended to be more in warfarin-treated group than rivaroxaban-treated group at score 0–1 and score 2–3, but the difference was no significance (Fig. 2A). Furthermore, in warfarin-treated group, patients with score 0–1 have more bleeding events than patients with score 2–3 and score ≥ 4 (Fig. 2B) (P < 0.05). In rivaroxaban-treated group, bleeding was not significantly different between patients with different scores (Fig. 2C).
IS events were more in warfarin-treated group than rivaroxaban-treated group at score 0–1 and score ≥ 4, but the difference was no statistical significance (Fig. 2D). Furthermore, in warfarin-treated group, patients with score ≥ 4 have more IS events than patients with score 2–3 (Fig. 2E) (P < 0.01). In rivaroxaban-treated group, IS events was not significantly different between patients with different scores (Fig. 2F).
To further study type of bleeding with CHA2DS2-VASc score, we divided the bleeding into four subgroups: hemorrhinia, fundus hemorrhage, gingival bleeding, and gastrointestinal bleeding, which have induced by warfarin or rivaroxaban (Fig. 3). Only hemorrhinia was more in the warfarin-treated group than the rivaroxaban-treated group with score 0–1 (Fig. 3A) (P < 0.05). The incidence rate of fundus hemorrhage, gingival bleeding, and gastrointestinal bleeding was not significantly different in warfarin or rivaroxaban-treated group with different scores (Fig. 3B-D).
Hospitalization
99 patients were hospitalized in the follow-up period. The incidence rates of hospitalization were 23.2% (45/194) in warfarin-treated group and 28.0% (54/193) in rivaroxaban-treated group (Fig. 4A). The incidence rates of hospitalization were not significantly different in warfarin or rivaroxaban-treated group with different scores (Fig. 4B).