Oral Anticoagulation in HF Patients With Atrial Fibrillation
Oral Anticoagulation in HF Patients With Atrial Fibrillation
Among 9,706 admissions with a primary diagnosis of HF, 2,358 (24.3%) patients had a prior history of AF, 674 (6.9%) had new-onset AF, and 6,674 (68.8%) had no AF. The median age of patients with prior AF was 71 years (25th-75th, 59–79 years); for patients with new-onset AF, it was 69 years (57–80 years); and for patients with no AF, it was 66 years (55–75 years) (P < .0001) (Table I). Patients with prior AF were more likely to have a history of stroke/TIA (17.4% vs 10.5% vs 11.01%; P < .0001). Patients with prior AF were also more likely to have peripheral vascular disease (7.5% vs 2.8% vs 5.7%; P < .0001) and chronic renal insufficiency with a serum creatinine level >2.0 (24.2% vs 14.1% vs 22.7%; P < .0001).
Patients with new-onset AF had higher heart rates (97 beat/min [80–120 beat/min]) than those with prior AF (89 beat/min [74–109 beat/min]) and those with no AF (90 beat/min [77–103 beat/min]; P < .0001) and were less likely to have a history of ischemic heart disease (32.6% vs 44.4% vs 52.5%; P < .0001) or pulmonary disease (10.7% vs 15.8% vs 12.0%; P < .0001). Patients with new-onset AF had a lower incidence of left ventricular systolic dysfunction (37.7% vs 39.0% vs 51.4 %) defined as a left ventricular ejection fraction <40%.
Among the 2,750 HF admissions with any AF (prior history or new onset), the overall rate of VKA use at discharge was 39.5%. There were 37 patients (1.3%) with contraindications to warfarin use not included in our analyses. Among eligible patients, the median VKA use at discharge was 37.8% (20.0%-55.2%) across hospitals, which was similar in the Asia Pacific region (39.7%) and in Latin America (37.2%). In the univariate analysis, we found that patients who were older and had a history of anemia, diabetes mellitus, hypertension, and ischemic heart disease were less likely to be discharged with a VKA (Table II). As shown in Table III, our multivariable logistic regression model identified prior stroke and history of implantable cardioverter defibrillator and pacemaker implantation as factors independently associated with an increased risk of being discharged on warfarin. There was less VKA use in older patients with a prior history of coronary artery disease and worsening renal function as measured by serum creatinine levels during this hospitalization. After adjusting for patient characteristics, the country with the highest VKA use was Australia (65.2%). The country with both the lowest unadjusted (18.3%) and adjusted (25.1%) VKA use was Taiwan (Table IV).
To examine the relationship between stroke risk factors and VKA use, we analyzed VKA use according to CHADS2 scores. There was significant risk-treatment mismatch between low-risk (CHADS2 score = 1) and higher-risk (CHADS2 score ≥ 2) patients, with greater VKA use in the low-risk patients (P < .0001 for trend). Figure 1 depicts the rates of VKA use at discharge in low (=1) versus higher (≥2) CHADS2 scores by country. Among patients with HF as their only risk factor, 50.6% were discharged with a VKA compared with 38.5% of patients with a CHADS2 score of 6. The lowest rate of VKA use was 30.5% in patients with a CHADS2 score of 4 (Figure 2). Aspirin use was significantly greater in higher-risk patients (42.2%) compared with low-risk patients (29.8%). The anticoagulation rates were 36.4% in patients with a history of hypertension, 28.1% in patients >75 years old, 34.8% in patients with diabetes mellitus, and 44.4% in patients with a history of stroke/TIA.
(Enlarge Image)
Figure 1.
Vitamin K antagonist use in low (=1) versus high (≥2) CHADS2 scores by country. Across all countries, HF patients with higher risk of stroke were less likely to receive anticoagulation than lower-risk patients. The only exception was Indonesia, where higher-risk patients were more likely to receive a VKA.
(Enlarge Image)
Figure 2.
Vitamin K antagonist use at discharge among HF patients according to CHADS2 score. Among eligible HF patients with AF, VKA use declined with increasing stroke risk defined by CHADS2 score (P < .0001 for trend).
Results
Baseline Characteristics
Among 9,706 admissions with a primary diagnosis of HF, 2,358 (24.3%) patients had a prior history of AF, 674 (6.9%) had new-onset AF, and 6,674 (68.8%) had no AF. The median age of patients with prior AF was 71 years (25th-75th, 59–79 years); for patients with new-onset AF, it was 69 years (57–80 years); and for patients with no AF, it was 66 years (55–75 years) (P < .0001) (Table I). Patients with prior AF were more likely to have a history of stroke/TIA (17.4% vs 10.5% vs 11.01%; P < .0001). Patients with prior AF were also more likely to have peripheral vascular disease (7.5% vs 2.8% vs 5.7%; P < .0001) and chronic renal insufficiency with a serum creatinine level >2.0 (24.2% vs 14.1% vs 22.7%; P < .0001).
Patients with new-onset AF had higher heart rates (97 beat/min [80–120 beat/min]) than those with prior AF (89 beat/min [74–109 beat/min]) and those with no AF (90 beat/min [77–103 beat/min]; P < .0001) and were less likely to have a history of ischemic heart disease (32.6% vs 44.4% vs 52.5%; P < .0001) or pulmonary disease (10.7% vs 15.8% vs 12.0%; P < .0001). Patients with new-onset AF had a lower incidence of left ventricular systolic dysfunction (37.7% vs 39.0% vs 51.4 %) defined as a left ventricular ejection fraction <40%.
Vitamin K Antagonist Use at Discharge
Among the 2,750 HF admissions with any AF (prior history or new onset), the overall rate of VKA use at discharge was 39.5%. There were 37 patients (1.3%) with contraindications to warfarin use not included in our analyses. Among eligible patients, the median VKA use at discharge was 37.8% (20.0%-55.2%) across hospitals, which was similar in the Asia Pacific region (39.7%) and in Latin America (37.2%). In the univariate analysis, we found that patients who were older and had a history of anemia, diabetes mellitus, hypertension, and ischemic heart disease were less likely to be discharged with a VKA (Table II). As shown in Table III, our multivariable logistic regression model identified prior stroke and history of implantable cardioverter defibrillator and pacemaker implantation as factors independently associated with an increased risk of being discharged on warfarin. There was less VKA use in older patients with a prior history of coronary artery disease and worsening renal function as measured by serum creatinine levels during this hospitalization. After adjusting for patient characteristics, the country with the highest VKA use was Australia (65.2%). The country with both the lowest unadjusted (18.3%) and adjusted (25.1%) VKA use was Taiwan (Table IV).
Risk Stratification and VKA Use
To examine the relationship between stroke risk factors and VKA use, we analyzed VKA use according to CHADS2 scores. There was significant risk-treatment mismatch between low-risk (CHADS2 score = 1) and higher-risk (CHADS2 score ≥ 2) patients, with greater VKA use in the low-risk patients (P < .0001 for trend). Figure 1 depicts the rates of VKA use at discharge in low (=1) versus higher (≥2) CHADS2 scores by country. Among patients with HF as their only risk factor, 50.6% were discharged with a VKA compared with 38.5% of patients with a CHADS2 score of 6. The lowest rate of VKA use was 30.5% in patients with a CHADS2 score of 4 (Figure 2). Aspirin use was significantly greater in higher-risk patients (42.2%) compared with low-risk patients (29.8%). The anticoagulation rates were 36.4% in patients with a history of hypertension, 28.1% in patients >75 years old, 34.8% in patients with diabetes mellitus, and 44.4% in patients with a history of stroke/TIA.
(Enlarge Image)
Figure 1.
Vitamin K antagonist use in low (=1) versus high (≥2) CHADS2 scores by country. Across all countries, HF patients with higher risk of stroke were less likely to receive anticoagulation than lower-risk patients. The only exception was Indonesia, where higher-risk patients were more likely to receive a VKA.
(Enlarge Image)
Figure 2.
Vitamin K antagonist use at discharge among HF patients according to CHADS2 score. Among eligible HF patients with AF, VKA use declined with increasing stroke risk defined by CHADS2 score (P < .0001 for trend).
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