Robert Martin, DO

Evidence summary

Recent UK study shows no difference by timing

A 2022 UK prospective, randomized, multicenter trial assigned 21,104 predominantly White adults (58% men) with hypertension to take their usual antihypertensive medication either in the morning (6 am to 10 am) or evening (8 pm to midnight).¹ A computer algorithm randomized patients, but neither the patients nor the investigators were masked to allocation.

All patient baseline characteristics were equivalent between groups. If troubled by nocturia, patients in the evening group taking diuretics were told to take only the diuretic earlier (6 pm) and subsequently to change to morning if they experienced persistent bothersome symptoms. More patients in the evening administration group than in the morning administration group reported having to change the time of day that they took their diuretic (546 [5.2%] vs 71 [0.7%]; P < .0001).

The median follow-up was 5.2 years. Data were collected at regular intervals through patient completion of online questionnaires and researcher analysis of ­National Health Service data on hospitalization and death. The intention-to-treat analysis showed no difference in the primary outcome (a composite of vascular death, nonfatal myocardial infarction, or nonfatal stroke) between the evening and morning administration groups (0.69 events vs 0.72 events per 100 person-years; hazard ratio [HR] = 0.95; 95% CI, 0.83-1.10; P = .53).

The controversial Hygia Project favored evening

Prior to the UK study was the Hygia Chronotherapy Trial, a prospective, controlled, multicenter study conducted within the primary care setting in Spain. Caucasian Spanish adults (N = 19,168; mean age, 61 years; 56% men) with hypertension were randomly assigned to take all prescribed antihypertensive medication either at bedtime or upon waking.²

The Hygia Project initially sought to establish the value of ambulatory blood pressure monitoring (ABPM) compared to office blood pressure (BP) monitoring and to explore the prognostic value of sleeping BP.³ The study objectives evolved over time. The randomization process was not clearly described,^2,3 but multiple randomizations were alluded to. The authors stated that “for any of these chronotherapy trials” randomizations were done separately for “each participating center” and “randomization of participants to treatment-time regimen is done separately for each hypertension medication or combination being tested.”

A 2022 UK multicenter trial found no difference between the evening and morning administration groups in a composite outcome of vascular death, nonfatal myocardial infarction, or nonfatal stroke.

The baseline characteristics of patients in the evening and morning administration groups were similar, but statistically significant differences existed in BMI (29.6 vs 29.7; P = .030) and sleep-time systolic BP percent decline (9.3 vs 9.0; P < .001). Mean baseline 48-hour BP was 132/77 mm Hg. Hypertension was defined as an awake systolic BP ≥ 135 mm Hg or diastolic BP ≥ 85 mm Hg, or asleep systolic BP ≥ 120 mm Hg or diastolic BP ≥ 70 mm Hg. BP readings were confirmed with 48-hour ABPM. Exclusion criteria included pregnancy, a history of substance use disorder, night-shift work, and cardiovascular disease (defined as unstable angina, heart failure, life-threatening arrhythmia, atrial fibrillation, kidney failure, and grade III-IV retinopathy).

Prescribers were free to prescribe medicines from 5 classes (diuretic, angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, calcium channel blocker, or beta-blocker) as they thought appropriate, were encouraged to use fixed-dose combination pills, and were told not to use split (eg, twice per day) dosing. Annual ­48-hour ABPM was completed, and patients’ electronic health records were analyzed by blinded investigators. Median follow-up was 6.3 years, and only 84 participants failed to complete the minimum 1-year participation requirement.

Continue to: The primary outcome...

The primary outcome—a composite of cardiovascular death, myocardial infarction, coronary revascularization, heart failure, or stroke—occurred in 1752 patients, favoring the bedtime group (HR = 0.55; 95% CI, 0.50-0.61; P < .001). The calculated number of events was 1130 in the morning administration group and 622 in the evening administration group; the authors did not explicitly report the event numbers in each group. Each component of the composite outcome also favored evening administration (P < .001 for all): cardiovascular death (HR = 0.44; 95% CI, 0.34-0.56), myocardial infarction (HR = 0.66; 95% CI, 0.52-0.84), coronary revascularization (HR = 0.60; 95% CI, 0.47-0.75), heart failure (HR = 0.58; 95% CI, 0.49-0.70), and stroke (HR = 0.51; 95% CI, 0.41-0.63).

The complicated, layered study design and randomization methods limit the ability to critically appraise the study.

Smaller Spanish study also supported evening administration

A prior, smaller, prospective randomized trial conducted by the same researchers as the Hygia Project found even greater benefits to evening BP medication administration.⁴ The 2156 Spanish patients (52% men; average age, 55 years) from multiple primary care offices were randomized 1:1 to BP medication administration either upon awakening or at bedtime. Dozens of baseline characteristics were evenly distributed except for age (55.0 vs 56.3; P = .021) and creatinine (0.96 vs 0.98; P = .028), both of which were lower in the evening group.

After a median follow-up of 5.6 years, the bedtime group had significantly lower total events (187 events in the morning group vs 68 in the evening group; relative risk [RR] = 0.39; 95% CI, 0.29-0.51; P < .001). Individual cardiovascular outcomes also dramatically favored the evening group: total deaths (12 vs 28; P = .008), cardiovascular deaths (3 vs 14; P = .006), cardiovascular disease events (30 vs 74; P < .001), stroke (7 vs 24; P = .001), and heart failure (8 vs 33; P < .001).

Limits of both the UK trial and the Hygia Project trial included single countries of study with a lack of racial and ethnic diversity, and greater nonadherence to the evening administration of the medications.

Recommendations from others

A 2022 consensus statement from the International Society of Hypertension, published before the UK trial, recommended against bedtime dosing until more high-quality data became available. They pointed to evidence showing higher medication adherence with morning dosing, risk for asleep BP dropping, and worsening daytime BP control as reasons to continue morning administration.⁵ Other reviewers have questioned the Hygia Project results due to their reported implausibly large effects on cardiovascular outcomes, noting that independent attempts to verify the methods and the data have proven challenging and are not completed.⁶

Editor’s takeaway

I confess that I was swayed by the results of the Hygia Project; for a year or so, I advised my patients to take at least 1 BP pill at night. But after the UK study came out, I needed to reconsider. I began to worry that the great outcomes of nocturnal therapy may have been a mirage. I have returned to counseling patients to take their BP medications in whichever way fosters consistency while minimizing adverse effects for them.

Evidence summary

Recent UK study shows no difference by timing

A 2022 UK prospective, randomized, multicenter trial assigned 21,104 predominantly White adults (58% men) with hypertension to take their usual antihypertensive medication either in the morning (6 am to 10 am) or evening (8 pm to midnight).¹ A computer algorithm randomized patients, but neither the patients nor the investigators were masked to allocation.

All patient baseline characteristics were equivalent between groups. If troubled by nocturia, patients in the evening group taking diuretics were told to take only the diuretic earlier (6 pm) and subsequently to change to morning if they experienced persistent bothersome symptoms. More patients in the evening administration group than in the morning administration group reported having to change the time of day that they took their diuretic (546 [5.2%] vs 71 [0.7%]; P < .0001).

The median follow-up was 5.2 years. Data were collected at regular intervals through patient completion of online questionnaires and researcher analysis of ­National Health Service data on hospitalization and death. The intention-to-treat analysis showed no difference in the primary outcome (a composite of vascular death, nonfatal myocardial infarction, or nonfatal stroke) between the evening and morning administration groups (0.69 events vs 0.72 events per 100 person-years; hazard ratio [HR] = 0.95; 95% CI, 0.83-1.10; P = .53).

The controversial Hygia Project favored evening

Prior to the UK study was the Hygia Chronotherapy Trial, a prospective, controlled, multicenter study conducted within the primary care setting in Spain. Caucasian Spanish adults (N = 19,168; mean age, 61 years; 56% men) with hypertension were randomly assigned to take all prescribed antihypertensive medication either at bedtime or upon waking.²

The Hygia Project initially sought to establish the value of ambulatory blood pressure monitoring (ABPM) compared to office blood pressure (BP) monitoring and to explore the prognostic value of sleeping BP.³ The study objectives evolved over time. The randomization process was not clearly described,^2,3 but multiple randomizations were alluded to. The authors stated that “for any of these chronotherapy trials” randomizations were done separately for “each participating center” and “randomization of participants to treatment-time regimen is done separately for each hypertension medication or combination being tested.”

A 2022 UK multicenter trial found no difference between the evening and morning administration groups in a composite outcome of vascular death, nonfatal myocardial infarction, or nonfatal stroke.

The baseline characteristics of patients in the evening and morning administration groups were similar, but statistically significant differences existed in BMI (29.6 vs 29.7; P = .030) and sleep-time systolic BP percent decline (9.3 vs 9.0; P < .001). Mean baseline 48-hour BP was 132/77 mm Hg. Hypertension was defined as an awake systolic BP ≥ 135 mm Hg or diastolic BP ≥ 85 mm Hg, or asleep systolic BP ≥ 120 mm Hg or diastolic BP ≥ 70 mm Hg. BP readings were confirmed with 48-hour ABPM. Exclusion criteria included pregnancy, a history of substance use disorder, night-shift work, and cardiovascular disease (defined as unstable angina, heart failure, life-threatening arrhythmia, atrial fibrillation, kidney failure, and grade III-IV retinopathy).

Prescribers were free to prescribe medicines from 5 classes (diuretic, angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, calcium channel blocker, or beta-blocker) as they thought appropriate, were encouraged to use fixed-dose combination pills, and were told not to use split (eg, twice per day) dosing. Annual ­48-hour ABPM was completed, and patients’ electronic health records were analyzed by blinded investigators. Median follow-up was 6.3 years, and only 84 participants failed to complete the minimum 1-year participation requirement.

Continue to: The primary outcome...

The primary outcome—a composite of cardiovascular death, myocardial infarction, coronary revascularization, heart failure, or stroke—occurred in 1752 patients, favoring the bedtime group (HR = 0.55; 95% CI, 0.50-0.61; P < .001). The calculated number of events was 1130 in the morning administration group and 622 in the evening administration group; the authors did not explicitly report the event numbers in each group. Each component of the composite outcome also favored evening administration (P < .001 for all): cardiovascular death (HR = 0.44; 95% CI, 0.34-0.56), myocardial infarction (HR = 0.66; 95% CI, 0.52-0.84), coronary revascularization (HR = 0.60; 95% CI, 0.47-0.75), heart failure (HR = 0.58; 95% CI, 0.49-0.70), and stroke (HR = 0.51; 95% CI, 0.41-0.63).

The complicated, layered study design and randomization methods limit the ability to critically appraise the study.

Smaller Spanish study also supported evening administration

A prior, smaller, prospective randomized trial conducted by the same researchers as the Hygia Project found even greater benefits to evening BP medication administration.⁴ The 2156 Spanish patients (52% men; average age, 55 years) from multiple primary care offices were randomized 1:1 to BP medication administration either upon awakening or at bedtime. Dozens of baseline characteristics were evenly distributed except for age (55.0 vs 56.3; P = .021) and creatinine (0.96 vs 0.98; P = .028), both of which were lower in the evening group.

After a median follow-up of 5.6 years, the bedtime group had significantly lower total events (187 events in the morning group vs 68 in the evening group; relative risk [RR] = 0.39; 95% CI, 0.29-0.51; P < .001). Individual cardiovascular outcomes also dramatically favored the evening group: total deaths (12 vs 28; P = .008), cardiovascular deaths (3 vs 14; P = .006), cardiovascular disease events (30 vs 74; P < .001), stroke (7 vs 24; P = .001), and heart failure (8 vs 33; P < .001).

Limits of both the UK trial and the Hygia Project trial included single countries of study with a lack of racial and ethnic diversity, and greater nonadherence to the evening administration of the medications.

Recommendations from others

A 2022 consensus statement from the International Society of Hypertension, published before the UK trial, recommended against bedtime dosing until more high-quality data became available. They pointed to evidence showing higher medication adherence with morning dosing, risk for asleep BP dropping, and worsening daytime BP control as reasons to continue morning administration.⁵ Other reviewers have questioned the Hygia Project results due to their reported implausibly large effects on cardiovascular outcomes, noting that independent attempts to verify the methods and the data have proven challenging and are not completed.⁶

Editor’s takeaway

I confess that I was swayed by the results of the Hygia Project; for a year or so, I advised my patients to take at least 1 BP pill at night. But after the UK study came out, I needed to reconsider. I began to worry that the great outcomes of nocturnal therapy may have been a mirage. I have returned to counseling patients to take their BP medications in whichever way fosters consistency while minimizing adverse effects for them.

Evidence summary

Recent UK study shows no difference by timing

A 2022 UK prospective, randomized, multicenter trial assigned 21,104 predominantly White adults (58% men) with hypertension to take their usual antihypertensive medication either in the morning (6 am to 10 am) or evening (8 pm to midnight).¹ A computer algorithm randomized patients, but neither the patients nor the investigators were masked to allocation.

All patient baseline characteristics were equivalent between groups. If troubled by nocturia, patients in the evening group taking diuretics were told to take only the diuretic earlier (6 pm) and subsequently to change to morning if they experienced persistent bothersome symptoms. More patients in the evening administration group than in the morning administration group reported having to change the time of day that they took their diuretic (546 [5.2%] vs 71 [0.7%]; P < .0001).

The median follow-up was 5.2 years. Data were collected at regular intervals through patient completion of online questionnaires and researcher analysis of ­National Health Service data on hospitalization and death. The intention-to-treat analysis showed no difference in the primary outcome (a composite of vascular death, nonfatal myocardial infarction, or nonfatal stroke) between the evening and morning administration groups (0.69 events vs 0.72 events per 100 person-years; hazard ratio [HR] = 0.95; 95% CI, 0.83-1.10; P = .53).

The controversial Hygia Project favored evening

Prior to the UK study was the Hygia Chronotherapy Trial, a prospective, controlled, multicenter study conducted within the primary care setting in Spain. Caucasian Spanish adults (N = 19,168; mean age, 61 years; 56% men) with hypertension were randomly assigned to take all prescribed antihypertensive medication either at bedtime or upon waking.²

The Hygia Project initially sought to establish the value of ambulatory blood pressure monitoring (ABPM) compared to office blood pressure (BP) monitoring and to explore the prognostic value of sleeping BP.³ The study objectives evolved over time. The randomization process was not clearly described,^2,3 but multiple randomizations were alluded to. The authors stated that “for any of these chronotherapy trials” randomizations were done separately for “each participating center” and “randomization of participants to treatment-time regimen is done separately for each hypertension medication or combination being tested.”

A 2022 UK multicenter trial found no difference between the evening and morning administration groups in a composite outcome of vascular death, nonfatal myocardial infarction, or nonfatal stroke.

The baseline characteristics of patients in the evening and morning administration groups were similar, but statistically significant differences existed in BMI (29.6 vs 29.7; P = .030) and sleep-time systolic BP percent decline (9.3 vs 9.0; P < .001). Mean baseline 48-hour BP was 132/77 mm Hg. Hypertension was defined as an awake systolic BP ≥ 135 mm Hg or diastolic BP ≥ 85 mm Hg, or asleep systolic BP ≥ 120 mm Hg or diastolic BP ≥ 70 mm Hg. BP readings were confirmed with 48-hour ABPM. Exclusion criteria included pregnancy, a history of substance use disorder, night-shift work, and cardiovascular disease (defined as unstable angina, heart failure, life-threatening arrhythmia, atrial fibrillation, kidney failure, and grade III-IV retinopathy).

Prescribers were free to prescribe medicines from 5 classes (diuretic, angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, calcium channel blocker, or beta-blocker) as they thought appropriate, were encouraged to use fixed-dose combination pills, and were told not to use split (eg, twice per day) dosing. Annual ­48-hour ABPM was completed, and patients’ electronic health records were analyzed by blinded investigators. Median follow-up was 6.3 years, and only 84 participants failed to complete the minimum 1-year participation requirement.

Continue to: The primary outcome...

The primary outcome—a composite of cardiovascular death, myocardial infarction, coronary revascularization, heart failure, or stroke—occurred in 1752 patients, favoring the bedtime group (HR = 0.55; 95% CI, 0.50-0.61; P < .001). The calculated number of events was 1130 in the morning administration group and 622 in the evening administration group; the authors did not explicitly report the event numbers in each group. Each component of the composite outcome also favored evening administration (P < .001 for all): cardiovascular death (HR = 0.44; 95% CI, 0.34-0.56), myocardial infarction (HR = 0.66; 95% CI, 0.52-0.84), coronary revascularization (HR = 0.60; 95% CI, 0.47-0.75), heart failure (HR = 0.58; 95% CI, 0.49-0.70), and stroke (HR = 0.51; 95% CI, 0.41-0.63).

The complicated, layered study design and randomization methods limit the ability to critically appraise the study.

Smaller Spanish study also supported evening administration

A prior, smaller, prospective randomized trial conducted by the same researchers as the Hygia Project found even greater benefits to evening BP medication administration.⁴ The 2156 Spanish patients (52% men; average age, 55 years) from multiple primary care offices were randomized 1:1 to BP medication administration either upon awakening or at bedtime. Dozens of baseline characteristics were evenly distributed except for age (55.0 vs 56.3; P = .021) and creatinine (0.96 vs 0.98; P = .028), both of which were lower in the evening group.

After a median follow-up of 5.6 years, the bedtime group had significantly lower total events (187 events in the morning group vs 68 in the evening group; relative risk [RR] = 0.39; 95% CI, 0.29-0.51; P < .001). Individual cardiovascular outcomes also dramatically favored the evening group: total deaths (12 vs 28; P = .008), cardiovascular deaths (3 vs 14; P = .006), cardiovascular disease events (30 vs 74; P < .001), stroke (7 vs 24; P = .001), and heart failure (8 vs 33; P < .001).

Limits of both the UK trial and the Hygia Project trial included single countries of study with a lack of racial and ethnic diversity, and greater nonadherence to the evening administration of the medications.

Recommendations from others

A 2022 consensus statement from the International Society of Hypertension, published before the UK trial, recommended against bedtime dosing until more high-quality data became available. They pointed to evidence showing higher medication adherence with morning dosing, risk for asleep BP dropping, and worsening daytime BP control as reasons to continue morning administration.⁵ Other reviewers have questioned the Hygia Project results due to their reported implausibly large effects on cardiovascular outcomes, noting that independent attempts to verify the methods and the data have proven challenging and are not completed.⁶

Editor’s takeaway

I confess that I was swayed by the results of the Hygia Project; for a year or so, I advised my patients to take at least 1 BP pill at night. But after the UK study came out, I needed to reconsider. I began to worry that the great outcomes of nocturnal therapy may have been a mirage. I have returned to counseling patients to take their BP medications in whichever way fosters consistency while minimizing adverse effects for them.

EVIDENCE SUMMARY

A meta-analysis of 12 randomized trials of stroke prevention in patients with atrial fibrillation (8932 patients, 63% male, mean age 72 years, 19.6% ≥ 80 years) examined outcomes of ischemic stroke, serious bleeding (systemic or intracranial hemorrhages requiring hospitalization, transfusion, or surgery) and cardiovascular events (ischemic stroke, myocardial infarction, systemic emboli, and vascular death).¹ Patients were randomized to oral anticoagulants (3430 patients), antiplatelet therapy (3531 patients), or no therapy (1971 patients).

Warfarin target international normalized ratios (INRs) ranged from 1.5 to 4.2. Previous stoke or transient ischemic attack varied across studies but averaged 22% (patient baseline characteristics were evenly distributed among all arms of all 12 studies, suggesting appropriate randomizations). Fifteen percent of patients had diabetes, 50% had hypertension, and 20% had congestive heart failure. They were followed for a mean of 2 years.

Overall, patients experienced 623 ischemic strokes, 289 serious bleeds, and 1210 cardiovascular events. After adjusting for treatment and covariates, age was independently associated with higher risk for each outcome. For every decade increase in age, the hazard ratio (HR) for ischemic stroke was 1.45 (95% confidence interval [CI], 1.26-1.66); serious hemorrhage, 1.61 (95% CI, 1.47-1.77); and cardiovascular events, 1.43 (95% CI, 1.33-1.53).

Benefits of warfarin outweigh increased risk of hemorrhage

Treatment with vitamin K antagonists, compared with placebo, reduced ischemic strokes (HR = 0.36; 95% CI, 0.29-0.45) and cardiovascular events (HR = 0.59; 95% CI, 0.52-0.66) but increased the risk of serious hemorrhage (HR = 1.56; 95% CI, 1.03-2.37) in patients from 50 to 90 years of age. The benefits of decreased ischemic strokes and cardiovascular events consistently surpassed the increased risk of hemorrhage, however.

Across all age groups, the absolute risk reductions (ARRs) for ischemic stroke and cardiovascular events were 2% to 3% and 3% to 8%, respectively, whereas the absolute risk increase for serious hemorrhage was 0.5% to 1%. For those ages 70 to 75, for example, warfarin decreased the rate of ischemic stroke by 3% per year (number needed to treat [NNT] = 34; rates estimated from graphs) and the rate of cardiovascular events by 7% (NNT = 14) but increased the risk of serious hemorrhage by approximately 0.5% per year (number need to harm = 200).

Warfarin prevents major strokes more effectively than aspirin

A randomized open-label trial with blind assessment of endpoints, included in the meta-analysis, followed 973 patients older than 75 years (mean 81.5 years) with atrial fibrillation for 2 to 7 years.² Researchers evaluated warfarin compared with aspirin for the outcomes of major stroke, arterial embolism, and intracranial hemorrhage. Major strokes comprised fatal or disabling strokes. Researchers excluded patients with minor strokes, rheumatic heart disease, a major nontraumatic hemorrhage within the previous 5 years, intracranial hemorrhage, peptic ulcer disease, esophageal varices, or a terminal illness.

Compared with aspirin, warfarin significantly reduced all primary events (ARR = 1.8% vs 3.8%; relative risk reduction [RRR] = 0.48; 95% CI, 0.28-0.80; NNT = 50). Warfarin decreased major strokes more than aspirin (21 vs 44 strokes; ARR = 1.8%; relative risk [RR] = 0.46; 95% CI, 0.26-0.79; NNT = 56) but didn’t alter the risk of hemorrhagic strokes (6 vs 5 absolute events, respectively; RRR = 1.15, 95% CI, 0.29-4.77) or other intracranial hemorrhages (2 vs 1 event, respectively; RR = 1.92; 95% CI, 0.10-113.3). Wide confidence intervals and the small number of hemorrhagic events suggest that the study wasn’t powered to detect a significant difference in hemorrhagic events.

Continue to: Large study finds net benefit for warfarin treatment

A retrospective cohort including all 182,678 Swedish Hospital Discharge Register patients with atrial fibrillation (260,000 patient-years) evaluated the net benefit of anticoagulation treatment decisions over an average of 1.5 years.³ The Swedish National Prescribed Drugs Registry, which includes all Swedish pharmacies, identified all patients who were prescribed warfarin during the study years of July 2005 through December 2008. The patients were divided into 2 groups, warfarin or no warfarin, and assigned risk scores using CHA2DS2-VASc and HAS-BLED.^4,5

Researchers defined net benefit as the number of ischemic strokes avoided in patients taking warfarin, minus the number of excess intracranial bleeds. They assigned a weight of 1.5 to intracranial bleeds vs 1 for ischemic strokes to compensate for the generally more severe outcomes of intracranial bleeding.

Warfarin produced a net benefit at every CHA2DS2-VASc score greater than 0 (aggregate result of 3.9 fewer events per 100 patient-years; 95% CI, 3.8-4.1; NNT = 26). Kaplan-Meier composite plots of all-cause mortality, ischemic stroke, and intracranial bleeds showed a net benefit favoring warfarin use for all combinations of CHA2DS2-VASc greater than 0 (patients older than 65 years never have a CHA2DS2-VASc score of 0 because they’re assigned 1 point at ages 65 to 74 years and 2 points at 75 years and older) and HAS-BLED scores (all curves P < .00001).

Patients with A-fib continue to benefit from vitamin K antagonist therapy (warfarin) at ages ranging from 50 through 90 years.

Hazard ratios (HRs) of every combination of scores favored warfarin use (HRs ranged from 0.26-0.72; 95% CIs, less than 1 for all HRs; aggregate benefit at all risk scores: HR = 0.51; 95% CI, 0.50-0.52,). The risk of intracranial bleed, or any bleed, on warfarin at all risk strata was less than the corresponding risk of ischemic stroke (or thromboembolic event) without warfarin except among the lowest risk patients (CHA2DS2-VASc = 0). The difference between thromboses and hemorrhages increased as the CHA2DS2-VASc score increased. Of note, a smaller percentage of the highest risk patients were on warfarin.

EDITOR’S TAKEAWAY

We have solid evidence that, although the risks of systemic and intracranial bleeding from warfarin therapy in older patients with atrial fibrillation increase steadily with advancing age, so do the benefits in reduced ischemic stroke, myocardial infarction, thrombotic emboli, and overall cardiovascular death. Most important, the benefits continue to outweigh the risks by a factor of 2 to 4, even in the oldest age groups.

EVIDENCE SUMMARY

A meta-analysis of 12 randomized trials of stroke prevention in patients with atrial fibrillation (8932 patients, 63% male, mean age 72 years, 19.6% ≥ 80 years) examined outcomes of ischemic stroke, serious bleeding (systemic or intracranial hemorrhages requiring hospitalization, transfusion, or surgery) and cardiovascular events (ischemic stroke, myocardial infarction, systemic emboli, and vascular death).¹ Patients were randomized to oral anticoagulants (3430 patients), antiplatelet therapy (3531 patients), or no therapy (1971 patients).

Warfarin target international normalized ratios (INRs) ranged from 1.5 to 4.2. Previous stoke or transient ischemic attack varied across studies but averaged 22% (patient baseline characteristics were evenly distributed among all arms of all 12 studies, suggesting appropriate randomizations). Fifteen percent of patients had diabetes, 50% had hypertension, and 20% had congestive heart failure. They were followed for a mean of 2 years.

Overall, patients experienced 623 ischemic strokes, 289 serious bleeds, and 1210 cardiovascular events. After adjusting for treatment and covariates, age was independently associated with higher risk for each outcome. For every decade increase in age, the hazard ratio (HR) for ischemic stroke was 1.45 (95% confidence interval [CI], 1.26-1.66); serious hemorrhage, 1.61 (95% CI, 1.47-1.77); and cardiovascular events, 1.43 (95% CI, 1.33-1.53).

Benefits of warfarin outweigh increased risk of hemorrhage

Treatment with vitamin K antagonists, compared with placebo, reduced ischemic strokes (HR = 0.36; 95% CI, 0.29-0.45) and cardiovascular events (HR = 0.59; 95% CI, 0.52-0.66) but increased the risk of serious hemorrhage (HR = 1.56; 95% CI, 1.03-2.37) in patients from 50 to 90 years of age. The benefits of decreased ischemic strokes and cardiovascular events consistently surpassed the increased risk of hemorrhage, however.

Across all age groups, the absolute risk reductions (ARRs) for ischemic stroke and cardiovascular events were 2% to 3% and 3% to 8%, respectively, whereas the absolute risk increase for serious hemorrhage was 0.5% to 1%. For those ages 70 to 75, for example, warfarin decreased the rate of ischemic stroke by 3% per year (number needed to treat [NNT] = 34; rates estimated from graphs) and the rate of cardiovascular events by 7% (NNT = 14) but increased the risk of serious hemorrhage by approximately 0.5% per year (number need to harm = 200).

Warfarin prevents major strokes more effectively than aspirin

A randomized open-label trial with blind assessment of endpoints, included in the meta-analysis, followed 973 patients older than 75 years (mean 81.5 years) with atrial fibrillation for 2 to 7 years.² Researchers evaluated warfarin compared with aspirin for the outcomes of major stroke, arterial embolism, and intracranial hemorrhage. Major strokes comprised fatal or disabling strokes. Researchers excluded patients with minor strokes, rheumatic heart disease, a major nontraumatic hemorrhage within the previous 5 years, intracranial hemorrhage, peptic ulcer disease, esophageal varices, or a terminal illness.

Compared with aspirin, warfarin significantly reduced all primary events (ARR = 1.8% vs 3.8%; relative risk reduction [RRR] = 0.48; 95% CI, 0.28-0.80; NNT = 50). Warfarin decreased major strokes more than aspirin (21 vs 44 strokes; ARR = 1.8%; relative risk [RR] = 0.46; 95% CI, 0.26-0.79; NNT = 56) but didn’t alter the risk of hemorrhagic strokes (6 vs 5 absolute events, respectively; RRR = 1.15, 95% CI, 0.29-4.77) or other intracranial hemorrhages (2 vs 1 event, respectively; RR = 1.92; 95% CI, 0.10-113.3). Wide confidence intervals and the small number of hemorrhagic events suggest that the study wasn’t powered to detect a significant difference in hemorrhagic events.

Continue to: Large study finds net benefit for warfarin treatment

A retrospective cohort including all 182,678 Swedish Hospital Discharge Register patients with atrial fibrillation (260,000 patient-years) evaluated the net benefit of anticoagulation treatment decisions over an average of 1.5 years.³ The Swedish National Prescribed Drugs Registry, which includes all Swedish pharmacies, identified all patients who were prescribed warfarin during the study years of July 2005 through December 2008. The patients were divided into 2 groups, warfarin or no warfarin, and assigned risk scores using CHA2DS2-VASc and HAS-BLED.^4,5

Researchers defined net benefit as the number of ischemic strokes avoided in patients taking warfarin, minus the number of excess intracranial bleeds. They assigned a weight of 1.5 to intracranial bleeds vs 1 for ischemic strokes to compensate for the generally more severe outcomes of intracranial bleeding.

Warfarin produced a net benefit at every CHA2DS2-VASc score greater than 0 (aggregate result of 3.9 fewer events per 100 patient-years; 95% CI, 3.8-4.1; NNT = 26). Kaplan-Meier composite plots of all-cause mortality, ischemic stroke, and intracranial bleeds showed a net benefit favoring warfarin use for all combinations of CHA2DS2-VASc greater than 0 (patients older than 65 years never have a CHA2DS2-VASc score of 0 because they’re assigned 1 point at ages 65 to 74 years and 2 points at 75 years and older) and HAS-BLED scores (all curves P < .00001).

Patients with A-fib continue to benefit from vitamin K antagonist therapy (warfarin) at ages ranging from 50 through 90 years.

Hazard ratios (HRs) of every combination of scores favored warfarin use (HRs ranged from 0.26-0.72; 95% CIs, less than 1 for all HRs; aggregate benefit at all risk scores: HR = 0.51; 95% CI, 0.50-0.52,). The risk of intracranial bleed, or any bleed, on warfarin at all risk strata was less than the corresponding risk of ischemic stroke (or thromboembolic event) without warfarin except among the lowest risk patients (CHA2DS2-VASc = 0). The difference between thromboses and hemorrhages increased as the CHA2DS2-VASc score increased. Of note, a smaller percentage of the highest risk patients were on warfarin.

EDITOR’S TAKEAWAY

We have solid evidence that, although the risks of systemic and intracranial bleeding from warfarin therapy in older patients with atrial fibrillation increase steadily with advancing age, so do the benefits in reduced ischemic stroke, myocardial infarction, thrombotic emboli, and overall cardiovascular death. Most important, the benefits continue to outweigh the risks by a factor of 2 to 4, even in the oldest age groups.

EVIDENCE SUMMARY

A meta-analysis of 12 randomized trials of stroke prevention in patients with atrial fibrillation (8932 patients, 63% male, mean age 72 years, 19.6% ≥ 80 years) examined outcomes of ischemic stroke, serious bleeding (systemic or intracranial hemorrhages requiring hospitalization, transfusion, or surgery) and cardiovascular events (ischemic stroke, myocardial infarction, systemic emboli, and vascular death).¹ Patients were randomized to oral anticoagulants (3430 patients), antiplatelet therapy (3531 patients), or no therapy (1971 patients).

Warfarin target international normalized ratios (INRs) ranged from 1.5 to 4.2. Previous stoke or transient ischemic attack varied across studies but averaged 22% (patient baseline characteristics were evenly distributed among all arms of all 12 studies, suggesting appropriate randomizations). Fifteen percent of patients had diabetes, 50% had hypertension, and 20% had congestive heart failure. They were followed for a mean of 2 years.

Overall, patients experienced 623 ischemic strokes, 289 serious bleeds, and 1210 cardiovascular events. After adjusting for treatment and covariates, age was independently associated with higher risk for each outcome. For every decade increase in age, the hazard ratio (HR) for ischemic stroke was 1.45 (95% confidence interval [CI], 1.26-1.66); serious hemorrhage, 1.61 (95% CI, 1.47-1.77); and cardiovascular events, 1.43 (95% CI, 1.33-1.53).

Benefits of warfarin outweigh increased risk of hemorrhage

Treatment with vitamin K antagonists, compared with placebo, reduced ischemic strokes (HR = 0.36; 95% CI, 0.29-0.45) and cardiovascular events (HR = 0.59; 95% CI, 0.52-0.66) but increased the risk of serious hemorrhage (HR = 1.56; 95% CI, 1.03-2.37) in patients from 50 to 90 years of age. The benefits of decreased ischemic strokes and cardiovascular events consistently surpassed the increased risk of hemorrhage, however.

Across all age groups, the absolute risk reductions (ARRs) for ischemic stroke and cardiovascular events were 2% to 3% and 3% to 8%, respectively, whereas the absolute risk increase for serious hemorrhage was 0.5% to 1%. For those ages 70 to 75, for example, warfarin decreased the rate of ischemic stroke by 3% per year (number needed to treat [NNT] = 34; rates estimated from graphs) and the rate of cardiovascular events by 7% (NNT = 14) but increased the risk of serious hemorrhage by approximately 0.5% per year (number need to harm = 200).

Warfarin prevents major strokes more effectively than aspirin

A randomized open-label trial with blind assessment of endpoints, included in the meta-analysis, followed 973 patients older than 75 years (mean 81.5 years) with atrial fibrillation for 2 to 7 years.² Researchers evaluated warfarin compared with aspirin for the outcomes of major stroke, arterial embolism, and intracranial hemorrhage. Major strokes comprised fatal or disabling strokes. Researchers excluded patients with minor strokes, rheumatic heart disease, a major nontraumatic hemorrhage within the previous 5 years, intracranial hemorrhage, peptic ulcer disease, esophageal varices, or a terminal illness.

Compared with aspirin, warfarin significantly reduced all primary events (ARR = 1.8% vs 3.8%; relative risk reduction [RRR] = 0.48; 95% CI, 0.28-0.80; NNT = 50). Warfarin decreased major strokes more than aspirin (21 vs 44 strokes; ARR = 1.8%; relative risk [RR] = 0.46; 95% CI, 0.26-0.79; NNT = 56) but didn’t alter the risk of hemorrhagic strokes (6 vs 5 absolute events, respectively; RRR = 1.15, 95% CI, 0.29-4.77) or other intracranial hemorrhages (2 vs 1 event, respectively; RR = 1.92; 95% CI, 0.10-113.3). Wide confidence intervals and the small number of hemorrhagic events suggest that the study wasn’t powered to detect a significant difference in hemorrhagic events.

Continue to: Large study finds net benefit for warfarin treatment

A retrospective cohort including all 182,678 Swedish Hospital Discharge Register patients with atrial fibrillation (260,000 patient-years) evaluated the net benefit of anticoagulation treatment decisions over an average of 1.5 years.³ The Swedish National Prescribed Drugs Registry, which includes all Swedish pharmacies, identified all patients who were prescribed warfarin during the study years of July 2005 through December 2008. The patients were divided into 2 groups, warfarin or no warfarin, and assigned risk scores using CHA2DS2-VASc and HAS-BLED.^4,5

Researchers defined net benefit as the number of ischemic strokes avoided in patients taking warfarin, minus the number of excess intracranial bleeds. They assigned a weight of 1.5 to intracranial bleeds vs 1 for ischemic strokes to compensate for the generally more severe outcomes of intracranial bleeding.

Warfarin produced a net benefit at every CHA2DS2-VASc score greater than 0 (aggregate result of 3.9 fewer events per 100 patient-years; 95% CI, 3.8-4.1; NNT = 26). Kaplan-Meier composite plots of all-cause mortality, ischemic stroke, and intracranial bleeds showed a net benefit favoring warfarin use for all combinations of CHA2DS2-VASc greater than 0 (patients older than 65 years never have a CHA2DS2-VASc score of 0 because they’re assigned 1 point at ages 65 to 74 years and 2 points at 75 years and older) and HAS-BLED scores (all curves P < .00001).

Patients with A-fib continue to benefit from vitamin K antagonist therapy (warfarin) at ages ranging from 50 through 90 years.

Hazard ratios (HRs) of every combination of scores favored warfarin use (HRs ranged from 0.26-0.72; 95% CIs, less than 1 for all HRs; aggregate benefit at all risk scores: HR = 0.51; 95% CI, 0.50-0.52,). The risk of intracranial bleed, or any bleed, on warfarin at all risk strata was less than the corresponding risk of ischemic stroke (or thromboembolic event) without warfarin except among the lowest risk patients (CHA2DS2-VASc = 0). The difference between thromboses and hemorrhages increased as the CHA2DS2-VASc score increased. Of note, a smaller percentage of the highest risk patients were on warfarin.

EDITOR’S TAKEAWAY

We have solid evidence that, although the risks of systemic and intracranial bleeding from warfarin therapy in older patients with atrial fibrillation increase steadily with advancing age, so do the benefits in reduced ischemic stroke, myocardial infarction, thrombotic emboli, and overall cardiovascular death. Most important, the benefits continue to outweigh the risks by a factor of 2 to 4, even in the oldest age groups.