The epidemiology of atrial fibrillation in adults depends on locale of diagnosis

Trends in Uptake and Adherence to Oral Anticoagulation for Patients With Incident Atrial Fibrillation at High Stroke Risk Across Health Care Settings

Background

Oral anticoagulation (OAC) therapy prevents morbidity and mortality in nonvalvular atrial fibrillation; whether location of diagnosis influences OAC uptake or adherence is unknown.

Methods and Results

Retrospective cohort study (2008–2019), identifying adults with incident nonvalvular atrial fibrillation across health care settings (emergency department, hospital, outpatient) at high risk of stroke. OAC uptake and adherence via proportion of days covered for direct OACs and time in therapeutic range for warfarin were measured. Proportion of days covered was categorized as low (0–39%), intermediate (40–79%), and high (80–100%). Warfarin control was defined as time in therapeutic range ≥65%. All‐cause mortality was examined at a 3‐year landmark. Among 75 389 patients with nonvalvular atrial fibrillation (47.0% women, mean 77.4 years), 19.7% were diagnosed in the emergency department, 59.1% in the hospital, and 21.2% in the outpatient setting. Ninety‐day OAC uptake was 51.6% in the emergency department, 50.9% in the hospital, and 67.9% in the outpatient setting (P<0.0001). High direct OAC adherence increased from 64.9% to 80.3% in the emergency department, 64.3% to 81.7% in the hospital, and 70.9% to 88.6% in the outpatient setting over time (P values for trend <0.0001). Warfarin control was 40.3% overall and remained unchanged. In multivariable analysis, outpatient diagnosis compared with the hospital was associated with greater OAC uptake (odds ratio [OR], 1.79; [95% CI, 1.72–1.87]) and direct OAC (OR, 1.42; [95% CI, 1.27–1.59]) and warfarin (OR, 1.49; [95% CI, 1.36–1.63]) adherence. Varying or persistently low adherence was associated with a poor prognosis, especially for warfarin.

Conclusions

Locale of nonvalvular atrial fibrillation diagnosis is associated with varying OAC uptake and adherence. Interventions specific to health care settings are needed to improve stroke prevention.

Nationwide study of sex differences in incident heart failure in newly diagnosed nonvalvular atrial fibrillation

Background

Heart failure (HF) is a leading complication of nonvalvular atrial fibrillation (NVAF), and the presence of both conditions worsens prognosis. Sex-specific associations between NVAF and outcomes focus on stroke; less is known about HF. We evaluated sex differences in incident HF in NVAF.

Methods

We identified adults age ≥ 65 years hospitalized for incident NVAF without prior HF from April 2010 to March 2018 in Canada. The primary outcome was incident HF hospitalization, with a secondary composite outcome of incident HF hospitalization or all-cause mortality at 1 year. Cox proportional hazard regression models were constructed for the association between sex and outcomes, adjusting for age, comorbidities, socioeconomic status, cardioversion, and medications.

Results

Of 68,909 NVAF patients, 53.8% were women. Women had a higher rate of the primary outcome (30.0% vs 25.6%, P < 0.001) and the composite outcome (39.5% vs 36.6%, P < 0.001) than men. In multivariable analysis without adjusting for medications, there was an 8% increase risk of HF (95% confidence interval [CI] 1.05-1.11, P < 0.001) for women, which was attenuated when accounting for medication (hazard ratio [HR] 1.01, 95% CI 0.98-1.04). After full adjustment, women age ≥ 75 years were at higher risk of the primary outcome (HR 1.10, 95% CI 1.06-1.13, P < 0.001) and the composite outcome (HR 1.04, 95% CI 1.01-1.07, P < 0.001), compared with men, whereas there was a significantly lower risk for those age 65-75 years.

Conclusions

In this nationwide study of incident NVAF without HF, women age ≥ 75 years were more likely to develop HF or die than men. Strategies to prevent HF in older women with NVAF are needed.

Emergency Department capacity to initiate thromboprophylaxis in patients with atrial fibrillation and thrombotic risk after discharge: URGFAICS cohort analysis

Atrial fibrillation (AF) is the most prevalent heart rhythm disorder in the general population. Stroke prevention is one of the leading management objectives in the treatment of AF patients. The variables associated with the non-initiation of thromboprophylaxis in patients with thrombotic risk consulting for an episode of AF in Emergency Departments (ED) were investigated. This was a multipurpose, analytical, non-interventionist, multicenter Spanish study with a prospective 30-day follow-up. All patients ≥ 18 years of age consulting to the ED for the casual finding of AF in an electrocardiogram (ECG) performed 12 h prior to the consultation or with symptoms related to AF were enrolled from September 1, 2016 to February 28, 2017. Patients not previously received thromboprophylaxis were selected. Multivariate analysis was performed to calculate the odds ratio (OR) and the 95% confidence interval (CI). A total of 634 patients, not received thromboprophylaxis and at high thrombotic risk, were included. Of these, 251 (39.6%) did not receive thromboprophylaxis at ED discharge. In the multivariate analysis, non-initiation of anticoagulation at discharge from the ED was mostly related to cognitive impairment (OR 3.95; (95% CI 2.02-7.72), cancer history (OR 2.12; (95%CI 1.18-3.81), AF duration < 48 h (OR 2.49; (95% CI 1.48-4.21) and patients with re-establishment of sinus rhythm (OR 3.65; (95% CI 1.47-9.06). Reinforcement of the use of CHA₂DS₂-VASC as a stroke risk scale and empowerment of ED physicians is a must to improve this gap in care.

Impact of Atrial Fibrillation Case Volume in the Emergency Department on Early and Late Outcomes of Patients With New Atrial Fibrillation

STUDY OBJECTIVE

To define the association between atrial fibrillation case volume in the emergency department and death or all-cause hospitalization at 30 days and 1 year in patients with new atrial fibrillation. Secondary objectives examined repeat ED visits and the management of atrial fibrillation within 90 days.

METHODS

We identified all adults presenting to an ED in Alberta, Canada, with a new primary diagnosis of atrial fibrillation/flutter between 2009 and 2015 using International Classification of Diseases, 10th Revision code I48. Volume was classified in tertiles weighted by annual ED number of atrial fibrillation cases. The association between volume and outcomes was evaluated using generalized linear mixed models, adjusting for prognostically important covariates as fixed effects and ED as a random effect to account for potential clustering within EDs.

RESULTS

The tertiles consisted of 4 high, 9 medium, and 68 low atrial fibrillation volume EDs, with 4,217, 4,193, and 4,112 patients, respectively. Volume was not independently associated with the primary outcome or individual components. However, medium- and high-volume EDs had fewer repeat ED visits at 30 days (respective adjusted odds ratio [aOR] 0.75 [95% confidence interval {CI} 0.66 to 0.87] and 0.64 [0.52 to 0.79]) and 1 year (respective aOR 0.77 [95% CI 0.67 to 0.90] and 0.71 [0.56 to 0.90]). Fewer patients were admitted from medium- (37.1%) and high- (32.0%) compared with low-volume (39.5%) EDs. Patients attending medium- and high-volume EDs were more likely to be cardioverted (aOR 3.28 [95% CI 1.94 to 5.53] and 3.81 [1.39 to 10.48] for medium- and high-volume EDs, respectively).

CONCLUSION

Treatment in higher volume EDs was associated with significantly lower admission rates and repeat ED visits but no difference in survival.

Detecting Patients With Nonvalvular Atrial Fibrillation and Atrial Flutter in the Canadian Primary Care Sentinel Surveillance Network: First Steps

Background

A recent feasibility assessment of quality indicators for nonvalvular atrial fibrillation/atrial flutter (NVAF/AFL) identified the Canadian Primary Care Sentinel Surveillance Network, a national outpatient electronic medical record (EMR) system, as a data source for measurement. As a first step, we adapted and validated an existing EMR case definition.

Methods

A diagnosis of NVAF/AFL was defined using International Classification of Disease, 9th Revision, Clinical Modification codes (427.3) in either the physician billing, encounter diagnosis, or health condition fields. We identified all presumed cases in a single clinical site with the algorithm and selected a random sample of those who were presumed NVAF/AFL negative with the same algorithm. A chart audit diagnosis of “definite” NVAF/AFL was confirmed by electrocardiogram and nonvalvular diagnosis confirmed after echocardiogram, attending physician, or specialist letter review. To demonstrate face validity, clinical characteristics were compared for patients with and without NVAF/AFL.

Results

The case definition identified a possible 184 patients with and 184 without NVAF/AFL. The case validation resulted in a sensitivity of 100% (95% confidence interval [CI], 100-100), specificity of 84.3% (95% CI, 78.8-89.9), and positive and negative predictive value of 74.7% (95% CI, 66.4-83.2) and 100% (95% CI 100-100), respectively. Patients with NVAF/AFL were older (63 vs 42 years) and had a higher proportion of cardiovascular comorbidities and relevant medications.

Conclusions

We think it is possible that with further validation work, NVAF/AFL can be accurately identified using this large pan-Canadian EMR system and used as a future tool to measure quality of care in the outpatient setting.

Practice Gap in Atrial Fibrillation Oral Anticoagulation Prescribing at Emergency Department Home Discharge

INTRODUCTION

Current U.S. cardiology guidelines recommend oral anticoagulation (OAC) to reduce stroke risk in selected patients with atrial fibrillation (AF), but no formal AF OAC recommendations exist to guide emergency medicine clinicians in the acute care setting. We sought to characterize emergency department (ED) OAC prescribing practices after an ED AF diagnosis.

METHODS

This retrospective study included index visits for OAC-naive patients ≥18 years old who were discharged home from the ED at an urban, academic, tertiary hospital with a primary diagnosis of AF from 2012-2014. Five hypothesis-blinded, chart reviewers abstracted data from patient problem lists and medical history in the electronic health record to assess stroke (CHA₂DS₂-VASc) and bleeding risk (HAS-BLED). The primary outcome was the provision of an OAC prescription at discharge in OAC-naive patients with high stroke risk. Descriptive statistics and multivariable logistic regression assessed associations between OAC prescription and patient characteristics.

RESULTS

We included 138 patient visits in our analysis, of whom 39.9% (n = 55) were low stroke risk (CHA₂DS₂-VASc = 0 in males and 1 in females), 15.9% (n = 22) were intermediate risk (CHA₂DS₂-VASc = 1 in males), and 44.2% (n = 61) were high risk (CHA₂DS₂-VASc ≥ 2). Of patients with high stroke risk and low-to-intermediate bleeding risk (n = 57), 80.7% were not prescribed an OAC at discharge. Cardiology consultation and female gender, but not stroke risk (CHA₂DS₂-VASc score), were predictors of an ED provider prescribing an OAC to an OAC-naive AF patient at ED discharge.

CONCLUSION

The majority of OAC-eligible patients were discharged home without an OAC prescription. In OAC-naive patients discharged home from the ED, cardiology consultation and female gender were associated with OAC prescription. Our findings suggest that access to expert opinion may improve provider comfort with OAC prescribing and highlight the need for improved guidelines specific to ED-management of AF.

Temporal Trends in Population Rates of Incident Atrial Fibrillation and Atrial Flutter Hospitalizations, Stroke Risk, and Mortality Show Decline in Hospitalizations

BACKGROUND

Hospitalization for nonvalvular atrial fibrillation (NVAF) is common and results in substantial cost burden. Current national data trends for the incidence, stroke risk profiles, and mortality of hospitalization for NVAF and atrial flutter (AFL) are sparse.

METHODS

The Canadian Institute of Health Information Discharge Abstract Database was used to identify patients ≥ 20 years with incident NVAF/AFL (NVAF, ICD-9 code 427.3 or ICD-10 I48) in any diagnosis field from 2006 to 2015 in Canada, except Québec. National and provincial trends in rate over time (rate ratio, 95% confidence interval [CI]) were calculated for age-sex standardized hospitalizations. Trends in stroke risk profiles and in-hospital mortality rates adjusted for stroke risk factors were also calculated.

RESULTS

A total of 578,947 patients were hospitalized with incident NVAF/AFL. The median age was 77 years (interquartile range: 68-84), 82% were ≥ 65 years, 54% were men, 54% had a CHADS2 ≥ 2, and 69% had a CHA2DS2-Vasc ≥ 3. The overall age- and sex-standardized rate of NVAF/AFL hospitalization was 315 per 100,000 population and declined by 2% per year (P < 0.001). There was an annual rate decline in NVAF/AFL hospitalizations in every province. The majority of hospitalized patients are at high risk of stroke, and this risk remained unchanged. The average adjusted in-hospital mortality was 8.80 per 100 patients 95% CI, 8.80-8.81 with a 2% annual decline in rate (P < 0.001).

CONCLUSION

Between 2006 and 2015, we found national and provincial hospitalization rates for incident NVAF/AFL are declining. The majority of patients are at high risk for stroke. In-hospital mortality has declined but remains substantial.

Stroke Prophylaxis for Atrial Fibrillation? To Prescribe or Not to Prescribe-A Qualitative Study on the Decisionmaking Process of Emergency Department Providers

STUDY OBJECTIVE

Although clinical guidelines recommend oral anticoagulation for atrial fibrillation patients at high risk of stroke, emergency physicians inconsistently prescribe it to patients with newly diagnosed atrial fibrillation. We interview emergency physicians to gain insight into themes influencing prescribing of oral anticoagulation for patients discharged from the ED with new-onset atrial fibrillation.

METHODS

From September 2015 to January 2017, we conducted semistructured qualitative interviews with a purposeful sampling of 18 ED attending physicians who had evaluated a patient with new-onset atrial fibrillation within the past 30 days. Interview prompts examined physicians' attitudes toward prescription of oral anticoagulation therapy and current clinical guidelines. We used a constructivist grounded theory approach to analyze data and develop a theory on prescribing practices among emergency physicians.

RESULTS

Three broad domains emerged from our analyses. (1) Oral anticoagulation prescribing practice: underlying themes affecting oral anticoagulation prescribing from the ED included physician practice patterns, beliefs, and barriers (including experience, comfort, and insurance coverage), and patient factors (including comorbidities, bleeding risk, and social concerns). Ultimately, these themes indicated physician discomfort and a sense of futility in prescribing oral anticoagulation for atrial fibrillation. (2) Guideline usage for oral anticoagulation prescribing: regardless of experience, most emergency physicians did not report using clinical guidelines when treating patients. (3) Recommendations for improved prescribing: physicians recommended the development of a validated, reliable, simple, accessible, and population-specific guideline that considers patient social factors.

CONCLUSION

The decision to prescribe oral anticoagulation in the ED is complex. Improving guideline adherence will require a multifaceted approach inclusive of system-level improvements, physician education, and the development of ED-specific tools and guidelines.

Parental Atrial Fibrillation and Stroke or Atrial Fibrillation in Young Adults

Background and Purpose- Cryptogenic strokes are often the first clinical manifestation of undiagnosed atrial fibrillation (AF). We designed this study to test whether parental AF is a risk factor for stroke in young adults. Methods- Population-based cohort study using linked administrative databases from April 1, 1972 to March 31, 2016 in Manitoba, Canada for 325 333 offspring (age ≥18 years) with at least 1 linked parent (total 582 195 parents). We examined the association between parental history of AF and stroke or transient ischemic attack (TIA) in the offspring using multivariable Cox proportional hazards models. Results- Offspring median age at study entry was 18 years. During 5.533 million person-years of follow-up (mean 17 years), 8678 offspring had an incident stroke or TIA (5.2% of the 24 583 offspring with a parental history of AF compared with 2.5% of the 300 750 offspring with no parental history of AF), and 1430 were diagnosed with AF (1.9% versus 0.3%). Incidence rates for stroke/TIA were higher in offspring with a parental history of AF (195.0 versus 156.6 per 100 000 person-years). Parental AF was associated with elevated risk in offspring of stroke/TIA (hazard ratio 1.11; 95% CI, 1.04-1.18) or AF (hazard ratio 1.75; 95% CI, 1.55-1.97) and a higher frequency of other cardiovascular risk factors. After adjusting for demographics, region of residence, socioeconomic status, and other stroke risk factors in offspring, parental AF was associated with AF in their offspring in young adulthood (adjusted hazard ratio 1.61; 95% CI, 1.43-1.82); the association of parental AF with offspring stroke/TIA was attenuated (adjusted hazard ratio 1.05; 95% CI, 0.99-1.12) after adjusting for the other cardiovascular risk factors. Conclusions- Parental AF is associated with increased risk of AF and other cardiovascular risk factors in their offspring during early adulthood, resulting in increased stroke risk.

Effects of a reminder to initiate oral anticoagulation in patients with atrial fibrillation/atrial flutter discharged from the emergency department: REMINDER study

CLINICIAN’S CAPSULE

What is known about the topic?

Oral anticoagulation (OAC) reduces stroke risk in patients with atrial fibrillation or flutter; however, initiation rates in patients discharged from the ED are low.

What did this study ask?

Can a simple quality improvement intervention increase the initiation of appropriate OAC in the ED?

What did this study find?

The rate of OAC initiation was increased by 8.5%.

Why does this study matter to clinicians?

This simple intervention is transferrable and therefore can improve patient care.

Although non-stroke outcomes are more common, stroke risk scores can be used for prediction in patients with atrial fibrillation

BACKGROUND

We investigated whether cardiovascular outcome patterns differ across atrial fibrillation (AF) subgroups defined by age, valvular status, newly diagnosed vs. prevalent cases, or anticoagulation status, and whether stroke risk models can accurately predict non-stroke outcomes.

METHODS AND RESULTS

We performed a retrospective cohort study of all 147,952 adults with AF in Alberta, Canada between January 2008 and March 2014: 23,095 (15.6%) had at least one thromboembolic event (stroke, TIA, or systemic embolism) and 52,618 (35.6%) had a non-stroke major adverse cardiovascular events (NS-MACE = all-cause mortality, new heart failure, new acute coronary syndrome) during follow-up (median 46 months). NS-MACE were 2-3 times more frequent than stroke in all subgroups. Newly diagnosed patients had higher rates of all outcomes in the first year than those with prevalent AF (and those with valvular AF had the highest rates): incident vs. prevalent NS-MACE rates per 100 patient years were 53.1 vs. 23.2 for anticoagulated valvular AF patients, 32.8 vs. 11.0 for non-anticoagulated NVAF patients, and 29.6 vs. 14.6 for anticoagulated NVAF patients. In non-anticoagulated NVAF patients, the stroke risk models exhibited similar accuracy for prediction of NS-MACE as they did for stroke prediction: C-statistics 0.66 [0.66-0.66] vs. 0.67 [0.66-0.68] for ATRIA-STROKE, 0.66 [0.66-0.67] vs. 0.62 [0.61-0.62] for CHADS₂, and 0.62 [0.61-0.62] vs. 0.52 [0.51-0.52] for CHA₂DS₂-VASc.

CONCLUSIONS

Non-stroke cardiovascular outcomes are more common than stroke in all AF subgroups but current stroke risk scores exhibit similar (modest) ability to predict risk for NS-MACE as for stroke, allowing identification of high-risk individuals for intervention.

Feasibility and outcomes of atrial fibrillation screening using intermittent electrocardiography in a primary healthcare setting: A cross-sectional study

Background

Atrial fibrillation (AF) is a major risk factor for ischemic stroke unless treated with an anticoagulant. Detecting AF can be difficult because AF is often paroxysmal and asymptomatic. The aims of this study were to develop a screening model to detect AF in a primary healthcare setting and to initiate oral anticoagulant therapy in high-risk patients to prevent stroke.

Methods

This was a cross-sectional study. All 70- to 74-year-old individuals registered at a single primary healthcare center in Stockholm were invited to participate in AF screening upon visiting the center during a ten-month period. Those who did not have contact with the center during this period were invited to participate by letter. Thirty-second intermittent ECG recordings were made twice a day using a handheld Zenicor device over a 2-week period in participants without AF. Oral anticoagulant therapy was offered to patients with newly detected AF.

Findings

Of the 415 eligible individuals, a total of 324 (78.1%) patients participated in the study. The mean age of the participants was 72 years, 52.2% were female, and the median CHA2DS2-VASc score of the participants was 3. In the target population, 34 (8.2%) individuals had previously diagnosed AF. Among participants without previously known AF, 16 (5.5%) cases of AF were detected. The final AF prevalence in the target population was 12%. Oral anticoagulant therapy was successfully initiated in 88% of these patients with newly detected AF.

Conclusions

The AF screening project exhibited a high participation rate and resulted in a high rate of newly discovered AF; of these newly diagnosed patients, 88% could be treated with an oral anticoagulant.

Emergency department presentations for atrial fibrillation and flutter in Alberta: a large population-based study

BACKGROUND

Atrial fibrillation or flutter (AFF) are not infrequent presenting problems in Emergency Departments (ED); however, little is known of the pattern of these presentations. This study provides a description of AFF presentations and outcomes after ED discharge in Alberta.

METHODS

Provincial administrative databases were used to obtain all primary ED encounters for AFF during 1999 to 2011 for patients aged >35 years. Data extracted included demographics, ED visit timing, and subsequent visits to non-ED settings. Analysis included summaries and standardized rates.

RESULTS

During the study period, there were 63,398 ED AFF visits from 32,104 distinct adults. Median ages for females and males were 75 and 67 years, respectively; more men (52%) and patients > 65 presented. Overall, the standardized rates remained similar (2.8 per 1,000 over the study period). Specific populations of human services recipients and First Nations had higher ED visit rates for AFF than other groups. Predictable daily, weekly, and monthly trends were observed. The ED visits were followed by numerous subsequent visits in non-ED settings; however, First Nations and women had lower rates of specialist follow-up.

CONCLUSIONS

Annually, over 5,000 ED presentations of patients experiencing AFF occur in Alberta and admissions proportions are declining. While presentation rates across the province are stable, follow-up with physicians, consultation with cardiologists and health outcomes vary based on socio-economic, age, sex, and First Nations status. Further research is required to understand the causes and consequences of these inequalities and to standardize care.

Are Existing Risk Scores for Nonvalvular Atrial Fibrillation Useful for Prediction or Risk Adjustment in Patients With Chronic Kidney Disease?

BACKGROUND

Comparative effectiveness studies are common in patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease (CKD), but the accuracy of current thromboembolic (n = 4) and bleeding (n = 3) prediction scores used for risk adjustment are uncertain in these patients because previous studies have included few CKD patients.

METHODS

This was a retrospective cohort study, using Cox models adjusted for time-varying coefficients, of nonanticoagulated adults with incident NVAF and kidney function (defined into Kidney Disease: Improving Global Outcomes [KDIGO] CKD categories) between 2002 and 2013.

RESULTS

Of 58,451 patients (mean age 66 years, 31.3% with CKD) followed for a median of 31 months, 21.3% died, 12.6% had a thromboembolic event (4.2 per 100 patient-years), and 7.8% had a major bleed (2.6 per 100 patient-years). There were graded associations between kidney function and all-cause mortality (adjusted hazard ratio [aHR], 1.88 [95% confidence interval (CI), 1.79-1.98] for very high vs low risk KDIGO category), major bleeding (aHR, 1.61 [95% CI, 1.47-1.76]), and thromboembolic events (aHR, 1.13 [95% CI, 1.04-1.23]). All 7 prediction scores had significantly poorer c statistics in patients with CKD: 0.50-0.59; all P < 0.0001 compared with those with normal kidney function (c statistics 0.69-0.70 for the 4 thromboembolic risk scores and 0.60-0.68 for the 3 bleeding risk scores). Inclusion of KDIGO category did not improve calibration or discrimination statistics for current prediction scores.

CONCLUSIONS

Existing NVAF risk scores exhibit poor discrimination in patients with CKD, limiting their utility for clinical decision-making or for risk adjustment in comparative effectiveness studies. Although CKD is an independent risk factor for adverse events, adding KDIGO class to current risk scores did not improve their performance.

Predictors and clinical outcomes of inpatient versus ambulatory management after an emergency department visit for atrial fibrillation: A population-based study

BACKGROUND

There is substantial variation in the management of atrial fibrillation (AF) in the emergency department (ED), particularly whether these patients are admitted to hospital. We sought to identify factors that predict admission and to examine the relationship between AF admission and outcomes.

METHODS

We performed a retrospective cohort analysis of patients ≥20 years of age who had an index ED visit with a primary diagnosis of AF from between April 1, 2005, and March 31, 2010, in Ontario, Canada. We excluded patients who died during the index ED visit or hospitalization. A hierarchical logistic regression model was used to determine predictors of hospital admission during the index ED visit. A propensity-matched analysis was used to test for associations between hospital admission and 1-year outcomes.

RESULTS

The cohort consisted of 33,699 patients, of whom 16,270 (48.3%) were admitted to hospital. Substantial variation was seen across the 154 hospitals, with admission rates ranging from 3.0% to 91.0%. Admitted patients had higher rates of comorbidities compared to discharged patients. Mortality rates at 1 year were significantly higher in matched admitted versus discharged patients (hazard ratio 1.45, 95% CI 1.33-1.57, P < .001), as were all-cause hospitalizations (hazard ratio 1.18, 95% CI 1.13-1.22, P < .001).

CONCLUSIONS

Wide practice variation was observed between hospitals in terms of the proportion of patients admitted. Our data suggest that selected patients when discharged have similar or improved outcomes compared to those who are initially admitted. Future research is needed to better standardize admission/discharge decisions for AF patients in the ED.

A Decision Analysis of Percutaneous Left Atrial Appendage Occlusion Relative to Novel and Traditional Oral Anticoagulation for Stroke Prevention in Patients with New-Onset Atrial Fibrillation

Background. Percutaneous left atrial appendage occlusion (LAAO) is a nonpharmacologic approach for stroke prevention in nonvalvular atrial fibrillation (NVAF). No direct comparisons to novel oral anticoagulants (OACs) exists, limiting decision making on the optimal strategy for stroke prevention in NVAF patients. Addressing this gap in knowledge is timely given the recent debate by the US Food and Drug Administration regarding the effectiveness of LAAO. Objective. To assess the cost-effectiveness of LAAO and novel OACs relative to warfarin in patients with new-onset NVAF without contraindications to OAC. Design. A cost-utility analysis using a patient-level Markov micro-simulation decision analytic model was undertaken to determine the lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) of LAAO and all novel OACs relative to warfarin. Effectiveness and utility data were obtained from the published literature and cost from the Ontario Drug Benefits Formulary and Case Costing Initiative. Results. Warfarin had the lowest discounted QALY (5.13 QALYs), followed by dabigatran (5.18 QALYs), rivaroxaban and LAAO (5.21 QALYs), and apixaban (5.25 QALYs). The average discounted lifetime costs were $15 776 for warfarin, $18 280 for rivaroxaban, $19 156 for apixaban, $20 794 for dabigatran, and $21 789 for LAAO. Apixaban dominated dabigatran and LAAO and demonstrated extended dominance over rivaroxaban. The ICER for apixaban relative to warfarin was $28 167/QALY. Apixaban was preferred in 40.2% of simulations at a willingness-to-pay threshold of $50 000/QALY. Limitations. Assumptions regarding clinical and methodological differences between published studies of each therapy were minimized. Conclusions. Apixaban is the most cost-effective therapy for stroke prevention in patients with new-onset NVAF without contraindications to OAC. Uncertainty around this conclusion exists, highlighting the need for further research.

Risk scoring and thromboprophylactic treatment of patients with atrial fibrillation with and without access to primary healthcare data: experience from the Stockholm health care system

BACKGROUND

Earlier validation studies of risk scoring by CHA2DS2VASc for assessments of appropriateness of warfarin treatment in patients with atrial fibrillation have been performed solely with diagnoses recorded in hospital based care, even though many patients to a large extent are managed in primary care.

METHODS

Cross-sectional registry study of all 43 353 patients with a diagnosis of non-valvular atrial fibrillation recorded in inpatient care, specialist ambulatory care or primary care in the Stockholm County during 2006-2010.

RESULTS

The mean CHA2DS2VASc score was 3.82 (4.67 for women and 3.14 for men). 64% of the entire cohort of patients with atrial fibrillation had the diagnosis in primary care (12% only there). The mean CHA2DS2VASc score of patients with a diagnosis only in inpatient care or specialist ambulatory care increased from 3.63 to 3.83 when comorbidities registered in primary care were added. In 2010 warfarin prescriptions were claimed by 47.2%, and ASA by 41.6% of the entire cohort. 34% of patients with CHA2DS2VASc=1 and 20% with CHA2DS2VASc=0 had warfarin treatment. ASA was more frequently used instead of warfarin among women and elderly patients.

CONCLUSIONS

Registry CHA2DS2VASc scores were underestimated without co-morbidity data from primary care. Many individuals with scores 0 and 1 were treated with warfarin, despite poor documentation of clinical benefit. In contrast, warfarin appears to be underused and ASA overused among high risk atrial fibrillation patients. Lack of diagnoses from primary care underestimated CHA2DS2VASc scores and may thereby have overestimated treatment benefits in low-risk patients in earlier studies.

Outcomes for people with atrial fibrillation in an Australian national audit of stroke care

BACKGROUND

Atrial fibrillation is associated with poorer outcomes poststroke. It is unclear how the quality of stroke care in hospitals influences outcomes in these patients.

AIMS

The study aims to compare outcomes in stroke patients with and without atrial fibrillation and identify hospital processes of care associated with poor outcomes.

METHODS

Data were collected using retrospective, consecutive medical record audits from participating hospitals in the 2009 and 2011 National Stroke Foundation acute services audit program. Patient characteristics, stroke severity, and hospital management data were compared for those with and without atrial fibrillation. Multiple regression analyses for outcomes of in-hospital death, dependency at discharge (modified Rankin Score 3-5), and discharge destination were undertaken, adjusted for patient clustering by hospital.

RESULTS

Atrial fibrillation status was known for 5473 (80%) cases; 2049 had atrial fibrillation. Atrial fibrillation was independently associated with in-hospital mortality (aOR 1.46, 95% CI 1.06, 2.02). Management on a stroke unit (aOR 0.57, 95% CI 0.40, 0.80) and having a swallow assessment within 24 h (aOR 0.71, 95% CI 0.51, 0.98) were associated with increased survival among all stroke types, as was receiving aspirin within 48 h poststroke (aOR 0.65, 95% CI 0.44, 0.97), for patients with an ischemic stroke. Stroke patients with atrial fibrillation were less likely to receive important processes of care associated with reduced mortality.

CONCLUSIONS

Hospital processes of care can influence outcomes in stroke patients with atrial fibrillation. The greater in-hospital mortality experienced by stroke patients with atrial fibrillation may be attenuated by admission to a stroke unit, and for ischemic stroke, early administration of aspirin.

Cardiovascular and non-cardiovascular hospital admissions associated with atrial fibrillation: a Danish nationwide, retrospective cohort study

OBJECTIVE

To examine the excess risk of hospitalisation in patients with incident atrial fibrillation (AF).

DESIGN

A nationwide, retrospective cohort study.

SETTING

Denmark.

PARTICIPANTS

Data on all admissions in Denmark from 1997 to 2009 were collected from nationwide registries. After exclusion of subjects previously admitted for AF, data on 4 602 264 subjects and 10 779 945 hospital admissions contributed to the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Age-stratified and sex-stratified admission rates were calculated for cardiovascular and non-cardiovascular admissions. Temporal patterns of readmission, relative risk and duration of frequent types of admission were calculated.

RESULTS

Of 10 779 945 hospital admissions, 729 088(6.8%) were associated with AF. Admissions for cardiovascular reasons after 1, 3 and 6 months occurred for 6.0, 14.3 and 28.4% of AF patients versus 0.2, 0.6 and 1.8 of non-AF patients. Admissions for non-cardiovascular reasons after 1, 3 and 6 months comprised 6.8, 16.1 and 33.3% of AF patients and 1.2, 3.2 and 9.7% of non-AF patients. When stratified for age, AF was associated with similar cardiovascular admission rates across all age groups, while non-cardiovascular admission rates were higher in older patients. Within each age group and for both cardiovascular and non-cardiovascular admissions, AF was associated with higher rates of admission. When adjusted for age, sex and time period, patients with AF had a relative risk of 8.6 (95% CI 8.5 to 8.6) for admissions for cardiovascular reasons and 4.0 (95% CI 4.0 to 4.0) for admission for non-cardiovascular reasons.

CONCLUSIONS

This study confirms that the burden of AF is considerable and driven by both cardiovascular and non-cardiovascular admissions. These findings underscore the importance of using clinical and pharmacological means to reduce the hospital burden of AF in Western healthcare systems.