The Relationship Between Cardiologist Care and Clinical Outcomes in Patients With New-Onset Atrial Fibrillation

Validation of the Use of Discharge Diagnostic Codes for the Verification of Secondary Atrial Fibrillation in Administrative Databases

Background

"Secondary" atrial fibrillation (AF) denotes AF that is precipitated by short-term triggers and that may be reversible. Using administrative data to study secondary AF is of interest, but the ability of these data to verify secondary AF has not been studied.

Methods

We conducted a cross-sectional analysis of 1000 randomly selected hospitalizations of patients discharged alive between January 1, 2016 and March 31, 2020, with AF coded as the most responsible diagnosis (type 1), post-admit comorbidity (type 2), or secondary diagnosis (type 3). We compared diagnosis types to AF category (secondary or not) as determined by a physician blinded to the discharge diagnosis type. We calculated the positive predictive value (PPV) of the designation of secondary AF in comparison to physician determination.

Results

A total of 421 hospitalizations had AF documented as a type 2 diagnosis; this had a PPV of 94.8% for physician determination of secondary AF. After excluding hospitalizations with preexisting AF, and those for which AF type could not be determined by the physician, the PPV of a type 2 diagnosis (n = 391) for secondary AF was 99.7%. Type 3 diagnoses of AF (n = 222) mostly captured hospitalizations with preexisting AF (87.8% of type 3 diagnoses).

Conclusions

A type 2 diagnosis can be used to verify secondary AF in people who were first diagnosed with AF while hospitalized for other causes. This verification facilitates cohort studies and clinical trial recruitment of people with this AF subtype, although it should not be used to determine the prevalence or incidence of secondary AF.

New-onset Heart Failure With Atrial Fibrillation: A Distinct Type of Cardiomyopathy?

Objective

There is limited research comparing demographic and clinical characteristics between patients who present with atrial fibrillation (AF) and new-onset cardiomyopathy (CM) to patients with new-onset CM without dysrhythmia. We aimed to evaluate clinical characteristics and outcomes in patients with new-onset CM with and without AF and to report their real-world treatment.

Methods and Results

The study population was identified using patient records from our healthcare system from January 1, 2012 to September 30, 2016. Patients with a left ventricular ejection fraction ≤40% without a prior history of CM were divided into two groups; those with an antecedent or concomitant diagnosis of AF (AF-CM group) and those with no history of dysrhythmia (CM group). Patients in the AF-CM group (n=196) were older, more likely to be male, had a higher burden of comorbidities but lower levels of cardiac biomarkers, and had lower voltage on surface electrocardiogram than the CM group (n=197). In AF-CM, symptom onset was insidious, leading to a higher likelihood of outpatient diagnosis; 88.3% of AF-CM patients presented with atypical symptoms of AF. The AF-CM group had higher mortality on follow-up. Only 8.7% of patients in this group underwent an ablation procedure. Women, those with a history of coronary artery disease, and older patients were less likely to receive a cardioversion or ablation procedure.

Conclusions

Patients presenting with new-onset CM associated with AF have a markedly different risk factor and demographic profile, clinical presentation, and outcomes. In real-world practice, a minority of patients undergo a rhythm control strategy.

Examination of anticoagulation prescription among elderly patients with atrial fibrillation after in-hospital fall

Mechanical fall is common among elders and has been associated with a lack of anticoagulant therapy among patients with atrial fibrillation (AF). However, anticoagulant therapy is recommended despite frequent fall due to an increased risk of a thromboembolic event. Using data from a large health system, we investigated the predictors of anticoagulation prescription on discharge in AF elderly patients after an in-hospital fall. In this retrospective analysis, we examined patients aged 60 years and older discharged from 2013 to 2018 with a diagnosis of AF and a secondary diagnosis of in-hospital fall. The primary outcome was the prescription of anticoagulation at discharge. We obtained patients' demographical (race, sex, and health insurance status) and clinical (management by a resident team, receipt of a head CT or a cardiology consultation, ambulation status and discharge location) data. We further categorized the type of anticoagulation prescribed as warfarin or novel oral anticoagulants (NOACs). We ran chi-square and Fischer's exact tests on all data and multivariable logistic regressions on those of patients with pre-existing AF to identify the predictors of anticoagulation prescription on discharge. In total, 67% of 235 patients were discharged on anticoagulation. Of patients admitted on anticoagulation, 91% were prescribed anticoagulation on discharge (p < 0.001), while only 40% of patients with new-onset AF were discharged on anticoagulation (p < 0.001). Patients over the age of 90, compared to those aged 60-89, with existing AF had lower odds (OR = 0.34 [95% CI 0.12-0.98]) of being prescribed anticoagulation on discharge. Among patients with preexisting AF, being admitted on anticoagulation increased the odds (OR = 39.8 [15.2-104.0]) of anticoagulation prescription on discharge. Asian patients with prior AF were less likely (OR = 0.12 [0.026-0.060]) to receive anticoagulation on discharge. Of patients with new AF, 81% were prescribed a NOAC as opposed to warfarin (p < 0.05). These results suggest that provider's decisions on anticoagulation initiation seem to be guided more by their concerns over bleeding complications than by the patient's risk for stroke. However, anchoring bias strongly influences anticoagulation prescription. It may benefit AF patients already on anticoagulation, but it may prevent anticoagulation prescription in patients with new AF and Asian patients.

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.

Impact of cardiology follow-up care on treatment and outcomes of patients with new atrial fibrillation discharged from the emergency department

Aims

The first presentation of atrial fibrillation (AF) is often to an emergency department (ED). We evaluated the association of subsequent specialist care with morbidity and mortality.

Methods and results

Retrospective cohort study of all adults in Alberta, Canada, with a new primary diagnosis of AF treated and released during an index ED visit between 2009 and 2015. Types of physician follow-up within 3 months of ED visit was analysed using Cox proportional hazards models with time-varying covariates. Outcomes were evaluated at 1 year. Of 7986 patients, 476 (6.0%) had no physician follow-up within 3 months, whereas 2730 (34.2%) attended a non-specialist only, 1277 (16.0%) an internal medicine specialist, and 3503 (43.9%) cardiology. An increasing gradient of cardiac investigations occurred across these groups. Cardiology compared with non-cardiologist care was associated with approximately two-fold greater electrophysiology interventions and revascularization, and increased use of beta-blockers (48.9% vs. 43.0%, P &lt; 0.0001), statins (31.4% vs. 26.7%, P &lt; 0.0001), and oral anticoagulation in patients with CHADS2 scores ≥1 (53.7% vs. 43.6%, P &lt; 0.0001). In the subsequent year, cardiology care was associated with fewer deaths [adjusted hazard ratio (aHR) 0.72, 95% confidence interval (CI) 0.55–0.93], strokes (aHR 0.60, 95% CI 0.37–0.96), or major bleeds (aHR 0.69, 95% CI 0.53–0.89). No differences in the risk of hospitalization or ED visits were associated with cardiology care.

Conclusion

Cardiology care after an ED visit for symptomatic new-onset AF is associated with better prognosis. The benefit may be mediated through more intensive investigation, identification, and treatment of cardiovascular risk factors and disease.

Effect of Electrophysiology Assessment on Mortality and Hospitalizations in Patients With New-Onset Atrial Fibrillation

Few patients with atrial fibrillation (AF) receive care by cardiac electrophysiologists. Although previous work has highlighted differential care for patients with AF treated by electrophysiologists, it is unclear whether this is associated with improved clinical outcomes. This retrospective population-level propensity score-matched cohort study included patients aged 20 to 80 years with new-onset AF presenting to an emergency department (ED) in Ontario, Canada, between 2010 and 2012. Patients were followed until March 31, 2015. Patients who saw an electrophysiologist within 1 year of the index ED visit were matched to patients who did not see an electrophysiologist. Linked administrative databases were used for cohort construction and allow 1-year follow-up to assess for the clinical end points of all-cause mortality and hospitalization for AF, heart failure, bleeding, and stroke. A total of 5,221 unique pairs of patients were matched. One hundred seventeen patients (2.2%) in the electrophysiologist cohort underwent an AF ablation procedure during the 1-year follow-up period. All-cause mortality (hazard ratio [HR] = 1.1, p = 0.17) and stroke (HR = 1.4, p = 0.09) were not significantly different between the 2 groups. Hospitalization for AF (HR = 1.4, p <0.001), bleeding (HR = 1.5, p = 0.0001), and congestive heart failure (HR = 1.5, p <0.0001) was increased in the group that saw an electrophysiologist. In conclusion, electrophysiologist care was not associated with improved clinical outcomes in patients with new-onset AF.