Description of flecainide usage from 2005-2018 in the Danish population

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Flecainide is an antiarrhythmic class 1C agent used to treat cardiac arrhythmias. Due to the risk of pro-arrhythmia and 1:1 conduction with flecainide, concomitant treatment with atrioventricular nodal blocking (AVNB) agents is advised. However, little data exist pertaining to the real-world use of flecainide and concomitant AVNB therapy.

Purpose

We sought to investigate the change over time in the use of flecainide and AVNB agents in relation to patient characteristics.

Methods

Using the Nationwide Danish registers, all Danish patients above 18 years with a redeemed prescription for flecainide between January 1st, 2005, and December 31st, 2018, and included at the date of the first prescription. The use of AVNB agents was identified in the period from 180 days prior to and 180 days after the inclusion date. Individual AVNB agents were divided into beta-blockers, class IV calcium channel blockers, and digoxin.

Results

The study cohort consisted of 6,594 patients with a median [IQR] age increasing from 59 [53-65] years in 2005 to 63 [56-69] in 2018, 59 % were men, and the most frequent arrhythmia diagnosis was AF (90.1%). In total, there were 297 patients starting flecainide in 2005 and 491 in 2018, with the highest number of patients in 2011, with 613 new users (Figure 1). Compared to the 144,215 patients with prevalent atrial fibrillation in Denmark in 2018, the number of patients using flecainide was only 0.3% this year.

The percentage of patients on concomitant AVNB treatment was high throughout the study period, with 93% in 2005 and 95% in 2018, giving an average increase of 0.3% per year over time. The most frequently used AVNB was beta-blockers, and the least frequently used were the class IV calcium channel blockers. (Figure 2)

Over time, the number of patients with concomitant AVNB treatment to flecainide decreased from 94% the first year in flecainide treatment to 90% between the second and third years. Between the firth and sixth year in flecainide treatment, the number was down to 86%.

The number of patients with a diagnosis of ischemic heart disease was 10% in 2005, dropping to 6% in 2018

Conclusions

Flecainide use increased from 2005 to 2018. The use of AVNB was high in patients prescribed with flecainide and increased over time, with beta-blocker as the most frequent.

3153Rate versus rhythm control and mortality in atrial fibrillation patients: a Danish nationwide cohort study

Background

Treatment of AF patients with rate or rhythm drug therapy have shown no difference in mortality in clinical trials. However, the generalizability of these trials to real-world populations can be questioned.

Purpose

We aimed to investigate the all-cause and cardiovascular (CV) mortality risk in a nationwide AF cohort by treatment strategy (rate vs. rhythm) and by individual drug classes.

Methods

We queried the Danish nationwide registries from 2000 to 2015 to identify patients with AF. A rate control strategy included the use of one or more of the following medications: beta-blocker, digoxin, and a class-4 calcium channel blocker (CCB). A rhythm control strategy included the use of an anti-arrhythmic drug (amiodarone and class-1C). Primary outcome was all-cause mortality. Secondary outcome was CV mortality. Adjusted incidence rate ratios (IRR) were computed using Poisson regression with time-dependent covariates allowing patients to switch treatment during follow-up.

Results

Of 140,697 AF patients, 131,793 were on rate control therapy and n=8,904 were on rhythm control therapy. At baseline, patients on rhythm control therapy were younger (71 yrs [IQR: 62–78] vs 74 [65–82], p<0.001) more likely male (63.5% vs 51.7% p<0.001), had more prevalent heart failure (31.1% vs 19.4%, p<0.001) and ischemic heart disease (40.1% vs. 23.3%, p<0.001), and had more prior CV-related procedures; PCI (7.4% vs. 4.0% p<0.001) and CABG (15.0% vs. 2.3%, p<0.001).

During a median follow up of 4.0 (IQR: 1.7–7.3) years, there were 64,653 (46.0%) deaths from any-cause, of which 27,025 (19.2%) were CVD deaths. After appropriate adjustments and compared to rate control therapy, we found a lower IRR of mortality and CV mortality in those treated with rhythm control therapy (IRR: 0.93 [95% CI: 0.90–0.97] and IRR 0.84 [95% CI: 0.79–0.90]). Compared with beta-blockers, digoxin was associated with increased risk of all-cause and CV mortality (IRR: 1.26 [95% CI: 1.24–1.29] and IRR: 1.32 [95% CI: 1.28–1.36]), so was amiodarone: IRR for all-cause mortality: 1.16 [95% CI: 1.11–1.21] and IRR for CV mortality: 1.12 [95% CI: 1.05–1.19]. Class-1C was associated with lower all-cause (0.43 [95% CI: 0.37–0.49]) and CV mortality (0.35 [95% CI: 0.28–0.44]).

Figure 1. Models were adjusted for age, sex, ischemic heart disease, stroke, chronic obstructive pulmonary disease, chronic kidney disease, valvular atrial fibrillation, bleeding, diabetes, ablation, pacemaker, implantable cardioverter defibrillator, hypertension, heart failure, use of loop diuretics, calendar year, and time on treatment. Abbreviations; CCB; calcium channel blocker, PY; person years.

Conclusions

In a real-world AF cohort, we found that compared with rate control therapy, rhythm control therapy was associated with a lower risk of all-cause and CV mortality. The reduced mortality risk with rhythm therapy could reflect an appropriate patient selection.

Acknowledgement/Funding

The Danish Heart Foundation

P4774Older patients with atrial fibrillation and comorbidities are less likely to be treated with oral anticoagulation: insights from a nationwide study

Background

Older patients with atrial fibrillation (AF) often have multiple chronic conditions adding complexity to treatment decisions. However, regarding older AF patients, the association between multimorbidity and quality of care has not been explored previously in a non-selected nationwide cohort.

Purpose

To investigate the association between morbidity burden and the treatment with oral anticoagulation therapy (OAC) and rhythm-control strategies in patients >65 years of age with incident AF in Denmark.

Methods

Using Danish nationwide registers, we identified all Danish AF patients >65 years of age hospitalized for incident AF between 2010 and 2016. Using logistic regression models, we estimated the association between morbidity burden (<2, 2–3, 4–5, and >5 comorbidities) and the likelihood of receiving AF specific treatments. Estimates were reported as odds ratios with 95% confidence intervals (OR, 95% CI) with <2 comorbidities as reference. The primary outcome of interest was OAC therapy initiation. Secondary outcomes were initiation of anti-arrhythmic drugs (Class IC and Class III) and AF related procedures (electrical cardioversion and radiofrequency ablation). All models were adjusted for age, sex and calendar year.

Results

A total of 49,802 AF patients were eligible for inclusion, with a median age of 77.5 years (Interquartile range [IQR] 71.8–83.8) and 24,983 (50.2%) were male. A total of 25,181 (50.6%) patients had <2 comorbidities, 18,714 (37.6%) had 2–3 comorbidities, 4,891 (9.8%) had 4–5 comorbidities, and 1,016 (2.0%) patients had >5 comorbidities. The median CHA2DS2-VASc score ranged from 3 (IQR 2–3) to 5 (IQR 4–5) in patients with <2 comorbidities and >5 comorbidities, respectively.

Increasing morbidity burden was associated with decreasing odds of being treated with OAC therapy with the lowest odds in patients with >5 comorbidities (OR 0.39, 95% CI 0.34–0.45) compared with AF patients with <2 comorbidities. (Figure 1) Using morbidity burden as a continuous variable, an increment of one comorbidity was associated with decreasing odds of initiating OAC therapy (OR 0.85, 95% CI 0.84–0.86).

Morbidity burden was associated with increased odds of being prescribed anti-arrhythmic medication with the highest odds in patients with >5 comorbidities (OR 2.50 95% CI 2.08–2.99). In contrast, having >5 comorbidities was associated with decreased odds of AF related procedures (OR 0.32, 95% CI 0.23–0.43) compared to patients with <2 comorbidities.

Forest plot of OAC initiation factors

Conclusion

Morbidity burden is strongly associated with OAC initiation and rhythm-control strategies in older patients with incident AF. Older AF patients with multimorbidity are less likely to be treated with OAC although these are the patients who benefit most from treatment. Therefore, initiatives and quality improvement programs should be done to close this important gap between clinical trials and clinical practice.