ATRIAL FIBRILLATION AT KUMLA HEALTHCENTRE – ANTICOAGULANT TREATMENTAND SYMPTOMS

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Örebro University Programme in Medicine Degree project, 15.0 ECTS June 2020

Author: Adam Jackson Supervisor: Anna Björkenheim (M.D. PhD)

Department of Cardiology Örebro University Hospital Örebro, Sweden

ATRIAL FIBRILLATION AT KUMLA HEALTH

CENTRE – ANTICOAGULANT TREATMENT

AND SYMPTOMS

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Abstract

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia affecting an estimated 3 % of the adult population in the western world. The prevalence of the disease increases with increasing age, thought to be due to structural changes in the heart as a result of ageing, long-term hypertension, or organic heart disease. The disorder increases the risk of thromboembolism with the most common manifestation surfacing as a stroke. Oral

anticoagulants such as novel oral anticoagulants or vitamin K antagonists are an essential preventative measure for strokes and are recommended by Socialstyrelsen and European cardiology guidelines. Patients with a high stroke risk not being treated according to these guidelines constitute a high-risk group of individuals. Patients who are contraindicated anticoagulants can undergo a left atrial appendage occlusion to reduce the risk of a stroke. Aim: To investigate anticoagulation treatment and symptoms of all patients aged 20 years and above with the diagnosis AF at Kumla Health Centre in Örebro county between 2015 and 2018.

Method: This care quality cohort study was based on all patients aged 20 years and above with the diagnosis AF at Kumla Health Centre. Data regarding their type of AF (paroxysmal, persistent or permanent), current medication, relevant comorbidities and risk factors for a stroke according to CHA2DS2-VASc score were obtained from the Medrave 4 database. The patients’ diagnoses were verified using records of their electrocardiograms. Patients were asked to fill out a validated symptom-questionnaire (AF-6) relating to their symptoms of AF. Data was collected and analysed using descriptive statistics.

Results: 34 out of 456 (7.5 %) patients at Kumla Health Centre displayed a high stroke risk and were also missing relevant treatment according to current guidelines. When accounting for contraindications for oral anticoagulation, there were 24 (5.3 %) eligible patients who did not have satisfactory treatment. The prevalence of AF in Kumla was estimated to be 2.1 %, permanent AF was the most common subtype (63.4 %), followed by paroxysmal (31.8 %) and finally persistent (4.8 %). 26 patients were offered a consultation with a cardiologist and 16 out of 24 eligible (66.7 %) for anticoagulation agreed to an updated treatment plan.

Conclusion: The vast majority of patients at Kumla Health Centre with an AF diagnosis were being treated according to current guidelines. The most common type of AF was permanent, and the least common was persistent. Most of the patients who were offered a consultation updated their treatment plan.

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Abbreviations and acronyms

AF – Atrial fibrillation ASA – Acetylsalicylic acid

CHA2DS2-VASc – Congestive heart failure, hypertension, age ≥ 75 (doubled), diabetes, prior stroke/transient ischemic attack/thromboembolism (doubled), vascular disease, age 65-74 and sex category (female)

CHF – Congestive heart failure

ESC – European Society of Cardiology LAAO – Left atrial appendage occlusion NOAC – Novel oral anticoagulant OAC – Oral anticoagulation SD – Standard deviation

TIA – Transient ischemic attack VKA – Vitamin K antagonist

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Introduction

Atrial fibrillation (AF) is the most common sustained arrhythmia affecting an estimated 3 % of adults aged 20 years and older. Prevalence rises as age increases and also in correlation to other conditions such as hypertension, congestive heart failure (CHF), coronary artery

disease, valvular heart disease, diabetes mellitus, and obesity. The main risks with the disease are associated with sequelae such as strokes, CHF, and premature death [1]. Unsynchronised atrial contractions lead to incomplete emptying of the left atrium and therefore blood

stagnation. This can prompt thrombus formation, subsequent dislodging of the thrombus and transportation in the blood (as an embolus) to the brain where it may block smaller arterioles and cause an ischemic stroke [2].

AF can be categorised into one of three subtypes: 1. Paroxysmal – Self-terminating episodes of AF.

2. Persistent – AF episodes that last longer than seven days and are terminated by electrical cardioversion or drug therapy.

3. Permanent – Persistent AF that is accepted as chronic by both the patient and physician [1].

Many patients initially experience short, infrequent episodes of paroxysmal AF in the early stages of the disease, but eventually it progresses to the more chronic subtypes: persistent or permanent AF. Common symptoms include palpitations, shortness of breath, tiredness as well as a decreased quality of life compared to both the general population and to patients with coronary heart disease [3]. Paroxysmal AF is the subtype that is most symptomatic and permanent the least. The prevalence of AF may be higher than what is commonly thought; this is due to a lack of symptoms in roughly one-third of all patients – also known as silent AF [4].

The aim when treating patients with AF is to improve quality of life by minimising

symptoms, and to prevent complications. One way to achieve this is by administering oral anticoagulation (OAC) such as novel oral anticoagulants (NOAC) or vitamin K antagonists (VKA) such as warfarin to patients with a high risk of suffering a stroke. By administering anticoagulation; the likelihood of a thrombus forming is reduced, thereby minimising the stroke risk and reducing mortality [5]. Guidelines from the European Society of Cardiology

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5 (ESC) issued 2018 also state that the use of NOAC should be prioritised over warfarin due to the overall clinical benefits of NOAC [6]. Acetylsalicylic acid (ASA) was previously thought to prevent an ischemic stroke to some extent but has since been proven ineffective and still carries a bleeding risk comparable to that of OAC. Swedish national guidelines now state that ASA should not be used to prevent strokes in patients with AF and that OAC should be the preferred treatment [7]. Due to this recommendation being recently updated, patients with AF could still be getting ASA prescribed instead of OAC treatment and these patients are

therefore insufficiently protected against strokes and premature death.

Left atrial appendage occlusion (LAAO) is a non-pharmacological treatment option for stroke prevention in patients with clear contraindications for OAC (such as previous life-threatening bleeding without a reversible cause, previous intracerebral haemorrhaging or allergy).The LAAO blocks blood flow into the left atrial appendage and therefore minimises the risk of thrombus formation. LAAO is at least as effective as VKA treatment in patients with a moderate stroke risk, also demonstrating a decreased risk of bleeding [1].

The most useful point-based tool when evaluating the stroke risk is CHA2DS2-VASc (congestive heart failure, hypertension, age ≥ 75, diabetes, prior stroke/transient ischemic attack/thromboembolism, vascular disease, age 65-74 and sex category (female)). Each condition gives the scorer one point except for age > 75 and prior stroke/transient ischemic attack/thromboembolism where two points are awarded (as shown by the subscript twos) [8]. A higher points-total indicates an increased stroke risk; regardless of the type of AF. Sex category (female) is not thought to lead to a higher stroke risk without the presence of other conditions and is therefore seen as a risk-modifying factor and not an independent risk factor. According to the latest guidelines from Socialstyrelsen in Sweden; anticoagulation treatment is recommended for patients with at least one point in CHA2DS2-VASc as long as the point is not due to being of the female sex [7].

The new stricter recommendations; coupled with the fact that patients with previously known AF are ageing and accumulating risk factors are both considered to be decisive facts that lead to the conception of this study. The project is part of an ongoing, larger study investigating the symptoms and treatment of all AF patients in Örebro county. The town of Kumla is seen as a fair representation with a population of 21 653 in the municipality (as of 2018-11-01). The mean age was 40.5 years and the mean annual income for ages 20+ was 303 000 kr, as of

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6 2018-12-31. This is comparable to the mean ages and annual incomes of Sweden (41.2 years and 314 700 kr) and Örebro county (41.6 years and 292 700 kr) for the same period [9]. The prevalence of AF in Kumla is estimated to be 2.1 % using the population in the municipality and the findings in this study (Kumla Health Centre covers the municipality and has 456 patients with AF). The prevalence in Sweden is 3 % [7].

Aim

The aim of this study is to investigate anticoagulation treatment and symptoms of all patients aged 20 years and above with the diagnosis atrial fibrillation at Kumla Health Centre to confirm that patients with the diagnosis are being treated according to current guidelines. Questions

1. What percentage of patients at Kumla Health Centre with AF are being treated with anticoagulation treatment according to current guidelines?

i. What percentage of patients with a high stroke risk do not have anticoagulation treatment or LAAO and should begin medicating with OAC or be referred for LAAO?

ii. What percentage of patients with a high stroke risk have contraindications for OAC?

iii. What percentage of patients with a high stroke risk started OAC therapy after being offered a consultation with a physician to discuss anticoagulation? 2. What is the prevalence of AF and what is the distribution of the different subtypes at

Kumla Health Centre?

3. What proportion of patients with AF are asymptomatic/symptomatic?

Material and method

Study design

A descriptive care-quality control study was conducted using patient data from the database Medrave 4. The compiling of data from the database was completed in November 2019. Symptom-questionnaires were sent out in January 2020 and the final dataset was completed in April 2020. Patients with a high stroke risk and no anticoagulation therapy or previous LAAO

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7 procedure were contacted and offered a consultation with a physician at the Department of Cardiology, Örebro University Hospital.

Sample/Cohort

Adults aged 20 years and above registered at Kumla Health Centre with the diagnosis ICD-10 code I48 (including I48.9, I48.0, I48.1 and I48.2) in the Medrave 4 Primary care database between 01-01-2015 and 31-12-2018.

Data collection

Medrave 4 Primary care – Statistics from Kumla Health Centre for the past five years. Data

on all patients with an AF diagnosis was collected as well as their personal identity number. The correct diagnosis of AF, type of AF, treatment, and comorbidities was then

cross-referenced with the regional electronic chart system (Klinisk portal). Deceased patients were excluded. The patient’s diagnoses of AF were confirmed by reviewing their

electrocardiograms after data collection was completed.

AF-6 – An AF-specific questionnaire validated for evaluating symptoms of AF (see

Appendix, page one). Patients state the severity of six AF-related symptoms on a scale of 0 (no symptoms) to 10 (severe symptoms) for the past seven days. The point totals are

summarised for an AF-6 sum between 0-60 [10–12]. Statistical analysis

Data from Medrave 4 was compiled in Microsoft Excel version 16.36, 2020 (Microsoft, Redmond, Washington, USA). The information from the AF-6 questionnaires was collected and subsequently added to the document. The results were then processed into descriptive statistics such as measures of central tendency (mean, median and mode) and measures of variance (standard deviation (SD)). Values were expressed as mean ± SD or “n” as a

proportion of the population in per cent (%). Tables and diagrams were created using Excel. Ethical considerations

Patients’ personal identity numbers were used to collect information from the database. All project-related data was then anonymised using code numbers. Each patient was assigned a code number instead of their personal identity number and they, therefore, remained

anonymous. All those working on the project signed a secrecy agreement. Coded data was handled in a password-protected excel document on a password-protected computer. The

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8 datasets were transferred from one computer to another using an encrypted USB-stick to avoid the risk of a data leak through information being online. Results were presented in groups and it will therefore not be possible to trace findings to any individual. The study has been approved by the Swedish Ethical Review Authority (registration number: 2019-03772). The relative risk is considered low compared to the potentially life-improving intervention for patients partaking in the study.

Results

463 subjects with the diagnosis AF between 2015 and 2018 were identified at Kumla Health Centre. After examining the dataset, 7 were found to have been wrongly diagnosed and were excluded. None of the excluded 7 patients were being treated with OAC. The remaining 456 were used as the final cohort. 400 (87.7 %) of all patients with AF were already being treated with OAC of which 306 (67.1 %) had NOAC and 94 (20.6 %) had warfarin, and 3 patients had previously undergone an LAAO procedure. 53 (11.6 %) patients were identified as initial possible candidates for OAC. Out of the 53, there were 19 with a low stroke risk (men with CHA2DS2-VASc = 0 (n = 9) or age < 65 years coupled with CHA2DS2-VASc = 1 (n = 7) and women with CHA2DS2-VASc = 1 (n = 0) or age < 65 years coupled with CHA2DS2-VASc = 2 (n = 3)). This left 34 (7.5 %) patients with a high stroke risk and without OAC. The mean CHA2DS2-VASc in this group was 3.8 ± 1.7 SD with a mean CHA2DS2-VASc of 2.9 ± 1.4 SD in men and 5.1 ± 1.2 SD in women. The mean age was 80.7 years ± 11.8 SD. 8 patients were (by reviewing of patients’ journals) considered not suitable for LAAO or OAC due to: prior intracerebral haemorrhage (n = 2), severe nosebleeds (n = 1), thrombocytopenia (n =1), fall-risk and palliative care (n = 2), metastasized cancer (n = 1) or current alcohol abuse (n = 1) and were therefore not offered a consultation with a cardiologist. The remaining 26 patients were all offered a consultation to discuss anticoagulation and no change was made in 2 of them due to a high bleeding-risk being discovered at that time. This meant that there were 10 (2.2 %) patients with a high stroke risk and contraindications for OAC, resulting in 24 (5.3 %) eligible patients without OAC treatment or an LAAO. 16 of the remaining 24 patients

approved the new therapy (66.7 %) (Figure 1).

Out of the 34 patients with a high stroke risk, there were a total of 7 (1.5 % of 456) with ASA. The 7 all attended a consultation with a cardiologist and ASA was subsequently withdrawn. 4 out of the 7 switched to NOAC and 3 declined OAC altogether.

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9 157 (34.4 %) AF-6 questionnaires were completed and registered. There were 30 out of the 157 (19.1 %) who described themselves as asymptomatic (AF-6 sum = 0) and 127 (80.9 %) with symptoms (AF-6 sum > 0). The most common symptom was fatigue (see Appendix – AF-6, question 5) due to AF with a mean score of 3.2 ± 3.0 SD out of 10.

Initial patients with AF identified (n = 463)

Figure 1. Patients with an AF diagnosis at Kumla Health Centre between 2015 and 2018. The patients were evaluated for current treatment, stroke risk and as possible candidates for a consultation aiming to give them an updated treatment plan.

Notes: CHA2DS2-VASc score for evaluating stroke risk in AF patients. Points are given for the following comorbidities: congestive heart

failure (1p), hypertension (1p), age ≥ 75 (2p), diabetes (1p), prior stroke/transient ischemic attack/thromboembolism (2p), vascular disease (1p), age 65-74 (1p) and sex category (female = 1p). A higher points-total indicates an increased stroke risk.

Abbreviations: AF, atrial fibrillation, LAAO, left atrial appendage occlusion, NOAC, novel oral anticoagulant, OAC, oral anticoagulation.

Patients included as cohort (n = 456)

Patients excluded: incorrectly diagnosed (n = 7)

Adequate stroke protection: 1. Already prescribed OAC (n = 400) 2. LAAO (n = 3)

Possible candidates for NOAC/warfarin (n = 53)

High stroke risk patients (n = 34)

Low stroke risk patients:

1. CHA2DS2-VASc = 0 (n = 9)

2. CHA2DS2-VASc = 1 in women (n = 0)

3. CHA2DS2-VASc = 1 in men, age < 65 years (n = 7)

4. CHA2DS2-VASc = 2 in women, age < 65 years (n = 3)

Consultation with a cardiologist (n = 26) NOAC/warfarin prescribed (n = 16) Patient declined NOAC/warfarin (n = 8)

No action, contraindications for OAC discovered at consultation: (n = 2) No consultation offered, contraindications for OAC:

1. Prior intracerebral bleeding (n = 2) 2. Severe nosebleeds (n = 1)

3. Thrombocytopenia (n = 1)

4. Fall-risk and palliative care (n = 2) 5. Metastasized cancer (n = 1) 6. Current alcohol abuse (n = 1)

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10 Ages in the cohort varied between 31 and 99 years with a mean age of 77.5 (±10.6 SD). There were 268 men (58.8 %, mean age 74.9 (± 10.5 SD)) and 188 women (41 % mean age 81.1 (± 9.7 SD)). The mean CHA2DS2-VASc for the whole cohort was 3.9 (± 1.7 SD); 3.3 (± 1.7 SD) for men and 4.8 (± 1.4 SD) for women. The most common type of AF was permanent and the least common was persistent (Table 1). More than 9 out of 10 patients with previous OAC treatment had a CHA2DS2-VASc score of 2 or above.

There were 13 (2.9 %) patients with ASA treatment in the cohort (Table 1). 7 of those are described above as attending a consultation and being offered an updated treatment plan. The remaining 6 were identified as having both OAC and ASA. The latter was withdrawn in 1 of the 6 patients.

Table 1. Baseline characteristics for 456 patients with an AF diagnosis at Kumla Health Centre between 2015 and 2018.

Cohort (n = 456) Men (n =268) Women (n = 188) Mean age, years (SD) 77.5 ±10.6 75.0 ±10.5 81.1 ±9.7 Hypertension, n (%) 372 (81.6) 205 (76.5) 167 (88.8) Diabetes mellitus, n (%) 129 (28.3) 70 (26.1) 59 (31.4) Vascular disease, n (%) 22 (22.4) 62 (23.1) 40 (21.3) Previous stroke/TIA, n (%) 62 (13.6) 40 (14.9) 22 (11.7) Congestive heart failure, n (%) 149 (32.7) 79 (29.5) 70 (37.2)

Dementia, n (%) 35 (7.7) 21 (7.8) 14 (7.4)

Pacemaker/ICD, n (%) 44 (9.6) 21 (7.8) 23 (12.2)

Mean CHA2DS2-VASc (SD) 3.9 ±1.7 3.3 ±1.7 4.8 ±1.4 Median CHA2DS2-VASc (IQR) 4.0 (2.0) 3.0 (2.0) 5.0 (2.0) CHA2DS2-VASc = 0, n (%) 11 (2.4) 11 (4.1) 0 (0.0) CHA2DS2-VASc = 1, n (%) 27 (5.9) 25 (9.3) 2 (1.1) CHA2DS2-VASc ≥ 2, n (%) 418 (91.7) 232 (86.6) 186 (98.9) Type of AF Paroxysmal, n (%) 145 (31.8) 80 (29.9) 65 (34.6) Persistent, n (%) 22 (4.8) 19 (7.1) 3 (1.6) Permanent, n (%) 289 (63.4) 169 (63.1) 120 (63.8) OAC, n (%) 400 (87.7) 230 (85.8) 170 (90.4) NOAC, n (%) 306 (67.1) 175 (65.3) 131 (69.7) Warfarin, n (%) 94 (20.6) 55 (20.5) 39 (20.7) ASA, n (%) 13 (2.9) 9 (3.4) 4 (2.1)

Notes: CHA2DS2-VASc score for evaluating stroke risk in AF patients. Points are given for the following comorbidities: congestive heart failure

(1p), hypertension (1p), age ≥ 75 (2p), diabetes (1p), prior stroke/transient ischemic attack/thromboembolism (2p), vascular disease (1p), age 65-74 (1p) and sex category (female = 1p). A higher points-total indicates an increased stroke risk.

Abbreviations: AF, atrial fibrillation, ASA, acetylsalicylic acid, ICD, implantable cardioverter defibrillator, IQR, interquartile range, NOAC, novel oral anticoagulant, OAC, oral anticoagulant, SD, standard deviation, TIA, transient ischemic attack.

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11 The likelihood of a stroke occurring was compared within the cohort (456 subjects) using mean CHA2DS2-VASc score. Patients with permanent AF had the highest risk of suffering a stroke with a mean CHA2DS2-VASc score of 4.3 (± 1.6 SD), persistent the lowest with a mean of 2.0 (± 1.3 SD) and paroxysmal in between with a mean of 3.4 (± 1.7 SD) (Figure 2).

Figure 2. Mean CHA2DS2-VASc scores compared for 456 patients with an AF diagnosis at Kumla Health Centre between 2015 and 2018.

Error bars represent the 95 % confidence interval.

Notes: CHA2DS2-VASc score for evaluating stroke risk in AF patients. Points are given for the following comorbidities: congestive heart

failure (1p), hypertension (1p), age ≥ 75 (2p), diabetes (1p), prior stroke/transient ischemic attack/thromboembolism (2p), vascular disease (1p), age 65-74 (1p) and sex category (female = 1p). A higher points-total indicates an increased stroke risk.

Abbreviations: AF, atrial fibrillation.

Discussion

The results of the study initially showed that 400 out of a possible 456 patients were being treated with OAC (87.7 %). When examining the dataset more thoroughly; 34 patients (7.5 %) were identified as having a high risk for stroke and also not having an LAAO or OAC prescribed. 10 (2.3 %) of those were found to have contraindications for OAC meaning that there were only 24 (5.3 %) who were at risk for a stroke and were also eligible for OAC. There were, therefore, 432 (94.7 %) out of 456 patients at Kumla Health Centre with sufficient treatment. This indicates that the vast majority of patients with AF were being treated according to the current guidelines.

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Type of AF Me an CH A2 DS 2 -VAS c sco re

Paroxysmal Persistent Permanent Figure 2. Candidates for anticoagulant treatment.

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12 Not all patients with AF are recommended OAC; only those with a high stroke risk according to their CHA2DS2-VASc score. This constitutes a majority of the patients with the diagnosis as there are correlations to the factors that give points for CHA2DS2-VASc and to the

symptoms and/or complications caused by AF. Patients with a high risk of suffering a stroke are also more susceptible to bleeding and risk-benefit should therefore be taken into

consideration when deciding which patients to medicate with OAC [8]. Including the two patients who were offered a consultation but denied OAC because of a high bleeding-risk; there were 10 out of the 34 high stroke risk patients (29.4 %) with contraindications for OAC. They could have been possible candidates for an LAAO.

Nine out of 10 patients (91.7 %) had a CHA2DS2-VASc score of two or above in the whole cohort and the mean CHA2DS2-VASc was 3.9 ± 1.7. Johansson et al had similar findings when investigating the incidence of AF in northern Sweden (CHA2DS2-VASc mean score of 3.3 ± 1.9 and 80.7 % with a score of 2 or above) [13]. This indicates that a large proportion of patients with AF also have a high risk of suffering a stroke and should, therefore, medicate with OAC.

The majority of patients who were offered a consultation with a cardiologist changed to OAC. 26 patients attended a consultation and 24 were eligible for the treatment. Two-thirds of those patients were administered OAC. Eight patients were reluctant to OAC and rejected the proposed treatment plan.

The prevalence of AF was estimated to be 2.1 % in the municipality of Kumla. Other studies have been conducted in Sweden showing a similar prevalence in general populations. For example, the prevalence of AF came to 3.0 % in a region in northern Sweden (population, n = 75 945) by Norberg et al [14]. The AF prevalence also rose with age in their study, a finding which is strengthened by this project (mean age of AF patients = 77.5 ± 10.6 years). The prevalence in Kumla would also have been higher if the patients living there but not attending Kumla Health Centre for AF care (e.g. diagnosed and followed at the University Hospital of Örebro instead) would have been included in the study. This additional data would need to be obtained from the National Patient Registry and is not included in the Medrave 4 Primary care database.

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13 The most common type of AF was permanent (63.4 %), which was in line with earlier studies of prevalence in similar populations. Johansson et al explored this; showing permanent as the most common subtype (32.5 %) [13]. Their study showed the prevalence of paroxysmal as 20.3 % and persistent as 24.2 % although they included a fourth group of patients

experiencing a single episode of AF (24.2 %). Another epidemiological study from 2014: Zoni-Berisso et al [15] estimated the prevalence of each type of AF in Europe through a systematic review. Their results showed similar findings on a larger scale: paroxysmal = 20 % - 30 %, persistent = 20 % - 30 % and permanent 40 % – 50 %. The figures at Kumla Health Centre show that the prevalence of the different types varied compared to other

epidemiological studies: paroxysmal = 31.8 %, persistent = 4.8 % and permanent = 63.4 %. This may be due to that the age of the population was higher (mean age = 77.5 ± 10.5). Earlier epidemiological studies have shown that AF generally progresses from paroxysmal to

persistent and thereafter permanent in a population and this could therefore be the explanation for the overrepresentation of permanent AF [16–20].

Only 157 AF-6 questionnaires were completed and returned (34.4 %).The low response rate may be due to that patients with AF are prone to many other comorbidities and may therefore not be capable of completing the questionnaires. Four patients had died and 35 patients (7.7 %) were diagnosed with dementia and could therefore not fill out the AF-6 forms. 30 (19.1 %) patients described themselves as asymptomatic. This also highlights the importance of the study with such a large proportion (80.9 %) of patients with AF describing a negative impact on their daily lives.

Limitations

The municipality of Kumla is seen as a fair representation of Sweden as a whole with a similar mean age distribution and comparable mean annual gross income. The population of Kumla however, is small (21 653) compared to that of Sweden (10 215 309 - as of 2018-11-01) [9]. The relatively small sample size could have affected the results in this study. This project is nonetheless part of a larger, more extensive study covering all of Örebro county (population – 301 890), which will hopefully show similar findings when completed at the end of 2020.

Silent AF may be a reason for the prevalence of AF to be higher than what has previously been thought. One study in Halmstad found that 49 % more AF was discovered when patients

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14 were examined using intermittent electrocardiography in their homes over a two-week period [21]. The STROKESTOP study in the region of Halland and Stockholm county found that the prevalence increased by 32 % when accounting for silent AF [22]. If true; this would mean that over 5 % of the adult population in Sweden have AF – more than 2 % higher than what is commonly reported [23].

Conclusion

This study has shown that the vast majority of patients at Kumla Health Centre with an AF diagnosis are being treated according to current guidelines. The prevalence of AF was 2.1 %, the most common type was permanent, and the least common was persistent. Similar findings have been reported in comparable studies. Most of the patients who were offered a

consultation and eligible for OAC updated their treatment plan. The findings reflect that of a relatively small population and further studies are therefore required to know for certain that guidelines for treatment of AF are being followed.

Acknowledgements

I would like to extend a special thanks to Anna Björkenheim at the Department of Cardiology, Örebro University Hospital for supervising me through this project and sharing her essential knowledge. This study would not have been possible without her.

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References

1. Kirchhof P, Benussi S, Kotecha D, Ahlsson A, Atar D, Casadei B, et al. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J. 2016;37(38):2893–962.

2. Thambidorai SK, Murray RD, Parakh K, Shah TK, Black IW, Jasper SE, et al. Utility of transesophageal echocardiography in identification of thrombogenic milieu in patients with atrial fibrillation (an ACUTE Ancillary Study). Am J Cardiol. 2005 Oct 1;96(7):935–41. 3. Dorian P, Jung W, Newman D, Paquette M, Wood K, Ayers GM, et al. The impairment of

health-related quality of life in patients with intermittent atrial fibrillation: Implications for the assessment of investigational therapy. J Am Coll Cardiol. 2000;36(4):1303–9.

4. Savelieva I, Camm AJ. Clinical relevance of silent atrial fibrillation: Prevalence, prognosis, quality of life, and management. Vol. 4, Journal of Interventional Cardiac Electrophysiology. 2000. p. 369–82.

5. Heidbuchel H, Verhamme P, Alings M, Antz M, Hacke W, Oldgren J, et al. European Heart Rhythm Association Practical Guide on the use of new oral anticoagulants in patients with non-valvular atrial fibrillation. EP Eur. 2013 May;15(5):625–51.

6. Steffel J, Verhamme P, Potpara TS, Albaladejo P, Antz M, Desteghe L, et al. The 2018 European Heart Rhythm Association Practical Guide on the use of non-Vitamin K antagonist oral anticoagulants in patients with atrial fibrillation. Eur Heart J. 2018 Apr 21;39(16):1330– 93.

7. Socialstyrelsen. Nationella riktlinjer för hjärtsjukvård - vetenskapligt underlag [Internet]. 2018-6-28. 2018 [cited 2020 Apr 23]. p. 187–303. Available from:

https://www.socialstyrelsen.se/globalassets/sharepoint-dokument/artikelkatalog/nationella-

riktlinjer/2018-6-28-vetenskapligt-underlag.pdf?fbclid=IwAR3J9C8xc_D-haC-bcF4X6n9t6SEtOnrC9lGVQMScUVrSS51Pz-7WkQwDVw

8. Lip GYH, Nieuwlaat R, Pisters R, Lane DA, Crijns HJGM, Andresen D, et al. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: The Euro Heart Survey on atrial fibrillation. Chest. 2010 Feb 1;137(2):263–72.

9. Statistiska centralbyrån (SCB) PxWeb [Internet]. The Statistics Database. 2018 [cited 2020 May 6]. Available from: http://www.statistikdatabasen.scb.se/pxweb/sv/ssd/

10. Härdén M, Nyström B, Kulich K, Carlsson J, Bengtson A, Edvardsson N. Validity and reliability of a new, short symptom rating scale in patients with persistent atrial fibrillation. Health Qual Life Outcomes. 2009 Jul 15;7(1):1–10.

11. Härdén M, Nyström B, Bengtson A, Medin J, Frison L, Edvardsson N. Responsiveness of AF6, a new, short, validated, atrial fibrillation- specific questionnaire - Symptomatic benefit of direct

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16

current cardioversion. J Interv Card Electrophysiol. 2010 Sep 12;28(3):185–91. 12. Kotecha D, Ahmed A, Calvert M, Lencioni M, Terwee CB, Lane DA. Patient-reported

outcomes for quality of life assessment in atrial fibrillation: A systematic review of measurement properties. PLoS One. 2016 Nov 1;11(11).

13. Johansson C, Dahlqvist E, Andersson J, Jansson JH, Johansson L. Incidence, type of atrial fibrillation and risk factors for stroke: A population-based cohort study. Clin Epidemiol. 2017;9:53–62.

14. Norberg J, Bäckström S, Jansson JH, Johansson L. Estimating the prevalence of atrial fibrillation in a general population using validated electronic health data. Clin Epidemiol. 2013;5(1):475–81.

15. Zoni-Berisso M, Lercari F, Carazza T, Domenicucci S. Epidemiology of atrial fbrillation: European perspective. Clin Epidemiol. 2014 Jun 16;6(1):213–20.

16. Nieuwlaat R, Prins MH, Le Heuzey JY, Vardas PE, Aliot E, Santini M, et al. Prognosis, disease progression, and treatment of atrial fibrillation patients during 1 year: Follow-up of the Euro Heart Survey on Atrial Fibrillation. Eur Heart J. 2008;29(9):1181–9.

17. De Sisti A, Leclercq JF, Halimi F, Fiorello P, Bertrand C, Attuel P. Evaluation of time course and predicting factors of progression of paroxysmal or persistent atrial fibrillation to permanent atrial fibrillation. PACE - Pacing Clin Electrophysiol. 2014;37(3):345–55.

18. Kerr CR, Humphries KH, Talajic M, Klein GJ, Connolly SJ, Green M, et al. Progression to chronic atrial fibrillation after the initial diagnosis of paroxysmal atrial fibrillation: Results from the Canadian Registry of Atrial Fibrillation. Am Heart J. 2005;149(3):489–96. 19. Jahangir A, Lee V, Friedman PA, Trusty JM, Hodge DO, Kopecky SL, et al. Long-term

progression and outcomes with aging in patients with lone atrial fibrillation: A 30-year follow-up study. Circulation. 2007;115(24):3050–6.

20. de Vos CB, Pisters R, Nieuwlaat R, Prins MH, Tieleman RG, Coelen RJS, et al. Progression From Paroxysmal to Persistent Atrial Fibrillation. Clinical Correlates and Prognosis. J Am Coll Cardiol. 2010;55(8):725–31.

21. Engdahl J, Andersson L, Mirskaya M, Rosenqvist M. Stepwise screening of atrial fibrillation in a 75-year-old population: Implications for stroke prevention. Circulation. 2013;127(8):930–7. 22. Svennberg E, Engdahl J, Al-Khalili F, Friberg L, Frykman V, Rosenqvist M. Mass screening

for untreated atrial fibrillation the STROKESTOP study. Circulation. 2015;131(25):2176–84. 23. Friberg L, Rosenqvist M. Epidemiologi och riskkategorisering. Information från