Hospital Diagnosis Of Atrial Fibrillation Research Articles

Time-trends of sex differences in stroke risk in atrial fibrillation: Are female patients still at higher risk today? A nationwide cohort study

Abstract Background Female sex is associated with higher risk of stroke in patients with atrial fibrillation (AF), particularly in the presence of other stroke risk factors. This has implications for oral anticoagulant treatment (OAC) decision-making, based on points of the CHA2DS2-VASc score. However, stroke rates have declined over recent years, and management has evolved over time towards a holistic approach that may have diminished the sex differences in AF-related stroke. Purpose To examine the changes in stroke risk over time in relation to risk differences between males and females not treated with oral anticoagulants in a nationwide cohort study. Methods This was an observational cohort study including patients with a hospital diagnosis of AF between 2007 and 2021. Data were obtained from the Danish nationwide registries. We identified a cohort of adult patients who were not receiving OAC treatment for up to 30 days after their AF diagnosis. Patients were followed up for thromboembolic events within one year after the AF diagnosis. Survival analysis was applied to describe the yearly rate of events and to estimate the risk ratio for females vs males of thromboembolism according to baseline risk levels, i.e., the CHA2DS2-VA score level (leaving out the ‘Sc’ sex criterion). Results A total of 188,704 AF patients (median age 75 years (IQR: 64 to 84); 49.7% female) who did not receive OAC treatment were included. The risk of thromboembolism during the entire study period was overall higher in females (3.5% in males vs. 4.7% among females). The overall one-year thromboembolic risk declined over time from 4.9% between 1997-2000 to 3.3% between 2017-2020, with male-female risk differences less evident in recent years (Figure 1a). The relative risk of stroke diminished from 1.22 (95%CI 1.10-1.34) in years 1997-2000 to 1.02 (95%CI 0.85-1.19) in years 2017-2020 for patients with a CHA2DS2-VA score of ≥2 (Figure 1b). For patients with a score of <2, the relative risk was lowest between 2005-2008 (1.02 (95%CI 0.63-1.42)) and was 1.18 (95%CI 0.54-1.83) in the latest time period. Formal statistical test for time trends according to score level revealed non-significant results (p-value=0.10 for score 0-1; p-value=0.17 for score levels of ≥2). Conclusion The risk of stroke among patients with AF has been declining over the last two decades. The excess stroke risk observed among females relative to males has also diminished, most evident among AF patients with ≥2 prevalent stroke risk factors.

Association Between Newly Diagnosed Atrial Fibrillation and Work Disability (from a Nationwide Danish Cohort Study)

It is previously shown that cardiovascular conditions have a negative effect on the ability to work. However, it is unknown if incident atrial fibrillation (AF) influences the ability to work. We examined the association between AF and the risk of work disability and the influence of socioeconomic factors. All Danish residents with a hospital diagnosis of AF and aged ≥30 and ≤63 years in the period January 1, 2000, to September 31, 2014, were included and matched 1:10 with an AF-free gender and age-matched random person from the general population. Permanent social security benefit was used as a marker of work disability. Risk difference (RD) and 95% confidence interval (95% CI) of work disability were calculated over 15 months. The analyses were furthermore stratified in low, medium, and high levels of socioeconomic factors. In total, 28,059 patients with AF and 312,667 matched reference persons were included. The risk of receiving permanent social security benefits within 15 months was 4.5% (4.3% to 4.8%) for the AF cohort and 1.3% (95% CI 1.3% to 1.4%) for the matched reference cohort. Adjusted RD (95% CI) was 2.3% (2.0% to 2.5%). Stratified on income, RDs were higher in low-income groups (adjusted RD 3.7% [95% CI 3.1% to 4.3%]) versus high-income groups (RD 1.3% [1.0% to 1.5%]). In conclusion, the risk of work disability within 15 months after incident AF was more than 3 times as high in patients with AF compared with the general population, especially when comparing individuals in lower socioeconomic strata.

Socioeconomic inequality in oral anticoagulation therapy initiation in patients with atrial fibrillation with high risk of stroke: a register-based observational study

ObjectiveThe study aimed to examine the association between socioeconomic factors (SEFs) and oral anticoagulation (OAC) therapy and whether it was influenced by changing guidelines. We hypothesised that inequities in initiation...

Short lookback periods causing exaggerated stroke risk estimates in atrial fibrillation may expose patients to unnecessary anticoagulant treatment.

The purpose was to investigate how different lookback periods in observational registry studies affect estimates of stroke risk in patients with atrial fibrillation and stroke risk score CHA2 DS2 -VASc 1, a level where the appreciated risk is likely to affect decisions about oral anticoagulation. All 354854 individuals in Sweden with a hospital diagnosis of atrial fibrillation during 2010-2016 were included. At least 13years of observational data prior to inclusion was available for all patients. The prevalence of hypertension, heart failure, diabetes, previous thromboembolism, and vascular disease was estimated from data with different lookback periods. The incident stroke rates at CHA2 DS2 -VASc score 1 was then assessed using data with successively longer lookback periods. Depending on duration of lookback period, the proportion of patients with heart failure varied 2.7 times, thromboembolism 3.7 times, hypertension 4.0 times, and diabetes and vascular disease both approximately 4.5 times. During follow-up, 22237 patients suffered an ischaemic stroke. The estimated risk without anticoagulant treatment at CHA2 DS2 -VASc score 1 was 51% higher if the scores had been calculated with the shortest lookback period than if all information had been used. Short lookback periods underestimate comorbidity, cause high-risk patients to be misclassified as low risk, and overestimate stroke risk at CHA2 DS2 -VASc 1. This may lead to unnecessary anticoagulant treatment of true low-risk patients. Transparency regarding lookback periods is essential for interpretation and comparison of registry studies.

Less dementia and stroke in low-risk patients with atrial fibrillation taking oral anticoagulation.

AimsTo investigate if patients with atrial fibrillation (AF) without clear indication for oral anticoagulant (OAC) due to perceived low stroke risk may benefit from OAC treatment when also dementia and intracerebral bleeding risks are considered.Methods and resultsRetrospective study of cross-matched national registries of all individuals in Sweden with a hospital diagnosis of AF between 2006 and 2014 (n = 456 960). Exclusion was made of patients with a baseline CHA2DS2-VASc score >1, not counting female sex, and of patients with previous diagnosis of dementia or intracranial bleeding. After exclusions, 91 254 patients remained in the study of whom 43% used OAC at baseline. Propensity score matching and falsification endpoints were used. Treatment with OAC was associated with lower risk of dementia after adjustment for death as a competing risk [subhazard ratio (sHR) 0.62 with 95% confidence interval (CI) 0.48–0.81]. Regarding the composite brain protection endpoint, OAC treatment was associated with an overall 12% lower risk (sHR 0.88, CI 0.72–1.00). This apparent benefit was restricted to patients aged >65 years, whereas OAC treatment of patients <60 years of age without risk factors appeared to do more harm than good.ConclusionLow-risk AF patients who take OAC have lower risk of dementia than those who do not use OAC. Patients age >65 years appear to benefit from OAC treatment irrespective of stroke risk score.

Association of plasma neopterin with risk of an inpatient hospital diagnosis of atrial fibrillation: results from two prospective cohort studies.

Link between inflammation and atrial fibrillation (AF) has been increasingly recognized. Neopterin, a biomarker of cellular immune activation, may be associated with incident AF. To investigate the association between plasma neopterin levels and risk of an inpatient hospital diagnosis of AF, and to evaluate a joint association of neopterin and a nonspecific inflammatory marker C-reactive protein (CRP) in two prospective cohorts. We performed a prospective analysis from a community-based cohort (the Hordaland Health Study (HUSK), n = 6891), and validated the findings in a cohort of patients with suspected stable angina pectoris (the Western Norway Coronary Angiography Cohort (WECAC), n = 2022). In both cohorts, higher plasma levels of neopterin were associated with an increased risk of incident AF after adjustment for age, sex, body mass index, current smoking, diabetes, hypertension and renal function. The multivariable-adjusted hazard ratio (HR) (95% CI) per one SD increment of log-transformed neopterin was 1.20 (1.10-1.32) in HUSK and 1.26 (1.09-1.44) in WECAC. Additional adjustment for CRP did not materially affect the risk association for neopterin. The highest risk of AF was found among individuals with both neopterin and CRP levels above the median (HR: 1.54; 95% CI: 1.16-2.05 in HUSK and HR: 1.67; 95% CI: 1.11-2.52 in WECAC). Our findings indicate an association of plasma neopterin with risk of an inpatient hospital diagnosis of AF, which remains after adjustment for traditional risk factors as well as for CRP. This study highlights a role of cellular immune activation, in addition to inflammation, in AF pathogenesis.

Cost of illness of atrial fibrillation: a nationwide study of societal impact

BackgroundThe prevalence of atrial fibrillation is increasing rapidly; however, to date, population-based data are lacking on the attributable cost of illness of atrial fibrillation from a societal perspective, including both direct and indirect costs.MethodsThe study was an incidence-based cost-of-illness study based on national registries covering the entire population of Denmark. We identified all patients with a first-time hospital diagnosis of atrial fibrillation between 2001 and 2012. For every atrial fibrillation patient, we identified three age- and sex-matched controls from the general population. Both the total and the attributable costs of atrial fibrillation were estimated based on individual level information on hospital care (in- and out-patient contacts), primary sector care, use of prescription drugs and productivity loss.ResultsAverage 3-year societal costs per patient attributable to atrial fibrillation were estimated to be €20,403–26,544 during the study period. The costs were highest during the first year after diagnosis of atrial fibrillation. Admission costs constituted the largest cost component, whereas primary sector costs and medicine costs only constituted minor components. The attributable costs were more than two-fold higher among patients experiencing a stroke. The total 3-year cost attributable to atrial fibrillation in Denmark was estimated to be €219–295 million.ConclusionsThe societal costs attributable to atrial fibrillation are significant. Reducing the need for hospitalizations, in particular from stroke, is a key factor in controlling the costs.

Less dementia with oral anticoagulation in atrial fibrillation

The association between atrial fibrillation (AF) and dementia is well documented, but it is not clear if oral anticoagulant treatment offers protection. The aim of the study is therefore to compare the incidence of new dementia in patients with AF with and without oral anticoagulants, and to explore if there is a difference between novel anticoagulants and warfarin in this respect. Retrospective registry study of all patients with hospital diagnosis of AF and no previous diagnosis of dementia in Sweden between 2006 and 2014. Propensity score matching, falsification endpoints, and analyses according to intention to treat as well as on-treatment principles were used. The study included 444 106 patients and over 1.5 million years at risk. Patients on anticoagulant treatment at baseline was associated with 29% lower risk of dementia than patients without anticoagulant treatment [hazard ratio (HR) 0.71, 95% confidence intervals (95% CI) 0.68-0.74] and 48% lower risk analysed on treatment (HR 0.52, 95% CI 0.50-055). Direct comparison between new oral anticoagulants and warfarin showed no difference (HR 0.97, 95% CI 0.67-1.40). The risk of dementia is higher without oral anticoagulant treatment in patients with AF. This suggests that early initiation of anticoagulant treatment in patients with AF could be of value in order to preserve cognitive function.

Societal Costs of First-Incident Ischemic Stroke in Patients with Atrial Fibrillation—A Danish Nationwide Registry Study

BackgroundOral anticoagulation therapy reduces the risk of ischemic stroke in patients with atrial fibrillation (AF). However, more data on the costs of stroke in patients with AF are needed to assess how this therapy affects societal costs. ObjectivesThe aim of the study was to estimate the average 3-year societal costs of first-incident ischemic stroke in Danish patients with AF, including costs of health care, social care services, and productivity loss. MethodsThe study was designed as an incidence-based cost-of-illness study covering the entire Danish population. All patients with a hospital diagnosis of AF were identified, and propensity score–matched analyses were used to estimate costs attributable to first-incident stroke among patients with AF in the period 2002 to 2012. All data were obtained from nationwide registries. ResultsA total of 21,673 patients with AF were identified with a first-incident stroke. The average 3-year costs attributable to stroke were US $30,925 per patient (present value) corresponding to US $19,989 in the incidence year and US $7,683 and US $5,176 1 and 2 years after the stroke, respectively. Health care accounted for 66% of the 3-year costs, with hospitalizations in the incidence year as the main cost driver. After the incidence year, costs of social care services exceeded health care costs. Sensitivity analyses showed that the cost estimates were relatively robust. ConclusionsThe societal costs of first-incident stroke in patients with AF are substantial. This new evidence can be valuable as an input for decision making regarding the treatment of AF and prevention of future strokes.

Long-term risk of atrial fibrillation after the death of a partner

ObjectivesSevere psychological stress is generally associated with an increased risk of acute cardiovascular diseases, such as myocardial infarction, but it remains unknown whether it also applies to atrial fibrillation. We...

Trends in stroke incidence after hospitalization for atrial fibrillation in Sweden 1987 to 2006

BackgroundTo investigate recent trends in incidence of hemorrhagic and non-hemorrhagic strokes in patients with atrial fibrillation (AF). MethodsThe Swedish Hospital Discharge and Cause of Death Registries were linked to provide outcome data. Results321,276 patients 35 to 84years (56.5% male, mean age 71.5years) free of prior stroke with a first AF diagnosis during 1987–2006 were included. Over 3year follow-up 24,733 patients (7.7%) were diagnosed with ischemic stroke and 2292 (0.7%) with hemorrhagic stroke. The 3-year incidence of ischemic stroke decreased from 8.7% for patients diagnosed in 1987–1991 to 6.6% for those diagnosed in 2002 to 2006. The corresponding incidence of hemorrhagic stroke increased from 0.38% for patients diagnosed in 1987–1991 to 0.57% for those diagnosed in 2002 to 2006. Covariable-adjusted risk of ischemic stroke was significantly reduced (HR 0.65; 0.63–0.68) while risk of hemorrhagic stroke was significantly increased (HR 1.19; 1.05–1.36). Compared to the general population, total stroke risk decreased more among AF patients. ConclusionWe found a considerable decrease in risk of ischemic stroke in Sweden in patients without prior stroke and with a first hospital diagnosis of AF. There was an increased risk of hemorrhagic stroke, but because hemorrhagic stroke represented only a small proportion of all strokes, the overall risk of stroke declined.

Non-steroidal anti-inflammatory drug use and risk of atrial fibrillation or flutter: population based case-control study

Objectives To examine the risk of atrial fibrillation or flutter associated with use of non-selective non-steroidal anti-inflammatory drugs (NSAIDs) or selective cyclo-oxygenase (COX) 2 inhibitors. Design Population based case-control study...

Advances in Population-Based Studies

In 2009, population-based studies have continued to generate many new results about stroke occurrence and interesting hypotheses about the relation between risk factors and stroke occurrence. High levels of C-reactive protein have been associated with the risk of myocardial infarction, whereas the association with stroke remains controversial.1 The association between high-sensitivity C-reactive protein (hsCRP)and stroke was examined in the multiethnic, stroke-free, community-based cohort study in Northern Manhattan.2 hsCRP measurements were available for 2240 subjects age 40 years and older. Compared with subjects whose hsCRP values were 3 mg/L were at increased risk for ischemic stroke (hazard ratio [HR]=1.20; 95% CI, 0.78 to 1.86), myocardial infarction (HR=1.70; 95% CI, 1.04 to 2.77), and death (HR=1.55; 95% CI, 1.23 to 1.96) after adjustment for demographic characteristics and risk factors. Different results among studies may depend on population characteristics such as age and other risk factors. Glucocorticoid (GCT) use is common for the treatment of many different diseases. However, treatment with high-dose GCT is associated with atherosclerosis, diabetes mellitus, and hypertension, and such treatment may increase the risk of cardiovascular disease, including stroke.3 A population-based, case-control study examined whether treatment with GCT was associated with atrial fibrillation,4 which is a well-established risk factor for stroke. All patients with a first hospital diagnosis of atrial fibrillation among a total population of 1.7 million were included, totalling 20 211 patients. Information about GCT treatment was based on linkage to national medical databases. For each case, 10 population controls were selected and matched by age and sex. Current GCT use was associated with an increased risk of atrial fibrillation compared with never use (adjusted odds ratio=1.92; 95% CI, 1.79 to 2.06); in new GCT users, the adjusted odds ratio was 3.62 (95% CI, 3.11 …

Serum Long-Chain n-3 Polyunsaturated Fatty Acids and Risk of Hospital Diagnosis of Atrial Fibrillation in Men

Atrial fibrillation (AF) is a common cardiac arrhythmia. Regular fish consumption has been shown to reduce the risk of AF in some but not all studies. Long-chain n-3 polyunsaturated fatty acids (PUFAs) from fish have been suggested to account for these beneficial effects. We tested this hypothesis by studying the association between the serum long-chain n-3 PUFAs eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid and risk of AF in men. A total of 2174 men from the prospective population-based Kuopio Ischemic Heart Disease Risk Factor Study, 42 to 60 years old and free of AF at baseline in 1984 to 1989, were studied. During the average follow-up time of 17.7 years, 240 AF events occurred. In the Cox proportional hazards model, the multivariable-adjusted hazard ratio in the highest (>5.33%) versus the lowest (<3.61%) quartile of eicosapentaenoic acid plus docosapentaenoic acid plus docosahexaenoic acid was 0.65 (95% confidence interval 0.44 to 0.96, P for trend=0.07). Evaluated individually, only serum docosahexaenoic acid was associated with the risk of AF (hazard ratio in the highest versus the lowest quartile 0.62, 95% confidence interval 0.42 to 0.92, P for trend=0.02). Exclusion of subjects (n=233) with myocardial infarction or congestive heart failure either at baseline or that preceded the AF event during follow-up slightly strengthened the associations. Serum intermediate chain-length n-3 PUFA, alpha-linolenic acid, or hair methylmercury concentration were not associated with the risk. An increased concentration of long-chain n-3 PUFAs in serum, a marker of fish or fish oil consumption, may protect against AF. Serum docosahexaenoic acid concentration had the greatest impact.

Glucocorticoid Use and Risk of Atrial Fibrillation or Flutter

Glucocorticoid use is associated with increased risk of myocardial infarction, stroke, and heart failure, but data are limited on the risk of atrial fibrillation or flutter. We examined whether glucocorticoid use is associated with the risk of atrial fibrillation or flutter. For this population-based, case-control study, we identified all patients with a first hospital diagnosis of atrial fibrillation or flutter from January 1, 1999, through December 31, 2005, in Northern Denmark (population, 1.7 million). For each case we selected 10 population controls matched by age and sex. We obtained data on glucocorticoid prescriptions within 60 days (current users) or longer before the index date (former users), comorbidity, and medications from medical databases. We used conditional logistic regression to compute odds ratios (ORs), controlling for potential confounders. Among 20,221 patients with atrial fibrillation or flutter, 1288 (6.4%) were current glucocorticoid users and 2375 (11.7%) were former users. Among 202,130 population controls, 5245 (2.6%) were current glucocorticoid users and 19 940 (9.9%) were former users. Current glucocorticoid use was associated with an increased risk of atrial fibrillation or flutter compared with never use (adjusted OR, 1.92; 95% confidence interval [CI], 1.79-2.06). Among new glucocorticoid users, the adjusted OR was 3.62 (95% CI, 3.11-4.22) and among long-term users it was 1.66 (95% CI, 1.53-1.80). The increased risk remained robust in patients with and without pulmonary and cardiovascular diseases. Former glucocorticoid use was not associated with increased risk (adjusted OR, 1.00; 95% CI, 0.96-1.06). Current glucocorticoid use was associated with an almost 2-fold increased risk of atrial fibrillation or flutter.

Lost Life Years Attributable to Stroke among Patients with Nonvalvular Atrial Fibrillation: A Nationwide Population-Based Follow-Up Study

Aim: We assessed the number of lost life years attributable to stroke among patients with a hospital diagnosis of nonvalvular atrial fibrillation. Methods: We identified all patients, aged 40–89 years, with an incident hospital diagnosis of atrial fibrillation or flutter in the Danish National Registry of Patients from calendar year 1980 to 2002, and no previous or concomitant diagnosis of stroke or heart valve disease. All patients were followed in the Danish National Registry of Patients for occurrence of an incident diagnosis of stroke of any type (ischemic and/or hemorrhagic) and in the Danish Civil Registration System for emigration or change in vital status. We used multivariate Cox regression analysis with stroke as a time dependent covariate to estimate excess mortality associated with incident stroke. The baseline hazard function for mortality was computed and used for modeling lost life years by sex, age, and time to incident stroke after diagnosis of atrial fibrillation, adjusted for conditions of comorbidity and calendar year of diagnosis of atrial fibrillation. Results: The mean loss of life years attributable to incident stroke within 20 years after a first diagnosis of atrial fibrillation was most frequently less than 5 years, but a mean of up to 10 years of lost life years was observed. The largest number of lost life years was observed in women, in younger patients, and in those who had a stroke early after the diagnosis of atrial fibrillation. The relative loss of life years was up to 90% of the estimated expected remaining lifetime without stroke within 20 years after the diagnosis of atrial fibrillation, and was highest in the elderly. Conclusion: Stroke causes a substantial loss of life years in patients with atrial fibrillation.

Trends in Risk of Stroke in Patients with a Hospital Diagnosis of Nonvalvular Atrial Fibrillation: National Cohort Study in Denmark, 1980–2002

Aim: We examined trends in incidence of stroke of any nature (ischemic and/or hemorrhagic) in subjects with a hospital diagnosis of nonvalvular atrial fibrillation or flutter in Denmark from 1980 to 2002 by sex, age and conditions of comorbidity. Methods: We identified all individuals, aged 40–89 years, with an incident hospital diagnosis of atrial fibrillation or flutter and no history of stroke or heart valve disease in the Danish National Registry of Patients, and subjects were followed in the Danish National Registry of Patients for occurrence of an incident diagnosis of stroke of any nature (ischemic and/or hemorrhagic) and in the Danish Civil Registration System (emigration and vital status). We used multivariate Cox proportional hazard regression analysis to estimate trends in incidence of stroke. Results: Nonvalvular atrial fibrillation or flutter was diagnosed in 141,493 subjects (75,126 men and 66,367 women), and during follow-up 15,964 subjects had an incident diagnosis of stroke. The hazard ratios for stroke in the last 3-year period compared to the first 5-year period, adjusted for 10-year age group, conditions of comorbidity, and general stroke trend in the Danish population were 0.78 (95% CI 0.70–0.86) in men, and 0.80 (95% CI 0.72–0.88) in women. The reduction in risk of stroke by calendar year was most prominent in patients aged 40–74 years. Conclusion: We observed a modest decrease in risk of stroke in subject with atrial fibrillation in Denmark during calendar years 1980–2002. However, we could not control for any changes in diagnostic performance, admission practice, and medical management of patients with atrial fibrillation.

Temporal trends in the prescription of vitamin K antagonists in patients with atrial fibrillation

Anticoagulation therapy is recommended in patients with atrial fibrillation (AF) and risk factors for stroke. We studied the temporal trends in the prescription of vitamin K antagonists (VKA) in patients with a first hospital diagnosis of AF in Denmark, 1995-2002. The Danish National Hospital Registry was used to identify subjects with a first hospital diagnosis of AF and the Danish Register of Medical Products Statistics to determine the proportion of these patients who claimed a prescription of VKA within 3 months from discharge. Amongst 68 546 patients aged 50-99 years with a diagnosis of AF who survived 3 months following discharge, 24 991 (36%) patients claimed a prescription of VKA within 3 months. In both men and women a gradual increase in the use of VKA with time was observed, the relative increase being largest amongst the 80- to 99-year olds. In all age groups, the prescription of VKA was lower in women than in men, including patients with a prior or concurrent stroke. From 1995 to 2002 the proportion of AF patients receiving VKA therapy increased significantly but the use of VKA therapy amongst women was lagging behind that of men. Even in patients with AF and prior stroke, the use of VKA seems to be less than optimal.

Trends in incidence and mortality in the hospital diagnosis of atrial fibrillation or flutter in Denmark, 1980–1999

Background The incidence of diagnosed atrial fibrillation is increasing in the USA, England, Wales, Scotland and Denmark, and the mortality rate in patients with diagnosed atrial fibrillation has been reported to be declining in Scotland and Denmark. We undertook this study to examine recent trends in incidence and mortality in subjects with a hospital diagnosis of atrial fibrillation or flutter in Denmark from 1980 to 1999 by sex, 10-year age group and conditions of comorbidity. Methods We identified all individuals, aged 40–89 years, with an incident hospital diagnosis of atrial fibrillation or flutter in the Danish National Registry of Patients, and subjects were followed in the Danish Civil Registration System. We used multivariate Cox proportional hazard models to estimate trends in mortality. Results Atrial fibrillation or flutter was diagnosed in 131,728 subjects (68,660 men and 63,068 women), and the incidence of a hospital diagnosis of atrial fibrillation or flutter more than doubled during the study period. The hazard ratios for mortality adjusted for 10-year age group, conditions of comorbidity and mortality trend in the Danish population in the last 5-year period compared to the first 5-year period were 0.80 (95% confidence interval 0.78–0.82) in men, and 0.82 (95% confidence interval 0.80–0.84) in women. Conclusions The incidence of a hospital diagnosis of atrial fibrillation or flutter more than doubled, and the 10-year age group- and comorbidity- and general population-adjusted mortality decreased, equally, from the first to the last 5-year period by 20% in men and 18% in women.

CV4 EVALUATION OF SURVIVAL AND ISCHAEMIC AND THROMBOEMBOLIC EVENT RATES IN PATIENTS WITH NONVALVULAR ATRIAL FIBRILLATION IN THE GENERAL POPULATION WHEN TREATED AND UNTREATED WITH WARFARIN

Objective: To compare survival and adverse outcome of patients with non-valvar atrial fibrillation (NVAF) treated with or without warfarin. Design: Record linkage method to identify patients with a previous hospital diagnosis of atrial fibrillation and to link these patients to international normalised ratio (INR) test results and mortality data. Setting: Cardiff and the Vale of Glamorgan, Wales. Main outcome measures: Mortality, specifically from ischaemic and thromboembolic events. Results: 6108 patients were identified with NVAF, of whom 36.4% received warfarin. Mean survival in the warfarin and non-warfarin groups was 52.0 months and 38.2 months, respectively (p < 0.001), and 14.4 months (p < 0.001) after adjustment for confounding factors. Warfarin treated patients in the upper quartile of INR control had significantly longer survival (57.5 months) than did those in the lowest quartile of control (38.1 months, p < 0.001). The risk of stroke in the warfarin group when treated was lower than that in the non-warfarin group (relative rate (RR) 0.74, p < 0.001). The risk of death from ischaemic stroke was lower in the warfarin group (RR 0.43, p < 0.001). The risk of all ischaemic and embolic events in the warfarin group was lower when they were taking warfarin (RR 0.74, p < 0.001). The risk of bleeding in the warfarin group when treated was greater (RR 1.78, p = 0.001). Conclusions: Patients with NVAF within the recommended target INR range of 2.0–3.0 survive longer and have reduced morbidity. Probably too few people are anticoagulated with warfarin in NVAF.