Data Resource Profile: Danish Heart Statistics

Ten-year trends in incidence and prevalence of atrial fibrillation and flutter in Denmark according to demographics, ethnicity, educational level, and area of residence (2009-2018)

BACKGROUND

Atrial fibrillation is the most common cardiac arrhythmia and a major global health burden. Updated trends in the epidemiology of atrial fibrillation or flutter (AF) are needed.

METHODS

Using the Danish Heart Statistics, we investigated nationwide trends 2009-2018 in incidence rate and prevalence of AF according to age as well as age-standardized incidence rate (ASIR) and prevalence (ASP) of AF according to sex, ethnicity, educational level, and area of residence. Comparing year 2018 to 2009, we calculated stratum-specific ASIR ratios (ASIRR) and changes in ASP.

RESULTS

During 2009-2015 the ASIR for AF increased for both men and women, followed by a decline from 2015-2018. Overall, this resulted in a 9% increase among men (ASIRR: 1.09, 95% CI: 1.06-1.12), but no change among women (ASIRR: 1.00, 95% CI: 0.97-1.04). The ASP increased by 29% among men and 26% among women. An increase in ASIR was observed in all ethnic groups except men of Far Eastern ethnicity. Lower educational level was associated with greater increases in both ASIR and ASP. ASIR and ASP differed slightly between the Danish regions but increased in all of them.

CONCLUSIONS

During 2009-2018 the incidence and prevalence of AF in Denmark increased although the increase in incidence was transient among women. Factors associated with higher incidence were male sex, higher age, Danish and Western ethnicity as well as Middle Eastern/North African ethnicity among women, and lower educational level. Within Denmark, we observed only minor regional differences in AF incidence and prevalence.

Calcium Channel Blockers and the Risk of Exacerbation in Patients with Chronic Obstructive Pulmonary Disease: A Nationwide Study of 48,488 Outpatients

Patients with chronic obstructive pulmonary disease (COPD) are prone to developing arterial hypertension, and many patients are treated with the calcium channel blocker amlodipine. However, it remains unclear whether using this drug potentially affects the risk of acute severe exacerbations (AECOPD) and all-cause mortality in these patients. The data were collected from Danish national registries, containing complete information on health, prescriptions, hospital admissions, and outpatient clinic visits. The COPD patients (n = 48,488) were matched via propensity score on known predictors of the primary outcome in an active comparator design. One group was exposed to amlodipine treatment, and the other was exposed to bendroflumethiazide, since both of these drugs are considered to be the first choice for the treatment of arterial hypertension according to Danish guidelines. The use of amlodipine was associated with a reduced risk of death from all causes at the 1-year follow-up (hazard ratio 0.69, 95% confidence interval: 0.62-0.76) compared with the use of bendroflumethiazide in the matched patients. No difference in the risk of severe AECOPD was found. In the COPD patients, amlodipine use was associated with a lower risk of death from all causes compared with the use of bendroflumethiazide. Amlodipine seems to be a safe first choice for the treatment of arterial hypertension in COPD patients.

The Association between Perceived Annoyances in the Indoor Home Environment and Respiratory Infections: A Danish Cohort Study with up to 19 Years of Follow-Up

The increasing prevalence of reported annoyances in the indoor environment threatens public health. This study aimed to investigate the association between perceived annoyances from the home environment and respiratory infections among individuals with and without asthma or chronic obstructive pulmonary disease (COPD). A total of 16,688 individuals from the Danish Health and Morbidity Survey initiated in 2000 were grouped according to their patterns of perceived annoyances. Information on respiratory infections (all causes, bacterial, viral, and those leading to hospital admissions) was obtained from Danish registers up to 19 years after the survey. Poisson regression of incidence rates (IRs) was applied to estimate incidence rate ratios (IRRs). Annoyances significantly increased the IR for respiratory infections of all causes and bacterial respiratory infections in individuals without asthma or COPD, adjusted IRR 1.16 (95% CI: 1.01, 1.34) and 1.15 (95% CI: 1.02, 1.31), respectively. However, no difference was observed for viral respiratory infections nor hospital admissions. Individuals with asthma or COPD and a high level of annoyances had a non-significantly increased IR in all four analyses of respiratory infections. These findings provide support for perceived annoyances as an important risk factor for respiratory infections.

Cardiovascular outcomes with GLP-1 receptor agonists vs. SGLT-2 inhibitors in patients with type 2 diabetes

AIMS

We examined cardiovascular outcomes associated with initiation of glucagon-like peptide-1 receptor agonist (GLP-1RA) vs. sodium-glucose co-transporter-2 inhibitor (SGLT-2i) treatment in a real-world setting among patients with type 2 diabetes.

METHODS AND RESULTS

This Danish nationwide registry-based cohort study included patients with type 2 diabetes with a first-ever prescription of either GLP-1RA or SGLT-2i from 2013 through 2015 with follow-up until end of 2018. All analyses were standardized with respect to age, sex, diabetes duration, comorbidity, and comedication. The main outcome was a composite of cardiovascular death, myocardial infarction, and stroke. Furthermore, the components of the composite outcome and hospitalization for heart failure were evaluated. Standardized average 3-year risks of outcomes and differences thereof were estimated using doubly robust estimation combining cause-specific Cox regression with propensity score regression. We identified 8913 new users of GLP-1RA and 5275 new users of SGLT-2i. The standardized 3-year risk associated with initiating GLP-1RA and SGLT-2i, respectively, was as follows: composite cardiovascular outcome, 5.6% [95% confidence interval (CI): 5.2-6.1] vs. 5.6% (95% CI: 4.8-6.3); cardiovascular mortality, 1.6% (95% CI: 1.3-1.9) vs. 1.5% (95% CI: 1.1-1.8); hospitalization for heart failure, 1.7% (95% CI: 1.5-2.0) vs. 1.8% (95% CI: 1.2-2.5); myocardial infarction, 2.1% (95% CI: 1.8-2.4) vs. 2.1% (95% CI: 1.5-2.6); and stroke, 2.5% (95% CI: 2.2-2.9) vs. 2.6% (95% CI: 2.2-3.1).

CONCLUSION

In this nationwide study of patients with type 2 diabetes, initiating GLP-1RA vs. SGLT-2i was not found to be associated with significant differences in cardiovascular risk.

Drinking water magnesium and cardiovascular mortality: A cohort study in Denmark, 2005-2016

INTRODUCTION

Cardiovascular diseases are globally a major cause of death. Magnesium deficiency is associated with several diseases including cardiovascular diseases.

OBJECTIVE

To examine if a low concentration of magnesium in drinking water is associated with increased cardiovascular mortality and mortality due to acute myocardial infarction and stroke.

METHODS

A nationwide population-based cohort study using national health registries was used. A total of 4,274,132 individuals aged 30 years or more were included. Magnesium concentration in drinking water was estimated by linkage of residential addresses in the period 2005-2016 with the national drinking water quality monitoring database. The association between magnesium concentration in drinking water and cardiovascular mortality and mortality due to acute myocardial infarction and stroke was examined using a Poisson regression of number of deaths and logarithmic transformation of follow-up time as offset. The incidence rate ratio (IRR) was adjusted for differences in age, sex, calendar year, cohabitation, country of origin, and socioeconomic status.

RESULTS

Median magnesium concentration in drinking water at inclusion was 12.4 mg/L (range: 1.37-54.2 mg/L). The adjusted IRR for cardiovascular mortality was 0.96 (95% CI: 0.94; 0.97) for the lowest magnesium quintile (<6.5 mg/L) as compared to the highest magnesium quintile (>21.9 mg/L). The adjusted IRR for mortality due to acute myocardial infarction and stroke was 1.22 (1.17; 1.27) and 0.96 (0.93; 0.99), respectively, for the lowest magnesium quintile as compared to the highest quintile A decreasing mortality due to acute myocardial infarction was seen with an increasing magnesium concentration in a dose-response manner.

CONCLUSION

Low concentrations of magnesium in drinking water were associated with an increased mortality due to acute myocardial infarction. Low concentrations of magnesium in drinking water were associated with decreased cardiovascular mortality, and mortality due to stroke.

Perceived return-to-work pressure following cardiovascular disease is associated with age, sex, and diagnosis: a nationwide combined survey- and register-based cohort study

Background

Return to work is a key rehabilitation goal for people with cardiovascular disease (CVD) because employment matters to individuals and societies. However, people recovering from CVD often struggle with returning to work and maintaining employment. To identify people in need of vocational counselling, we examined the probability of feeling under pressure to return to work following CVD.

Methods

We conducted a combined survey- and register-based study in a randomly selected, population-based cohort of 10,000 people diagnosed with atrial fibrillation, heart failure, heart valve disease, or ischaemic heart disease in 2018. The questionnaire covered return-to-work items, and we reported the probabilities of feeling under pressure to return to work with 95% confidence intervals (CIs) in categories defined by sex, age, and CVD diagnosis.

Results

The survey response rate was 51.1%. In this study, we included 842 respondents (79.7% men) aged 32–85 years, who had returned to work following a sick leave. Overall, 249 (29.7%) had felt pressure to return to work. The probability of feeling under pressure to return to work ranged from 18.3% (95% CI: 13.1–24.6) among men aged > 55 years with atrial fibrillation to 51.7% (95% CI: 32.5–70.6) among women aged ≤ 55 years with atrial fibrillation. In addition, 66.0% of all respondents had not been offered vocational rehabilitation, and 48.6% of those who reported a need for vocational counselling had unmet needs. Survey responses also indicated that many respondents had returned to work before feeling mentally and physically ready.

Conclusion

A substantial proportion of people with cardiovascular disease feel under pressure to return to work, and this pressure is associated with age, sex, and diagnosis. The results show that vocational rehabilitation must be improved and emphasize the importance of ensuring that cardiac rehabilitation programmes include all core rehabilitation components.

Prediction of first cardiovascular disease event in 2.9 million individuals using Danish administrative healthcare data: a nationwide, registry-based derivation and validation study

Aims

The aim of this study was to derive and validate a risk prediction model with nationwide coverage to predict the individual and population-level risk of cardiovascular disease (CVD).

Methods and results

All 2.98 million Danish residents aged 30–85 years free of CVD were included on 1 January 2014 and followed through 31 December 2018 using nationwide administrative healthcare registries. Model predictors and outcome were pre-specified. Predictors were age, sex, education, use of antithrombotic, blood pressure-lowering, glucose-lowering, or lipid-lowering drugs, and a smoking proxy of smoking-cessation drug use or chronic obstructive pulmonary disease. Outcome was 5-year risk of first CVD event, a combination of ischaemic heart disease, heart failure, peripheral artery disease, stroke, or cardiovascular death. Predictions were computed using cause-specific Cox regression models. The final model fitted in the full data was internally-externally validated in each Danish Region. The model was well-calibrated in all regions. Area under the receiver operating characteristic curve (AUC) and Brier scores ranged from 76.3% to 79.6% and 3.3 to 4.4. The model was superior to an age-sex benchmark model with differences in AUC and Brier scores ranging from 1.2% to 1.5% and −0.02 to −0.03. Average predicted risks in each Danish municipality ranged from 2.8% to 5.9%. Predicted risks for a 66-year old ranged from 2.6% to 25.3%. Personalized predicted risks across ages 30–85 were presented in an online calculator (https://hjerteforeningen.shinyapps.io/cvd-risk-manuscript/).

Conclusion

A CVD risk prediction model based solely on nationwide administrative registry data provided accurate prediction of personal and population-level 5-year first CVD event risk in the Danish population. This may inform clinical and public health primary prevention efforts.

Impact of Male-Origin Microchimerism on Cardiovascular Disease in Women: A Prospective Cohort Study

Increasing parity is associated with an increased risk of ischemic heart disease (IHD) and stroke in women. This is probably attributable to biological responses of pregnancy. Male cells of presumed fetal origin are commonly present in women years after pregnancy-a phenomenon termed male-origin microchimerism (MOM). In this study, we investigated whether MOM was associated with risk of IHD and ischemic stroke in women. We evaluated the association between MOM and ischemic events in a cohort of 766 Danish women enrolled in the Diet, Cancer and Health cohort during 1993-1997 when aged 50-64 years. Of these women, 545 (71.2%) tested positive for MOM through targeting of the Y chromosome (DYS14 DNA sequence) in their blood. Multiple Cox regression models were used to calculate hazard ratios with 95% confidence intervals. We found that MOM was associated with a significantly reduced rate of IHD (hazard ratio = 0.44, 95% confidence interval: 0.23, 0.83) but not ischemic stroke (hazard ratio = 0.80, 95% confidence interval: 0.46, 1.41). Our findings show that microchimerism positivity is associated with a lower rate of later IHD development in women. Although the underlying mechanisms are presently unknown, MOM may be relevant in women's cardiovascular health. More studies are needed to confirm these findings.

Trends in Antiarrhythmic Drug Use in Denmark Over 19 Years

Antiarrhythmic drugs are widely used in the treatment of supraventricular and ventricular arrhythmias. Yet, nationwide long-term utilization trends remain unexplored. We examined 19-year trends in the use of antiarrhythmic drugs in Denmark. Using nationwide prescription data, we obtained information on hospital and primary healthcare use of Class I-V antiarrhythmic drugs from 1999 to 2017. Data was stratified according to sex and age groups. From 1999 to 2017, the total use of antiarrhythmic drugs per 1000 inhabitants/day increased 16% from 36.3 in 1999 to 41.9 in 2017 with peak consumption in 2008 (46.5). In primary healthcare, Class I usage decreased from 0.8 to 0.5 defined daily doses (DDD) per 1000 inhabitants/day, driven by a decreased prescription rate of propafenone (0.4 to 0.1) whereas prescription of flecainide (Class Ic) increased from 0.3 to 0.4 DDD per 1000 inhabitants/day (mainly in men of age 45 to 79 years). Class II usage increased from 15.4 to 33.6 DDD per 1000 inhabitants/day. Class III usage decreased from 2.6 to 1.1 DDD per 1000 inhabitants/day, reflecting reduced prescription rate of sotalol (2.1 to 0.2) whereas amiodarone increased from 0.5 to 0.9 (mainly due to increased prescription among men and women >80 years). Class IV usage declined from 8.6 to 2.8 DDD per 1000 inhabitants/day. Finally, Class V drugs decreased 8.1 to 3.3 DDD per 1000 inhabitants/day. In conclusion, during the past 2 decades considerable changes in prescription rate of antiarrhythmic drugs have occurred, most notably a reduction in sotalol and increased usage of flecainide, Class II drugs, and amiodarone.

The Danish health care system and epidemiological research: from health care contacts to database records

Denmark has a large network of population-based medical databases, which routinely collect high-quality data as a by-product of health care provision. The Danish medical databases include administrative, health, and clinical quality databases. Understanding the full research potential of these data sources requires insight into the underlying health care system. This review describes key elements of the Danish health care system from planning and delivery to record generation. First, it presents the history of the health care system, its overall organization and financing. Second, it details delivery of primary, hospital, psychiatric, and elderly care. Third, the path from a health care contact to a database record is followed. Finally, an overview of the available data sources is presented. This review discusses the data quality of each type of medical database and describes the relative technical ease and cost-effectiveness of exact individual-level linkage among them. It is shown, from an epidemiological point of view, how Denmark’s population represents an open dynamic cohort with complete long-term follow-up, censored only at emigration or death. It is concluded that Denmark’s constellation of universal health care, long-standing routine registration of most health and life events, and the possibility of exact individual-level data linkage provides unlimited possibilities for epidemiological research.

Soluble Urokinase Plasminogen Activator Receptor (suPAR) as a Predictor of Incident Atrial Fibrillation

Soluble urokinase plasminogen activator receptor (suPAR) is a biomarker of chronic low-grade inflammation and a potent predictor of cardiovascular events. We hypothesized that plasma suPAR levels would predict new-onset atrial fibrillation (AF) in a large cohort of con-secutively admitted acute medical patients during long-term follow-up. In 14,764 acutely ad-mitted patients without prior or current AF, median suPAR measured upon admission was 2.7 ng/ml (interquartile range (IQR) 1.9-4.0). During a median follow-up of 392 days (IQR 218-577), 349 patients (2.4%) were diagnosed with incident AF. suPAR levels at admission significantly predicted subsequent incident AF (HR per doubling of suPAR: 1.21, 95% CI 1.05-1.41, adjusted for age and sex). After further adjustment for Charlson score, plasma C-reactive protein (CRP), plasma creatinine and blood hemoglobin-levels, the result remained essentially unaltered (HR per doubling of suPAR: 1.20, 95% CI: 1.01-1.42). In multivariate ROC curve analysis, combining age, sex, Charlson score, CRP, creatinine, and hemoglobin (AUC 0.77, 95% CI 0.75-0.79), the addition of suPAR did not improve the prediction of incident AF (AUC 0.77, 95% CI 0.75-0.79, P=0.89). Plasma suPAR is independently associated with subsequent new-onset AF in a population of recently hospitalized patients, but the addition of suPAR to baseline risk markers appears not to improve the prediction of AF.