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Aims: Opioid use has substantially increased in the last decade and is associated with overdose mortality, but also with increased mortality from cardiovascular causes. This finding may partly reflect an association between opioids and out‐of‐hospital cardiac arrest (OHCA). Therefore, we aimed to investigate OHCA‐risk of opioids in the community. Methods: We conducted 2 population‐based case–control studies separately in the Netherlands (2009–2018) and Denmark (2001–2015). Cases were individuals who experienced OHCA of presumed cardiac cause. Each case was matched with up to 5 non‐OHCA‐controls according to age, sex and OHCA‐date. Conditional logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results: We included 5473 OHCA‐cases matched with 21 866 non‐OHCA‐controls in the Netherlands, and 35 017 OHCA‐cases matched with 175 085 non‐OHCA‐controls in Denmark. We found that use of opioids (the Netherlands: cases: 5.4%, controls: 1.8%; Denmark: cases: 11.9%, controls: 4.4%) was associated with increased OHCA‐risk in both regions (the Netherlands: OR 2.1 [95% CI 1.8–2.5]; Denmark: OR 1.8 [95% CI 1.5–2.1]). The association was observed in both sexes, and in individuals with cardiovascular disease (the Netherlands: OR 1.8 [95% CI 1.5–2.1]; Denmark: OR 1.6 [95% CI 1.5–1.7]) or without (the Netherlands: OR 3.4 [95% CI: 2.4–4.8], Pinteraction <.0001; Denmark: OR 2.3 [95% CI: 2.0–2.5], Pinteraction <.0001). Conclusion: Use of opioids is associated with increased OHCA‐risk in both sexes, independently of concomitant cardiovascular disease. These findings should be considered when evaluating the harms and benefits of treatment with opioids. [ABSTRACT FROM AUTHOR]

Aims: Drugs that prolong the QT interval, either by design (cardiac QT‐prolonging drugs: anti‐arrhythmics) or as off‐target effect (non‐cardiac QT‐prolonging drugs), may increase the risk of ventricular arrhythmias and out‐of‐hospital cardiac arrest (OHCA). Risk mitigation measures were instituted, in particular, surrounding prescription of cardiac QT‐prolonging drugs. We studied OHCA risk of both drug types in current clinical practice. Methods: Using data from large population‐based OHCA registries in the Netherlands and Denmark, we conducted two independent case–control studies. OHCA cases with presumed cardiac causes were matched on age/sex/index date with up to five non‐OHCA controls. We calculated odds ratios (ORs) for the association of cardiac or non‐cardiac QT‐prolonging drugs with OHCA risk using conditional logistic regression analyses. Results: We identified 2503 OHCA cases and 10 543 non‐OHCA controls in the Netherlands, and 35 017 OHCA cases and 175 085 non‐OHCA controls in Denmark. Compared to no use of QT‐prolonging drugs, use of non‐cardiac QT‐prolonging drugs (Netherlands: cases: 3.0%, controls: 1.9%; Denmark: cases: 14.9%, controls: 7.5%) was associated with increased OHCA risk (Netherlands: OR 1.37 [95% CI: 1.03–1.81]; Denmark: OR 1.63 [95% CI: 1.57–1.70]). The association between cardiac QT‐prolonging drugs (Netherlands: cases: 4.0%, controls: 2.5%; Denmark: cases: 2.1%, controls: 0.9%) and OHCA was weaker (Netherlands: OR 1.17 [95% CI: 0.92–1.50]; Denmark: OR 1.21 [95% CI: 1.09–1.33]), although users of cardiac QT‐prolonging drugs had more medication use and comorbidities associated with OHCA risk than users of non‐cardiac QT‐prolonging drugs. Conclusion: In clinical practice, cardiac QT‐prolonging drugs confer lower OHCA risk than non‐cardiac QT‐prolonging drugs, although users of the former have higher a priori risk. This is likely due to risk mitigation measures surrounding prescription of cardiac QT‐prolonging drugs. [ABSTRACT FROM AUTHOR]

Objective: Patients with bipolar disorder and schizophrenia are at high cardiovascular risk; yet, the risk of out-of-hospital cardiac arrest (OHCA) compared with the general population remains scarcely investigated.Methods: We conducted a nested case-control study using Cox regression to assess the association of bipolar disorder and schizophrenia with the HRs of OHCA of presumed cardiac cause (2001-2015). Reported are the HRs with 95% CIs overall and in subgroups defined by established cardiac disease, cardiovascular risk factors and psychotropic drugs.Results: We included 35 017 OHCA cases and 175 085 age-matched and sex-matched controls (median age 72 years and 66.9% male). Patients with bipolar disorder or schizophrenia had overall higher rates of OHCA compared with the general population: HR 2.74 (95% CI 2.41 to 3.13) and 4.49 (95% CI 4.00 to 5.10), respectively. The association persisted in patients with both cardiac disease and cardiovascular risk factors at baseline (bipolar disorder HR 2.14 (95% CI 1.72 to 2.66), schizophrenia 2.84 (95% CI 2.20 to 3.67)) and among patients without known risk factors (bipolar disorder HR 2.14 (95% CI 1.09 to 4.21), schizophrenia HR 5.16 (95% CI 3.17 to 8.39)). The results were confirmed in subanalyses only including OHCAs presenting with shockable rhythm or receiving an autopsy. Antipsychotics-but not antidepressants, lithium or antiepileptics (the last two only tested in bipolar disorder)-increased OHCA hazard compared with no use in both disorders.Conclusions: Patients with bipolar disorder or schizophrenia have a higher rate of OHCA compared with the general population. Cardiac disease, cardiovascular risk factors and antipsychotics represent important underlying mechanisms. [ABSTRACT FROM AUTHOR]

Aim: Regional variation in incidence and survival after out-of-hospital cardiac arrest (OHCA) may be caused by many factors including differences in definitions and reporting. We examined regional differences in Denmark.Methods: From the Danish Cardiac Arrest Registry we identified adult OHCA patients between 2009-2014 of presumed cardiac cause. Patients were grouped according to the five administrative/geographical regions of Denmark and survival was examined based on all arrest-cases (30-day survival percentage) and number of survivors per 100,000 inhabitants.Results: We included 12,902 OHCAs of which 1550 (12.0 %) were alive 30 days after OHCA. No regional differences were observed in age, sex or comorbidities. Incidence of OHCA ranged from 32.9 to 42.4 per 100,000 inhabitants; 30-day survival percentages ranged from 8.5% to 13.8% and number of survivors per 100,000 inhabitants ranged from 3.5 to 5.9, across the regions. In one of the regions car-manned pre-hospital physicians were discontinued from 2011. Here, the incidence of OHCA per 100,000 inhabitants increased markedly from 37.1 in 2011 to 52.2 in 2014 and 30-day survival percentage decreased from 10.9 % in 2011 to 7.5 % in 2014; while the number of survivors per 100,000 inhabitants stagnated from 4.0 in 2011 to 3.9 in 2014. In comparison, survival increased in the other four regions.Conclusion: Differences in incidence and 30-day survival after OHCA were observed between the five regions of Denmark. Comparisons of survival should not only be based on survival percentages, but also on number of survivors of the background population as inclusion bias can influence survival outcomes. [ABSTRACT FROM AUTHOR]

Background: The effect of bystander interventions on long-term functional outcomes among survivors of out-of-hospital cardiac arrest has not been extensively studied.Methods: We linked nationwide data on out-of-hospital cardiac arrests in Denmark to functional outcome data and reported the 1-year risks of anoxic brain damage or nursing home admission and of death from any cause among patients who survived to day 30 after an out-of-hospital cardiac arrest. We analyzed risks according to whether bystander cardiopulmonary resuscitation (CPR) or defibrillation was performed and evaluated temporal changes in bystander interventions and outcomes.Results: Among the 2855 patients who were 30-day survivors of an out-of-hospital cardiac arrest during the period from 2001 through 2012, a total of 10.5% had brain damage or were admitted to a nursing home and 9.7% died during the 1-year follow-up period. During the study period, among the 2084 patients who had cardiac arrests that were not witnessed by emergency medical services (EMS) personnel, the rate of bystander CPR increased from 66.7% to 80.6% (P<0.001), the rate of bystander defibrillation increased from 2.1% to 16.8% (P<0.001), the rate of brain damage or nursing home admission decreased from 10.0% to 7.6% (P<0.001), and all-cause mortality decreased from 18.0% to 7.9% (P=0.002). In adjusted analyses, bystander CPR was associated with a risk of brain damage or nursing home admission that was significantly lower than that associated with no bystander resuscitation (hazard ratio, 0.62; 95% confidence interval [CI], 0.47 to 0.82), as well as a lower risk of death from any cause (hazard ratio, 0.70; 95% CI, 0.50 to 0.99) and a lower risk of the composite end point of brain damage, nursing home admission, or death (hazard ratio, 0.67; 95% CI, 0.53 to 0.84). The risks of these outcomes were even lower among patients who received bystander defibrillation as compared with no bystander resuscitation.Conclusions: In our study, we found that bystander CPR and defibrillation were associated with risks of brain damage or nursing home admission and of death from any cause that were significantly lower than those associated with no bystander resuscitation. (Funded by TrygFonden and the Danish Heart Foundation.). [ABSTRACT FROM AUTHOR]

Aim To investigate diurnal variations in incidence and outcomes following out-of-hospital cardiac arrest (OHCA). Methods OHCA of presumed cardiac etiology were identified through the nationwide Danish Cardiac Arrest Registry (2001-2010). Time of day was divided into three time periods: daytime 07.00-14.59; evening 15.00-22.59; and nighttime 23.00-06.59. Results We identified 18,929 OHCA patients, aged ≥18 years. The median age was 72 years (IQR 62-80) and the majority were male (67.5%). OHCA occurrence varied across time periods, with 43.9%, 35.7% and 20.6% occurring during daytime, evening and nighttime, respectively. Nighttime patients were more likely to have: severe comorbidity (i.e. COPD), arrest in private home (87.2% vs. 69.0% and 73.0% daytime and evening, respectively), non-witnessed arrest (51.2% vs. 48.4% and 43.7%), no bystander CPR (75.9% vs. 68.4% and 66.1%), longer time interval from recognition of OHCA to rhythm analysis (12 min vs. 11 min and 11 min), and non-shockable heart rhythm (80.1% vs. 70.3% and 69.4%), all p < 0.0001. Nighttime patients were less likely to achieve return of spontaneous circulation on arrival at the hospital (7.5% vs. 14.8% and 15.1%) and 1-year survival (2.8% vs. 7.2% and 7.1%), p < 0.0001. Overall, the lower 1-year survival rate persisted after adjusting for patient-related and cardiac-arrest related characteristics mentioned above (OR 0.47, 95%CI 0.37-0.59; OR 0.51, 95%CI 0.40-0.65, compared to daytime and evening, respectively). Conclusions We found nighttime patients to have a lower survival compared to daytime and evening that persisted when adjusting for patient-related and cardiac-arrest related characteristics including comorbidities. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to examine rates of redeemed prescriptions of antidepressants and anxiolytics, used as markers for cerebral dysfunction in out-of-hospital cardiac arrest (OHCA) survivors, and examine the association between bystander CPR and these psychoactive drugs.Methods: We included all 30-day survivors of OHCA in Denmark between 2001 and 2011, who had not redeemed prescriptions for antidepressants or anxiolytics in the last six months prior to OHCA. Main outcome measures were redeemed prescriptions of antidepressants and anxiolytics within one year after OHCA.Results: Among 2,001 30-day survivors, 174 (8.6% died and 12.0% redeemed a first prescription for an antidepressant and 8.2% for an anxiolytic drug within one year after arrest. The corresponding frequencies for redeemed prescribed drugs among age- and sex-matched population controls were 7.5% and 5.2%, respectively. Among survivors who received bystander CPR, prescriptions for antidepressants and anxiolytics were redeemed in 11.1% [95% CI 9.2-13.3%] and 6.3% [95% CI 4.9-8.0%] of the cases, respectively, versus 17.2% [95% CI 13.9-21.1%] and 13.4% [95% CI 10.5-17.0%], respectively, among patients who had not received bystander CPR. Adjusted for age, sex, year of arrest, comorbidity, witnessed status and socioeconomic status, bystander CPR was associated with significant reductions in redeemed prescriptions for antidepressants, Hazard Ratio (HR) 0.71 [95% CI 0.52-0.98], P=0.031; and anxiolytics, HR 0.55 [95% CI 0.38-0.81], P=0.002.Conclusion: Relative to no bystander CPR, redeemed prescriptions for antidepressants and anxiolytics were significantly lower among 30-day survivors of OHCA who received bystander CPR, suggesting a cerebral dysfunction-lowering potential of bystander CPR. [ABSTRACT FROM AUTHOR]

Aim: Survival after out-of-hospital cardiac arrest (OHCA) has tripled during the past decade in Denmark as a likely result of improvements in cardiac arrest management. This study analyzed whether these improvements were applicable for patients with chronic obstructive pulmonary disease (COPD).Methods: Patients ≥18 years with OHCA of presumed cardiac cause were identified through the Danish Cardiac Arrest Registry, 2001-2011. Patients with a history of COPD up to ten years prior to arrest were identified from the Danish National Patient Register and compared to non-COPD patients.Results: Of 21,480 included patients, 3056 (14.2%) had history of COPD. Compared to non-COPD patients, COPD patients were older (75 vs. 71 years), less likely male (61.2% vs. 68.5%), had higher prevalence of other comorbidities, and were less likely to have: arrests outside private homes (17.7% vs. 28.3%), witnessed arrests (48.7% vs. 52.9%), bystander cardiopulmonary resuscitation (25.8% vs. 34.8%), and shockable heart rhythm (15.6% vs. 29.9%), all p<0.001; while no significant difference in the time-interval from recognition of arrest to rhythm analysis by ambulance-crew; p=0.24. From 2001 to 2011, survival upon hospital arrival increased in both patient-groups (from 6.8% to 17.1% in COPD patients and from 8.2% to 25.6% in non-COPD patients, p<0.001). However, no significant change was observed in 30-day survival in COPD patients (from 3.7% to 2.1%, p=0.27), in contrast to non-COPD patients (from 3.5% to 13.0%, p<0.001).Conclusions: Despite generally improved 30-day survival after OHCA over time, no improvement was observed in 30-day survival in COPD patients. [ABSTRACT FROM AUTHOR]

Background It remains challenging to identify patients at risk of out-of-hospital cardiac arrest (OHCA). We aimed to examine health care contacts in patients before OHCA compared with the general population that did not experience an OHCA. Methods and Results Patients with OHCA with a presumed cardiac cause were identified from the Danish Cardiac Arrest Registry (2001-2014) and their health care contacts (general practitioner [GP]/hospital) were examined up to 1 year before OHCA. In a case-control study (1:9), OHCA contacts were compared with an age- and sex-matched background population. Separately, patients with OHCA were examined by the contact type (GP/hospital/both/no contact) within 2 weeks before OHCA. We included 28 955 patients with OHCA. The weekly percentages of patient contacts with GP the year before OHCA were constant (25%) until 1 week before OHCA when they markedly increased (42%). Weekly percentages of patient contacts with hospitals the year before OHCA gradually increased during the last 6 months (3.5%-6.6%), peaking at the second week (6.8%) before OHCA; mostly attributable to cardiovascular diseases (21%). In comparison, there were fewer weekly contacts among controls with 13% for GP and 2% for hospital contacts ( P <0.001). Within 2 weeks before OHCA, 57.8% of patients with OHCA had a health care contact, and these patients had more contacts with GP (odds ratio [OR], 3.17; 95% CI, 3.09-3.26) and hospital (OR, 2.32; 95% CI, 2.21-2.43) compared with controls. Conclusions The health care contacts of patients with OHCA nearly doubled leading up to the OHCA event, with more than half of patients having health care contacts within 2 weeks before arrest. This could have implications for future preventive strategies.

Aims: Various drugs increase the risk of out-of-hospital cardiac arrest (OHCA) in the general population by impacting cardiac ion channels, thereby causing ventricular tachycardia/fibrillation (VT/VF). Dihydropyridines block L-type calcium channels, but their association with OHCA risk is unknown. We aimed to study whether nifedipine and/or amlodipine, often-used dihydropyridines, are associated with increased OHCA risk, and how these drugs impact on cardiac electrophysiology., Methods and Results: We conducted a case-control study with VT/VF-documented OHCA cases with presumed cardiac cause from ongoing population-based OHCA registries in the Netherlands and Denmark, and age/sex/index date-matched non-OHCA controls (Netherlands: PHARMO Database Network, Denmark: Danish Civil Registration System). We included 2503 OHCA cases, 10 543 non-OHCA controls in Netherlands, and 8101 OHCA cases, 40 505 non-OHCA controls in Denmark. To examine drug effects on cardiac electrophysiology, we performed single-cell patch-clamp studies in human-induced pluripotent stem cell-derived cardiomyocytes. Use of high-dose nifedipine (≥60 mg/day), but not low-dose nifedipine (<60 mg/day) or amlodipine (any-dose), was associated with higher OHCA risk than non-use of dihydropyridines [Netherlands: adjusted odds ratios (ORadj) 1.45 (95% confidence interval 1.02-2.07), Denmark: 1.96 (1.18-3.25)] or use of amlodipine [Netherlands: 2.31 (1.54-3.47), Denmark: 2.20 (1.32-3.67)]. Out-of-hospital cardiac arrest risk of (high-dose) nifedipine use was not further increased in patients using nitrates, or with a history of ischaemic heart disease. Nifedipine and amlodipine blocked L-type calcium channels at similar concentrations, but, at clinically used concentrations, nifedipine caused more L-type calcium current block, resulting in more action potential shortening., Conclusion: High-dose nifedipine, but not low-dose nifedipine or any-dose amlodipine, is associated with increased OHCA risk in the general population. Careful titration of nifedipine dose should be considered., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Research regarding out-of-hospital cardiac arrest (OHCA) survival of diabetes patients is sparse and it remains unknown whether initiatives to increase OHCA survival benefit diabetes and non-diabetes patients equally. We therefore examined overall and temporal survival in diabetes and non-diabetes patients following OHCA., Methods: Adult presumed cardiac-caused OHCAs were identified from the Danish Cardiac Arrest Registry (2001-2014). Associations between diabetes and return of spontaneous circulation upon hospital arrival and 30-day survival were estimated with logistic regression adjusted for patient- and OHCA-related characteristics., Results: In total, 28,955 OHCAs were included of which 4276 (14.8%) had diabetes. Compared with non-diabetes patients, diabetes patients had more comorbidities, same prevalence of bystander-witnessed arrests (51.7% vs. 52.7%) and bystander cardiopulmonary resuscitation (43.2% vs. 42.0%), more arrests in residential locations (77.3% vs. 73.0%) and were less likely to have shockable heart rhythm (23.5% vs. 27.9%). Temporal increases in return of spontaneous circulation and 30-day survival were seen for both groups (return of spontaneous circulation: 8.8% in 2001 to 22.3% in 2014 (diabetes patients) vs. 7.8% in 2001 to 25.7% in 2014 (non-diabetes patients); and 30-day survival: 2.8% in 2001 to 9.7% in 2014 vs. 3.5% to 14.8% in 2014, respectively). In adjusted models, diabetes was associated with decreased odds of return of spontaneous circulation (odds ratio 0.74 (95% confidence interval 0.66-0.82)) and 30-day survival (odds ratio 0.56 (95% confidence interval 0.48-0.65)) (interaction with calendar year p =0.434 and p =0.243, respectively)., Conclusion: No significant difference in temporal survival was found between the two groups. However, diabetes was associated with lower odds of return of spontaneous circulation and 30-day survival.

Aim: It remains unclear whether socioeconomic differences exist in post-resuscitation care in out-of-hospital cardiac arrests (OHCA). We aimed to examine socioeconomic differences in coronary procedures and survival after OHCA., Methods: OHCA patients ≥30 years of cardiac cause with a hospital admission from the Danish Cardiac Arrest Registry, 2001-2014, were divided according to quartiles of household income (lowest, low, high, highest). Associations of income, coronary procedures and 30-day survival were examined by age-standardized incidence rates and incidence rate ratios (IRR), and by logistic regression., Results: A total of 6105 patients were included. Higher-income patients were younger, males and had less comorbidity-burden. Higher-income patients had higher incidence rates for coronary angiographies both day 0-1 and day 2-7 after OHCA (day 0-1: highest: IRR 1.79, 95%CI 1.46-2.21; high: IRR 1.28, 95%CI 1.10-1.51; low: IRR 1.05, 95%CI 0.90-1.23), compared to lowest. Fifty-four percentage of the patients undergoing a coronary angiography received percutaneous-coronary-intervention or coronary-artery-bypass-grafting with no difference among three of the four groups, but lower IRR in low-income patients (IRR 0.74, 95%CI 0.61-0.89) compared to lowest. Higher-income patients had also higher odds for 30-day survival compared to lowest, both in patients with (highest: OR 1.61, 95%CI 1.12-2.32; high: OR 1.13, 95%CI 0.80-1.60; low: OR 1.14, 95%CI 0.81-1.61) and without (highest: OR 2.54, 95%CI 1.83-3.53; high: OR 1.41, 95%CI 1.06-1.87; low: OR 1.12, 95%CI 0.86-1.47) coronary angiography day 0-1., Conclusion: Higher-income patients were found associated with more performed coronary angiographies after OHCA, and higher odds for 30-day survival., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Aims: To investigate whether the recent improvements in pre-hospital cardiac arrest-management and survival following out-of-hospital cardiac arrest (OHCA) also apply to OHCA patients with psychiatric disorders., Methods: We identified all adult Danish patients with OHCA of presumed cardiac cause, 2001-2015. Psychiatric disorders were defined by hospital diagnoses up to 10 years before OHCA and analyzed as one group as well as divided into five subgroups (schizophrenia-spectrum disorders, bipolar disorder, depression, substance-induced mental disorders, other psychiatric disorders). Association between psychiatric disorders and pre-hospital OHCA-characteristics and 30-day survival were assessed by multiple logistic regression., Results: Of 27,523 OHCA-patients, 4772 (17.3%) had a psychiatric diagnosis. Patients with psychiatric disorders had lower odds of 30-day survival (0.37 95% confidence interval 0.32-0.43) compared with other OHCA-patients. Likewise, they had lower odds of witnessed status (0.75 CI 0.70-0.80), bystander cardiopulmonary resuscitation (CPR) (0.77 CI 0.72-0.83), shockable heart rhythm (0.37 95% CI, 0.33-0.40), and return of spontaneous circulation (ROSC) at hospital arrival (0.66 CI 0.59-0.72). Similar results were seen in all five psychiatric subgroups. The difference in 30-day survival between patients with and without psychiatric disorders increased in recent years: from 8.4% (CI 7.0-10.0%) in 2006 to 13.9% (CI 12.4-15.4%) in 2015 and from 7.0% (4.3-10.8%) in 2006 to 7.0% (CI 4.5-9.7%) in 2015, respectively., Conclusion: Patients with psychiatric disorders have lower survival following OHCA compared to non-psychiatric patients and the gap between the two groups has widened over time., (Copyright © 2019. Published by Elsevier B.V.)

Background Healthcare disparities for psychiatric patients are common. Whether these inequalities apply to postresuscitation management in out-of-hospital cardiac arrest (OHCA) is unknown. We investigated differences in in-hospital cardiovascular procedures following OHCA between patients with and without psychiatric disorders. Methods and Results Using the Danish nationwide registries, we identified patients admitted to the hospital following OHCA of presumed cardiac cause (2001-2015). Psychiatric disorders were identified using hospital diagnoses or redeemed prescriptions for psychotropic drugs. We calculated age- and sex-standardized incidence rates and incidence rate ratios (IRRs) of cardiovascular procedures during post-OHCA admission in patients with and without psychiatric disorders. Differences in 30-day and 1-year survival were assessed by multivariable logistic regression in the overall population and among 2-day survivors who received acute coronary angiography (CAG). We included 7288 hospitalized patients who had experienced an OHCA: 1661 (22.8%) had a psychiatric disorder. Compared with patients without psychiatric disorders, patients with psychiatric disorders had lower standardized incidence rates for acute CAG (≤1 day post-OHCA) (IRR, 0.51; 95% CI, 0.45-0.57), subacute CAG (2-30 days post-OHCA) (IRR, 0.40; 95% CI, 0.30-0.52), and implantable cardioverter-defibrillator implantation (IRR, 0.67; 95% CI, 0.48-0.95). Conversely, we did not detect differences in coronary revascularization among patients undergoing CAG (IRR, 1.11; 95% CI, 0.94-1.30). Patients with psychiatric disorders had lower survival even among 2-day survivors who received acute CAG: (odds ratio of 30-day survival, 0.68; 95% CI, 0.52-0.91; and 1-year survival, 0.66; 95% CI, 0.50-0.88). Conclusions Psychiatric patients had a lower probability of receiving post-OHCA CAG and implantable cardioverter-defibrillator implantation compared with nonpsychiatric patients but the same probability of coronary revascularization among patients undergoing CAG. However, their survival was lower irrespective of angiographic procedures.

Aims: Optimization of automated external defibrillator (AED) placement and accessibility are warranted. We examined the associations between AED accessibility, at the time of an out-of-hospital cardiac arrest (OHCA), bystander defibrillation, and 30-day survival, as well as AED coverage according to AED locations., Methods: In this registry-based study we identified all OHCAs registered by mobile emergency care units in Copenhagen, Denmark (2008-2016). Information regarding registered AEDs (2007-2016) was retrieved from the nationwide Danish AED Network. We calculated AED coverage (AEDs located ≤200 m route distance from an OHCA) and, according to AED accessibility, the likelihoods of bystander defibrillation and 30-day survival., Results: Of 2500 OHCAs, 22.6% (n = 566) were covered by a registered AED. At the time of OHCA, <50% of these AEDs were accessible (n = 276). OHCAs covered by an accessible AED were nearly three times more likely to receive bystander defibrillation (accessible: 13.8% vs. inaccessible: 4.8%, p < 0.001) and twice as likely to achieve 30-day survival (accessible: 28.8% vs. inaccessible: 16.4%, p < 0.001). Among bystander-witnessed OHCAs with shockable heart rhythms (accessible vs. inaccessible AEDs), bystander defibrillation rates were 39.8% vs. 20.3% (p = 0.01) and 30-day survival rates were 72.7% vs. 44.1% (p < 0.001). Most OHCAs were covered by AEDs at offices (18.6%), schools (13.3%), and sports facilities (12.9%), each with a coverage loss >50%, due to limited AED accessibility., Conclusions: The chance of a bystander defibrillation was tripled, and 30-day survival nearly doubled, when the nearest AED was accessible, compared to inaccessible, at the time of OHCA, underscoring the importance of unhindered AED accessibility., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Aims: Bystander cardiopulmonary resuscitation (CPR) has increased in several countries following nationwide initiatives to facilitate bystander resuscitative efforts in out-of-hospital cardiac arrest (OHCA). We examined the importance of public or residential location of arrest on temporal changes in bystander CPR and outcomes., Methods and Results: From the nationwide Danish Cardiac Arrest Registry, all OHCAs from 2001 to 2014 of presumed cardiac cause and between 18 and 100 years of age were identified. Arrests witnessed by emergency medical services personnel were excluded. Of 25 505 OHCAs, 26.4% (n = 6738) and 73.6% (n = 18 767) were in public and residential locations, respectively. Bystander CPR increased during 2001-2014 in both locations: from 36.4% [95% confidence interval (CI) 30.6-42.6%] to 83.1% (95% CI 80.0-85.8%) in public (P < 0.001) and from 16.0% (95% CI 13.2-19.3%) to 61.0% (95% CI 58.7-63.2%) in residential locations (P < 0.001). Concurrently, 30-day survival increased in public from 6.4% (95% CI 4.0-10.0%) to 25.2% (95% CI 22.1-28.7%) (P < 0.001), and in residential from 2.9% (95% CI 1.8-4.5%) to 10.0% (95% CI 8.7-11.4%) (P < 0.001). Among 2281 30-day survivors, 1-year risk of anoxic brain damage/nursing home admission during 2001-2014 decreased from 18.8% (95% CI 6.6-43.0%) to 6.8% (95% CI 3.9-11.8%) in public (P < 0.001), whereas the corresponding change was insignificant in residential locations from 11.8% (95% CI 3.3-34.3) to 17.6% (95% CI 12.7-23.9%) (P = 0.52)., Conclusion: During 2001-2014, bystander CPR and 30-day survival more than doubled in both public and residential OHCA locations. A significant decrease in anoxic brain damage/nursing home admission was observed among 30-day survivors in public, but not among survivors from residential OHCAs.

Background: In the last decade, there has been a rapid increase in the dissemination of automated external defibrillators (AEDs) for prehospital defibrillation of out-of-hospital cardiac arrest patients. The aim of this study was to study the association between different defibrillation strategies on survival rates over time in Copenhagen, Stockholm, Western Sweden and Amsterdam, and the hypothesis was that non-EMS defibrillation increased over time and was associated with increased survival., Methods: We performed a retrospective analysis of four prospectively collected cohorts of out-of-hospital cardiac arrest patients between 2008 and 2013. Emergency medical service (EMS)-witnessed arrests were excluded., Results: A total of 22 453 out-of-hospital cardiac arrest patients with known survival status were identified, of whom 2957 (13%) survived at least 30 days postresuscitation. Of all survivors with a known defibrillation status, 2289 (81%) were defibrillated, 1349 (59%) were defibrillated by EMS, 454 (20%) were defibrillated by a first responder AED and 429 (19%) were defibrillated by an onsite AED and 57 (2%) were unknown. The percentage of survivors defibrillated by first responder AEDs (from 13% in 2008 to 26% in 2013, p<0.001 for trend) and onsite AEDs (from 14% in 2008 to 30% in 2013, p<0.001 for trend) increased. The increased use of these non-EMS AEDs was associated with the increase in survival rate of patients with a shockable initial rhythm., Conclusion: Survivors of out-of-hospital cardiac arrest are increasingly defibrillated by non-EMS AEDs. This increase is primarily due to a large increase in the use of onsite AEDs as well as an increase in first-responder defibrillation over time. Non-EMS defibrillation accounted for at least part of the increase in survival rate of patients with a shockable initial rhythm., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Introduction: Ischemic heart disease (IHD) is associated with a shockable rhythm in out-of-hospital cardiac arrest (OHCA). However, the impact of IHD severity on first recorded rhythm is unknown. We hypothesized that the strength of the association between IHD and shockable rhythm increases with increasing IHD severity., Methods: OHCA patients were identified in the Danish Cardiac Arrest Registry (2001-2014). Population-based registries were used to identify chronic diseases, drug prescriptions and cardiac procedures such as coronary angiography (CAG), percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). Severity of IHD was categorized as 1) No diagnosis of IHD, 2) IHD without previous CAG, PCI or CABG, 3) IHD with CAG, 4) IHD with PCI, and 5) IHD with CABG. Adjusted odds ratios (ORs) for a shockable rhythm was computed using multivariable logistic regression., Results: Of 34,749 patients with OHCA, 6325 (18.2%) patients had a diagnosis of IHD. The prevalence of a shockable rhythm was higher for patients with a previous diagnosis of IHD (25.6%) and for those with previous CAG (33.3%), PCI (36.4%) or CABG (34.0%) when compared to patients without IHD (21.2%). IHD was associated with shockable rhythm (OR = 1.69, 95%CI 1.55-1.85) when compared to patients without IHD. The association with shockable rhythm was higher for patients with a history of CAG (OR = 1.92, 95%CI 1.67-2.20) and PCI (OR = 1.93, 95%CI 1.67-2.23), but similar in patients with CABG (OR = 1.69, 95%CI 1.37-2.10)., Conclusion: IHD was associated with a shockable rhythm, with a moderate increase in the association in patients with a CAG or PCI procedure., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Chronic obstructive pulmonary disease (COPD) is associated with a non-shockable rhythm as presenting rhythm in out-of-hospital cardiac arrest (OHCA). Whether the severity of the underlying disease is related to presenting rhythm is unknown. We hypothesized that increased severity of COPD in OHCA patients is associated with an increased prevalence of non-shockable rhythm., Methods: This study included OHCA patients ≥40 years from the Danish Cardiac Arrest Registry (2001-2014). Population-based registries were used to identify chronic diseases and drug prescriptions. COPD was defined as a COPD diagnosis or pharmacological therapy for COPD. The severity of COPD was based on either 1) pharmacological therapy (mild/moderate/severe), 2) admission for exacerbation, 3) prescription for corticosteroids, or 4) forced expiratory volume in 1 s (FEV1). For each of these, a multivariable logistic regression model was used to estimate odds ratios (ORs) for a non-shockable rhythm., Results: Of 33,228 patients with OHCA 7789 (23.4%) had COPD. Of these 6702 (86.0%) had a non-shockable rhythm. Compared to patients without COPD, mild COPD was associated with a non-shockable rhythm (OR = 1.46, 95%CI 1.29-1.65). This association was more pronounced for moderate (OR = 1.78, 95%CI 1.45-2.19) and severe COPD (OR = 2.01 95%CI 1.82-2.20). Recent admission for exacerbation (OR = 2.12, OR 95%CI 1.81-2.49) or prescription for corticosteroids (OR = 1.82, 95%CI 1.55-2.14) was also associated with a non-shockable rhythm. FEV1 ≤ 50% was associated with a non-shockable rhythm compared to FEV1 > 50% (OR = 1.74, 95%CI 1.07-2.82, n = 1122)., Conclusion: Incremental severity of COPD is associated with increasing prevalence of a non-shockable rhythm as presenting rhythm in OHCA patients., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aims: Despite wide dissemination of automated external defibrillators (AEDs), bystander defibrillation rates remain low. We aimed to investigate how route distance to the nearest accessible AED was associated with probability of bystander defibrillation in public and residential locations., Methods: We used data from the nationwide Danish Cardiac Arrest Registry and the Danish AED Network to identify out-of-hospital cardiac arrests and route distances to nearest accessible registered AED during 2008-2013. The association between route distance and bystander defibrillation was described using restricted cubic spline logistic regression., Results: We included 6971 out-of-hospital cardiac arrest cases. The proportion of arrests according to distance in meters (≤100, 101-200, >200) to the nearest accessible AED was: 4.6% (n=320), 5.3% (n=370), and 90.1% (n=6281), respectively. For cardiac arrests in public locations, the probability of bystander defibrillation at 0, 100 and 200m from the nearest AED was 35.7% (95% confidence interval 28.0%-43.5%), 21.3% (95% confidence interval 17.4%-25.2%), and 13.7% (95% confidence interval 10.1%-16.8%), respectively. The corresponding numbers for cardiac arrests in residential locations were 7.0% (95% confidence interval -2.1%-16.1%), 1.5% (95% confidence interval 0.002%-2.8%), and 0.9% (95% confidence interval 0.0005%-1.7%), respectively., Conclusions: In public locations, the probability of bystander defibrillation decreased rapidly within the first 100m route distance from cardiac arrest to nearest accessible AED whereas the probability of bystander defibrillation was low for all distances in residential areas., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Importance: Bystander-delivered defibrillation (hereinafter referred to as bystander defibrillation) of patients with out-of-hospital cardiac arrests (OHCAs) remains limited despite the widespread dissemination of automated external defibrillators (AEDs)., Objective: To examine calendar changes in bystander defibrillation and subsequent survival according to a public or a residential location of the cardiac arrest after nationwide initiatives in Denmark to facilitate bystander-mediated resuscitative efforts, including bystander defibrillation., Design, Setting, and Participants: This nationwide study identified 18 688 patients in Denmark with first-time OHCA from June 1, 2001, to December 31, 2012, using the Danish Cardiac Arrest Registry. Patients had a presumed cardiac cause of arrest that was not witnessed by emergency medical services personnel. Data were analyzed from April 1, 2015, to December 10, 2016., Exposures: Nationwide initiatives to facilitate bystander resuscitative efforts, including bystander defibrillation, consisted of resuscitation training of Danish citizens, dissemination of on-site AEDs, foundation of an AED registry linked to emergency medical dispatch centers, and dispatcher-assisted guidance of bystander resuscitation efforts., Main Outcomes and Measures: The proportion of patients who received bystander defibrillation according to the location of the cardiac arrest and their subsequent 30-day survival., Results: Of the 18 688 patients with OHCAs (67.8% men and 32.2% women; median [interquartile range] age, 72 [62-80] years), 4783 (25.6%) had a cardiac arrest in a public location and 13 905 (74.4%) in a residential location. The number of registered AEDs increased from 141 in 2007 to 7800 in 2012. The distribution of AED location was consistently skewed in favor of public locations. Bystander defibrillation increased in public locations from 3 of 245 (1.2%; 95% CI, 0.4%-3.5%) in 2001 to 78 of 510 (15.3%; 95% CI, 12.4%-18.7%) in 2012 (P < .001) but remained unchanged in residential locations from 7 of 542 (1.3%; 95% CI, 0.6%-2.6%) in 2001 to 21 of 1669 (1.3%; 95% CI, 0.8%-1.9%) in 2012 (P = .17). Thirty-day survival after bystander defibrillation increased in public locations from 8.3% (95% CI, 1.5%-35.4%) in 2001/2002 to 57.5% (95% CI, 48.6%-66.0%) in 2011/2012 (P < .001) in residential locations, from 0.0% (95% CI, 0.0%-19.4%) in 2001/2002 to 25.6% (95% CI, 14.6%-41.1%) in 2011/2012 (P < .001)., Conclusions and Relevance: Initiatives to facilitate bystander defibrillation were associated with a marked increase in bystander defibrillation in public locations, whereas bystander defibrillation remained limited in residential locations. Concomitantly, survival increased after bystander defibrillation in residential and public locations.

Objectives: This study sought to describe the use of pharmacotherapy in a nationwide cohort of young patients with sudden cardiac death (SCD)., Background: Several drugs have been associated with an increased risk of SCD and sudden arrhythmic death syndrome (SADS). It remains unclear how pharmacotherapy may contribute to the overall burden of SCD in the general population., Methods: This was a nationwide study that included all deaths that occurred between 2000 and 2009 and between 2007 and 2009 in people age 1 to 35 years and 36 to 49 years, respectively. Two physicians identified all SCDs through review of death certificates. Autopsy reports were collected. Pharmacotherapy prescribed within 90 days before SCD was identified in the Danish Registry of Medicinal Product Statistics., Results: We identified 1,363 SCDs; median age was 38 years (interquartile range: 29 to 45 years), and 72% (n = 975) were men. Autopsy was performed in 55%. Overall, 58% of SCD cases (n = 786) received at least 1 drug within 90 days before death. The most common drugs were analgesic drugs (n = 239; 18%), antihypertensive drugs (n = 234; 17%), and antibiotic drugs (n = 218; 16%). After multivariable adjustment, prescription of "brugadogenic" drugs or >1 QT-prolonging drug was associated with an increased risk of SADS compared with explained SCD (odds ratio: 2.16 [95% confidence interval: 1.12 to 4.17] and 2.91 [95% confidence interval: 1.46 to 5.81], respectively)., Conclusions: Pharmacotherapy was identified in 58% of the SCD cases. After multivariable adjustment, there was a 2- and 3-fold increased risk of SADS compared with explained SCD in patients receiving brugadogenic drugs or >1 QT-prolonging drug, respectively. Identification of high-risk patients is warranted to lower the burden of SCD., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Data on long-term function of out-of-hospital cardiac arrest survivors are sparse. We examined return to work as a proxy of preserved function without major neurologic deficits in survivors., Methods and Results: In Denmark, out-of-hospital cardiac arrests have been systematically reported to the Danish Cardiac Arrest Register since 2001. During 2001-2011, we identified 4354 patients employed before arrest among 12 332 working-age patients (18-65 years), of whom 796 survived to day 30. Among 796 survivors (median age, 53 years [quartile 1-3, 46-59 years]; 81.5% men), 610 (76.6%) returned to work in a median time of 4 months [quartile 1-3, 1-19 months], with a median time of 3 years spent back at work. A total of 74.6% (N=455) remained employed without using sick leave during the first 6 months after returning to work. This latter proportion of survivors returning to work increased over time (66.1% in 2001-2005 versus 78.1% in 2006-2011; P=0.002). In multivariable Cox regression analysis, factors associated with return to work with ≥6 months of sustainable employment were as follows: (1) arrest during 2006-2011 versus 2001-2005, hazard ratio (HR), 1.38 (95% CI, 1.05-1.82); (2) male sex, HR, 1.48 (95% CI, 1.06-2.07); (3) age of 18 to 49 versus 50 to 65 years, HR, 1.32 (95% CI, 1.02-1.68); (4) bystander-witnessed arrest, HR, 1.79 (95% CI, 1.17-2.76); and (5) bystander cardiopulmonary resuscitation, HR, 1.38 (95% CI, 1.02-1.87)., Conclusions: Of 30-day survivors employed before arrest, 76.6% returned to work. The percentage of survivors returning to work increased significantly, along with improved survival during 2001-2011, suggesting an increase in the proportion of survivors with preserved function over time., (© 2015 American Heart Association, Inc.)

Background: On the performance of an autopsy, sudden deaths may be divided into 2 classifications: (1) sudden cardiac deaths and (2) sudden noncardiac deaths (SNCDs). Families of SNCD victims should not be followed up as a means of searching for cardiac disease., Objective: The purpose of this study was to report the risk factors and causes of SNCD., Methods: We conducted a retrospective, nationwide study including all deaths between 2000 and 2006 of individuals aged 1-35 years and all deaths between 2007 and 2009 of individuals aged 1-49 years. Two physicians identified all sudden death cases through review of death certificates. Autopsy reports were collected. A multivariable logistic regression model was used to identify both clinical characteristics and risk factors associated with SNCD., Results: We identified 1039 autopsied cases of sudden death, of which 286 (28%) were classified as SNCD. The median age in the SNCD death population was 32 years. Increasing age was inversely associated with SNCD (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.87-0.98). Female sex, in-hospital location, and the absence of cardiac comorbidities were positively associated with SNCD (OR 1.7, 95% CI 1.3-2.3; OR 3.0, 95% CI 2.0-4.4; and OR 4.3, 95% CI 2.5-7.4, respectively). The most common cause of SNCD was pulmonary disease (n = 115 [40%])., Conclusion: Sudden death among individuals aged <50 years was caused by noncardiac diseases in 28% of cases. Risk factors were female sex, age, and the absence of cardiac comorbidities. These data may guide future strategies for the follow-up of family members of nonautopsied sudden death victims, improve risk stratification, and influence public health strategies., (Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: There is insufficient knowledge of out-of-hospital cardiac arrest (OHCA) in the very young., Objectives: This nationwide study sought to examine age-stratified OHCA characteristics and the role of parental socioeconomic differences and its contribution to mortality in the young population., Methods: All OHCA patients in Denmark, ≤21 years of age, were identified from 2001 to 2010. The population was divided into infants (<1 year); pre-school children (1-5 years); school children (6-15 years); and high school adolescents/young adults (16-21 years). Multivariate logistic regression analyses were used to investigate associations between pre-hospital factors and study endpoints: return of spontaneous circulation and survival., Results: A total of 459 individuals were included. Overall incidence of OHCA was 3.3 per 100,000 inhabitants per year. The incidence rates for infants, pre-school children, school children and high school adolescents were 11.5, 3.5, 1.3 and 5.3 per 100,000 inhabitants. Overall bystander CPR rate was 48.8%, and for age groups: 55.4%, 41.2%, 44.9% and 63.0%, respectively. Overall 30-day survival rate was 8.1%, and for age groups: 1.4%, 4.5%, 16.1% and 9.3%, respectively. High parental education was associated with improved survival after OHCA (OR 3.48, CI 1.27-9.41). Significant crude difference in survival (OR 3.18, CI 1.22-8.34) between high household incomes vs. low household incomes was found., Conclusion: OHCA incidences and survival rates varied significantly between age groups. High parental education was found to be associated with improved survival after OHCA., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: The revised cardiac risk index (RCRI) holds a central role in preoperative cardiac risk stratification in noncardiac surgery. Its performance in unselected populations, including different age groups, has, however, not been systematically investigated. We assessed the relationship of RCRI with major adverse cardiovascular events in an unselected cohort of patients undergoing elective, noncardiac surgery overall and in different age groups., Methods and Results: We followed up all individuals ≥ 25 years who underwent major elective noncardiac surgery in Denmark (January 1, 2005, to November 30, 2011) for the 30-day risk of major adverse cardiovascular events (ischemic stroke, myocardial infarction, or cardiovascular death). There were 742 of 357,396 (0.2%), 755 of 74.889 (1.0%), 521 of 11,921 (4%), and 257 of 3146 (8%) major adverse cardiovascular events occurring in RCRI classes I, II, III, and IV. Multivariable odds ratio estimates were as follows: ischemic heart disease 3.30 (95% confidence interval, 2.96-3.69), high-risk surgery 2.70 (2.46-2.96), congestive heart failure 2.65 (2.29-3.06), cerebrovascular disease 10.02 (9.08-11.05), insulin therapy 1.62 (1.37-1.93), and kidney disease 1.45 (1.33-1.59). Modeling RCRI classes as a continuous variable, C statistic was highest among age group 56 to 65 years (0.772) and lowest for those aged >85 years (0.683). Sensitivity of RCRI class >I (ie, having ≥ 1 risk factor) for capturing major adverse cardiovascular events was 59%, 71%, 64%, 66%, and 67% in patients aged ≤ 55, 56 to 65, 66 to 75, 76 to 85, and >85 years, respectively; the negative predictive values were >98% across all age groups., Conclusions: In a nationwide unselected cohort, the performance of the RCRI was similar to that of the original cohort. Having ≥ 1 risk factor was of moderate sensitivity, but high negative predictive value for all ages., (© 2015 American Heart Association, Inc.)

Aim: Crude survival has increased following an out-of-hospital cardiac arrest (OHCA). We aimed to study sex-related differences in patient characteristics and survival during a 10-year study period., Methods: Patients≥12 years old with OHCA of a presumed cardiac cause, and in whom resuscitation was attempted, were identified through the Danish Cardiac Arrest Registry 2001-2010. A total of 19,372 patients were included., Results: One-third were female, with a median age of 75 years (IQR 65-83). Compared to females, males were five years younger; and less likely to have severe comorbidities, e.g., chronic obstructive pulmonary disease (12.8% vs. 16.5%); but more likely to have arrest outside of the home (29.4% vs. 18.7%), receive bystander CPR (32.9% vs. 25.9%), and have a shockable rhythm (32.6% vs. 17.2%), all p<0.001. Thirty-day crude survival increased in males (3.0% in 2001 to 12.9% in 2010); and in females (4.8% in 2001 to 6.7% in 2010), p<0.001. Multivariable logistic regression analyses adjusted for patient characteristics including comorbidities, showed no survival difference between sexes in patients with a non-shockable rhythm (OR 1.00; CI 0.72-1.40), while female sex was positively associated with survival in patients with a shockable rhythm (OR 1.31; CI 1.07-1.59). Analyses were rhythm-stratified due to interaction between sex and heart rhythm; there was no interaction between sex and calendar-year., Conclusions: Temporal increase in crude survival was more marked in males due to poorer prognostic characteristics in females with a lower proportion of shockable rhythm. In an adjusted model, female sex was positively associated with survival in patients with a shockable rhythm., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Importance: Out-of-hospital cardiac arrest is a major health problem associated with poor outcomes. Early recognition and intervention are critical for patient survival. Bystander cardiopulmonary resuscitation (CPR) is one factor among many associated with improved survival., Objective: To examine temporal changes in bystander resuscitation attempts and survival during a 10-year period in which several national initiatives were taken to increase rates of bystander resuscitation and improve advanced care., Design, Setting, and Participants: Patients with out-of-hospital cardiac arrest for which resuscitation was attempted were identified between 2001 and 2010 in the nationwide Danish Cardiac Arrest Registry. Of 29,111 patients with cardiac arrest, we excluded those with presumed noncardiac cause of arrest (n = 7390) and those with cardiac arrests witnessed by emergency medical services personnel (n = 2253), leaving a study population of 19,468 patients., Main Outcomes and Measures: Temporal trends in bystander CPR, bystander defibrillation, 30-day survival, and 1-year survival., Results: The median age of patients was 72 years; 67.4% were men. Bystander CPR increased significantly during the study period, from 21.1% (95% CI, 18.8%-23.4%) in 2001 to 44.9% (95% CI, 42.6%-47.1%) in 2010 (P < .001), whereas use of defibrillation by bystanders remained low (1.1% [95% CI, 0.6%-1.9%] in 2001 to 2.2% [95% CI, 1.5%-2.9%] in 2010; P = .003). More patients achieved survival on hospital arrival (7.9% [95% CI, 6.4%-9.5%] in 2001 to 21.8% [95% CI, 19.8%-23.8%] in 2010; P < .001). Also, 30-day survival improved (3.5% [95% CI, 2.5%-4.5%] in 2001 to 10.8% [95% CI, 9.4%-12.2%] in 2010; P < .001), as did 1-year survival (2.9% [95% CI, 2.0%-3.9%] in 2001 to 10.2% [95% CI, 8.9%-11.6%] in 2010; P < .001). Despite a decrease in the incidence of out-of-hospital cardiac arrests during the study period (40.4 to 34.4 per 100,000 persons in 2001 and 2010, respectively; P = .002), the number of survivors per 100,000 persons increased significantly (P < .001). For the entire study period, bystander CPR was positively associated with 30-day survival, regardless of witnessed status (30-day survival for nonwitnessed cardiac arrest, 4.3% [95% CI, 3.4%-5.2%] with bystander CPR and 1.0% [95% CI, 0.8%-1.3%] without; odds ratio, 4.38 [95% CI, 3.17-6.06]). For witnessed arrest the corresponding values were 19.4% (95% CI, 18.1%-20.7%) vs 6.1% (95% CI, 5.4%-6.7%); odds ratio, 3.74 (95% CI, 3.26-4.28)., Conclusions and Relevance: In Denmark between 2001 and 2010, an increase in survival following out-of-hospital cardiac arrest was significantly associated with a concomitant increase in bystander CPR. Because of the co-occurrence of other related initiatives, a causal relationship remains uncertain.

Aims: Administrative discharge codes are widely used in epidemiology, but the specificity and sensitivity of this coding is unknown and must be validated. We assessed the validity of the discharge diagnosis of syncope in administrative registers and reviewed the etiology of syncope after workup., Methods and Results: Two samples were investigated. One sample consisted of 5262 randomly selected medical patients. The other sample consisted of 750 patients admitted or seen in the emergency department (ED) for syncope (ICD-10: R55.9) in three hospitals in Denmark. All charts were reviewed for baseline characteristics and to confirm the presence/absence of syncope and to compare with the administrative coding. In a sample of 600 admitted patients 570 (95%) and of 150 patients from ED 140 (93%) had syncope representing the positive predictive values. Median age of the population was 69 years (IQR: ± 14). In the second sample of 5262 randomly selected medical patients, 75 (1.4%) had syncope, of which 47 were coded as R55.9 yielding a sensitivity of 62.7%, a negative predictive value of 99.5%, and a specificity of 99.9%., Conclusion: ED and hospital discharge diagnostic coding for syncope has a positive predictive value of 95% and a sensitivity of 63%.

Background: The underlying etiology of sudden cardiac death varies with age and is likely to be reflected in type and number of healthcare contacts. We aimed to determine the specific type of healthcare contact shortly before out-of-hospital cardiac arrest (OHCA) across ages., Methods: OHCA patients were identified in the nationwide Danish Cardiac Arrest Register and Copenhagen Medical Emergency Care Unit (2001-2006). We matched every OHCA patients with 10 controls on sex and age. Healthcare contacts were evaluated 30 days before event by individual-level-linkage of nationwide registers., Results: We identified 16,924 OHCA patients, median age 70.0 years (Q1-Q3: 59-80). OHCA patients had a higher number of hospitalizations and received more pharmacotherapy compared to the control population across all ages (p for difference <0.001). OHCA patients aged 70-79 and 80-89 years had the highest proportion of hospitalizations (70%) and pharmacotherapy (73%), respectively. In general, the association between OHCA and hospitalizations and pharmacotherapy was more pronounced among the youngest OHCA patients compared to controls. OHCA patients in age groups 14-19, 20-29, 30-39 were ~5 times more likely to be in contact with the healthcare service than the control population (p for difference <0.001). Similarly, OHCA patients in the oldest age groups (60-69, 70-79, 80-89, >89) were <2 times more likely to be in contact with the healthcare services shortly before OHCA compared to the control population (p for difference <0.001)., Conclusion: Young OHCA patients are more likely to be in contact with the healthcare services compared with an age and sex matched control population suggestive of traits that make them stand out from the general population., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)