The Danish in-hospital cardiac arrest registry (DANARREST)

Blood laboratory analyses preceding in-hospital cardiac arrest: A matched case-control study

BACKGROUND

Whether blood laboratory analyses differ in patients who later suffer in-hospital cardiac arrest (IHCA) compared to other hospitalised patients remains unknown. The aim of this study was to describe pre-arrest sampling frequencies, results, and trends in blood laboratory analyses in patients with IHCA compared to controls.

METHODS

This study was a matched case-control study using national registries in Denmark. Cases were defined as patients with IHCA from 2017 to 2021. Controls were defined as hospitalised patients and were matched on age, sex, and date and length of admission. Data on a total of 51 different blood laboratory analyses were obtained. The laboratory analyses of primary interest were lactate, sodium, potassium, and haemoglobin. The index time for cases was defined as the time of cardiac arrest, and a corresponding index time was defined for controls based on the time to cardiac arrest for their corresponding case. Blood sampling frequencies were reported for blood laboratory analyses obtained either within the last 24 h before the index time or between the time of hospital admission and the index time. Blood sampling results were reported for blood laboratory analyses obtained within the last 24 h before the index time.

RESULTS

A total of 9268 cases and 92,395 controls were included in this study. Cases underwent more frequent sampling of all blood laboratory analyses compared to controls. This higher sampling frequency was more pronounced for lactate compared to sodium, potassium, or haemoglobin. The last measured lactate was higher in cases (median [IQR]: 2.3 [1.3, 4.9]) compared to controls (median [IQR]: 1.3 [0.9, 2.0]). Differences in sodium, potassium, and haemoglobin were negligible. The proportion of abnormally elevated levels of lactate and potassium increased as time to cardiac arrest decreased; no such effect was seen in controls. No temporal trend was evident for sodium or haemoglobin.

CONCLUSIONS

Patients with IHCA undergo more frequent blood sampling prior to IHCA and have higher levels of lactate compared to matched controls.

Incidence and case ascertainment of treated in-hospital cardiac arrest events in a national quality registry - A comparison of reported and non-reported events

BACKGROUND

Approximately 2500 in-hospital cardiac arrest (IHCA) events are reported annually to the Swedish Registry of Cardiopulmonary Resuscitation (SRCR) with an estimated incidence of 1.7/1000 hospital admissions. The aim of this study was to evaluate the compliance in reporting IHCA events to the SRCR and to compare reported IHCA events with possible non-reported events, and to estimate IHCA incidence.

METHODS

Fifteen diagnose codes, eight Classification of Care Measure codes, and two perioperative complication codes were used to find all treated IHCAs in 2018-2019 at six hospitals of varying sizes and resources. All identified IHCA events were cross-checked against the SRCR using personal identity numbers. All non-reported IHCA events were retrospectively reported and compared with the prospectively reported events.

RESULTS

A total of 3638 hospital medical records were reviewed and 1109 IHCA events in 999 patients were identified, with 254 of the events not found in the SRCR. The case completeness was 77% (range 55-94%). IHCA incidence was 2.9/1000 hospital admissions and 12.4/1000 admissions to intensive care units. The retrospectively reported events were more often found on monitored wards, involved patients who were younger, had less comorbidity, were often found in shockable rhythm and more often achieved sustained spontaneous circulation, compared with in prospectively reported events.

CONCLUSION

IHCA case completeness in the SRCR was 77% and IHCA incidence was 2.9/1000 hospital admissions. The retrospectively reported IHCA events were found in monitored areas where the rapid response team was not alerted, which might have affected regular reporting procedures.

Socioeconomic status and outcomes after in-hospital cardiac arrest

AIM

To investigate the association between socioeconomic status and outcomes after in-hospital cardiac arrest in Denmark.

METHODS

We conducted an observational cohort study based on nationwide registries and prospectively collected data on in-hospital cardiac arrest from 2017 and 2018 in Denmark. Unadjusted and adjusted analyses using regression models were performed to assess the association between socioeconomic status and outcomes after in-hospital cardiac arrest. Outcomes included return of spontaneous circulation (ROSC), survival to 30 days, survival to one year, and the duration of resuscitation among patients without ROSC.

RESULTS

A total of 3,223 patients with in-hospital cardiac arrest were included in the study. In the adjusted analyses, high household assets were associated with 1.20 (95 %CI: 0.96, 1.51) times the odds of ROSC, 1.49 (95 %CI: 1.14, 1.96) times the odds of survival to 30 days, 1.40 (95 %CI: 1.04, 1.90) times the odds of survival to one year, and 2.8 (95 %CI: 0.9, 4.7) minutes longer duration of resuscitation among patients without ROSC compared to low household assets. Similar albeit attenuated associations were observed for education. While high household income was associated with better outcomes in the unadjusted analyses, these associations largely disappeared in the adjusted analyses.

CONCLUSIONS

In this study of patients with in-hospital cardiac arrest, we found that high household assets were associated with a higher odds of survival and a longer duration of resuscitation among patients without ROSC compared to low household assets. However, the effect size may potentially be small. The results varied based on socioeconomic status measure, outcome of interest, and across adjusted analyses.

Sex-Based Differences in 30-Day Readmissions After Cardiac Arrest: Analysis of the Nationwide Readmissions Database

Background There are limited data on the sex-based differences in the outcome of readmission after cardiac arrest. Methods and Results Using the Nationwide Readmissions Database, we analyzed patients hospitalized with cardiac arrest between 2010 and 2015. Based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes, we identified comorbidities, therapeutic interventions, and outcomes. Multivariable logistic regression was performed to assess the independent association between sex and outcomes. Of 835 894 patients, 44.4% (n=371 455) were women, of whom 80.7% presented with pulseless electrical activity (PEA)/asystole. Women primarily presented with PEA/asystole (80.7% versus 72.4%) and had a greater comorbidity burden than men, as assessed using the Elixhauser Comorbidity Score. Thirty-day readmission rates were higher in women than men in both PEA/asystole (20.8% versus 19.6%) and ventricular tachycardia/ventricular fibrillation arrests (19.4% versus 17.1%). Among ventricular tachycardia/ventricular fibrillation arrest survivors, women were more likely than men to be readmitted because of noncardiac causes, predominantly infectious, respiratory, and gastrointestinal illnesses. Among PEA/asystole survivors, women were at higher risk for all-cause (adjusted odds ratio [aOR], 1.07; [95% CI, 1.03-1.11]), cardiac-cause (aOR, 1.15; [95% CI, 1.06-1.25]), and noncardiac-cause (aOR, 1.13; [95% CI, 1.04-1.22]) readmission. During the index hospitalization, women were less likely than men to receive therapeutic procedures, including coronary angiography and targeted therapeutic management. While the crude case fatality rate was higher in women, in both ventricular tachycardia/ventricular fibrillation (51.8% versus 47.4%) and PEA/asystole (69.3% versus 68.5%) arrests, sex was not independently associated with increased crude case fatality after adjusting for differences in baseline characteristics. Conclusions Women are at increased risk of readmission following cardiac arrest, independent of comorbidities and therapeutic interventions.

Duration of Resuscitation and Long-Term Outcome After In-Hospital Cardiac Arrest: A Nationwide Observational Study

BACKGROUND

Prior studies have investigated the association between duration of resuscitation and short-term outcomes following in-hospital cardiac arrest (IHCA). However, it remains unknown whether there is an association between duration of resuscitation and long-term survival and functional outcomes.

METHOD

We linked data from the Danish in-hospital cardiac arrest registry with nationwide registries and identified 8,727 patients between 2013 and 2019. Patients were stratified into four groups (A-D) according to quartiles of duration of resuscitation. Standardized average probability of outcomes was estimated using logistic regression.

RESULTS

Of 8,727 patients, 53.1% (n=4,604) achieved return of spontaneous circulation. Median age was 74 (1^st-3^rd quartile [Q1-Q3] 65-81 years) and 63.1% were men. Among all IHCA patients the standardized 30-day survival was 62.0% (95% CI 59.8%-64.2%) for group A (< 5 minutes), 32.7% (30.8%-34.6%) for group B (5-11 minutes), 14.4% (12.9%-15.9%) for group C (12-20 minutes) and 8.1% (7.0%-9.1%) for group D (21 minutes or more). Similarly, 1-year survival was also highest for group A (50.4%; 48.2%-52.6%) gradually decreasing to 6.6% (5.6%-7.6%) in group D. Among 30-day survivors, survival without anoxic brain damage or nursing home admission within one-year post-arrest was highest for group A (80.4%; 78.2%-82.6%), decreasing to 73.3% (70.0%-76.6%) in group B, 67.2% (61.7%-72.6%) in group C and 73.3% (66.9%-79.7%) in group D.

CONCLUSION

Shorter duration of resuscitation attempt during an IHCA is associated with higher 30-day and 1-year survival. Furthermore, we found that the majority of 30-day survivors were still alive 1-year post-arrest without anoxic brain damage or nursing home admission despite prolonged resuscitation.

Trends in survival after cardiac arrest: a Swedish nationwide study over 30 years

AIMS

Trends in characteristics, management, and survival in out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) were studied in the Swedish Cardiopulmonary Resuscitation Registry (SCRR).

METHODS AND RESULTS

The SCRR was used to study 106 296 cases of OHCA (1990-2020) and 30 032 cases of IHCA (2004-20) in whom resuscitation was attempted. In OHCA, survival increased from 5.7% in 1990 to 10.1% in 2011 and remained unchanged thereafter. Odds ratios [ORs, 95% confidence interval (CI)] for survival in 2017-20 vs. 1990-93 were 2.17 (1.93-2.43) overall, 2.36 (2.07-2.71) for men, and 1.67 (1.34-2.10) for women. Survival increased for all aetiologies, except trauma, suffocation, and drowning. OR for cardiac aetiology in 2017-20 vs. 1990-93 was 0.45 (0.42-0.48). Bystander cardiopulmonary resuscitation increased from 30.9% to 82.2%. Shockable rhythm decreased from 39.5% in 1990 to 17.4% in 2020. Use of targeted temperature management decreased from 42.1% (2010) to 18.2% (2020). In IHCA, OR for survival in 2017-20 vs. 2004-07 was 1.18 (1.06-1.31), showing a non-linear trend with probability of survival increasing by 46.6% during 2011-20. Myocardial ischaemia or infarction as aetiology decreased during 2004-20 from 67.4% to 28.3% [OR 0.30 (0.27-0.34)]. Shockable rhythm decreased from 37.4% to 23.0% [OR 0.57 (0.51-0.64)]. Approximately 90% of survivors (IHCA and OHCA) had no or mild neurological sequelae.

CONCLUSION

Survival increased 2.2-fold in OHCA during 1990-2020 but without any improvement in the final decade, and 1.2-fold in IHCA during 2004-20, with rapid improvement the last decade. Cardiac aetiology and shockable rhythms were halved. Neurological outcome has not improved.

Barriers and facilitators for successful AED usage during in-situ simulated in-hospital cardiac arrest

Introduction

Methods

Results

Conclusion

Distribution and use of automated external defibrillators and their effect on return of spontaneous circulation in Danish hospitals

Introduction

Automated external defibrillators (AEDs) increase survival after out-of-hospital cardiac arrest. However, the effect of AEDs for in-hospital cardiac arrest (IHCA) remains uncertain. This study aims to describe the distribution and use of AEDs in Danish hospitals and investigate whether early rhythm analysis is associated with return of spontaneous circulation (ROSC).

Methods

All Danish public hospitals with a cardiac arrest team were included and sent a questionnaire on the in-hospital distribution of AEDs and manual defibrillators. Further, we collected data on IHCAs including rhythm analysis, device type, cardiac arrest team arrival, and ROSC from the national database on IHCA (DANARREST).

Results

Of 46 hospitals, 93% had AEDs and 93% had manual defibrillators. AEDs were often placed in wards or non-clinical areas, whereas manual defibrillators were often placed in areas with high-risk patients. We identified 3,204 IHCAs. AEDs were used in 13% of IHCAs. After adjustment for confounders, chance of ROSC was higher if the first rhythm analysis was performed before the arrival of the cardiac arrest team (RR: 1.28 (95% CI: 1.12–1.46)). The relative risk of ROSC was 1.09 (0.84–1.41) when analyzing with an AED before cardiac arrest team arrival and 1.19 (1.00–1.41) when using a manual defibrillator. However, there was no significant effect modification for AED vs manual defibrillator (p = 0.26).

Conclusion

AEDs are widely distributed in Danish hospitals but less commonly used for IHCAs compared to manual defibrillators. Rhythm analysis before arrival of the cardiac arrest team was associated with ROSC without significant effect modification of device type.

Hospital-level variation in outcomes after in-hospital cardiac arrest in Denmark

BACKGROUND

We investigated hospital-level variation in outcomes after in-hospital cardiac arrest (IHCA) in Denmark, and assessed whether variation in outcomes could be explained by differences in patient characteristics.

METHODS

Adult patients (≥18 years old) with IHCA in 2017 and 2018 were included from the Danish IHCA Registry (DANARREST). Data on patient characteristics and outcomes were obtained from population-based registries. Predicted probabilities, likelihood ratio tests, intraclass correlation coefficients (ICCs), and median odds ratios (ORs) were calculated for return of spontaneous circulation (ROSC), survival to 30 days, and survival to 1 year.

RESULTS

A total of 3340 patients with IHCA from 24 hospitals were included. We found that hospital-level variation in outcomes after IHCA existed across all measures of variation. The unadjusted median OR for ROSC, survival to 30 days, and survival to 1 year were 1.28 (95% confidence interval [CI]: 1.24, 1.45), 1.38 (95% CI: 1.33, 1.60), and 1.44 (95% CI: 1.39, 1.70), respectively. The unadjusted ICC suggest that 2.0% (95%: 1.6%, 4.4%), 3.3% (95%: 2.7%, 6.8%), and 4.3% (95%: 3.5%, 8.6%) of the total individual variation in ROSC, survival to 30 days, and survival to 1 year was attributable to hospital-level variation. These results decreased but persisted in the analyses adjusted for select patient characteristics.

CONCLUSIONS

In this study, we found that outcomes after IHCA varied across hospitals in Denmark. However, only about 2%-4% of the total individual variation in outcomes after IHCA was attributable to differences between hospitals, suggesting that most of the individual variation in outcomes was attributable to patient-level variation.

Why Do Not Physicians Attend Hospital Cardiopulmonary Resuscitation Training?

Introduction

Cardiopulmonary resuscitation (CPR) training is mandatory in most hospitals. Despite this, some hospital staff do not attend CPR training on a regular basis, but the barriers to training attendance are sparsely investigated. This study aimed to investigate CPR course attendance, barriers to participation, and possible initiatives to increase CPR course attendance.

Methods

Physicians from one university hospital and one regional hospital in the Central Denmark Region were included. Questionnaires were handed out at daily staff meetings at departments of internal medicine and surgery.

Results

In total, 233 physicians responded (response rate: 92%, male: 54%). Overall, 32% of physicians had not attended CPR training at the hospital. Mean (±standard deviation) time since the last CPR course participation was 17 (±3) months. Frequent barriers to attending courses included not knowing when courses are conducted (70%) and where to sign up for training (45%). The majority (60%) of physicians responded that the reason why they prioritize course participation is to be professionally updated. In contrast, 16% stated that they had sufficient CPR skills and therefore CPR training was unnecessary. Physicians stated that the following factors would improve CPR training participation: an annual day protected (no clinical work) for course attendance (72%), use of short booster sessions (49%), shorter courses combined with e-learning (51%) and shorter courses held over 2 days (46%).

Conclusion

One-third of physicians did not attend hospital CPR training at two Danish hospitals. Several barriers to course participation exist, of which course registration seems to be a crucial factor. Alternative CPR training methods may help improve training participation.

Case completeness in the Norwegian Cardiac Arrest Registry

Introduction

This study aimed to assess the case completeness of out-of-hospital cardiac arrests (OHCA) in the Norwegian Cardiac Arrest Registry (NorCAR) and describe the differences between the registered and missing patients identified from the case-control assessment.

Methods

We identified the relevant patients in the Norwegian Patient Registry and the Norwegian Cause of Death Registry and compared them with the patients in NorCAR. Data processors used patient records to confirm if the potential cardiac arrest cases met the inclusion criteria in NorCAR.

Results

Between 2015 and 2017, 8612 OHCA patients were registered in NorCAR. Through the Patient Registry and the Cause of Death Registry we identified 11,114 potential OHCA patients, 3469 of these were already registered in NorCAR. After evaluating the patient records for the remaining 7645 patients, we found 344 patients (4%), were eligible for inclusion in NorCAR, giving a case completeness of 96%. The registered and missing patients were similar in age and gender distribution. Initial shockable rhythm and presumed cause were also comparable. However, the missing patients more frequently achieved return of spontaneous circulation, were more often transported to hospital, and had higher survival rates. The already registered patients had more key variables registered than the missing patients.

Conclusion

Our results indicate high case completeness in NorCAR. The missing patients were too few to introduce significant changes in the distribution of patient characteristics, indicating that NorCAR is representative of the Norwegian OHCA population.

Clinical Characteristics and In-Hospital Mortality of Cardiac Arrest Survivors in Brazil: A Large Retrospective Multicenter Cohort Study

Supplemental Digital Content is available in the text.

Data on cardiac arrest survivors from developing countries are scarce. This study investigated clinical characteristics associated with in-hospital mortality in resuscitated patients following cardiac arrest in Brazil.

Incidence of in-hospital cardiac arrest at general wards before and after implementation of an early warning score

BACKGROUND

In order to reduce the incidence of in-hospital cardiac arrest (IHCA) at general wards, medical emergency teams (MET) were implemented in the Capital Region of Denmark in 2012 as the efferent part of a track and trigger system. The National Early Warning Score (NEWS) system became the afferent part. This study aims at investigating the incidence of IHCA at general wards before and after the implementation of the NEWS system.

MATERIAL AND METHODS

We included patients at least 18 years old with IHCA at general wards in our hospital in the periods of 2006 to 2011 (pre-EWS group) and 2013 to 2018 (post-EWS group). Data was obtained from a local database and the National In-Hospital Cardiac Arrest Registry (DANARREST). We calculated incidence rate ratios (IRR) for IHCA at general wards with 95% confidence interval (95% CI). Odds ratios (OR) for return of spontaneous circulation (ROSC) and 30-day survival were also calculated with 95% CI.

RESULTS

A total of 444 IHCA occurred before the implementation of NEWS at general wards while 494 IHCA happened afterwards. The incidence rate of IHCA at general wards was 1.13 IHCA per 1000 admissions in the pre-EWS group (2006-2011) and 1.11 IHCA per 1000 admissions in the post-EWS group (2013-2018). The IRR between the two groups was 0.98 (95% CI [0.86;1.11], p = 0.71). The implementation did not affect the chance of ROSC with a crude OR of 1.14 (95% CI [0.88;1.47], p = 0.32) nor did it change the 30-day survival with a crude OR 1.30 (95% CI [0.96;1.75], p = 0.09).

CONCLUSION

Implementation of the EWS system at our hospital did not decrease the incidence rate of in-hospital cardiac arrest at general wards.

Age and sex differences in outcomes after in-hospital cardiac arrest

INTRODUCTION

While specific factors have been associated with outcomes after in-hospital cardiac arrest, the association between sex and outcomes remains debated. Moreover, age-specific sex differences in outcomes have not been fully characterized in this population.

METHODS

Adult patients (≥18 years) with an index in-hospital cardiac arrest were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST) from January 1st, 2017 to December 31st, 2018. Population-based registries were used to obtain data on patient characteristics, cardiac arrest characteristics, and outcomes. Unadjusted and adjusted estimates for return of spontaneous circulation (ROSC), survival to 30 days, survival to one year, duration of resuscitation, and post-cardiac arrest time-to-death were computed.

RESULTS

A total of 3266 patients were included, of which 2041 (62%) patients were male with a median age of 73 years (quartiles: 64, 80). Among 1225 (38%) female patients, the median age was 76 years (quartiles: 67, 83). Younger age was associated with higher odds of ROSC and survival. Sex was not associated with ROSC and survival in the unadjusted analyses. In the adjusted analyses, women had 1.32 (95%CI: 1.12, 1.54) times the odds of survival to 30 days and 1.26 (95%CI: 1.02, 1.57) times the odds of survival to one year compared to men. The overall association between sex and survival did not vary substantially across age categories, although female sex was associated with a higher survival within certain age categories. Among patients who did not achieve ROSC, female sex was associated with a shorter duration of resuscitation, which was more pronounced in younger age categories.

CONCLUSIONS

In this study of patients with in-hospital cardiac arrest, female sex was associated with a shorter duration of resuscitation among patients without ROSC but a higher survival to 30 days and one year. While the overall association between sex and outcomes did not vary substantially across age categories, female sex was associated with a higher survival within certain age categories.

Pulseless electrical activity vs. asystole in adult in-hospital cardiac arrest: Predictors and outcomes

AIM

This observational cohort study aimed to identify factors associated with pulseless electrical activity (PEA) and asystole in in-hospital cardiac arrest (IHCA) patients and to determine whether differences in outcome based on the initial rhythm were explained by patient- and cardiac arrest characteristics.

METHODS

Adults with IHCA from 2017 to 2018 were included from the Danish IHCA Registry (DANARREST). Additional data came from population-based registries. Unadjusted (RRs) and adjusted risk ratios (aRRs) were estimated for predictors of initial rhythm, return of spontaneous circulation (ROSC), and survival.

RESULTS

We included 1495 PEA and 1285 asystole patients. The patients did not differ substantially in patient characteristics. Female sex, age>90 years, pulmonary disease, and obesity were associated with initial asystole. Ischemic heart disease and witnessed and monitored cardiac arrest were associated with initial PEA. In unadjusted and adjusted analyses, PEA was associated with increased ROSC (aRR = 1.21, 95% confidence interval [CI] 1.10; 1.33). PEA was also associated with increased 30-day and 1-year survival in the unadjusted analysis, while there was no clear association between the initial rhythm and 30-day (aRR = 0.88, 95% CI 0.71; 1.11) and 1-year (aRR = 0.85, 95% CI 0.69; 1.04) survival when patient- and cardiac arrest characteristics were adjusted for.

CONCLUSION

In patients with IHCA presenting with PEA or asystole, there were no major differences in patient demographics and comorbidities. The patients differed substantially in cardiac arrest characteristics. Initial PEA was associated with higher risk of ROSC, but there was no difference in 30-day and 1-year survival.

Factors associated with shockable versus non-shockable rhythms in patients with in-hospital cardiac arrest

AIM

To identify factors associated with the initial rhythm in patients with in-hospital cardiac arrest and to assess whether potential differences in outcomes based on the initial rhythm can be explained by patient and event characteristics.

METHODS

Adult patients (≥18 years old) with in-hospital cardiac arrest in 2017 and 2018 were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST). We used population-based registries to obtain data on comorbidities, cardiac procedures, and medications. Unadjusted and adjusted risk ratios (RRs) for initial rhythm, return of spontaneous circulation (ROSC), and survival were estimated in separate models including an incremental number of prespecified variables.

RESULTS

A total of 3422 patients with in-hospital cardiac arrest were included, of which 639 (19%) had an initial shockable rhythm. Monitored cardiac arrest, witnessed cardiac arrest, and specific cardiac diseases (i.e. ischemic heart disease, dysrhythmias, and valvular heart disease) were associated with initial shockable rhythm. Conversely, higher age, female sex, and specific non-cardiovascular comorbidities (e.g. overweight and obesity, renal disease, and pulmonary cancer) were associated with an initial non-shockable rhythm. Initial shockable rhythm remained strongly associated with increased ROSC (RR = 1.63, 95%CI 1.51-1.76), 30-day survival (RR = 2.31, 95%CI 2.02-2.64), and 1-year survival (RR = 2.36, 95%CI 2.02-2.76) compared to initial non-shockable rhythm in the adjusted analyses.

CONCLUSION

In this study, specific patient and cardiac arrest characteristics were associated with initial rhythm in patients with in-hospital cardiac arrest. However, differences in patient and cardiac arrest characteristics did not fully explain the association with survival for initial shockable rhythm compared to a non-shockable rhythm.

In-Hospital vs. Out-of-Hospital Cardiac Arrest: Patient Characteristics and Survival

BACKGROUND

Cardiac arrests are often categorized into two separate groups depending on the location of the arrest: in-hospital cardiac arrest (IHCA) and out-of-hospital cardiac arrest (OHCA). Despite this distinction, few studies have compared the two groups directly. The aim of this study was to compare patient characteristics, cardiac arrest characteristics, and outcomes for IHCA and OHCA patients.

METHODS

Data on IHCA and OHCA in Denmark were obtained from two nationwide, prospective registries. All adult (≥18 years old) patients with index IHCA or OHCA from January 1, 2017 to December 31, 2018 were included. Supplementary information on outcomes, hospitalizations, and chronic diseases came from additional national registries. The primary outcome was 30-day survival and secondary outcomes were return of spontaneous circulation (ROSC) and 1-year survival.

RESULTS

The study included 3501 patients with IHCA and 8846 patients with OHCA. The two groups were similar in demographics, most comorbidities, and initial cardiac arrest rhythm. In the unadjusted analysis, IHCA was associated with increased survival to 30 days compared to OHCA (risk ratio [RR] = 1.41; 95% CI, 1.30; 1.54) and 1 year (RR = 1.46; 95% CI, 1.33; 1.61). Adjusting for age, sex, and comorbidities did not change the RR substantially. When cardiac arrest characteristics were added to the model, the RR decreased from 1.51 (95% CI, 1.39; 1.65) to 1.06 (95% CI, 0.93; 1.20) for survival to 30 days and from 1.66 (95% CI, 1.50; 1.84) to 1.09 (95% CI, 0.94; 1.26) for survival to 1 year. In all subgroup analyses based on cardiac arrest characteristics (e.g. witnessed status), the association between location and outcome was substantially mitigated compared to the primary analyses.

CONCLUSIONS

In this large, national study, we found that IHCA and OHCA patients were remarkably similar in demographics and most comorbidities. IHCA patients had better outcomes compared to OHCA patients, although these differences disappeared when comparing patients with similar cardiac arrest characteristics.

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.

Adult in-hospital cardiac arrest in Denmark

AIM

The aim of this study was to describe patient characteristics, event characteristics, and outcomes for patients with in-hospital cardiac arrest in Denmark.

METHODS

Data was obtained from DANARREST. DANARREST is a nationwide registry that covers all in-hospital cardiac arrests in Denmark with a clinical indication for cardiopulmonary resuscitation (i.e. without a prior "do-not-resuscitate" order).

RESULTS

A total of 4069 adult in-hospital cardiac arrests were registered between January 1st, 2017 and December 31st, 2018. The median age was 74 years (quartiles: 65, 81) and 37% were female. 71% had a non-shockable rhythm and the presumed etiology was primarily non-cardiac (57%). A total of 2180 patients (53.8%) achieved ROSC, with an additional 36 patients (0.9%) receiving extracorporeal cardiopulmonary resuscitation. At 30-days 1124 patients (27.8%) were alive. Of cardiac arrests from 2017, 404 patients (20.0%) survived to 1 year after the cardiac arrest. The incidence of adult in-hospital cardiac arrest in Denmark was estimated at 1.8 per 1000 admissions or 0.6 per 1000 in-patient days.

CONCLUSION

In-hospital cardiac arrest occurs in at least 2000 patients each year in Denmark with a 30-day survival of approximately 28%. The establishment of a national registry for in-hospital cardiac arrest in Denmark will allow for quality improvement and research projects.