Rikke Nørmark Mortensen

Return to Work in Out-of-Hospital Cardiac Arrest Survivors: A Nationwide Register-Based Follow-Up Study

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.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. # CLINICAL PERSPECTIVE {#article-title-36}

Bystander Efforts and 1-Year Outcomes in Out-of-Hospital Cardiac Arrest

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.)

Short-term mortality risk of serum potassium levels in hypertension: a retrospective analysis of nationwide registry data

Aims Diuretics and renin–angiotensin–aldosterone system inhibitors are central in the treatment of hypertension, but may cause serum potassium abnormalities. We examined mortality in relation to serum potassium in hypertensive patients. Methods and results From Danish National Registries, we identified 44 799 hypertensive patients, aged 30 years or older, who had a serum potassium measurement within 90 days from diagnosis between 1995 and 2012. All-cause mortality was analysed according to seven predefined potassium levels: <3.5 (hypokalaemia), 3.5–3.7, 3.8–4.0, 4.1–4.4, 4.5–4.7, 4.8–5.0, and >5.0 mmol/L (hyperkalaemia). Outcome was 90-day mortality, estimated with multivariable Cox proportional hazard model, with the potassium interval of 4.1–4.4 mmol/L as reference. During 90-day follow-up, mortalities in the seven strata were 4.5, 2.7, 1.8, 1.5, 1.7, 2.7, and 3.6%, respectively. Adjusted risk for death was statistically significant for patients with hypokalaemia [hazard ratio (HR): 2.80, 95% confidence interval (95% CI): 2.17–3.62], and hyperkalaemia (HR: 1.70, 95% CI: 1.36–2.13). Notably, normal potassium levels were also associated with increased mortality: K: 3.5–3.7 mmol/L (HR: 1.70, 95% CI: 1.36–2.13), K: 3.8–4.0 mmol/L (HR: 1.21, 95% CI: 1.00–1.47), and K: 4.8–5.0 mmol/L (HR: 1.48, 95% CI: 1.15–1.92). Thus, mortality in relation to the seven potassium ranges was U-shaped, with the lowest mortality in the interval of 4.1–4.4 mmol/L. Conclusion Potassium levels outside the interval of 4.1–4.7 mmol/L were associated with increased mortality risk in patients with hypertension.

Survival After Out-of-Hospital Cardiac Arrest in Relation to Age and Early Identification of Patients With Minimal Chance of Long-Term Survival

Background— Survival after out-of-hospital cardiac arrest has increased during the last decade in Denmark. We aimed to study the impact of age on changes in survival and whether it was possible to identify patients with minimal chance of 30-day survival. Methods and Results— Using data from the nationwide Danish Cardiac Arrest Registry (2001─2011), we identified 21 480 patients ≥18 years old with a presumed cardiac-caused out-of-hospital cardiac arrest for which resuscitation was attempted. Patients were divided into 3 preselected age-groups: working-age patients 18 to 65 years of age (33.7%), early senior patients 66 to 80 years of age (41.5%), and late senior patients >80 years of age (24.8%). Characteristics in working-age patients, early senior patients, and late senior patients were as follows: witnessed arrest in 53.8%, 51.1%, and 52.1%; bystander cardiopulmonary resuscitation in 44.7%, 30.3%, and 23.4%; and prehospital shock from a defibrillator in 54.7%, 45.0%, and 33.8% (all P<0.05). Between 2001 and 2011, return of spontaneous circulation on hospital arrival increased: working-age patients, from 12.1% to 34.6%; early senior patients, from 6.4% to 21.5%; and late senior patients, from 4.0% to 15.0% (all P<0.001). Furthermore, 30-day survival increased: working-age patients, 5.8% to 22.0% (P<0.001); and early senior patients, 2.7% to 8.4% (P<0.001), whereas late senior patients experienced only a minor increase (1.5% to 2.0%; P=0.01). Overall, 3 of 9499 patients achieved 30-day survival if they met 2 criteria: had not achieved return of spontaneous circulation on hospital arrival and had not received a prehospital shock from a defibrillator. Conclusions— All age groups experienced a large temporal increase in survival on hospital arrival, but the increase in 30-day survival was most prominent in the young. With the use of only 2 criteria, it was possible to identify patients with a minimal chance of 30-day survival.

Short-term mortality risk of serum potassium levels in acute heart failure following myocardial infarction

Aims Diuretic treatment is often needed in acute heart failure following myocardial infarction (MI) and carries a risk of abnormal potassium levels. We examined the relation between different levels of potassium and mortality. Methods and results From Danish national registries we identified 2596 patients treated with loop diuretics after their first MI episode where potassium measurement was available within 3 months. All-cause mortality was examined according to seven predefined potassium levels: hypokalaemia <3.5 mmol/L, low normal potassium 3.5–3.8 mmol/L, normal potassium 3.9–4.2 mmol/L, normal potassium 4.3–4.5 mmol/L, high normal potassium 4.6–5.0 mmol/L, mild hyperkalaemia 5.1–5.5 mmol/L, and severe hyperkalaemia: >5.5 mmol/L. Follow-up was 90 days and using normal potassium 3.9–4.2 mmol/L as a reference, we estimated the risk of death with a multivariable-adjusted Cox proportional hazard model. After 90 days, the mortality rates in the seven potassium intervals were 15.7, 13.6, 7.3, 8.1, 10.6, 15.5, and 38.3%, respectively. Multivariable-adjusted risk for death was statistically significant for patients with hypokalaemia [hazard ratio (HR): 1.91, confidence interval (95%CI): 1.14–3.19], and mild and severe hyperkalaemia (HR: 2, CI: 1.25–3.18 and HR: 5.6, CI: 3.38–9.29, respectively). Low and high normal potassium were also associated with increased mortality (HR: 1.84, CI: 1.23–2.76 and HR: 1.55, CI: 1.09–2.22, respectively). Conclusion Potassium levels outside the interval 3.9–4.5 mmol/L were associated with a substantial risk of death in patients requiring diuretic treatment after an MI.

Age-dependent trends in postoperative mortality and preoperative comorbidity in isolated coronary artery bypass surgery: a nationwide study.

OBJECTIVES An increasing number of octogenarians are being subjected to coronary artery bypass grafting (CABG). The purpose of this study was to examine age-dependent trends in postoperative mortality and preoperative comorbidity over time following CABG. METHODS All patients who underwent isolated CABG surgery between January 1996 and December 2012 in Denmark were included. Patients were identified through nationwide administrative registers. Age was categorized into five different groups and time into three periods to see if mortality and preoperative comorbidity had changed over time. Predictors of 30-day mortality were analysed in a multivariable Cox proportional-hazard models and survival at 1 and 5 years was estimated by Kaplan-Meier curves. RESULTS A total of 38 830 patients were included; the median age was 65.4 ± 9.5 years, increasing over time to 66.6 ± 9.5 years. Males comprised 80%. The number of octogenarians was 1488 (4%). The median survival was 14.7 years (60-69 years), 10.7 years (70-74 years), 8.9 years (75-79 years) and 7.2 years (≥80 years). The 30-day mortality rate was 3%, increasing with age (1% in patients <60 years, 8% in octogenarians). The long-term mortality rate at 1 and 5 years was 2 and 7% (age <60 years) and 14 and 36% (age >80 years), respectively. The proportion of patients >75 years increased from 10 to 20% during the study period as well as the proportion of patients undergoing urgent or emergency surgery. The burden of comorbidities increased over time, e.g. congestive heart failure 13-17%, diabetes 12-21%, stroke 9-11%, in all age groups. Age and emergency surgery were the main predictors of 30-day mortality: age >80 years [hazard ratio (HR): 5.75, 95% confidence interval (CI): 4.41-7.50], emergency surgery (HR: 5.23, 95% CI: 4.38-6.25). CONCLUSION Patients are getting older at the time of surgery and have a heavier burden of comorbidities than before. The proportion of patients undergoing urgent or emergency surgery increased with age and over time. Despite this, the 30-day mortality decreased over time and long-term survival increased, except in octogenarians where it was stable. Octogenarians had substantially higher 30-day mortality compared with younger patients but surgery can be performed with acceptable risks and good long-term outcomes.

Associations between follow-up screening after gestational diabetes and early detection of diabetes – a register based study

BackgroundWomen whose pregnancy was complicated by gestational diabetes have a 7-fold higher risk of developing diabetes, primarily type 2. Early detection can prevent or delay the onset of late complications, for which follow-up screening is important. This study investigated the extent of participation in follow-up screening and the possible consequences of nonattendance in the Region of North Jutland, Denmark.MethodIn Danish national registers covering the years 1994–2011 we identified 2171 birthing women whose pregnancy was complicated by first-time gestational diabetes. Control visits to general practitioners and biochemical departments after giving birth were charted. Following national guidelines we defined four intervals for assessment of participation in follow-up screening. Diagnosis of diabetes or treatment with glucose-lowering agents after giving birth were also identified. Participation in follow-up screening and risk of diabetes was calculated. Time to obtaining diagnosis of diabetes or initiating treatment was analysed by Cox regression models. All models were adjusted for age, ethnicity and income.ResultsHigh attendance was found during the first control interval, after which attendance decreased with time after giving birth for both controls at general practitioners and biochemical departments. All differences in proportions were statistically significant. Women attending controls at general practitioners had a significantly higher risk of diabetes diagnosis and treatment after gestational diabetes than women not attending. The results for women attending testing at biochemical departments also showed an increased risk of initiation of treatment. Women attending at least one general practitioners control had a significantly higher risk of early diabetes diagnosis or treatment. Time to initiation of treatment was significantly higher for testing at biochemical departments. Women with high incomes had a significantly lower risk of diabetes diagnosis or initiation of treatment compared to low-income women.ConclusionParticipation in follow-up screening after gestational diabetes is low in the North Denmark Region. Follow-up screening ensures early detection of diabetes and initiation of treatment. Our results emphasize the importance of development of interventions to improve early detection and prevention of diabetes after gestational diabetes.

Individual social capital and survival: a population study with 5-year follow-up.

BackgroundThe concept of social capital has received increasing attention as a determinant of population survival, but its significance is uncertain. We examined the importance of social capital on survival in a population study while focusing on gender differences.MethodsWe used data from a Danish regional health survey with a five-year follow-up period, 2007–2012 (n = 9288, 53.5% men, 46.5% women). We investigated the association between social capital and all-cause mortality, performing separate analyses on a composite measure as well as four specific dimensions of social capital while controlling for covariates. Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated.ResultsFor women, higher levels of social capital were associated with lower all-cause mortality regardless of age, socioeconomic status, health, and health behaviour (HR = 0.586, 95% CI = 0.421-0.816) while no such association was found for men (HR = 0.949, 95% CI = 0.816-1.104). Analysing the specific dimensions of social capital, higher levels of trust and social network were significantly associated with lower all-cause mortality in women (HR = 0.827, 95% CI = 0.750-0.913 and HR = 0.832, 95% CI = 0.729-0.949, respectively). For men, strong social networks were associated with a higher risk of all-cause mortality (HR = 1.132, 95% CI = 1.017-1.260). Civic engagement had a similar effect for both men (HR = 0.848, 95% CI = 0.722-0.997) and women (HR = 0.848, 95% CI = 0.630-1.140).ConclusionsWe found differential effects of social capital in men compared to women. The predictive effects on all-cause mortality of four specific dimensions of social capital varied. Gender stratified analysis and the use of multiple indicators to measure social capital are thus warranted in future research.

Socioeconomic inequality and mortality - a regional Danish cohort study

BackgroundSocioeconomic inequalities in mortality pose a serious impediment to enhance public health even in highly developed welfare states. This study aimed to improve the understanding of socioeconomic disparities in all-cause mortality by using a comprehensive approach including a range of behavioural, psychological, material and social determinants in the analysis.MethodsData from The North Denmark Region Health Survey 2007 among residents in Northern Jutland, Denmark, were linked with data from nationwide administrative registries to obtain information on death in a 5.8-year follow-up period (1stFebruary 2007- 31stDecember 2012). Socioeconomic position was assessed using educational status as a proxy. The study population was assigned to one of five groups according to highest achieved educational level. The sample size was 8,837 after participants with missing values or aged below 30 years were excluded. Cox regression models were used to assess the risk of death from all causes according to educational level, with a step-wise inclusion of explanatory covariates.ResultsParticipants’ mean age at baseline was 54.1 years (SD 12.6); 3,999 were men (45.3%). In the follow-up period, 395 died (4.5%). With adjustment for age and gender, the risk of all-cause mortality was significantly higher in the two least-educated levels (HR = 1.5, 95%, CI = 1.2-1.8 and HR = 3.7, 95% CI = 2.4-5.9, respectively) compared to the middle educational level. After adjustment for the effect of subjective and objective health, similar results were obtained (HR = 1.4, 95% CI = 1.1-1.7 and HR = 3.5, 95% CI = 2.0-6.3, respectively). Further adjustment for the effect of behavioural, psychological, material and social determinants also failed to eliminate inequalities found among groups, the risk remaining significantly higher for the least educated levels (HR = 1.4, 95% CI = 1.1-1.9 and HR = 4.0, 95% CI = 2.3-6.8, respectively). In comparison with the middle level, the two highest educated levels remained statistically insignificant throughout the entire analysis.ConclusionSocioeconomic inequality influenced mortality substantially even when adjusted for a range of determinants that might explain the association. Further studies are needed to understand this important relationship.

Office blood pressure or ambulatory blood pressure for the prediction of cardiovascular events.

Aims To determine the added value of (i) 24-h ambulatory blood pressure relative to office blood pressure and (ii) night-time ambulatory blood pressure relative to daytime ambulatory blood pressure for 10-year person-specific absolute risks of fatal and non-fatal cardiovascular events. Methods and results A total of 7927 participants were included from the International Database on Ambulatory blood pressure monitoring in relation to Cardiovascular Outcomes. We used cause-specific Cox regression to predict 10-year person-specific absolute risks of fatal and non-fatal cardiovascular events. Discrimination of 10-year outcomes was assessed by time-dependent area under the receiver operating characteristic curve (AUC). No differences in predicted risks were observed when comparing office blood pressure and ambulatory blood pressure. The median difference in 10-year risks (1st; 3rd quartile) was −0.01% (−0.3%; 0.1%) for cardiovascular mortality and −0.1% (−1.1%; 0.5%) for cardiovascular events. The difference in AUC (95% confidence interval) was 0.65% (0.22–1.08%) for cardiovascular mortality and 1.33% (0.83–1.84%) for cardiovascular events. Comparing daytime and night-time blood pressure, the median difference in 10-year risks was 0.002% (−0.1%; 0.1%) for cardiovascular mortality and −0.01% (−0.5%; 0.2%) for cardiovascular events. The difference in AUC was 0.10% (−0.08 to 0.29%) for cardiovascular mortality and 0.15% (−0.06 to 0.35%) for cardiovascular events. Conclusion Ten-year predictions obtained from ambulatory blood pressure are similar to predictions from office blood pressure. Night-time blood pressure does not improve 10-year predictions obtained from daytime measurements. For an otherwise healthy population sufficient prognostic accuracy of cardiovascular risks can be achieved with office blood pressure.