The positive predictive value of spontaneous subarachnoid hemorrhage diagnoses in the Danish National Patient Register

Subarachnoid haemorrhage and intracranial aneurysms in Greenland in the period 2018-2021: incidence, outcome and familial disposition

Subarachnoid haemorrhages (SAH) caused by rupture of intracranial aneurysms (IA) are a severe condition. Earlier studies found a higher incidence of SAH in Greenlandic patients compared to Danish patients, with familial aggregation also higher in Greenland. However, updated data is lacking. To investigate the contemporary incidence, outcome, and familial disposition of SAH/IA in Greenlandic patients in 2018-2021. Greenlandic patients diagnosed with ruptured or unruptured IA (UIA) during 2018-2021 were included. Data was obtained from patient files, x-ray department, and discharge registry. Incidence rates were estimated as cases/100,000/year. Direct age-standardised incidence rates were calculated using WHO 2000-2025 as standards. Of 30 SAH patients, 20 (66.7%) were females, 10 (33.3%) males. Of 36 UIA patients, 27 (75.0%) were females, 9 (25.0%) males. For SAH, crude incidence was 13.4/100,000/year, age-standardised incidence was 10.8/100,000/year. Familial history was observed in 30.0% of SAH patients. 5 patients (16.7%) died before treatment, 28-day case-fatality rate (CFR) for all patients was 23.3%. Overall and age-standardised incidence rates were similar to previous studies but higher among females and compared to neighbouring countries. A high occurrence of familial history was reported. SAH remains a serious condition in Greenland, as evidenced by five fatalities before treatment was administered.

Positive Predictive Value of Non-Traumatic Bleeding Diagnoses in the Danish National Patient Register

Purpose

The majority of bleeding diagnoses in the Danish National Patient Registry have not been validated despite extensive use in epidemiological research. Therefore, we examined the positive predictive value (PPV) of non-traumatic bleeding diagnoses in the Danish National Patient Registry.

Study Design

Population-based validation study.

Patients and Methods

Based on a manual review of electronic medical records, we estimated the PPV of diagnostic coding (International Classification of Diseases, Tenth Revision (ICD-10)) for non-traumatic bleeding for all patients ≥65 years of age with any hospital contact in the North Denmark Region during March-December 2019 as registered in the Danish National Patient Registry. We calculated PPVs and associated 95% confidence intervals (CI) for non-traumatic bleeding diagnoses overall and stratified according to primary or secondary diagnosis, and according to major anatomical sites.

Results

A total of 907 electronic medical records were available for review. The population mean age was 79.33 years (standard deviation (SD)=7.73) and 57.6% were males. Primary bleeding diagnoses accounted for 766 of the records and 141 were secondary bleeding diagnoses. The overall PPV for bleeding diagnoses was 94.0% (95% CI: 92.3-95.4). The PPV was 98.7% (95% CI: 97.6-99.3) for the primary diagnoses and 68.8% (95% CI: 60.7-75.9) for the secondary diagnoses. When stratified according to subgroups of major anatomical sites, the PPVs ranged between 94.1% and 100% for the primary diagnoses, and between 53.8% and 100% for secondary diagnoses.

Conclusion

The overall validity of non-traumatic bleeding diagnoses in the Danish National Patient Registry is high and considered acceptable for epidemiological research. However, PPVs were substantially higher for primary than for secondary diagnosis.

Frequency of Neurological Diseases After COVID-19, Influenza A/B and Bacterial Pneumonia

Introduction

COVID-19 might affect the incidence of specific neurological diseases, but it is unknown if this differs from the risk following other infections. Here, we characterized the frequency of neurodegenerative, cerebrovascular, and immune-mediated neurological diseases after COVID-19 compared to individuals without COVID-19 and those with other respiratory tract infections.

Methods

This population-based cohort study utilized electronic health records covering ~50% of Denmark's population (n = 2,972,192). Between 02/2020 and 11/2021, we included individuals tested for COVID-19 or diagnosed with community-acquired bacterial pneumonia in hospital-based facilities. Additionally, we included individuals tested for influenza in the corresponding pre-pandemic period between 02/ 2018 and 11/2019. We stratified cohorts for in- and outpatient status, age, sex, and comorbidities.

Results

In total, 919,731 individuals were tested for COVID-19, of whom 43,375 tested positive (35,362 outpatients, 8,013 inpatients). Compared to COVID-negative outpatients, COVID-19 positive outpatients had an increased RR of Alzheimer's disease (RR = 3.5; 95%CI: 2.2–5.5) and Parkinson's disease (RR = 2.6; 95%CI: 1.7–4.0), ischemic stroke (RR = 2.7; 95%CI: 2.3–3.2) and intracerebral hemorrhage (RR = 4.8; 95%CI: 1.8–12.9). However, when comparing to other respiratory tract infections, only the RR for ischemic stroke was increased among inpatients with COVID-19 when comparing to inpatients with influenza (RR = 1.7; 95%CI: 1.2–2.4) and only for those >80 years of age when comparing to inpatients with bacterial pneumonia (RR = 2.7; 95%CI: 1.2–6.2). Frequencies of multiple sclerosis, myasthenia gravis, Guillain-Barré syndrome and narcolepsy did not differ after COVID-19, influenza and bacterial pneumonia.

Conclusion

The risk of neurodegenerative and cerebrovascular, but not neuroimmune, disorders was increased among COVID-19 positive outpatients compared to COVID-negative outpatients. However, except for ischemic stroke, most neurological disorders were not more frequent after COVID-19 than after other respiratory infections.

Risk of subarachnoid haemorrhages and aneurysms in Danish People Living With HIV, a nationwide cohort study

OBJECTIVE

It remains unclear whether people with HIV (PWH) have increased risk of aneurysms. We aimed to investigate if the risk of subarachnoid haemorrhage, cerebral aneurysm, aortic aneurysm and other arterial aneurysms and dissections is increased in PWH compared with the general population.

DESIGN

We performed a nationwide population-based matched cohort study.

METHODS

We compared PWH with age-matched and sex-matched comparison cohort members to calculate incidence rate ratios (IRR) of subarachnoid haemorrhage, cerebral aneurysm, aortic aneurysm and other arterial aneurysms and dissections as well as surgery for these conditions.

RESULTS

We included all PWH, who were Danish residents and treated at a HIV healthcare centre between January 1995 and February 2018 (n = 6935) and an age-matched and sex-matched comparison cohort (n = 55 480). PWH had increased risk of subarachnoid haemorrhage (IRR 1.7, 95% CI, 1.1-2.6), but no increased risk of surgery for this condition. PWH had no increased risk of cerebral aneurysm or aortic aneurysm or surgery for these conditions. The risk of other arterial aneurysms and dissections was increased in PWH (IRR 2.0, 95% CI, 1.4-2.9), but this only applied for PWH who reported intravenous substance use as route of HIV transmission (IRR 18.4, 95% CI, 9.3-36.6), and not for PWH without reported injection drug use (IRR 1.2, 95% CI, 0.73-1.7).

CONCLUSION

PWH were not at an increased risk of cerebral, aortic or other arterial aneurysms and dissections. Although PWH were at an increased risk of subarachnoid haemorrhage, subarachnoid haemorrhages were rare among PWH.

Stroke and Risk of Mental Disorders Compared With Matched General Population and Myocardial Infarction Comparators

BACKGROUND

Accurate estimates of risks of poststroke outcomes from large population-based studies can provide a basis for public health policy decisions. We examined the absolute and relative risks of a spectrum of incident mental disorders following ischemic stroke and intracerebral hemorrhage.

METHODS

During 2004 to 2018, we used Danish registries to identify patients (≥18 years and with no hospital history of mental disorders), with a first-time ischemic stroke (n=76767) or intracerebral hemorrhage (n=9344), as well as age-,sex-, and calendar year-matched general population (n=464 840) and myocardial infarction (n=92 968) comparators. We computed risk differences, considering death a competing event, and hazard ratios adjusted for income, occupation, education, and history of cardiovascular and noncardiovascular comorbidity.

RESULTS

Compared with the general population, following ischemic stroke, the 1-year risk difference was 7.3% (95% CI, 7.0-7.5) for mood disorders (driven by depression), 1.4% (95% CI, 1.3-1.5) for organic brain disorders (driven by dementia and delirium), 0.8% (95% CI, 0.7-0.8) for substance abuse disorders (driven by alcohol and tobacco abuse), and 0.5% (95% CI, 0.4-0.5) for neurotic disorders (driven by anxiety and stress disorders). For suicide, risk differences were near null. Hazard ratios were particularly elevated in the first year of follow-up, ranging from a 2- to a 4-fold increased hazard, decreasing thereafter. Compared with myocardial infarction patients, the 1-year risk difference was 4.9% (95% CI, 4.6 to 5.3) for mood disorders, 1.0% (95% CI, 0.8 to 1.1) for organic brain disorders, 0.1% (95% CI, 0.0 to 0.2) for substance abuse disorders, but -0.2% (95% CI, -0.2 to -0.1) for neurotic disorders. Hazard ratios during the first year of follow-up were elevated 1.1- to 1.8-fold for mood, organic brain, and neurotic disorders, while decreased 0.8-fold for neurotic disorders.

CONCLUSIONS

The considerably greater risks of mental disorders following a stroke, particularly mood disorders, underline the importance of mental health evaluation after stroke.

Intracranial Hemorrhage Following Anticoagulant Treatment in Denmark: Spontaneous Adverse Drug Reaction Reports Versus Real-World Data

INTRODUCTION

In Denmark, physicians are legally obliged to report serious adverse drug reactions (ADRs), such as intracranial hemorrhage (ICH) following anticoagulant (AC) treatment, to the Danish Medicines Agency. We were therefore puzzled to discover a high number of reports concerning ICHs following treatment with the direct oral anticoagulants (DOACs) dabigatran, rivaroxaban, and apixaban compared with warfarin. This was surprising, as all DOACs have been found to be associated with a lower risk of ICH compared with warfarin in phase III randomized controlled trials.

OBJECTIVES

The primary aim of the study was to estimate the level of underreporting of ICH as an ADR following treatment with warfarin, dabigatran, rivaroxaban, and apixaban.

METHODS

This observational study covered a 5-year period (2014-2018). Using nationwide registries held by the Danish Health Data Authority, the number of users, exposure time in person-years, and related ICH events for each of the study drugs were estimated. Data on ADR-ICH reports were extracted from the interactive ADR overviews held by the Danish Medicines Agency.

RESULTS

From 2014 to 2018, 97.0% of the identified warfarin-related ICH events were not reported as ADRs. For the DOACs, the level of underreporting ranged from 88.8 to 90.8%.

CONCLUSION

We found a heavy and differentiated level of underreporting of ICH as an ADR following treatment with the four study drugs.

Risks of Stroke Recurrence and Mortality After First and Recurrent Strokes in Denmark: A Nationwide Registry Study

BACKGROUND AND OBJECTIVES

To examine risks of stroke recurrence and mortality after first and recurrent stroke.

METHODS

Using Danish nationwide health registries, we included patients age ≥18 years with first-time ischemic stroke (n = 105,397) or intracerebral hemorrhage (ICH) (n = 13,350) from 2004 to 2018. Accounting for the competing risk of death, absolute risks of stroke recurrence were computed separately for each stroke subtype and within strata of age groups, sex, stroke severity, body mass index, smoking, alcohol use, Essen stroke risk score, and atrial fibrillation. Mortality risks were computed after first and recurrent stroke.

RESULTS

After adjusting for competing risks, the overall 1-year and 10-year risks of recurrence were 4% and 13% following first-time ischemic stroke and 3% and 12% following first-time ICH. For ischemic stroke, the risk of recurrence increased with age and was higher for men and following mild vs more severe stroke. The most marked differences were across Essen risk scores, for which recurrence risks increased with increasing scores. For ICH, risks were similar for both sexes and did not increase with Essen risk score. For ischemic stroke, the 1-year and 10-year risks of all-cause mortality were 17% and 56% after a first-time stroke and 25% and 70% after a recurrent stroke; corresponding estimates for ICH were 37% and 70% after a first-time event and 31% and 75% after a recurrent event.

DISCUSSION

The risk of stroke recurrence was substantial following both subtypes, but risks differed markedly among patient subgroups. The risk of mortality was higher after a recurrent than first-time stroke.

Neurosurgical Admission Later Than 4 h After the Emergency Call Does Not Result in Worse Long-Term Outcome in Subarachnoid Haemorrhage

Background: Few studies have investigated the importance of the time interval between contact to the emergency medical service and neurosurgical admission in patients with spontaneous subarachnoid haemorrhage. We hypothesised that longer time to treatment would be associated with an increased risk of death or early retirement.

Methods: This was a retrospective observational study with 4 years follow-up. Those who reached a neurosurgical department in fewer than 4 h were compared with those who reached it in more than 4 h. Individual level data were merged from the Danish National Patient Register, medical records, the Copenhagen Emergency Medical Dispatch Centre, the Civil Registration System, and the Ministry of Employment and Statistics Denmark. Patients were ≥18 years and had a verified diagnosis of spontaneous subarachnoid haemorrhage. The primary outcome was death or early retirement after 4 years.

Results: Two hundred sixty-two patients admitted within a three-and-a-half-year time period were identified. Data were available in 124 patients, and 61 of them were in their working age. Four-year all-cause mortality was 25.8%. No significant association was found between time to neurosurgical admission and risk of death or early retirement (OR = 0.35, 95% confidence interval [CI]: 0.10–1.23, p = 0.10).

Conclusion: We did not find an association between the time from emergency telephone call to neurosurgical admission and the risk of death or early retirement.

Predictive value of the transcranial Doppler and mean arterial flow velocity for early detection of cerebral vasospasm in aneurysmal subarachnoid hemorrhage

Objectives

We aimed to predict cerebral vasospasm in acute aneurysmal subarachnoid hemorrhage and to determine the cut-off values of the mean flow velocity by the use of transcranial Doppler.

Methods

A total of 40 patients with acute aneurysmal subarachnoid hemorrhage were included in this study and classified into two groups. The first group was 26 patients (65%) with cerebral vasospasm and the second group was 14 patients (35%) without vasospasm. Initial evaluation using the Glasgow Coma Scale and the severity of aneurysmal subarachnoid hemorrhage was detected by using both the clinical Hunt and Hess and radiological Fisher grading scales. All patients underwent transcranial Doppler evaluations five times in 10 days measuring the mean flow velocities (MFV) of cerebral arteries.

Results

Patients with cerebral vasospasm were associated with significantly higher mean Glasgow Coma Scale score (p = 0.03), significantly higher mean Hunt and Hess scale grades (p = 0.04), with significantly higher mean diabetes mellitus (p = 0.03), significantly higher mean systolic blood pressure and diastolic blood pressure (p = 0.02 and p = 0.005 respectively) and significantly higher MFVs measured within the first 10 days. Logistic regression analysis demonstrated that MFV ≥81 cm/s in the middle cerebral artery is accompanied by an almost five-fold increased risk of vasospasm (OR 4.92, p < 0.01), while MFV ≥63 cm/s in the anterior cerebral artery is accompanied by a three-fold increased risk of vasospasm (OR 3.12, p < 0.01), and MFV ≥42 cm/s in the posterior cerebral artery is accompanied by a two-fold increased risk of vasospasm (OR 2.11, p < 0.05).

Conclusion

Transcranial Doppler is a useful tool for early detection, monitoring, and prediction of post subarachnoid vasospasm and valuable for early therapeutic intervention before irreversible ischemic neurological deficits take place.

Symptoms presented during emergency telephone calls for patients with spontaneous subarachnoid haemorrhage

Background

A spontaneous subarachnoid haemorrhage (SAH) is one of the most critical neurological emergencies a dispatcher can face in an emergency telephone call. No study has yet investigated which symptoms are presented in emergency telephone calls for these patients. We aimed to identify symptoms indicative of SAH and to determine the sensitivity of these and their association (odds ratio, OR) with SAH.

Methods

This was a nested case–control study based on all telephone calls to the medical dispatch center of Copenhagen Emergency Medical Services in a 4-year time period. Patients with SAH were identified in the Danish National Patient Register; diagnoses were verified by medical record review and their emergency telephone call audio files were extracted. Audio files were replayed, and symptoms extracted in a standardized manner. Audio files of a control group were replayed and assessed as well.

Results

We included 224 SAH patients and 609 controls. Cardiac arrest and persisting unconsciousness were reported in 5.8% and 14.7% of SAH patients, respectively. The highest sensitivity was found for headache (58.9%), nausea/vomiting (46.9%) and neck pain (32.6%). Among conscious SAH patients these symptoms were found to have the strongest association with SAH (OR 27.0, 8.41 and 34.0, respectively). Inability to stand up, speech difficulty, or sweating were reported in 24.6%, 24.2%, and 22.8%. The most frequent combination of symptoms was headache and nausea/vomiting, which was reported in 41.6% of SAH patients. More than 90% of headaches were severe, but headache was not reported in 29.7% of conscious SAH patients. In these, syncope was described by 49.1% and nausea/vomiting by 37.7%.

Conclusion

Headache, nausea/vomiting, and neck pain had the highest sensitivity and strongest association with SAH in emergency telephone calls. Unspecific symptoms such as inability to stand up, speech difficulty or sweating were reported in 1 out of 5 calls. Interestingly, 1 in 3 conscious SAH patients did not report headache.

Trial registration NCT03980613 (www.clinicaltrials.gov).

Nationwide Trends in Incidence and Mortality of Stroke Among Younger and Older Adults in Denmark

OBJECTIVE

To investigate the extent to which the incidence and mortality of a first-time stroke among younger and older adults changed from 2005 to 2018 in Denmark using nationwide registries.

METHODS

We used the Danish Stroke Registry and the Danish National Patient Registry to identify patients 18 to 49 years of age (younger adults) and those ≥50 years of age (older adults) with a first-time ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. We computed age-standardized incidence rates and 30-day and 1-year mortality risks separately for younger and older adults and according to smaller age groups, stroke subtype, sex, and severity (Scandinavian Stroke Scale score). Average annual percentage changes (AAPCs) were computed to assess temporal trends.

RESULTS

We identified 8,680 younger adults and 105,240 older adults with an ischemic stroke or intracerebral hemorrhage. The incidence rate per 100,000 person-years of ischemic stroke (20.8 in 2005 and 21.9 in 2018, AAPC -0.6 [95% confidence interval (CI) -1.5 to 0.3]) and intracerebral hemorrhage (2.2 in 2005 and 2.5 in 2018, AAPC 0.6 [95% CI -1.0 to 2.3]) remained steady in younger adults. In older adults, rates of ischemic stroke and intracerebral hemorrhage declined, particularly in those ≥70 years of age. Rates of subarachnoid hemorrhage declined, but more so in younger than older adults. Stroke mortality declined over time in both age groups, attributable largely to declines in the mortality after severe strokes. Most trends were similar for men and women.

CONCLUSION

The incidence of ischemic stroke and intracerebral hemorrhage was steady in younger adults from 2005 to 2018, while it dropped in adults >70 years of age. Stroke mortality declined during this time.

Spontaneous Subarachnoid Haemorrhage as a Cause of Out-of-Hospital Death

BACKGROUND

There are no recent studies on the incidence rate of out-of-hospital death due to spontaneous subarachnoid haemorrhage (SAH). The primary aim of this study was to determine how often SAH was the cause of out-of-hospital death. The secondary aim was to determine if decedents had contacted any health care services within the last 72 h prior to the time of death.

METHODS

This was a retrospective cohort study. The reports of all autopsies carried out at the Department of Forensic Medicine in the Capital Region of Denmark in a ten-year period were read. Police records and Emergency Medical Services (EMS) telephone records were searched for health care contacts within the last 72 h prior to the time of death. Descriptive statistics were used, and to analyse the incidence rates for trend Poisson regression was used.

RESULTS

In total, 6,903 decedents underwent autopsy. Out-of-hospital SAH was the cause of death in 58 decedents, resulting in an average incidence rate of 0.34 per 100.000 persons per year. No significant change in the incidence rate over time was found (p = 0.52). No EMS data were available for eleven decedents in the first part of the study period. Of the remaining 47 decedents, 2 (3.5%, 95% CI: 0.4-11.9) had called the EMS, and in regards to 27 of the 58 decedents, the police records contained information on health care system contacts. Five (8.6%, 95% CI: 2.9-18.9) patients had contacted a general practitioner and three (5.2%, 95% CI: 1.1-14.4) patients had been admitted to hospital but were discharged again within 72 h prior to their death.

CONCLUSION

The incidence rate of out-of-hospital death from SAH was 0.34 per 100.000 persons per year and remained stable across the years 2009-2018. Several patients had sought medical attention shortly before their death, emphasizing the vital importance of recognizing the early symptoms of SAH.