Predictive value of pediatric thrombosis diagnoses in the Danish National Patient Registry

The Positive Predictive Value of Pediatric Stroke Diagnoses in Administrative Data: A Retrospective Validation Study

Background

This retrospective cohort study aimed to examine the positive predictive value (PPV) of pediatric stroke diagnoses in the Danish National Registry of Patients (DNRP) and the impact of different stroke definitions on the PPV.

Methods

We included children registered with a stroke or stroke-related diagnosis in the DNRP between January 2017 through December 2020. Two assessors reviewed medical records and validated cases according to the American Heart and American Stroke Association (AHA/ASA) stroke definition. The level of interrater agreement was examined using kappa statistics. Validation by the AHA/ASA definition was compared with validation according to the definition in the International Classification of Disease 11th version (ICD-11) and the World Health Organization's definition.

Results

Stroke was confirmed in 120 of 309 included children, yielding an overall PPV of 0.39 (95% CI: 0.33-0.45). PPV varied across stroke subtypes from 0.83 (95% CI: 0.71-0.92) for ischemic stroke (AIS), 0.57 (95% CI: 0.37-0.76) for unspecified stroke, 0.42 (95% CI: 0.33-0.52) for intracerebral hemorrhage (ICH) to 0.31 (95% CI: 0.55-0.98) and 0.07 (95% CI: 0.01-0.22) for cerebral venous thrombosis and subarachnoid hemorrhage (SAH), respectively. Most non-confirmed ICH and SAH diagnoses were in children with traumatic intracranial hemorrhages (36 and 66% respectively). Among 70 confirmed AIS cases, 25 (36%) were identified in non-AIS code groups. PPV varied significantly across stroke definitions with the highest for the AHA/ASA definition (PPV = 0.39, 95% CI: 0.34-0.45) and the lowest for the WHO definition (PPV = 0.29, 95% CI: 0.24-0.34). Correspondingly, the incidence of pediatric AIS per 100.000 person-years changed from 1.5 for the AHA/ASA definition to 1.2 for ICD-11 and 1.0 for the WHO-definition. The overall interrater agreement was considered excellent (κ=0.85).

Conclusion

After validation, stroke was confirmed in only half of the children registered in the DNRP with a stroke-specific diagnosis. Non-validated administrative data should be used with caution in pediatric stroke research. Pediatric stroke incidence rates may vary markedly depending on which stroke definition is used.

Risk factors for suicide one year after discharge from hospitalization for physical illness in Denmark

While suicide risk following psychiatric hospitalization has been studied extensively, risk following hospitalization for physical illness is less well understood. We used random forests to examine risk factors for suicide in the year following physical illness hospitalization in Denmark. In this case-cohort study, suicide cases were all individuals who died by suicide within one year of a hospitalization for a physical illness (n = 4563) and the comparison subcohort was a 5% random sample of individuals living in Denmark on January 1, 1995 who had a hospitalization for a physical illness between January 1, 1995 and December 31, 2015 (n = 177,664). We used random forests to examine identify the most important predictors of suicide stratified by sex. For women, the top 10 most important variables for random forest prediction were all related to psychiatric diagnoses. For men, many physical health conditions also appeared important to suicide prediction. Among the top 10 variables in the variable importance plot for men were influenza, injuries to the head, nervous system surgeries, and cerebrovascular diseases. Suicide prediction after a physical illness hospitalization requires comprehensive consideration of different and multiple factors for each sex.

Validation of Postsurgical Venous Thromboembolism Diagnoses of Patients Undergoing Lower Limb Orthopedic Surgery in the Danish National Patient Registry

Background

Healthcare databases can be a valuable source of epidemiological research regarding postoperative venous thromboembolism (VTE), ie, deep vein thrombosis (DVT) and pulmonary embolism (PE), following orthopedic procedures, but only if the diagnoses are valid. We examined the validity of VTE diagnosis codes in the Danish National Patient Registry (DNPR) by calculating their positive predictive value (PPV) and negative predictive value (NPV) versus actual medical records.

Methods

We identified patients who had undergone lower limb surgery during the period 2009–2019 at a hospital in the North Denmark Region. Of these, 420 patients had at least one VTE diagnosis registered in the DNPR within 180 days after lower limb surgery. Each patient with a VTE diagnosis was matched with two patients on age and sex, as well as type, location and period of surgery. The entire medical record and diagnostic imaging were reviewed to confirm VTE diagnosis.

Results

The overall PPVs was 85.2% (95% CI: 81.5–88.5%) for first time VTE diagnosis following lower limb surgery, 82.6% (95% CI: 77.5–82.8%) for DVT, and 90.3% (95% CI: 84.3–94.6%) for PE. We found improvement in PPV during the study period when stratifying for three periods of the whole period. There were no significant differences when stratifying for sex, age, or surgery site. All negative predictive values were higher than 99%. A total of 113 additional VTE diagnoses were registered among 88 VTE patients during follow-up. Only four of the suspected recurrent VTEs were confirmed to be true recurrent VTEs.

Conclusion

The VTE diagnosis codes in the DNPR after lower limb orthopedic surgery were highly valid against the actual medical records, and we observed better PPV over recent years.

Predictors of venous thromboembolism among infants in children's hospitals in the United States: a retrospective Pediatric Health Information Study

OBJECTIVES

Examine: (1) Prevalence of diagnosed venous thromboembolism (VTE) in infants <6 months discharged from U.S. NICUs; (2) Associations between sociodemographic and clinical factors and VTE; (3) Secondary outcomes related to VTE.

STUDY DESIGN

Multivariable logistic regressions examined associations between VTE and sociodemographic and clinical factors among infants <6 months discharged from Pediatric Health Information System (PHIS) NICUs between 2016 and 2019.

RESULTS

Of 201,033 infants, 2720 (1.35%) had diagnosed VTE. Birthweight 300-1000 g (aOR 3.14, 95% CI 2.54-3.88), 1000-1500 g (aOR 1.77, 95% CI 1.40-2.42) versus 2500-3999 g, and public (aOR 1.18, 95% CI 1.02-1.37) versus private insurance were associated with increased odds of VTE, as were CVC, TPN, mechanical ventilation, infection, ECMO, and surgery. All types of central lines (non-tunneled and tunneled CVCs, PICCs, and umbilical catheters) had higher odds of VTE than not having that type of line. CVCs in upper versus lower extremities had higher odds of VTE.

CONCLUSION

Infants with risk factors may require monitoring for VTE. Results may inform VTE prevention.

Predicting Sex-Specific Nonfatal Suicide Attempt Risk Using Machine Learning and Data From Danish National Registries

Suicide attempts are a leading cause of injury globally. Accurate prediction of suicide attempts might offer opportunities for prevention. This case-cohort study used machine learning to examine sex-specific risk profiles for suicide attempts in Danish nationwide registry data. Cases were all persons who made a nonfatal suicide attempt between 1995 and 2015 (n = 22,974); the subcohort was a 5% random sample of the population at risk on January 1, 1995 (n = 265,183). We developed sex-stratified classification trees and random forests using 1,458 predictors, including demographic factors, family histories, psychiatric and physical health diagnoses, surgery, and prescribed medications. We found that substance use disorders/treatment, prescribed psychiatric medications, previous poisoning diagnoses, and stress disorders were important factors for predicting suicide attempts among men and women. Individuals in the top 5% of predicted risk accounted for 44.7% of all suicide attempts among men and 43.2% of all attempts among women. Our findings illuminate novel risk factors and interactions that are most predictive of nonfatal suicide attempts, while consistency between our findings and previous work in this area adds to the call to move machine learning suicide research toward the examination of high-risk subpopulations.

Using machine learning to predict suicide in the 30 days after discharge from psychiatric hospital in Denmark

BACKGROUND

Suicide risk is high in the 30 days after discharge from psychiatric hospital, but knowledge of the profiles of high-risk patients remains limited.

AIMS

To examine sex-specific risk profiles for suicide in the 30 days after discharge from psychiatric hospital, using machine learning and Danish registry data.

METHOD

We conducted a case-cohort study capturing all suicide cases occurring in the 30 days after psychiatric hospital discharge in Denmark from 1 January 1995 to 31 December 2015 (n = 1205). The comparison subcohort was a 5% random sample of all persons born or residing in Denmark on 1 January 1995, and who had a first psychiatric hospital admission between 1995 and 2015 (n = 24 559). Predictors included diagnoses, surgeries, prescribed medications and demographic information. The outcome was suicide death recorded in the Danish Cause of Death Registry.

RESULTS

For men, prescriptions for anxiolytics and drugs used in addictive disorders interacted with other characteristics in the risk profiles (e.g. alcohol-related disorders, hypnotics and sedatives) that led to higher risk of postdischarge suicide. In women, there was interaction between recurrent major depression and other characteristics (e.g. poisoning, low income) that led to increased risk of suicide. Random forests identified important suicide predictors: alcohol-related disorders and nicotine dependence in men and poisoning in women.

CONCLUSIONS

Our findings suggest that accurate prediction of suicide during the high-risk period immediately after psychiatric hospital discharge may require a complex evaluation of multiple factors for men and women.

Validation of venous thromboembolism diagnoses in patients receiving rivaroxaban or warfarin in The Health Improvement Network

Purpose

To describe the effect that validation of venous thromboembolism (VTE) coded entries in the health improvement network (THIN) has on incidence rates of VTE among a cohort of rivaroxaban/warfarin users.

Methods

Among 36 701 individuals with a first prescription for rivaroxaban/warfarin between 2012 and 2015, we performed a two‐step VTE case identification process followed by a two‐step case validation process involving manual review of patient records. A valid case required a coded entry for VTE at some point after their first rivaroxaban/warfarin prescription with evidence of referral/hospitalization either as a coded entry or entered as free text. Positive predictive values (PPVs) with 95% confidence intervals (CIs) were calculated using validated cases as the gold standard. Incidence rates were calculated per 1000 person‐years with 95% CIs.

Results

We identified 2166 patients with a coded entry of VTE after their initial rivaroxaban/warfarin prescription; incidence rate of 45.31 per 1000 person‐years (95% CI: 43.49‐47.22). After manual review of patient records including the free text, there were 712 incident VTE cases; incidence rate of 14.90 per 1000 person‐years (95% CI: 13.85‐16.02). The PPV for coded entries of VTE alone was 32.9%, and the PPV for coded entries of VTE with a coded entry of referral/hospitalization was 39.8%; this increased to 69.6% after manual review of coded clinical entries in patient records.

Conclusions

Among rivaroxaban/warfarin users in THIN, valid VTE case identification requires manual review of patient records including the free text to prevent outcome misclassification and substantial overestimation of VTE incidence rates.

Associations between adjustment disorder and hospital-based infections in the Danish population

OBJECTIVE

There is some evidence that posttraumatic stress disorder (PTSD) is associated with increased risk of infections, and it is unknown whether adjustment disorder is as well. We assessed the association between adjustment disorder and subsequent infections, and assessed additive interaction with sex.

METHODS

The study population included a nationwide cohort of all Danish-born residents of Denmark diagnosed with adjustment disorder between 1995 and 2011, and an age- and sex-matched general population comparison cohort. We compared rates of infections requiring inpatient or outpatient hospitalization in the two cohorts. We fit Cox proportional hazards models to compute adjusted hazard ratios (aHR) for the associations between adjustment disorder and 32 types of infections, and calculated interaction contrasts to assess interaction between adjustment disorder and sex.

RESULTS

Adjustment disorder was associated with increased rates of infections overall (n = 19,838 infections, aHR = 1.8, 95% confidence interval = 1.8. 1.9), and increased rates of each individual infection type (aHRs for 30 infections ranged from 1.5 to 2.3), adjusting for baseline psychiatric and somatic comorbidities and marital status. For many infection types (e.g., skin infections, pneumonia), interaction contrasts indicated rate differences were greater among men than women, while for two (urinary tract infections and sexually transmitted infections), rate differences were greater for women.

CONCLUSIONS

These findings are consistent with studies examining the relationship between psychological stress and infections, and between PTSD and infections. They may be explained by a combination of the triggering of unhealthy behaviors as well as immune responses to stress.

Prediction of Sex-Specific Suicide Risk Using Machine Learning and Single-Payer Health Care Registry Data From Denmark

Importance

Suicide is a public health problem, with multiple causes that are poorly understood. The increased focus on combining health care data with machine-learning approaches in psychiatry may help advance the understanding of suicide risk.

Objective

To examine sex-specific risk profiles for death from suicide using machine-learning methods and data from the population of Denmark.

Design, Setting, and Participants

A case-cohort study nested within 8 national Danish health and social registries was conducted from January 1, 1995, through December 31, 2015. The source population was all persons born or residing in Denmark as of January 1, 1995. Data were analyzed from November 5, 2018, through May 13, 2019.

Exposures

Exposures included 1339 variables spanning domains of suicide risk factors.

Main Outcomes and Measures

Death from suicide from the Danish cause of death registry.

Results

A total of 14 103 individuals died by suicide between 1995 and 2015 (10 152 men [72.0%]; mean [SD] age, 43.5 [18.8] years and 3951 women [28.0%]; age, 47.6 [18.8] years). The comparison subcohort was a 5% random sample (n = 265 183) of living individuals in Denmark on January 1, 1995 (130 591 men [49.2%]; age, 37.4 [21.8] years and 134 592 women [50.8%]; age, 39.9 [23.4] years). With use of classification trees and random forests, sex-specific differences were noted in risk for suicide, with physical health more important to men's suicide risk than women's suicide risk. Psychiatric disorders and possibly associated medications were important to suicide risk, with specific results that may increase clarity in the literature. Generally, diagnoses and medications measured 48 months before suicide were more important indicators of suicide risk than when measured 6 months earlier. Individuals in the top 5% of predicted suicide risk appeared to account for 32.0% of all suicide cases in men and 53.4% of all cases in women.

Conclusions and Relevance

Despite decades of research on suicide risk factors, understanding of suicide remains poor. In this study, the first to date to develop risk profiles for suicide based on data from a full population, apparent consistency with what is known about suicide risk was noted, as well as potentially important, understudied risk factors with evidence of unique suicide risk profiles among specific subpopulations.

Positive predictive value and misclassification of diagnosis of pulmonary embolism and deep vein thrombosis in Swedish patient registries

Purpose

To validate diagnoses of pulmonary embolism (PE) and deep vein thrombosis (DVT) in administrative registries. We also estimated the frequency of misclassified PE and DVT events.

Patients and methods

A registry search for ICD codes representing PE and DVT was performed between 1985 and 2014 in a large population-based cohort in northern Sweden. An additional search using an extended set of ICD codes was performed to identify misclassified events. Diagnoses were validated manually by reviewing medical records and radiology reports.

Results

Searching ICD codes in the National Patient Registry and Cause of Death Registry identified 2,450 participants with a first-time diagnosis of PE or DVT. The positive predictive value (PPV) for a diagnosis of PE or DVT was 80.7% and 59.2%, respectively. For the period of 2009 to 2014, the PPV was higher for PE (85.8%) but lower for DVT (54.1%). Misclassification occurred in 16.4% of DVT events and 1.1% of PE events.

Conclusion

Registry-based data on PE, especially in recent years, are of acceptable quality and can be considered for use in registry-based studies. For DVT, we found that data were of low quality in regards to both PPV and misclassification and should not be used without validation.

Positive predictive value of diagnosis coding for hemolytic anemias in the Danish National Patient Register

Purpose

The nationwide public health registers in Denmark provide a unique opportunity for evaluation of disease-associated morbidity if the positive predictive values (PPVs) of the primary diagnosis are known. The aim of this study was to evaluate the predictive values of hemolytic anemias registered in the Danish National Patient Register.

Patients and methods

All patients with a first-ever diagnosis of hemolytic anemia from either specialist outpatient clinic contact or inpatient admission at Odense University Hospital from January 1994 through December 2011 were considered for inclusion. Patients with mechanical reason for hemolysis such as an artificial heart valve, and patients with vitamin-B12 or folic acid deficiency were excluded.

Results

We identified 412 eligible patients: 249 with a congenital hemolytic anemia diagnosis and 163 with acquired hemolytic anemia diagnosis. In all, hemolysis was confirmed in 359 patients, yielding an overall PPV of 87.1% (95% confidence interval [CI]: 83.5%–90.2%). A diagnosis could be established in 392 patients of whom 355 patients had a hemolytic diagnosis. Diagnosis was confirmed in 197 of the 249 patients with congenital hemolytic anemia, yielding a PPV of 79.1% (95% CI: 73.5%–84.0%). Diagnosis of acquired hemolytic anemia could be confirmed in 136 of the 163 patients, resulting in a PPV of 83.4% (95% CI: 76.8%–88.8%). For hemoglobinopathy PPV was 84.1% (95% CI: 77.4%–89.4%), for hereditary spherocytosis PPV was 80.6% (95% CI: 69.5%–88.9%), and for autoimmune hemolytic anemia PPV was 78.4% (95% CI: 70.4%–85.0%).

Conclusion

The PPV of hemolytic anemias was moderately high. The PPVs were comparable in the three main categories of overall hemolysis, and congenital and acquired hemolytic anemia.

The Danish National Patient Registry: a review of content, data quality, and research potential

Background

The Danish National Patient Registry (DNPR) is one of the world’s oldest nationwide hospital registries and is used extensively for research. Many studies have validated algorithms for identifying health events in the DNPR, but the reports are fragmented and no overview exists.

Objectives

To review the content, data quality, and research potential of the DNPR.

Methods

We examined the setting, history, aims, content, and classification systems of the DNPR. We searched PubMed and the Danish Medical Journal to create a bibliography of validation studies. We included also studies that were referenced in retrieved papers or known to us beforehand. Methodological considerations related to DNPR data were reviewed.

Results

During 1977–2012, the DNPR registered 8,085,603 persons, accounting for 7,268,857 inpatient, 5,953,405 outpatient, and 5,097,300 emergency department contacts. The DNPR provides nationwide longitudinal registration of detailed administrative and clinical data. It has recorded information on all patients discharged from Danish nonpsychiatric hospitals since 1977 and on psychiatric inpatients and emergency department and outpatient specialty clinic contacts since 1995. For each patient contact, one primary and optional secondary diagnoses are recorded according to the International Classification of Diseases. The DNPR provides a data source to identify diseases, examinations, certain in-hospital medical treatments, and surgical procedures. Long-term temporal trends in hospitalization and treatment rates can be studied. The positive predictive values of diseases and treatments vary widely (<15%–100%). The DNPR data are linkable at the patient level with data from other Danish administrative registries, clinical registries, randomized controlled trials, population surveys, and epidemiologic field studies – enabling researchers to reconstruct individual life and health trajectories for an entire population.

Conclusion

The DNPR is a valuable tool for epidemiological research. However, both its strengths and limitations must be considered when interpreting research results, and continuous validation of its clinical data is essential.

Use of psychotropic drugs following venous thromboembolism in youth. A nationwide cohort study

INTRODUCTION

The mental health prognosis following a venous thromboembolism in youth has not been investigated comprehensively. Using psychotropic drug purchase as a proxy for mental health status, we investigated this issue in a large cohort of young incident venous thromboembolism patients.

METHODS

Using Danish nationwide administrative registries from the period 1997-2010, we identified 4,132 patients aged 13-33 years with a first-time venous thromboembolism diagnosis and no history of psychotropic drug usage. We sampled comparison cohort of random general population controls, matched individually in a 1:5 ratio based on sex and birth year. Participants were followed in prescription purchase registries for their first psychotropic drug purchase.

RESULTS

Among young venous thromboembolism case cases, the 1-year risk of psychotropic drug purchase was 7.1% (95% confidence interval [CI] 6.3, 7.9) and the 5-year risk 22.1% (95% CI 20.7, 23.5). This was substantially higher than among population controls, with 1- and 5-year risk differences relative to the controls of 4.7% (95% CI 3.9, 5.5), and 10.8% (95% CI 9.4, 12.3), respectively. Adjustment for the effects of recent pregnancy or somatic provocations attenuated risk differences to 4.1% (95% CI 3.5, 5.1) after 1 year and 9.6% (95% CI 8.3, 11.2) after 5 years.

CONCLUSIONS

A venous thromboembolism diagnosis in youth is associated with a poorer mental health prognosis: one in five patients are prescribed psychotropic medication within the first 5 year after diagnosis.

Validation of administrative health data for the pediatric population: a scoping review

BACKGROUND

The purpose of this research was to perform a scoping review of published literature on the validity of administrative health data for ascertaining health conditions in the pediatric population (≤20 years).

METHODS

A comprehensive search of OVID Medline (1946 - present), CINAHL (1937 - present) and EMBASE (1947 - present) was conducted. Characteristics of validation studies that were abstracted included the study population, health condition, topic of the validation (e.g., single diagnosis code versus case-finding algorithm), administrative and validation data sources. Inter-rater agreement was measured using Cohen's κ. Extracted data were analyzed using descriptive statistics.

RESULTS

A total of 37 articles met the study inclusion criteria. Cohen's κ for study inclusion/exclusion and data abstraction was 0.88 and 0.97, respectively. Most studies validated administrative data from the USA (43.2%) and Canada (24.3%), and focused on inpatient records (67.6%). Case-finding algorithms (56.7%) were more frequently validated than diagnoses codes alone (37.8%). Five conditions were validated in more than one study: diabetes mellitus, inflammatory bowel disease, asthma, rotavirus infection, and tuberculosis.

CONCLUSIONS

This scoping review identified a number of gaps in the validation of administrative health data for pediatric populations, including limited investigation of outpatient populations and older pediatric age groups.

Femoral arterial thrombosis after cardiac catheterization in infancy: impact of Doppler ultrasound for diagnosis

Femoral arterial thrombosis (FAT) is a nonnegligible complication after cardiac catheterization (CC) in infancy. The aim of this study was to evaluate the impact of Doppler ultrasound (US) for diagnostic work-up after catheterization. We compared standard follow-up (FU) without Doppler US by relying on clinical signs of FAT with advanced FU using Doppler US of the femoral vessels. Between January and December 2009, we evaluated the rate of FAT in infants <12 months of age using a multicenter, prospective observational survey. We analysed 171 patients [mean age 4.1 ± 3.3 (SD) months; mean body weight 5.3 ± 1.8 kg] from 6 participating centres. The mean duration of catheter studies was 57.7 ± 38.0 min. The overall rate of FAT based on clinical diagnosis was 4.7% and was comparable in both groups [3.4% undergoing standard FU vs. 7.4% undergoing advanced FU (p = 0.15)]. However, the overall rate of thrombosis as screened by Doppler US was greater at 7.1 %, especially in patients after advanced FU [18.5% advanced vs. standard FU 1.7% (p < 0.01)]. In conclusion, FAT remains a relevant and underestimated complication after catheterization in young infants when relying only on clinical signs of FAT. Therefore, to start effective treatment as soon as possible, we recommend Doppler US to be performed the day after CC.

Trends in venous thromboembolism-related hospitalizations, 1994-2009

OBJECTIVE

Information on trends in venous thromboembolism (VTE) in US children is scant and inconsistent. We assessed national trends in VTE-associated pediatric hospitalizations.

METHODS

All nonroutine newborn hospitalizations for children 0 to 17 years of age in the 1994-2009 Nationwide Inpatient Samples were included; routine newborn discharges were excluded. VTE diagnoses were identified by using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Variance weighted least square regression was used to assess trends in patient characteristics and rates of hospitalization per 100000 population <18 years of age. Multivariable logistic regression models were used to estimate the probability of VTE diagnosis over the study period.

RESULTS

The rate of VTE-associated hospitalization increased for all age subgroups (<1, 1-5, 6-11, and 12-17 years), with the largest increase noted among children <1 year of age (from 18.1 per 100000 during 1994 to 49.6 per 100000 during 2009). Compared with 1994-1997, the adjusted odds of hospitalization with a VTE diagnosis were 88% higher during 2006-2009 (adjusted odds ratio: 1.88 [95% confidence interval: 1.64-2.17]). Venous catheter use, mechanical ventilation, malignancy, hospitalization ≥ 5 days, and VTE-related medical conditions were associated with increased likelihood of VTE diagnosis.

CONCLUSIONS

The rate of VTE-associated hospitalization among US children increased from 1994 through 2009. Increases in venous catheter procedures were associated with and may have contributed to the observed trends. The degree to which increased awareness of VTE influenced the temporal differences could not be determined.

Pediatric venous and arterial noncerebral thromboembolism in Denmark: a nationwide population-based study

OBJECTIVE

To assess the incidence rate (IR), changes in IR over time, risk factors, treatment, and outcomes of pediatric noncerebral thromboembolism (TE).

STUDY DESIGN

The study included all patients aged 0 to 18 years diagnosed with first-ever noncerebral venous thromboembolism (VTE) and/or arterial TE in Denmark between 1994 and 2006. Patients were identified in national registries, followed by validation of diagnoses by medical records review.

RESULTS

We confirmed 331 cases of VTE and 46 cases of arterial TE during 15.8 million person-years of observation, with corresponding IRs of 2.09 and 0.29 per 100 000 person-years. The IR peaked in infancy (age <1 year) for both VTE and arterial TE, with an additional peak among adolescents (age 15 to 18 years) for VTE. Boys predominated in IR of VTE in infancy, whereas girls did so in adolescence (P < .01). The IRs of VTE and arterial TE remained stable during the study period, but with an trend toward increasing VTE in 2001 to 2006 (P = .064). Underlying diseases/external triggers were present in 86.6% of the patients, and thrombophilia was present in 47.9% of the VTE cases. All-cause and TE-related 30-day case fatalities were 4.0% and 1.6%, respectively.

CONCLUSIONS

We found age- and sex-related disparities in the IRs of pediatric VTE and arterial TE, but insignificant changes in IR from 1994 to 2006.

Paediatric arterial ischaemic stroke and cerebral sinovenous thrombosis in Denmark 1994-2006: a nationwide population-based study

AIM

To assess the incidence rates (IR), clinical characteristics, risk factors, treatment and outcomes of paediatric arterial ischaemic stroke (AIS) and cerebral sinovenous thrombosis (CSVT).

METHODS

Using population-based, nationwide medical registries, we identified all patients aged 0-18 years at the time of hospitalization with first-ever AIS and/or CSVT in Denmark between 1994 and 2006. Medical records were retrieved and reviewed.

RESULTS

We identified 211 patients with AIS and 40 patients with CSVT corresponding to IRs of 1.33 (95% CI 1.16-1.52) and 0.25 (95% CI 0.19-0.34) per 100,000 person-years, respectively. The IRs peaked in infancy (<1 year) for both AIS and CSVT with an additional peak among adolescents (15-18 years) for CSVT. The IR of AIS increased 3.9% per year (p=0.036), whereas no changes were found for CSVT. In total, 48.2% of the patients received antithrombotic treatment; no major complications were observed. All-cause and thrombosis-related 30-day case fatality ratios were 3.6% and 2.4%, respectively; neurological sequelae were found in 56.2% of patients.

CONCLUSION

The IR of AIS was highest in infants and had increased with 3.9% annually during the observation period. The IR of CSVT had an additional peak in adolescence and remained unchanged over time.