Adverse perinatal events and maternal interpregnancy weight change: A population-based observational study

OBJECTIVE

Mothers whose newborn experiences adversity may neglect their own health to care for their affected infant or following a perinatal death. Weight gain after pregnancy is one measure of maternal self-care. We measured interpregnancy weight gain among women whose child had an adverse perinatal event.

METHODS

This population-based observational study included 192 154 primigravid women with two consecutive singleton births in Ontario, Canada. Outcomes included net weight gain, and adjusted odds ratios (aOR) of moving to a higher body mass index (BMI) category between pregnancies, comparing women whose child did versus did not experience either a perinatal death, prematurity, severe neonatal morbidity, major congenital anomaly, or severe neurologic impairment.

RESULTS

Perinatal death was associated with a +3.5 kg (95% confidence interval [CI]: 2.1-4.9) net higher maternal weight gain in the subsequent pregnancy. Relative to term births, preterm birth <32 weeks (+3.2 kg, 95% CI: 1.9-4.6), 32-33 weeks (+1.8 kg, 95% CI: 0.7-2.8) and 34-36 weeks (+0.9 kg, 95% CI: 0.6-1.3) were associated with higher net weight gain. Having an infant with severe neonatal morbidity was associated with a +1.2 kg (95% CI: 0.3-2.1) weight gain. Likewise, the aOR of moving to a higher BMI category was 1.27 (95% CI, 1.14-1.42) following a perinatal death, 1.21 (95% CI: 1.04-1.41) after a preterm birth <32 weeks, and 1.11 (95% CI: 1.02-1.22) with severe neonatal morbidity.

CONCLUSION

Greater interpregnancy weight gain, and movement to a higher BMI category, are each more likely in a woman whose first-born was affected by certain major adverse perinatal events.

Diverticular disease and risk of dementia: a Danish population-based cohort study

BACKGROUND AND AIM

Patients with diverticular disease (DD) have ongoing chronic inflammation associated with changes in the gut microbiome, which might contribute to the development of dementia.

METHODS

Using Danish medical and administrative registries from 1980 to 2013, we conducted a nationwide population-based cohort study including all DD patients and a matched (5:1) general population comparison cohort without DD. A nested case-control analysis was then conducted using a risk set sampling, matching four DD controls without dementia to each DD patient with dementia. Clinical severity was categorized as uncomplicated DD (outpatient), conservatively treated DD (inpatient), and surgically treated DD.

RESULTS

149 527 DD patients and 747 635 general population comparators were identified. The 30-year cumulative incidence of dementia among DD patients and general population comparators were 12.4 (95% confidence interval [CI] 12.1-12.7) and 13.73% (95% CI 13.6-13.9), respectively. This corresponded to a 30-year hazard ratio (HR) of 1.10 (95% CI 1.1-1.1). The highest HRs were found in the conservatively treated DD group (1.15 95% CI 1.1-1.2) and the group with young onset of DD (1.52 95% CI 1.2-2.0). In the nested case-control analysis, we identified 8875 dementia cases and 35 491 matched controls. The adjusted odds ratio (OR) for conservatively treated DD was increased (1.08, 95% CI; 1.0-1.2) compared to the reference of uncomplicated DD.

CONCLUSIONS

We observed a slight increased risk of dementia in patients with young onset DD and conservatively treated DD. Findings suggest an association between disease duration, perhaps reflecting the duration of gut inflammation, and the risk of developing dementia.

Use of Latent Class Analysis to Predict Intensive Care Unit Admission and Mortality in Children with a Major Congenital Anomaly

OBJECTIVE

To define major congenital anomaly (CA) subgroups and assess outcome variability based on defined subgroups.

STUDY DESIGN

This population-based cohort study used registries in Denmark for children born with a major CA between January 1997 and December 2016, with follow-up until December 2018. We performed a latent class analysis (LCA) using child and family clinical and sociodemographic characteristics present at birth, incorporating additional variables occurring until age of 24 months. Cox proportional hazards regression models estimated hazard ratios (HRs) of pediatric mortality and intensive care unit (ICU) admissions for identified LCA classes.

RESULTS

The study included 27 192 children born with a major CA. Twelve variables led to a 4-class solution (entropy = 0.74): (1) children born with higher income and fewer comorbidities (55.4%), (2) children born to young mothers with lower income (24.8%), (3) children born prematurely (10.0%), and (4) children with multiorgan involvement and developmental disability (9.8%). Compared with those in Class 1, mortality and ICU admissions were highest in Class 4 (HR = 8.9, 95% CI = 6.4-12.6 and HR = 4.1, 95% CI = 3.6-4.7, respectively). More modest increases were observed among the other classes for mortality and ICU admissions (Class 2: HR = 1.7, 95% CI = 1.1-2.5 and HR = 1.3, 95% CI = 1.1-1.4, respectively; Class 3: HR = 2.5, 95% CI = 1.5-4.2 and HR = 1.5, 95% CI = 1.3-1.9, respectively).

CONCLUSIONS

Children with a major CA can be categorized into meaningful subgroups with good discriminative ability. These groupings may be useful for risk-stratification in outcome studies.

Risk and adverse clinical outcomes of thrombocytopenia among patients with solid tumors-a Danish population-based cohort study

BACKGROUND

Knowledge about thrombocytopenia among patients with solid tumors is scarce. We examined the risk of thrombocytopenia among patients with solid tumors and its association with adverse outcomes.

METHODS

Using Danish health registries, we identified all patients with incident solid tumors from 2015-2018 (n = 52,380) and a platelet count measurement within 2 weeks prior to or on their cancer diagnosis date. The risk of thrombocytopenia was categorized as grades 0 (any platelet count × 109/L): <150; 1: <100; 2: <75; 3: <50; 4: <25, and 5: <10. To study the outcomes, each patient with thrombocytopenia was matched with up to five cancer patients without thrombocytopenia by age, sex, cancer type, and stage. Cox regression was used to compute hazard ratios (HRs) of bleeding, transfusion, or death, adjusting for confounding factors.

RESULTS

The 1-year risk of thrombocytopenia was 23%, increasing to 30% at 4 years. This risk was higher in patients receiving chemotherapy (43% at 1 year and 49% at 4 years). Overall, patients with thrombocytopenia had higher 30-days rates of bleeding (HR = 1.72 [95% confidence interval, CI: 1.41-2.11]). Thrombocytopenia was also associated with an increased rate of transfusion, and death, but some of the risk estimates were imprecise.

CONCLUSIONS

The risk of thrombocytopenia was substantial among patients with solid tumors and associated with adverse outcomes.

Association between maternal employment status and presence of children with major congenital anomalies in Denmark

IMPORTANCE

The burden of caring for children with complex medical problems such as major congenital anomalies falls principally on mothers, who in turn suffer a variety of potentially severe economic consequences. As well, health consequences of caregiving often further impact the social and economic prospects of mothers of children with major congenital anomalies (MCMCAs). Evaluating the long-term economic consequences of extensive in-home caregiving among MCMCAs can inform strategies to mitigate these effects.

OBJECTIVE

To assess whether MCMCAs face reduced employment and increased need for disability benefits over a 20-year period.

DESIGN

A population-based matched cohort study.

SETTING

Denmark.

PARTICIPANTS

All women who gave birth to a singleton child with a major congenital anomaly in Denmark between January 1, 1997 and December 31, 2017 (n = 23,637) and a comparison cohort of mothers matched by maternal age, parity, and infant's year of birth (n = 234,586).

EXPOSURES

Liveborn infant with a major congenital anomaly.

MAIN OUTCOMES AND MEASURES

The primary outcome was mothers' employment status, stratified by their child's age. Employment status was categorized as employed, outside the workforce (on temporary leave, holding a flexible job, or pursuing education), or unemployed; the number of weeks in each category was measured over time. The secondary outcome was time to receipt of a disability pension, which in Denmark implies permanent exit from the labor market. We used a negative binomial regression model to estimate the number of weeks in each employment category, stratified by the child's age (i.e., 0-1 year, > 1-6 years, 7-13 years, 14-18 years). A Cox proportional hazards regression model was used to compute hazard ratios as a measure of the relative risk of receiving a disability pension. Rate ratios and hazard ratios were adjusted for maternal demographics, pregnancy history, health, and infant's year of birth.

RESULTS

During 1-6 years after delivery, MCMCAs were outside the workforce for a median of 50 weeks (IQR, 6-107 weeks), while members of the comparison cohort were outside the workforce for a median of 48 weeks (IQR, 4-98 weeks), corresponding to an adjusted rate ratio [ARR] of 1.05 (95% confidence interval [CI], 1.04-1.07). During the first year after delivery, MCMCAs were more likely to be employed than mothers in the comparison cohort (ARR, 1.08; 95% CI, 1.06-1.10). At all timepoints thereafter, MCMCAs had a lower rate of workforce participation. The rate of being outside the workforce was 5% higher than mothers in the comparison cohort during 1-6 years after delivery (ARR, 1.05; 95% CI, 1.04-1.07), 9% higher during 7-13 years after delivery (ARR, 1.09; 95% CI, 1.06-1.12), and 12% higher during 14-18 years after delivery (ARR, 1.12; 95% CI, 1.07-1.18). Overall, MCMCAs had a 20% increased risk of receiving a disability pension during follow-up than mothers in the matched comparison cohort [incidence rates 3.10 per 1000 person-years (95% CI, 2.89-3.32) vs. 2.34 per 1000 person-years (95% CI, 2.29-2.40), adjusted hazard ratio, 1.20; 95% CI, 1.11-1.29].

CONCLUSION AND RELEVANCE

MCMCAs were less likely to participate in the Danish workforce, less likely to be employed, and more likely to receive disability pensions than mothers of unaffected children. The rate of leaving the workforce intensified as their affected children grew older. The high demands of caregiving among MCMCAs may have long-term employment consequences even in nations with comprehensive and heavily tax-supported childcare systems, such as Denmark.

Sex Differences in Psychopathology Following Potentially Traumatic Experiences

Importance

Various psychopathology may follow trauma; however, sex differences in these ranging manifestations of posttraumatic psychopathology remain understudied.

Objective

To investigate sex-specific incidence of posttraumatic psychopathology.

Design, Setting, and Participants

This population-based cohort study of Danish national health registries included a cohort of individuals who experienced a potentially traumatic event (PTE) from 1994 to 2016. Individuals were further categorized by presence of any pretrauma psychopathology. A comparison group of individuals who experienced a nontraumatic stressor (nonsuicide death of a first-degree relative) was examined as a reference cohort.

Exposures

At least 1 of 8 PTEs (eg, physical assault, transportation accident) derived through health registry International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes, with additional qualifiers to improve classification accuracy.

Main Outcomes and Measures

Incidence of 9 categories of ICD-10 psychiatric disorders recorded in registries within 5 years of PTEs. The standardized morbidity ratios (SMRs) for psychopathology outcomes were also calculated to compare individuals experiencing PTEs with those experiencing a nontraumatic stressor.

Results

This study included 1 398 026 individuals who had been exposed to trauma (475 280 males [34.0%]; 922 750 females [66.0%]). The group of males who had been exposed to trauma were evenly distributed across age, while most females in the trauma-exposed group were aged 16 to 39 years (592 385 [64.2%]). Males and females were equally distributed across income quartiles and predominantly single. Following PTEs, the most common diagnosis was substance use disorders for males (35 160 [7.4%]) and depressive disorders for females (29 255 [3.2%]); incidence proportions for these and other disorders were higher among males and females with any pretrauma psychopathology. Certain PTEs had elevated onset of various psychiatric disorders and some sex differences emerged. Following physical assault, associations were found with schizophrenia or psychotic disorders for males (SMR, 17.5; 95% CI, 15.9-19.3) and adult personality disorders for females (SMR, 16.3; 95% CI, 14.6-18.3). For noninterpersonal PTEs, males had larger SMRs for substance use, schizophrenia or psychotic disorders, and adult personality disorders (SMR, 43.4; 95% CI, 41.9-45.0), and females had larger SMRs for depressive disorders (SMR, 19.0; 95% CI, 18.6-19.4). Sex differences were also observed, particularly when considering pretrauma psychopathology. For example, among interpersonal PTEs, males were most likely to develop substance use disorders after physical assault, whereas females were more likely to develop various disorders, with stronger associations seen for females without pretrauma psychiatric diagnoses. Among noninterpersonal PTEs, exposure to toxic substance showed robust associations with psychopathology, particularly in those without pretrauma psychopathology, with sex-specific differences across psychiatric categories.

Conclusions and Relevance

Mental disorders after trauma were wide-ranging for males and females, and sex differences in patterns of posttraumatic psychopathology were more pronounced when accounting for pretrauma psychopathology. Findings provide new insights for sex-relevant PTEs and their mental health consequences. It also outlines future directions for advancing understanding of a constellation of posttraumatic psychopathology in males and females.

Incidence and prevalence of fibrous dysplasia/McCune-Albright syndrome - a nationwide registry-based study in Denmark

CONTEXT

Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare genetic disorder. Incidence and prevalence are not well-studied. Epidemiological research is complicated by the rarity of FD/MAS, absence of registries, heterogeneous presentation and possibly asymptomatic phenotype. FD/MAS may present with FGF23-mediated hypophosphatemia, of which the epidemiology is also unclear.

OBJECTIVE

Evaluate incidence and prevalence of FD/MAS and FD/MAS-related hypophosphatemia.

DESIGN

Cohort study based on nation-wide Danish registry from 1995-2018.

SETTING

Population of Denmark.

PATIENTS

Identified from the Danish National Patient Registry by ICD-10 codes M85.0 (monostotic FD, MFD) and Q78.1 (polyostotic FD(PFD)/MAS).

MAIN OUTCOMES MEASURES

Incidence rates and prevalence were calculated and stratified by sex, age, calendar period and diagnosis code. Cases were screened for FD-associated hypophosphatemia by diagnosis code 'disorder of mineral metabolism' (E.83) and dispatched vitamin D analogues. Measures were presented with 95% confidence intervals.

RESULTS

408 patients were identified, 269 with MFD (66%), 139 with PFD/MAS (34%), comparable between sexes. Incidence of FD/MAS demonstrated increasing secular trend with a rate of 3.6 per 1,000,000 person years [95%CI 2.9,4.5] in 2015-2018. Incidence peaked between age 11-20. Prevalence of FD/MAS increased over time to 61.0 [95%CI 54.6,67.4] per 1,000,000 persons in 2018. Incidence rate of MFD was 1.5-fold of PFD/MAS in the first decade, rising to 2.5-fold in the last decade. No FD/MAS cases were registered with diagnosis code or treatment for hypophosphatemia.

CONCLUSIONS

FD/MAS is rare, diagnosis peaks during adolescence without sex predominance, MFD is most prevalent. Hypophosphatemia may be underdiagnosed and undertreated, or underregistered, comparing this study to literature.

Association between pregnancy affected by vaginal bleeding and women's mortality: A cohort study

OBJECTIVE

To investigate the association between vaginal bleeding (VB) in pregnancy and women's mortality, using VB-unaffected pregnancies, terminations and miscarriages as comparators.

DESIGN

Observational cohort study.

SETTING

Nationwide registries of Denmark linked at an individual level.

POPULATION OR SAMPLE

1 354 181 women and their 3 162 317 pregnancies (1979-2017), including 70 835 VB-affected pregnancies and comparators: 2 236 359 VB-unaffected pregnancies ending in childbirth; 589 697 terminations; and 265 426 miscarriages.

METHODS

We followed pregnancies until the earliest date of woman's death, emigration or end of data.

MAIN OUTCOME MEASURES

All-cause and cause-specific mortality rates per 10 000 person-years (PY) and hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted using Cox proportional hazards regression for age, calendar year, pre-existing chronic conditions and socio-economic factors.

RESULTS

There were 2320 deaths from any cause among women following VB-affected pregnancy (mortality rate 15.2, 95% CI 14.6-15.9 per 10 000 PY); 55 030 deaths following VB-unaffected pregnancy (mortality rate 12.7, 95% CI 12.6-12.8); 27 500 deaths following a termination (mortality rate 21.9, 95% CI 21.6-22.1), and 10 865 deaths following a miscarriage (mortality rate 19.2, 95% CI 18.8-19.6). For comparison of VB-affected versus VB-unaffected pregnancies, associations with all-cause (HR 1.14, 95% CI 1.09-1.19), natural causes (HR 1.15, 95% CI 1.09-1.22) and non-natural causes (HR 1.27, 95% CI 1.08-1.48) mortality were attenuated in a sensitivity analysis of pregnancies recorded in 1994-2017 (HR 1.00, 95% CI 0.90-1.12, HR 0.98, 95% CI 0.85-1.14 and HR 1.04, 95% CI 0.72-1.51, respectively). Contrasts with remaining comparators did not suggest increased risks of all-cause, natural or non-natural mortality causes.

CONCLUSION

We found no evidence of an increased risk of women's mortality following VB-affected versus VB-unaffected pregnancy, termination or miscarriage.

Risk of Bleeding and Venous Thromboembolism after Colorectal Cancer Surgery in Patients with and without Type 2 Diabetes: A Danish Cohort Study

Background  Bleeding and venous thromboembolism (VTE) are adverse outcomes after colorectal cancer (CRC) surgery. Type 2 diabetes (T2D) clusters with bleeding and VTE risk factors. We examined the bleeding and VTE risk in patients with T2D undergoing CRC surgery and the prognosis after these adverse outcomes. Methods  We conducted a prognostic population-based cohort study of 48,295 patients with and without T2D undergoing surgery for incident CRC during 2005 to 2019. Patients with T2D were diagnosed in a hospital setting or had redeemed a glucose-lowering drug prescription; the remaining cohort was patients without diabetes. We estimated the 30-day and 1-year risks of bleeding and VTE and used a Fine-Gray model to compute age-, sex-, and calendar year-adjusted subdistribution hazard ratios (SHRs). The Kaplan-Meier method was used to calculate 1-year mortality after bleeding or VTE. Results  Within 30 days after CRC surgery, the risk of bleeding was 2.7% in patients with T2D and 2.0% in patients without diabetes (SHR: 1.30 [95% confidence interval [CI]: 1.10-1.53]). For VTE, the 30-day risks were 0.6% for patients with T2D and 0.6% for patients without diabetes (SHR: 1.01 [95% CI: 0.71-1.42]). The SHRs for bleeding and VTE within 1 year after CRC surgery were similar. The 1-year mortality was 26.0% versus 24.9% in the bleeding cohort and 25.8% versus 27.5% in the VTE cohort for patients with T2D versus without diabetes, respectively. Conclusion  Although absolute risks were low, patients with T2D have an increased risk of bleeding but not VTE after CRC surgery.

Risk of diabetes and cardiovascular diseases in women with vaginal bleeding before 20 gestational weeks: Danish population-based cohort study

BACKGROUND

Women's reproductive health is associated with cardiovascular morbidity. However, an association of vaginal bleeding (VB) in pregnancy with diabetes and cardiovascular outcomes has scarcely been investigated.

METHODS

We conducted a population-based cohort study in Denmark (1994-2018). Using nationwide registries, among 903 327 women we identified 1 901 725 pregnancies: 39 265 ended in childbirth and were affected by VB; 1 389 285 ended in childbirth and were unaffected by VB; 333 785 ended in a termination, and 139 390 ended in a miscarriage. The outcomes were diabetes types 1 and 2, hypertension, ischaemic heart disease including myocardial infarction, atrial fibrillation or flutter, heart failure and ischaemic and haemorrhagic stroke. We computed incidence rates and hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for age, calendar year of pregnancy end, morbidities and reproductive and socioeconomic factors, using inverse probability of treatment-weighted Cox proportional hazards regression.

RESULTS

In analyses of VB-affected vs VB-unaffected pregnancies, aHRs were 1.15 (1.03-1.28) for diabetes type 1, 1.19 (1.13-1.26) for diabetes type 2, 1.19 (1.14-1.25) for hypertension, 1.26 (1.16-1.37) for ischaemic heart disease, 1.21 (1.03-1.42) for myocardial infarction, 1.32 (1.14-1.51) for atrial fibrillation or flutter and 1.23 (0.99-1.52) for heart failure. aHRs were 1.41 (1.26-1.57) and 1.46 (1.23-1.72) for ischaemic and haemorrhagic stroke, respectively. When contrasting VB-affected pregnancies with terminations, aHRs were up to 1.3-fold increased for diabetes and hypertension; however, when contrasting VB-affected pregnancies with miscarriages, estimates were below or close to the null value.

CONCLUSIONS

Women's risks of diabetes and cardiovascular outcomes later in life were increased following VB-affected vs VB-unaffected pregnancy or termination, but not following VB-affected pregnancy vs miscarriage.

Prediction of Suicide Attempts Among Persons with Depression: A Population-Based Case Cohort Study

Studies have highlighted the potential importance of modeling interactions for suicide attempt prediction. This case-cohort study identified risk factors for suicide attempts among persons with depression in Denmark using statistical approaches that do (random forests) or do not model interactions (least absolute shrinkage and selection operator regression [LASSO]). Cases made a non-fatal suicide attempt (n = 6,032) between 1995 and 2015. The comparison subcohort was a 5% random sample of all persons in Denmark on January 1, 1995 (n = 11,963). We used random forests and LASSO for sex-stratified prediction of suicide attempts from demographic variables, psychiatric and somatic diagnoses, and treatments. Poisonings, psychiatric disorders, and medications were important predictors for both sexes. Area under the receiver operating characteristic curve (AUC) values were higher in LASSO models (0.85 [95% CI = 0.84, 0.86] in men; 0.89 [95% CI = 0.88, 0.90] in women) than random forests (0.76 [95% CI = 0.74, 0.78] in men; 0.79 [95% CI = 0.78, 0.81] in women). Automatic detection of interactions via random forests did not result in better model performance than LASSO models that did not model interactions. Due to the complex nature of psychiatric comorbidity and suicide, modeling interactions may not always be the optimal statistical approach to enhancing suicide attempt prediction in high-risk samples.

High-intensity versus moderate-intensity statin treatment for patients with ischemic stroke: Nationwide cohort study

PURPOSE

Guidelines recommend high-intensity statin treatment after ischemic stroke, but evidence is sparse on the effectiveness and safety of different statin treatment intensities. We examined effectiveness and safety outcomes among patients initiating high-intensity versus moderate-intensity statins after ischemic stroke.

METHODS

In this population-based new-user active-comparator cohort study, we used the Danish Stroke Registry, covering all Danish hospitals, to identify patients with a first-time ischemic stroke during 2012-2021. Using multiple Danish registries, patients who redeemed a statin prescription within 21 days after stroke admission were classified as high-intensity statin initiators or moderate-intensity statin initiators. Propensity score inverse probability of treatment weighting was used to balance patient characteristics. We used competing risk methods to compute 5 year risk differences (RDs) and Cox proportional hazards regression to compute 5 year hazard ratios (HRs) of stroke recurrence, myocardial infarction, heart failure, venous thromboembolism, and all-cause mortality (effectiveness outcomes) and diabetes, liver disease, and kidney disease (safety outcomes).

RESULTS

High-intensity (n = 13,032) and moderate-intensity (n = 14,355) statin initiators were identified. Risks of most examined effectiveness outcomes were comparable between statin intensities. There was no clear association between statin intensity and stroke recurrence (RD: 0.8% [95% CI: 0.1, 1.4], HR: 1.08 [95% CI: 0.96, 1.22]). All-cause mortality was slightly reduced among high-intensity statin initiators (RD: -1.1% [95% CI: -0.1, -2.1], HR: 0.93 [95% CI: 0.85, 1.01]. Risks of most safety outcomes were comparable between statin intensities, but high-intensity statin use was associated with an increased risk of diabetes (RD: 1.2% [95% CI: 0.4, 1.9], HR: 1.10 [95% CI: 1.00, 1.21]).

DISCUSSION AND CONCLUSION

Compared with initiation of moderate-intensity statins, initiation of high-intensity statins after ischemic stroke was associated with similar risks of most effectiveness and safety outcomes. However, mortality risk was reduced, and diabetes risk was increased.

Long-Term Medical Treatment and Adherence in Patients With Left Ventricular Assist Devices: A Danish Nationwide Cohort Study

The use of a left ventricular assist device (LVAD) in treating advanced heart failure has increased. However, data regarding medical treatment and adherence following LVAD implantation is sparse, particularly whether socioeconomic factors (cohabitation status, educational level, employment status, and income) and multimorbidity influence these aspects, which are known to impact adherence in heart failure patients. We performed a nationwide cohort study of 119 patients with LVAD implanted between January 1, 2006, and December 31, 2018, who were discharged alive with LVAD therapy. We linked individual-level data from clinical LVAD databases, the Scandiatransplant Database, and Danish medical and administrative registers. Medical treatment 90-day pre-LVAD and 720-day post-LVAD were assessed using descriptive statistics in 90-day intervals. Medication adherence (proportion of days covered ≥80%) was assessed 181- to 720-day post-LVAD. The proportions of patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (88.7%), beta-blockers (67.0%), mineralocorticoid receptor antagonists (62.9%), warfarin (87.6%), and aspirin (55.7%) within 90-day post-LVAD were higher than pre-LVAD and were stable during follow-up. Medication adherence ranged from 86.7% (aspirin) to 97.8% (warfarin). Socioeconomic factors and multimorbidity did not influence medical medication use and adherence. Among LVAD patients, medical treatment and adherence are at high levels, regardless of socioeconomic background and multimorbidity.

Stillbirths: Contribution of preterm birth and size-for-gestational age for 125.4 million total births from nationwide records in 13 countries, 2000-2020

OBJECTIVE

To examine the contribution of preterm birth and size-for-gestational age in stillbirths using six 'newborn types'.

DESIGN

Population-based multi-country analyses.

SETTING

Births collected through routine data systems in 13 countries.

SAMPLE

125 419 255 total births from 22+0 to 44+6 weeks' gestation identified from 2000 to 2020.

METHODS

We included 635 107 stillbirths from 22+0  weeks' gestation from 13 countries. We classified all births, including stillbirths, into six 'newborn types' based on gestational age information (preterm, PT, <37+0  weeks versus term, T, ≥37+0  weeks) and size-for-gestational age defined as small (SGA, <10th centile), appropriate (AGA, 10th-90th centiles) or large (LGA, >90th centile) for gestational age, according to the international newborn size for gestational age and sex INTERGROWTH-21st standards.

MAIN OUTCOME MEASURES

Distribution of stillbirths, stillbirth rates and rate ratios according to six newborn types.

RESULTS

635 107 (0.5%) of the 125 419 255 total births resulted in stillbirth after 22+0  weeks. Most stillbirths (74.3%) were preterm. Around 21.2% were SGA types (PT + SGA [16.2%], PT + AGA [48.3%], T + SGA [5.0%]) and 14.1% were LGA types (PT + LGA [9.9%], T + LGA [4.2%]). The median rate ratio (RR) for stillbirth was highest in PT + SGA babies (RR 81.1, interquartile range [IQR], 68.8-118.8) followed by PT + AGA (RR 25.0, IQR, 20.0-34.3), PT + LGA (RR 25.9, IQR, 13.8-28.7) and T + SGA (RR 5.6, IQR, 5.1-6.0) compared with T + AGA. Stillbirth rate ratios were similar for T + LGA versus T + AGA (RR 0.7, IQR, 0.7-1.1). At the population level, 25% of stillbirths were attributable to small-for-gestational-age.

CONCLUSIONS

In these high-quality data from high/middle income countries, almost three-quarters of stillbirths were born preterm and a fifth small-for-gestational age, with the highest stillbirth rates associated with the coexistence of preterm and SGA. Further analyses are needed to better understand patterns of gestation-specific risk in these populations, as well as patterns in lower-income contexts, especially those with higher rates of intrapartum stillbirth and SGA.

Impact of venous thromboembolism on the mortality in patients with cancer: a population-based cohort study

Background

Despite recent improvements in the treatment of cancer, little is known about the long-term survival in patients with cancer and venous thromboembolism. We aimed to examine the five-year mortality of venous thromboembolism in cancer patients in a large population-based cohort study.

Methods

Using Danish healthcare registries from 1995 to 2020, we obtained data on cancer patients with venous thromboembolism and comparison cohorts of cancer patients without venous thromboembolism, matched in terms of cancer type, age, sex, and year of cancer diagnosis, and adjusted for level of comorbidity and frailty using the Charlson Comorbidity Index Score and Hospital Frailty Risk Score, marital status, use of selected medications, and recent surgery (<90 days).

Findings

During the study period, 886,536 patients were diagnosed with cancer. Of 1882 cancer patients diagnosed at the time of their venous thromboembolism, 44.4% (835/1882) had distant metastases. In this cohort, the one- and five-year mortality cumulative incidences were 68% (1284/1882) and 84% (1578/1882), respectively, in contrast to 38% (2135/5549) and 67% (3653/5549) in the comparison cohort. The mortality rate ratio was 4.34 (95% confidence interval [CI], 3.95-4.78) for the first year of follow-up and 3.44 (95% CI 3.17-3.73) for the five-year follow-up period. Of the 23,366 patients diagnosed with venous thromboembolism after cancer diagnosis, 18% (4183/23,366) had distant metastases at the time of cancer diagnosis. The cumulative incidence of death at one year was 45% (10,465/23,366; mortality rate ratio 3.48, 95% CI 3.37-3.60) and at five years 69% (15,669/23,366; mortality rate ratio 2.57, 95% CI 2.50-2.63).

Interpretation

Despite improved cancer treatment, venous thromboembolism in cancer patients is strongly associated with a poor prognosis.

Funding

The study was supported by grants from the Independent Research Fund Denmark (record no. 3101-00102B) and the Karen Elise Jensen Foundation.

Adherence to Pharmacotherapies After Heart Transplantation in Relation to Multimorbidity and Socioeconomic Position: A Nationwide Register-Based Study

No studies have examined the impact of multimorbidity and socioeconomic position (SEP) on adherence to the pharmacological therapies following heart transplantation (HTx). Using nationwide Danish registers, we tested the hypothesis that multimorbidity and SEP affect treatment patterns and adherence to pharmacological therapies in first-time HTx recipients. Pharmacological management included cost-free immunosuppressants and adjuvant medical treatment (preventive and hypertensive pharmacotherapies; loop diuretics). We enrolled 512 recipients. The median (IQR) age was 51 years (38-58 years) and 393 recipients (77%) were males. In recipients with at least two chronic diseases, prevalence of treatment with antihypertensive pharmacotherapies and loop diuretics was higher. The overall prevalence of adherence to treatment with tacrolimus or mycophenolate mofetil was at least 80%. Prevalence of adherence to preventive pharmacotherapies ranged between 65% and 95% and between 66% and 88% for antihypertensive pharmacotherapies and loop diuretics, respectively. In socioeconomically disadvantaged recipients, both the number of recipients treated with and adherence to cost-free everolimus, lipid modifying agents, angiotensin-converting enzyme/angiotensin II inhibitors, calcium channel blockers, and loop diuretics were lower. In recipients with multimorbidity, prevalence of treatment with antihypertensive pharmacotherapies and loop diuretics was higher. Among socioeconomically disadvantaged recipients, both number of patients treated with and adherence to cost-free everolimus and adjuvant pharmacotherapies were lower.

Comorbidities and mortality among patients with chronic obstructive pulmonary disease

INTRODUCTION

Comorbidities are common in patients with chronic obstructive pulmonary disease (COPD). Estimates of prevalence, incidence and prognostic impact of comorbidities provide foundational knowledge of COPD epidemiology. We examined the prevalence, incidence and prognostic impact of 21 comorbidities among patients with COPD compared with the Danish general population.

METHODS

We conducted a nationwide, population-based cohort study based on longitudinal Danish registry data, covering all Danish hospitals (2010-2021). The cohorts comprised 142 973 patients with a first-time hospital-based diagnosis of COPD and 428 917 age-matched and sex-matched comparators from the general population. During follow-up, we estimated the 5-year risk and risk difference, using competing risk methods when applicable.

RESULTS

At time of diagnosis, the comorbidities with the highest prevalence were mood, stress-related or anxiety disorders (25.2% for patients with COPD vs 13.1% for comparators), osteoporosis/hip fractures (17.4% vs 9.9%), diabetes (15.6% vs 10.5%), peripheral arterial disease (13.5% vs 4.9%) and heart failure (13.3% vs 4.0%). During follow-up, the risk of most incident comorbidities was markedly elevated among patients with COPD. The five comorbidities associated with the highest 5-year absolute risk difference with respect to the risk in the general population were mood, stress-related or anxiety disorders (5.7%), osteoporosis/hip fractures (5.6%), heart failure (4.2%), smoking-related cancers (2.8%) and peripheral arterial disease (2.7%). The 5-year mortality risk was 43% vs 17.7%. Among patients with COPD, the 5-year mortality risk markedly increased with the number of comorbidities present.

CONCLUSIONS

Our population-based findings underscore the importance of considering comorbidities in the management of COPD.

Risk of psychopathology following traumatic events among immigrants and native-born persons in Denmark

PURPOSE

Immigrants may have increased risk of mental disorders compared with native-born persons. We aimed to expand the limited research on immigrants' posttraumatic psychopathology related to traumatic experiences in their country of resettlement.

METHODS

We obtained data from a cohort of Danish residents with ≥ 1 traumatic event recorded in health and administrative national registries during 1994-2016. We calculated risks of posttraumatic stress disorder (PTSD), depression, and substance use disorders (SUD) within 5 years post-trauma among native-born Danes and immigrants who had been in Denmark for ≥ 10 years at the time of their index trauma (including immigrants overall and immigrants from specific regions). Risks were compared via age- and sex-standardized risk ratios (SRR) with 95% confidence intervals (CI). We restricted to persons with no record of the disorder under investigation in the 10 years pre-trauma, and stratified by non-interpersonal (e.g., transport accidents) versus interpersonal trauma (e.g., assaults).

RESULTS

Following non-interpersonal trauma, immigrants were more likely than native-born Danes to be diagnosed with PTSD (SRR = 5.2, 95% CI 4.6, 5.9), about as likely to be diagnosed with depression (SRR = 0.98, 95% CI 0.92, 1.1), and less likely to be diagnosed with SUD (SRR = 0.89, 95% CI 0.82, 0.95). Results were similar following interpersonal trauma, except the SRR for PTSD was reduced in magnitude (SRR = 3.0, 95% CI 1.7, 5.4). There were differences by region of birth.

CONCLUSION

Immigrants to Denmark have higher risk of PTSD following traumatic experiences than do native-born Danes, possibly due to the combined influence of adverse pre-, peri-, and/or post-migration experiences.

Association of Early-, Middle-, and Late-Life Depression With Incident Dementia in a Danish Cohort

Importance

Late-life depressive symptoms are associated with subsequent dementia diagnosis and may be an early symptom or response to preclinical disease. Evaluating associations with early- and middle-life depression will help clarify whether depression influences dementia risk.

Objective

To examine associations of early-, middle-, and late-life depression with incident dementia.

Design, Setting, and Participants

This was a nationwide, population-based, cohort study conducted from April 2020 to March 2023. Participants included Danish citizens from the general population with depression diagnoses who were matched by sex and birth year to individuals with no depression diagnosis. Participants were followed up from 1977 to 2018. Excluded from analyses were individuals followed for less than 1 year, those younger than 18 years, or those with baseline dementia.

Exposure

Depression was defined using diagnostic codes from the International Classification of Diseases (ICD) within the Danish National Patient Registry (DNPR) and Danish Psychiatric Central Research Register (DPCRR).

Main Outcomes and Measure

Incident dementia was defined using ICD diagnostic codes within the DPCRR and DNPR. Cox proportional hazards regression was used to examine associations between depression and dementia adjusting for education, income, cardiovascular disease, chronic obstructive pulmonary disease, diabetes, anxiety disorders, stress disorders, substance use disorders, and bipolar disorder. Analyses were stratified by age at depression diagnosis, years since index date, and sex.

Results

There were 246 499 individuals (median [IQR] age, 50.8 [34.7-70.7] years; 159 421 women [64.7%]) with diagnosed depression and 1 190 302 individuals (median [IQR] age, 50.4 [34.6-70.0] years; 768 876 women [64.6%]) without depression. Approximately two-thirds of those diagnosed with depression were diagnosed before the age of 60 years (684 974 [67.7%]). The hazard of dementia among those diagnosed with depression was 2.41 times that of the comparison cohort (95% CI, 2.35-2.47). This association persisted when the time elapsed from the index date was longer than 20 to 39 years (hazard ratio [HR], 1.79; 95% CI, 1.58-2.04) and among those diagnosed with depression in early, middle, or late life (18-44 years: HR, 3.08; 95% CI, 2.64-3.58; 45-59 years: HR, 2.95; 95% CI, 2.75-3.17; ≥60 years: HR, 2.31; 95% CI, 2.25-2.38). The overall HR was greater for men (HR, 2.98; 95% CI, 2.84-3.12) than for women (HR, 2.21; 95% CI, 2.15-2.27).

Conclusions and Relevance

Results suggest that the risk of dementia was more than doubled for both men and women with diagnosed depression. The persistent association between dementia and depression diagnosed in early and middle life suggests that depression may increase dementia risk.

Association between vaginal bleeding in pregnancy that resulted in delivery and risk of cancer: A Danish registry-based cohort study

BACKGROUND

Vaginal bleeding (VB) before 20 gestational weeks of a viable pregnancy is a manifestation of a threatened miscarriage. VB is associated with increased levels of pro-inflammatory cytokines such as interferon-gamma, tumour necrosis factor-alpha and interleukin-6. Increased levels of these cytokines and oxidative stress are risk factors for cancer. The risk of cancer following a VB-affected pregnancy that ended in childbirth is unknown.

OBJECTIVES

To investigate the associations between VB in pregnancy that resulted in delivery and risk of incident cancer.

METHODS

We conducted a cohort study (1995-2018) in Denmark using administrative and healthcare registries. We included 37,082 VB-affected deliveries, 1,363,614 VB-unaffected deliveries, 324,328 pregnancies ending in terminations, and 137,104 miscarriages. We computed the absolute risk of cancer and hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, calendar year, morbidities, and socio-economic factors using Cox proportional hazards regression. Multiple pregnancies to the same woman were accounted for in the analysis.

RESULTS

The median (25th-75th percentile) follow-up in the study was 12.6 (6.9, 18.2) years. The prevalence of VB in the present study was 3%. At the end of the follow-up, there were 1320 cancer cases among the VB-affected delivery cohort, 40,420 among the VB-unaffected delivery cohort, 10,300 among the termination cohort and 4790 among the miscarriage cohort. HRs for any cancer among VB-affected deliveries were 1.03 (95% CI 0.97, 1.08) compared with VB-unaffected deliveries, 1.03 (95% CI 0.97, 1.09) compared with terminations and 0.90 (95% CI 0.84, 0.95) compared with miscarriages. There were no increased risks of premenopausal breast cancer, cervical cancer, ovary and fallopian tube cancer or uterine cancer following VB-affected deliveries vs. comparison cohorts.

CONCLUSIONS

We found no evidence of an association between vaginal bleeding in pregnancy and an increased risk of cancer.

Antihypertensive Medications and PTSD Incidence in a Trauma Cohort

Objective: Antihypertensive medications have been examined as agents for posttraumatic stress disorder (PTSD) prevention in trauma-exposed individuals, given well-documented associations between PTSD and increased risk of cardiovascular disease and purported trauma-relevant mechanisms of action for these medications. Evidence regarding the effectiveness of such drugs for this purpose remains mixed.

Methods: We conducted a national population-based cohort study using data from Danish national registries to assess whether 4 classes of antihypertensive drugs (beta-adrenoceptor blockers [beta blockers], angiotensin II receptor blockers [ARBs], angiotensin-converting enzyme [ACE] inhibitors, and calcium channel blockers) were associated with a decreased incidence of PTSD (diagnosed according to ICD-10) over a 22-year study period. Data for this study originated from a population-based cohort of over 1.4 million persons who experienced a traumatic event between 1994 and 2016 in Denmark. We calculated the incidence rate of PTSD per 100,000 person-years among persons who filled a prescription for each class of drug in the 60 days prior to a traumatic event and for corresponding unexposed comparison groups. We then used Cox proportional hazards regression to compare the rate of PTSD among persons who filled an antihypertensive medication prescription within 60 days before their trauma to the rate among persons who did not.

Results: We found evidence that calcium channel blockers were associated with a decreased incidence of PTSD (adjusted hazard ratio = 0.63, 95% confidence interval [CI] = 0.34, 1.2); all other antihypertensive medication classes had null or near null associations.

Conclusions: These findings lay a foundation for additional research focusing on antihypertensive medications that appear most effective in reducing PTSD incidence following trauma and for additional replication work aimed at continuing to clarify the disparate findings reported in the literature to date.

Long-Term Temporal Trends in Survival Among Danish Patients with Advanced Cutaneous Melanoma: A Nationwide Follow-Up Study

Introduction

Population-based data on survival trends over time among patients with advanced cutaneous melanoma are lacking. We examined changes in mortality for patients diagnosed from 1980 to 2011 in a nationwide historical follow-up study using population-based medical registries from Denmark.

Material and Methods

The study population included all Danish patients with an incident diagnosis of advanced (metastatic or unresectable stage IIIA, IIIB, IIIC, or IV) cutaneous melanoma (ie, initial diagnosis for melanoma at stage III/IV) between 1980-2011 and who were followed-up until 2013. For each patient, we randomly matched 100 individuals from the general population on sex and year of birth. Age-standardized mortality rates were calculated by calendar year of diagnosis overall, 30 days after diagnosis, and during 31 to 364 days and 0-10 years after diagnosis. Stratified Cox's proportional hazards regression was used to compute hazard ratios.

Results

We identified a total of 1236 patients and 123,600 comparison cohort members. We observed that the standardized mortality rates of patients with advanced melanoma dropped from the 1980s onwards, but remain high (eg, 74.3 and 248.4 per 1000 person-years in 0-30 days and 31-364 days after diagnosis, respectively, for patients diagnosed during 2008-2011). Compared with the general population, patients with advanced melanoma had a 10.4-fold increased hazard of death during 0-10 years of follow-up. The highest relative mortality was found for the first year following melanoma diagnosis. No improvements in survival compared to the general population were observed in the most recent years of the study period, thus in 2004-2007 and 2008-2011.

Discussion and Conclusion

Survival of patients with advanced cutaneous melanoma in Denmark improved between 1980 and 2013 but appears to have leveled off in the years leading up to more widespread introduction of newer immuno-oncology therapies.

Burden of Chronic Obstructive Pulmonary Disease Attributable to Tuberculosis: A Microsimulation Study

Tuberculosis (TB) is a risk factor for chronic obstructive pulmonary disease (COPD), but COPD is also a predictor of TB. The excess life-years lost to COPD caused by TB can potentially be saved by screening for and treating TB infection. We examined the number of life-years that could be saved by preventing TB and TB-attributable COPD. We compared the observed (no intervention) and counterfactual microsimulation models constructed from observed rates in the Danish National Patient Registry (covering all Danish hospitals between 1995 and 2014). In the Danish population of TB and COPD-naive individuals (n = 5,206,922), 27,783 persons (0.5%) developed TB. Among those who developed TB, 14,438 (52.0%) developed TB with COPD. Preventing TB saved 186,469 life-years overall. The excess number of life-years lost to TB alone was 7.07 years per person, and the additional number of life-years lost among persons who developed COPD after TB was 4.86 years per person. The life-years lost to TB-associated COPD are substantial, even in regions where TB can be expected to be identified and treated promptly. Prevention of TB could prevent a substantial amount of COPD-related morbidity; the benefit of screening and treatment for TB infection is underestimated by considering morbidity from TB alone.

Sarcoidosis rates in BCG-vaccinated and unvaccinated young adults: A natural experiment using Danish registers

OBJECTIVES

Sarcoidosis may have an infectious trigger, including Mycobacterium spp. The Bacille Calmette-Guérin (BCG) vaccine provides partial protection against tuberculosis and induces trained immunity. We examined the incidence rate (IR) of sarcoidosis in Danish individuals born during high BCG vaccine uptake (born before 1976) compared with individuals born during low BCG vaccine uptake (born in or after 1976).

METHODS

We performed a quasi-randomized registry-based incidence study using data from the Danish Civil Registration System and the Danish National Patient Registry between 1995 and 2016. We included individuals aged 25-35 years old and born between 1970 and 1981. Using Poisson regression models, we calculated the incidence rate ratio (IRR) of sarcoidosis in individuals born during low BCG vaccine uptake versus high BCG vaccine uptake, adjusting for age and calendar year (separately for men and women).

RESULTS

The IR of sarcoidosis was increased for individuals born during low BCG vaccine uptake compared with individuals born during high BCG vaccine uptake, which was largely attributed to men. The IRR of sarcoidosis for men born during low BCG vaccine uptake versus high BCG vaccine uptake was 1.22 (95% confidence interval [CI] 1.02-1.45). In women, the IRR was 1.08 (95% CI 0.88-1.31).

CONCLUSION

In this quasi-experimental study that minimizes confounding, the time period with high BCG vaccine uptake was associated with a lower incidence rate of sarcoidosis in men, with a similar effect seen in women that did not reach significance. Our findings support a potential protective effect of BCG vaccination against the development of sarcoidosis. Future interventional studies for high-risk individuals could be considered.

Long-term Risk of Epilepsy Following Invasive Group B Streptococcus Disease in Neonates in Denmark

Importance

The risk of epilepsy after neonatal invasive Group B Streptococcus (iGBS) disease, particularly iGBS sepsis, is poorly understood.

Objective

To examine the association between neonatal iGBS (sepsis or meningitis) and long-term risk of epilepsy, stratified by sex, prematurity, and maternal socioeconomic position (SEP).

Design, Setting, and Participants

This population-based cohort study was conducted in Denmark with an inclusion period from 1997 through 2017 and follow-up until the end of 2018. A general population comparison cohort was randomly sampled and matched up to 10:1 to the exposed cohort. Linkage between Danish national registers were applied for data collection. Participants were infants aged 0 to 89 days. The general population comparison cohort was matched by sex, the child's year and month of birth, and gestational age. SEP was defined by maternal income and education.

Exposure

Hospital-diagnosed iGBS (sepsis or meningitis) during the first 89 days after birth.

Outcomes and measures

Epilepsy was defined by International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes and/or prescription codes for antiepileptic drugs using Danish medical registry data. Cumulative risk (CR) of epilepsy was calculated by treating death as a competing event. Cox proportional hazards regression was used to estimate hazard ratios with 95% CIs. Effect modification by sex, prematurity, and maternal SEP was assessed on an additive scale.

Results

A total of 1432 children (792 [55.3%] boys; 1126 [78.6%] with gestational age ≥37 weeks) were identified with iGBS disease: 1264 with sepsis and 168 with meningitis. In the comparison cohort, there were 14 211 children (7869 [55.4%] boys; 11 260 [79.2%] with gestational age ≥37 weeks). The overall (0 to 22 years) CR of epilepsy was 3.6% (95% CI, 2.6%-5.0%) in children with iGBS disease and 2.3% (95% CI, 1.9%-2.7%) in the comparison cohort. The overall CR of epilepsy for iGBS meningitis was 15.1% (95% CI, 8.9%-22.8%) and 2.2% (95% CI, 1.4%-3.4%) for iGBS sepsis. The adjusted hazard ratio for epilepsy in children with iGBS disease was 2.04 (95% CI, 1.46-2.85). Being a boy, born premature, or born to a mother belonging to a low SEP group was associated with an increased risk of epilepsy in later childhood.

Conclusion

In this population-based cohort study of 1432 neonates, iGBS disease was associated with a higher incidence of epilepsy in later childhood, notably after meningitis. Premature birth, sex, and low maternal SEP modified the association.

Incidence and prognosis of superficial vein thrombosis during pregnancy and the post-partum period: a Danish nationwide cohort study

BACKGROUND

The incidence of superficial vein thrombosis (SVT) of the legs and the subsequent risk of venous thromboembolism during pregnancy and the post-partum period is unknown. To better understand the clinical course of SVT during these times, we aimed to estimate the incidence rate of SVT during pregnancy and in the post-partum period, as well as the risk of subsequent venous thromboembolism.

METHODS

In this nationwide cohort study, we collected data on all pregnant women who delivered between Jan 1, 1997, and Dec 31, 2017, in Denmark were extracted from the Danish Medical Birth Register, the Danish National Patient Registry, and the Danish National Prescription Registry. Data on ethnicity were not available. Incidence rates per 1000 person-years were calculated for each trimester and the antepartum and post-partum period. Among women with a pregnancy-related SVT, risk of subsequent venous thromboembolism within the same pregnancy or post-partum period were calculated and compared with a matched cohort of pregnant women without SVT using Cox proportional hazards analysis.

FINDINGS

During 1 276 046 deliveries, 710 diagnoses of lower extremity SVT occurred from conception up to 12 weeks postpartum (0·6 per 1000 person-years [95% CI 0·5-0·6]). The incidence rates of SVT per 1000 person-years were 0·1 (95% CI 0·1-0·2) during the during the first trimester, 0·2 (0·2-0·3) during the second trimester, and 0·5 (0·5-0·6) during the third trimester. The incidence rate was 1·6 per 1000 person-years (95% CI 1·4-1·7) during the post-partum period. Of the 211 women with antepartum SVT included in the analysis, 22 (10·4%) were diagnosed with venous thromboembolism, compared with 25 (0·1%) in women without SVT (hazard ratio 83·3 [95% CI 46·3-149·7]).

INTERPRETATION

The incidence rate of SVT during pregnancy and the post-partum period was low. However, if SVT during pregnancy was diagnosed, the risk of developing venous thromboembolism during the same pregnancy was high. These results might help physicians and patients to make decisions about anticoagulant management of pregnancy-related SVT.

FUNDING

None.

Individual-Level Socioeconomic Position and Long-Term Prognosis in Danish Heart-Transplant Recipients

Socioeconomic deprivation can limit access to healthcare. Important gaps persist in the understanding of how individual indicators of socioeconomic disadvantage may affect clinical outcomes after heart transplantation. We sought to examine the impact of individual-level socioeconomic position (SEP) on prognosis of heart-transplant recipients. A population-based study including all Danish first-time heart-transplant recipients (n = 649) was conducted. Data were linked across complete national health registers. Associations were evaluated between SEP and all-cause mortality and first-time major adverse cardiovascular event (MACE) during follow-up periods. The half-time survival was 15.6 years (20-year period). In total, 330 (51%) of recipients experienced a first-time cardiovascular event and the most frequent was graft failure (42%). Both acute myocardial infarction and cardiac arrest occurred in ≤5 of recipients. Low educational level was associated with increased all-cause mortality 10-20 years post-transplant (adjusted hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.19-3.19). During 1-10 years post-transplant, low educational level (adjusted HR 1.66, 95% CI 1.14-2.43) and low income (adjusted HR 1.81, 95% CI 1.02-3.22) were associated with a first-time MACE. In a country with free access to multidisciplinary team management, low levels of education and income were associated with a poorer prognosis after heart transplantation.

Preadmission Opioid Use and 1-Year Mortality Following Incident Myocardial Infarction: A Danish Population-Based Cohort Study (1997-2016)

Background Opioid use has been linked to an increased risk of myocardial infarction and cardiovascular mortality, but the prognostic impact of opioid use before an incident myocardial infarction is largely unknown. Methods and Results We conducted a nationwide population-based cohort study including all patients hospitalized for an incident myocardial infarction in Denmark (1997-2016). Based on their last redeemed opioid prescription before admission, patients were categorized as current users (0-30 days), recent users (31-365 days), former users (>365 days), and nonusers. One-year all-cause mortality was calculated using the Kaplan-Meier method. Hazard ratios (HRs) were computed using Cox proportional hazards regression analyses, adjusting for age, sex, comorbidity, any preceding surgery within 6 months before the myocardial infarction admission, and medication use before the myocardial infarction admission. We identified 162 861 patients with an incident myocardial infarction. Of these, 8% were current opioid users, 10% were recent opioid users, 24% were former opioid users, and 58% were nonusers of opioids. One-year mortality was highest among current users (42.5% [95% CI, 41.7%-43.3%]) and lowest among nonusers (20.5% [95% CI, 20.2%-20.7%]). Compared with nonusers, current users had an elevated 1-year all-cause mortality risk (adjusted HR, 1.26 [95% CI, 1.22-1.30]). Following adjustment, neither recent users nor former users of opioids were at elevated risk. Conclusions Preadmission opioid use was associated with an increased 1-year all-cause mortality risk following an incident myocardial infarction. Opioid users thus represent a high-risk subgroup of patients with myocardial infarction.

Maternal Smoking During Pregnancy and Risk of Appendicitis in the Offspring

BACKGROUND

Existing evidence on the link between smoking and appendicitis is scarce and ambiguous. We therefore conducted a population-based cohort study in Denmark to investigate whether smoking during pregnancy is associated with an increased risk of appendicitis in offspring.

METHODS

We used the Danish Birth Registry to include all singletons born during 1991-2017 and to identify maternal smoking status during pregnancy. We followed the children from birth until date of appendicitis, emigration, death, or administrative end of study (31 December 2018), whichever came first. We calculated crude and adjusted hazard ratios (HRs) of appendicitis with 95% confidence intervals (CIs) comparing children of mothers who smoked during pregnancy to children of nonsmokers. Further, we conducted a bias analysis and sibling analysis.

RESULTS

We included 1,659,526 singletons of whom 19% were born to mothers who smoked during pregnancy. After maximum 28 years of follow-up, hazard rates for children of smokers were slightly higher than for children of nonsmokers [adjusted HR: 1.07 (95% CI = 1.04, 1.10)]. Stratification by sex revealed no association for males [adjusted HR: 1.02 (95% CI = 0.99, 1.06)], but a higher HR for females [adjusted HR: 1.13 (95% CI = 1.09, 1.18)]. This association increased with increasing length of follow-up, indicating that the association may be mediated by later-life exposures. The bias analysis indicated that misclassification of maternal smoking could attenuate a true association, while the sibling analysis showed no association.

CONCLUSIONS

Maternal smoking during pregnancy and appendicitis in the offspring may be associated.

Recurrent venous thromboembolism and bleeding with extended anticoagulation: the VTE-PREDICT risk score

AIMS

Deciding to stop or continue anticoagulation for venous thromboembolism (VTE) after initial treatment is challenging, as individual risks of recurrence and bleeding are heterogeneous. The present study aimed to develop and externally validate models for predicting 5-year risks of recurrence and bleeding in patients with VTE without cancer who completed at least 3 months of initial treatment, which can be used to estimate individual absolute benefits and harms of extended anticoagulation.

METHODS AND RESULTS

Competing risk-adjusted models were derived to predict recurrent VTE and clinically relevant bleeding (non-major and major) using 14 readily available patient characteristics. The models were derived from combined individual patient data from the Bleeding Risk Study, Hokusai-VTE, PREFER-VTE, RE-MEDY, and RE-SONATE (n = 15,141, 220 recurrences, 189 bleeding events). External validity was assessed in the Danish VTE cohort, EINSTEIN-CHOICE, GARFIELD-VTE, MEGA, and Tromsø studies (n = 59 257, 2283 recurrences, 3335 bleeding events). Absolute treatment effects were estimated by combining the models with hazard ratios from trials and meta-analyses. External validation in different settings showed agreement between predicted and observed risks up to 5 years, with C-statistics ranging from 0.48-0.71 (recurrence) and 0.61-0.68 (bleeding). In the Danish VTE cohort, 5-year risks ranged from 4% to 19% for recurrent VTE and 1% -19% for bleeding.

CONCLUSION

The VTE-PREDICT risk score can be applied to estimate the effect of extended anticoagulant treatment for individual patients with VTE and to support shared decision-making.

Labour market participation and retirement after stroke in Denmark: registry based cohort study

OBJECTIVE

To examine labour market participation and retirement among patients with stroke and matched people in the general population according to stroke subtype.

DESIGN

Nationwide, population based, matched cohort study.

SETTING

Danish Stroke Registry, covering all Danish hospitals, and other nationwide registries (2005-18).

PARTICIPANTS

Patients (aged 18-60 years and active in the labour market) with a first time diagnosis of ischaemic stroke (n=16 577), intracerebral haemorrhage (n=2025), or subarachnoid haemorrhage (n=4305), and individuals from the general population, matched on age, sex, and calendar year (n=134 428). The median Scandinavian stroke scale score was 55.

MAIN OUTCOME MEASURES

Unweighted prevalences of labour market participation, receipt of sick leave benefits, receipt of disability pension, voluntary early retirement, state pension, and death were computed for each week and up to five years after stroke diagnosis. A log-linear Poisson model was used to obtain exact prevalence estimates as well as propensity score weighted prevalence differences and prevalence ratios at six months, one year, two years, and five years after stroke diagnosis.

RESULTS

Most patients (62% of those with ischaemic stroke, 69% of those with intracerebral haemorrhage, and 52% of those with subarachnoid haemorrhage) went on sick leave within three weeks of diagnosis. Prevalence of labour market participation among patients with ischaemic stroke compared with matched individuals from the general population was 56.6% versus 96.6% at six months, and 63.9% versus 91.6% at two years. Prevalence of sick leave was 39.8% versus 2.6% at six months, and 15.8% versus 3.8% at two years. Prevalence of receipt of a disability pension was 0.9% versus 0.2% at six months, and 12.2% versus 0.6% at two years. Adjusting for socioeconomic and comorbidity differences between patients and matched individuals from the general population using propensity score weighting methods had little impact on contrasts. Patients with intracerebral haemorrhage had higher prevalences of sick leave and receipt of a disability pension and thus a lower prevalence of labour market participation, while prevalences for patients with subarachnoid haemorrhage were similar in magnitude to those for patients with ischaemic stroke.

CONCLUSIONS

In a highly resourced country, about two thirds of working age adults with ischaemic stroke of primarily mild severity participated in the labour market two years after diagnosis. Sick leave and receipt of a disability pension were the most common reasons for non-participation. Patients with intracerebral haemorrhage were less likely to return to the labour market than patients with ischaemic stroke and subarachnoid haemorrhage.

Registry-based cohort study of alpha-1 antitrypsin deficiency prevalence, incidence and mortality in Denmark 2000-2018

OBJECTIVE

To estimate the prevalence of diagnosed alpha-1 antitrypsin deficiency (dAATD) in Denmark as of 31 December 2018, and dAATD incidence and mortality from 1 January 2000 to 31 December 2018.

STUDY DESIGN AND SETTING

We used the Danish National Patient Registry to identify patients with dAATD based on the International Classification of Diseases, 10th Revision (ICD-10) code E88.0A and the Danish Civil Registration System (CRS) for population counts and vital status. We estimated dAATD prevalence, incidence and mortality. We compared mortality among patients with dAATD and an age-matched and sex-matched cohort extracted from the Danish CRS. We conducted a sensitivity analysis to examine whether coding changes during 2000-2018, from a general to a more specific ICD-10 code for AATD, and left truncation affected results appreciably.

RESULTS

The prevalence of dAATD was 12.9 (95% CI 11.9 to 13.8) per 100 000 persons. The age distribution was bimodal, with peaks at ages ≤12 and ≥45 years. The incidence rate per 100 000 person-years was 0.90 (95% CI 0.85 to 0.96), again with a bimodal age distribution. Mortality was higher for patients with dAATD than for the general population (mortality rate ratio (mRR) 4.7, 95% CI 4.1 to 5.3), especially for children (mRR 33.8, 95% CI 6.8 to 167.4). The sensitivity analysis indicated that dAATD prevalence might have been as high as 19.7 per 100 000 persons due to less specific ICD-10 coding for AATD early in the study period or 21.4 per 100 000 persons correcting for left truncation.

CONCLUSION

Diagnosed AATD was associated with increased mortality, especially for children. The finding for children was based on few deaths and had very wide 95% CIs.

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.

Sarcoidosis incidence after mTOR inhibitor treatment

OBJECTIVE

Mechanistic target of rapamycin (mTOR) inhibitors are effective in animal models of granulomatous disease, but their benefit in sarcoidosis patients is unknown. We evaluated the incidence of sarcoidosis in patients treated with mTOR inhibitors versus calcineurin inhibitors.

METHODS

This was a cohort study using the Optum Clinformatics® Data Mart (CDM) Database (2003-2019), IBM® MarketScan® Research Database (2006-2016), and Danish health and administrative registries (1996-2018). Patients aged ≥18 years with ≥1 year continuous enrollment before and after kidney, liver, heart, or lung transplant treated with an mTOR inhibitor or calcineurin inhibitor were included. Patients diagnosed with sarcoidosis before, or up to 90 days after, transplant were excluded. The incidence of sarcoidosis by treatment group was calculated.

RESULTS

In the Optum CDM/IBM MarketScan cohort, 1,898 patients were treated with an mTOR inhibitor (mean age 49 years; 34% female) and 9,894 patients were treated with a calcineurin inhibitor (mean age 50 years; 37% female). The mean follow-up in the mTOR inhibitor group was 1.1 years, with no incident sarcoidosis diagnosed. In the calcineurin inhibitor group, the mean follow-up was 2.2 years, with 12 incident sarcoidosis cases diagnosed. In the Danish cohort, 230 patients were treated with an mTOR inhibitor (mean age 49; 45% female), with no incident sarcoidosis diagnosed. There were 3,411 patients treated with a calcineurin inhibitor (mean age 45; 40% female), with 10 incident cases of sarcoidosis diagnosed.

CONCLUSIONS

This study indicates a potential protective effect of mTOR inhibitor treatment compared with calcineurin inhibitor treatment against the development of sarcoidosis.

Short-term and long-term risk of mortality and neurodevelopmental impairments after bacterial meningitis during infancy in children in Denmark and the Netherlands: a nationwide matched cohort study

Background

Few studies have reported the long-term consequences of bacterial meningitis during infancy, and studies that have been done usually do not include a comparison cohort. We aimed to assess short-term and long-term risk of mortality, neurodevelopmental impairment (NDI), and health-care use and household income in cohorts of children with and without a history of bacterial meningitis during infancy in Denmark and the Netherlands.

Methods

In this nationwide cohort study, infants with a history of bacterial meningitis before age 1 year were identified through the Danish Medical Birth Registry and Danish National Patient Registry using International Classification of Diseases (ICD)-10 codes and through the Netherlands Reference Laboratory for Bacterial Meningitis. Infants were matched (1:10) by sex and birth month and year to a comparison cohort of the general population without a history of bacterial meningitis. We analysed mortality using Cox proportional hazards regression. In Denmark, diagnoses of NDIs were based on ICD-10 codes; in the Netherlands, special educational needs were used as a functional NDI outcome. Risk ratios (RRs) of NDIs were estimated using modified Poisson regression. We also analysed long-term health-care use in Denmark and household income in both countries. All regression analyses were adjusted for sex and year of birth, and stratified by pathogen whenever sample size allowed.

Findings

We included 2216 children with a history of bacterial meningitis (570 [25·7%] in Denmark between Jan 1, 1997, and Dec 31, 2018, and 1646 [74·3%] in the Netherlands between Jan 1, 1995, and Dec 31, 2018), matched to 22 127 comparison cohort members. Median age at diagnosis was 2·8 months (IQR 0·4–7·1) in Denmark and 4·3 months (0·7–7·4) in the Netherlands. Mortality risks within 3 months after disease onset were 3·9% (95% CI 2·6–5·8%) in Denmark and 5·9% (4·7–7·0) in the Netherlands, compared with 0·0% (p<0·0001) and 0·1% (p<0·0001) in the comparison cohorts. Survivors had an increased risk of moderate or severe NDIs at age 10 years (RR 5·0 [95% CI 3·5–7·1] in Denmark and 4·9 [4·0–6·2] in the Netherlands) compared to children in the comparison cohort, particularly after pneumococcal and group B streptococcal meningitis. In Denmark, a history of bacterial meningitis was associated with increased health-care use in the 10 years following diagnosis (rate ratio 4·5 [95% CI 3·9–5·2] for outpatient visits and 4·1 [3·6–4·7] for hospital admissions).

Interpretation

Our study shows increased risk of mortality in the short and long term, a five times increase in risk of NDIs, and increased health-care use after bacterial meningitis during infancy. Together with context-specific incidence data, our results can advance pathogen-specific estimation of the meningitis burden and inform service provision at the individual and population level.

Funding

Bill & Melinda Gates Foundation, the Stichting Remmert Adriaan Laan Fonds, and the Netherlands Organisation for Health Research and Development.

Risk of Major Cardiovascular and Cerebrovascular Events in Users of Lisdexamfetamine and Other Medications for Attention-Deficit/Hyperactivity Disorder in Denmark and Sweden: A Population-Based Cohort Study

INTRODUCTION

This study aimed to estimate risks of cardiovascular and cerebrovascular events in patients treated with lisdexamfetamine dimesylate (LDX) compared with patients previously treated with other attention-deficit/hyperactivity disorder (ADHD) medications (amphetamine, dexamphetamine, methylphenidate or atomoxetine).

METHODS

This population-based cohort study used data from Danish and Swedish medical and administrative national registers. The LDX cohort included adult patients initiating LDX with at least 12 months' data preceding first LDX dispensing (index date). A random sample of patients treated with at least one non-LDX ADHD medication in the 6-24 months (but not less than 6 months) before index date (previous-users cohort) were matched to LDX users on age, sex, region and calendar year. The primary outcome, a composite of major adverse cardiovascular and cerebrovascular events (MACE), included first hospitalisation for acute myocardial infarction or stroke and out-of-hospital coronary heart disease or cerebrovascular disease death. Incidence rates (IRs) and IR ratios (IRRs) with 95% confidence intervals (CIs) of MACE were estimated using Poisson regression.

RESULTS

From Denmark/Sweden, 5516/40,163 LDX users and 27,494/200,389 previous users were included. In Denmark, IRs of MACE/1000 person-years (95% CI) were similar for LDX (1.63 [0.85-3.14]) and previous users (1.61 [1.28-2.01]). In Sweden, IRs (95% CI) were 1.40 (1.09-1.79) in LDX users and 1.17 (1.00-1.38) in previous users. Adjusted MACE IRRs (95% CI) for LDX versus previous use were 1.01 (0.48-2.13) in Denmark, 1.13 (0.75-1.71) in Sweden, and 1.10 (0.77-1.58) in the pooled analysis.

CONCLUSION

Our findings suggest little to no increased risk of cardiovascular and cerebrovascular events in patients treated with LDX compared with patients previously treated with other ADHD medications.

Group B streptococcus infection during pregnancy and infancy: estimates of regional and global burden

BACKGROUND

Group B streptococcus (GBS) colonisation during pregnancy can lead to invasive GBS disease (iGBS) in infants, including meningitis or sepsis, with a high mortality risk. Other outcomes include stillbirths, maternal infections, and prematurity. There are data gaps, notably regarding neurodevelopmental impairment (NDI), especially after iGBS sepsis, which have limited previous global estimates. In this study, we aimed to address this gap using newly available multicountry datasets.

METHODS

We collated and meta-analysed summary data, primarily identified in a series of systematic reviews published in 2017 but also from recent studies on NDI and stillbirths, using Bayesian hierarchical models, and estimated the burden for 183 countries in 2020 regarding: maternal GBS colonisation, iGBS cases and deaths in infants younger than 3 months, children surviving iGBS affected by NDI, and maternal iGBS cases. We analysed the proportion of stillbirths with GBS and applied this to the UN-estimated stillbirth risk per country. Excess preterm births associated with maternal GBS colonisation were calculated using meta-analysis and national preterm birth rates.

FINDINGS

Data from the seven systematic reviews, published in 2017, that informed the previous burden estimation (a total of 515 data points) were combined with new data (17 data points) from large multicountry studies on neurodevelopmental impairment (two studies) and stillbirths (one study). A posterior median of 19·7 million (95% posterior interval 17·9-21·9) pregnant women were estimated to have rectovaginal colonisation with GBS in 2020. 231 800 (114 100-455 000) early-onset and 162 200 (70 200-394 400) late-onset infant iGBS cases were estimated to have occurred. In an analysis assuming a higher case fatality rate in the absence of a skilled birth attendant, 91 900 (44 800-187 800) iGBS infant deaths were estimated; in an analysis without this assumption, 58 300 (26 500-125 800) infant deaths from iGBS were estimated. 37 100 children who recovered from iGBS (14 600-96 200) were predicted to develop moderate or severe NDI. 40 500 (21 500-66 200) maternal iGBS cases and 46 200 (20 300-111 300) GBS stillbirths were predicted in 2020. GBS colonisation was also estimated to be potentially associated with considerable numbers of preterm births.

INTERPRETATION

Our analysis provides a comprehensive assessment of the pregnancy-related GBS burden. The Bayesian approach enabled coherent propagation of uncertainty, which is considerable, notably regarding GBS-associated preterm births. Our findings on both the acute and long-term consequences of iGBS have public health implications for understanding the value of investment in maternal GBS immunisation and other preventive strategies.

FUNDING

Bill & Melinda Gates Foundation.

Neurodevelopmental and growth outcomes after invasive Group B Streptococcus in early infancy: A multi-country matched cohort study in South Africa, Mozambique, India, Kenya, and Argentina

BACKGROUND

Data are limited regarding long-term consequences of invasive GBS (iGBS) disease in early infancy, especially from low- and middle-income countries (LMIC) where most cases occur. We aimed to estimate risk of neurodevelopmental impairment (NDI) in children with a history of iGBS disease.

METHODS

A multi-country matched cohort study was undertaken in South Africa, India, Mozambique, Kenya, and Argentina from October 2019 to April 2021. The exposure of interest was defined as a history of iGBS disease (sepsis or meningitis) before 90 days of age, amongst children now aged 1·5-18 years. Age and sex-matched, children without history of GBS were also recruited. Age-appropriate, culturally-adapted assessments were used to define NDI across multiple domains (cognitive, motor, hearing, vision, emotional-behaviour, growth). Pooled NDI risk was meta-analysed across sites. Association of iGBS exposure and NDI outcome was estimated using modified Poisson regression with robust variance estimator.

FINDINGS

Amongst 138 iGBS survivors and 390 non-iGBS children, 38·1% (95% confidence interval [CI]: 30·0% - 46·6%) of iGBS children had any NDI, compared to 21·7% (95% CI: 17·7% - 26·0%) of non- iGBS children, with notable between-site heterogeneity. Risk of moderate/severe NDI was 15·0% (95% CI: 3·4% - 30·8%) among GBS-meningitis, 5·6% (95% CI: 1·5% - 13·7%) for GBS-sepsis survivors. The adjusted risk ratio (aRR) for moderate/severe NDI among iGBS survivors was 1.27 (95% CI: 0.65, 2.45), when compared to non-GBS children. Mild impairment was more frequent in iGBS (27.6% (95% CI: 20.3 - 35.5%)) compared to non-GBS children (12.9% (95% CI: 9.7% - 16.4%)). The risk of emotional-behavioural problems was similar irrespective of iGBS exposure (aRR=0.98 (95% CI: 0.55, 1.77)).

INTERPRETATION

Our findings suggest that iGBS disease is on average associated with a higher risk of moderate/severe NDI, however substantial variation in risk was observed between sites and data are consistent with a wide range of values. Our study underlines the importance of long-term follow-up for at-risk neonates and more feasible, standardised assessments to facilitate diagnosis in research and clinical practice.

FUNDING

This work was supported by a grant (INV-009018) from the Bill & Melinda Gates Foundation to the London School of Hygiene &Tropical Medicine.

The Interaction Effect between Comorbidity Burden and Venous Thromboembolism on Mortality: A Nationwide Cohort Study

BACKGROUND

Comorbidity influences venous thromboembolism (VTE) mortality, but it is unknown whether this is due to comorbidity alone or whether biological interaction exists.

OBJECTIVES

We examined whether comorbidity and VTE interact to increase VTE mortality beyond their individual effects.

METHODS

This nationwide population-based cohort study included all VTE patients ≥18 years during 2000 to 2016, and an age-, sex-, and comorbidity-matched comparison cohort of individuals without VTE. We computed age-standardized mortality rates and examined interaction on the additive scale using interaction contrasts (difference in rate differences).

RESULTS

After 30-day follow-up, the mortality rate per 1,000 person-years among individuals with no comorbidity was 419 (95% confidence interval [CI]: 391-447) in the VTE and 16 (95% CI: 13-18) in the comparison cohort (rate difference: 403). The corresponding mortality rate increased to 591 (95% CI: 539-643) in the VTE cohort and 38 (95% CI: 33-44) in the comparison cohort among individuals with low comorbidity (rate difference: 553). The interaction contrast (150) showed that 25% (150/591) of mortality was explained by the interaction in individuals with low comorbidity. This percentage increased to 56% for moderate and 63% for severe comorbidity. Interaction effects were largest within 30-day follow-up, for provoked VTE, in young individuals, and in individuals noncompliant to anticoagulant therapy. Dose-response patterns for interaction effects were also observed after 31-365-day and >1-5-year follow-up (p < 0.0001). Interaction effects varied between individual comorbidities.

CONCLUSION

Biological interaction between comorbidity and VTE explained a substantial proportion of VTE mortality. The interaction effect increased with comorbidity burden.

Using Danish national registry data to understand psychopathology following potentially traumatic experiences

Research on posttraumatic psychopathology has focused primarily on posttraumatic stress disorder (PTSD); other posttraumatic psychiatric diagnoses are less well documented. The present study aimed to (a) develop a methodology to derive a cohort of individuals who experienced potentially traumatic events (PTEs) from registry-based data and (b) examine the risk of psychopathology within 5 years of experiencing a PTE. Using data from Danish national registries, we created a cohort of individuals with no age restrictions (range: 0-108 years) who experienced at least one of eight possible PTEs between 1994 and 2016 (N = 1,406,637). We calculated the 5-year incidence of nine categories of ICD-10 psychiatric disorders among this cohort and examined standardized morbidity ratios (SMRs) comparing the incidence of psychopathology in this group to the incidence in a nontraumatic stressor cohort (i.e., nonsuicide death of a relative; n = 423,270). Stress disorders (2.5%), substance use disorders (4.1%), and depressive disorders (3.0%) were the most common diagnoses following PTEs. Overall, the SMRs for the associations between any PTE and psychopathology varied from 1.9, 95% CI [1.9, 2.0], for stress disorders to 5.2, 95% CI [5.1. 5.3], for personality disorders. All PTEs except pregnancy-related trauma were associated with all forms of psychopathology. Associations were consistent regardless of whether a stress disorder was present. Traumatic experiences have a broad impact on psychiatric health. The present findings demonstrate one approach to capturing trauma exposure in medical record registry data. Increased traumatic experience characterization across studies will help improve the field's understanding of posttraumatic psychopathology.

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.

The Joint Effects of Depression and Comorbid Psychiatric Disorders on Suicide Deaths: Competing Antagonism as an Explanation for Subadditivity

BACKGROUND

Previous studies of the effect of interaction between psychiatric disorders on suicide have reported mixed results. We investigated the joint effect of depression and various comorbid psychiatric disorders on suicide.

METHODS

We conducted a population-based case-cohort study with all suicide deaths occurring between 1 January 1995 and 31 December 2015 in Denmark (n = 14,103) and a comparison subcohort comprised of a 5% random sample of the source population at baseline (n = 265,183). We quantified the joint effect of pairwise combinations of depression and major psychiatric disorders (e.g., organic disorders, substance use disorders, schizophrenia, bipolar disorder, neurotic disorders, eating disorders, personality disorders, intellectual disabilities, developmental disorders, and behavioral disorders) on suicide using marginal structural models and calculated the relative excess risk due to interaction. We assessed for the presence of competing antagonism for negative relative excess risk due to interactions.

RESULTS

All combinations of depression and comorbid psychiatric disorders were associated with increased suicide risk. For example, the rate of suicide among men with depression and neurotic disorders was 20 times (95% CI = 15, 26) the rate in men with neither disorder. Most disorder combinations were associated with subadditive suicide risk, and there was evidence of competing antagonism in most of these cases.

CONCLUSIONS

Subadditivity may be explained by competing antagonism. When both depression and a comorbid psychiatric disorder are present, they may compete to cause the outcome such that having 2 disorders may be no worse than having a single disorder with respect to suicide risk.

Interpregnancy Weight Change Among Mothers of a Child with a Major Congenital Anomaly: A Danish Nationwide Cohort Study

Background

The mother of an infant with a major congenital anomaly is at a higher risk of premature cardiometabolic disease, possibly from chronic caregiver stress and distraction from self-care, including maintaining a healthy lifestyle and body weight.

Objective

To compare the interpregnancy weight gain in women whose first infant had a major congenital anomaly vs those without an affected child.

Methods

Multivariable linear regression compared women whose infant had an anomaly vs those whose infant did not, adjusting for interpregnancy time interval, demographics, smoking and health status at the first pregnancy.

Results

Of the 199,536 women who had two consecutive singleton births, 4035 (2.0%) had a child with an anomaly at the first birth. The mean (SD) maternal BMI at the start of the first pregnancy was 24.1 (4.7) and 23.7 (4.4) kg/m² in women with, and without, an anomaly-affected newborn. By the start of the second pregnancy, 3 years later, they had gained a mean (SD) of 2.2 (5.5) and 1.8 (5.2) kg, respectively – an adjusted absolute higher gain of 0.26 kg (95% CI 0.10 to 0.42) in women with an anomaly-affected first-born infant compared to those with an unaffected pregnancy. The adjusted interpregnancy weight gain difference was greatest in women whose first-born infant had a multi-organ anomaly at 0.59 kg (95% CI 0.02 to 1.16). The adjusted odds ratio of moving from a normal BMI category of 18.5–24.9 kg/m² in the first pregnancy, to an overweight or obese BMI category of 25+ kg/m² in the second, was 1.18 (95% CI 1.06 to 1.32) comparing mothers with vs without an anomaly-affected child in the first pregnancy.

Conclusion

Mothers of an infant with a major congenital anomaly have a modestly higher interpregnancy weight gain and tend to climb to a higher BMI category. The long-term implications of this greater weight trajectory require further study.

Pre-trauma predictors of severe psychiatric comorbidity 5 years following traumatic experiences

BACKGROUND

A minority of persons who have traumatic experiences go on to develop post-traumatic stress disorder (PTSD), leading to interest in who is at risk for psychopathology after these experiences. Complicating this effort is the observation that post-traumatic psychopathology is heterogeneous. The goal of this nested case-control study was to identify pre-trauma predictors of severe post-traumatic psychiatric comorbidity, using data from Danish registries.

METHODS

The source population for this study was the population of Denmark from 1994 through 2016. Cases had received three or more psychiatric diagnoses (across all ICD-10 categories) within 5 years of a traumatic experience (n = 20 361); controls were sampled from the parent cohort using risk-set sampling (n = 81 444). Analyses were repeated in samples stratified by pre-trauma psychiatric diagnoses. We used machine learning methods (classification and regression trees and random forest) to determine the important predictors of severe post-trauma psychiatric comorbidity from among hundreds of pre-trauma predictor variables spanning demographic and social variables, psychiatric and somatic diagnoses and filled medication prescriptions.

RESULTS

In the full sample, pre-trauma psychiatric diagnoses (e.g. stress disorders, alcohol-related disorders, personality disorders) were the most important predictors of severe post-trauma psychiatric comorbidity. Among persons with no pre-trauma psychiatric diagnoses, demographic and social variables (e.g. marital status), type of trauma, medications used primarily to treat psychiatric symptomatology, anti-inflammatory medications and gastrointestinal distress were important to prediction. Results among persons with pre-trauma psychiatric diagnoses were consistent with the overall sample.

CONCLUSIONS

This study builds on the understanding of pre-trauma factors that predict psychopathology following traumatic experiences, by examining a broad range of predictors of post-trauma psychopathology and comorbidity beyond PTSD.

Risk of Parkinson Disease and Secondary Parkinsonism in Myocardial Infarction Survivors

Background

In addition to primary neurodegenerative processes, vascular disorders, such as stroke, can lead to parkinsonism. However, some cardiovascular risk factors, such as smoking and elevated cholesterol levels, are associated with reduced risk of Parkinson disease. We examined the risk of Parkinson disease and secondary parkinsonism in 1‐year survivors of myocardial infarction (MI).

Methods and Results

We conducted a nationwide population‐based matched cohort study using Danish medical registries from 1995 to 2016. We identified all patients with a first‐time MI diagnosis and sampled a sex‐, age‐, and calendar year–matched general population comparison cohort without MI. Cox regression analysis was used to compute adjusted hazard ratios (aHRs) for Parkinson disease and secondary parkinsonism, controlled for matching factors and adjusted for relevant comorbidities and socioeconomic factors. We identified 181 994 patients with MI and 909 970 matched comparison cohort members (median age, 71 years; 62% men). After 21 years of follow‐up, the cumulative incidence was 0.9% for Parkinson disease and 0.1% for secondary parkinsonism in the MI cohort. Compared with the general population cohort, MI was associated with a decreased risk of Parkinson disease (aHR, 0.80; 95% CI, 0.73–0.87) and secondary parkinsonism (aHR, 0.72; 95% CI, 0.54–0.94).

Conclusions

MI was associated with a 20% decreased risk of Parkinson disease and 28% decreased risk of secondary parkinsonism. Reduced risk may reflect an inverse relationship between cardiovascular risk factors and Parkinson disease.