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.

Risk-stratified selection to colonoscopy in FIT colorectal cancer screening: development and temporal validation of a prediction model

BACKGROUND

Faecal immunochemical tests (FITs) yield many false positives and challenge colonoscopy capacity in colorectal cancer (CRC) screening programmes. We aimed to develop a risk-based selection of participants to undergo diagnostic colonoscopy.

METHODS

The study was observational and used registry data from the Danish CRC screening programme. We included all participants invited 2014-2016 with a positive FIT (≥ 20 μg fHb/g) who underwent colonoscopy (n = 56,459). We predicted the risk of CRC or advanced neoplasia (AN) from age, gender and FIT value using logistic regression. We evaluated calibration and discrimination and conducted temporal validation. We compared the number of CRCs and adenomas identified by risk cut-offs and by a corresponding FIT cut-off.

RESULTS

AUCs were 74.9% (95% CI: 73.6; 76.3) and 67.4% (95% CI: 66.8%; 68.0%) for the models predicting CRC and AN in the validation dataset. The cut-off of CRC risk calculated from age, gender and FIT value identified 1.03 times (95% CI: 1.02; 1.05) more CRCs and 1.01 times (95% CI: 1.01; 1.01) more medium/high-risk adenomas compared with the corresponding FIT cut-off.

CONCLUSIONS

With existing data, risk-stratified FIT screening using a risk cut-off instead of a FIT cut-off can slightly improve the selection to colonoscopy of those at highest risk of cancer and adenomas.

Characteristics and Survival of Patients With Inflammatory Bowel Disease and Postcolonoscopy Colorectal Cancers

BACKGROUND & AIMS

Postcolonoscopy colorectal cancers (PCCRCs) account for up to 50% of colorectal cancers (CRCs) in patients with inflammatory bowel disease (IBD). We investigated characteristics of IBD patients with PCCRC and their survival.

METHODS

We identified IBD patients (ulcerative colitis [UC] and Crohn's disease) diagnosed with CRC from 1995 to 2015. We defined PCCRC as diagnosed between 6 and 36 months, and detected CRC (dCRC) as diagnosed within 6 months after colonoscopy. We computed prevalence ratios comparing PCCRC vs dCRC and followed up patients from the diagnosis of PCCRC/dCRC until death, emigration, or study end. Mortality was compared using Cox proportional hazards regression models adjusted for sex, age, year of CRC diagnosis, and stage. The main analyses focused on patients with UC.

RESULTS

Among 23,738 UC patients undergoing colonoscopy, we identified 352 patients with CRC, of whom 103 (29%) had PCCRC. Compared with dCRC, PCCRC was associated with a higher prevalence of metastatic cancer (33% vs 20%; prevalence ratio, 1.64; 95% CI, 1.13-2.38), cancers showing mismatch repair deficiency (79% vs 56%; prevalence ratio, 1.40; 95% CI, 1.13-1.72), and proximally located cancers (54% vs 40%; prevalence ratio, 1.34; 95% CI, 1.06-1.69). The 1- and 5-year adjusted hazard ratios of death for PCCRC vs dCRC among UC patients were 1.29 (95% CI, 0.77-2.18) and 1.24 (95% CI, 0.86-1.79), respectively.

CONCLUSIONS

The characteristics of UC-related PCCRC suggest tumor biology as an important factor in the progression to cancer. However, the prognosis of PCCRC appears similar to that of dCRC.

Type 2 diabetes classification: a data-driven cluster study of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort

INTRODUCTION

A Swedish data-driven cluster study identified four distinct type 2 diabetes (T2D) clusters, based on age at diagnosis, body mass index (BMI), hemoglobin A1c (HbA1c) level, and homeostatic model assessment 2 (HOMA2) estimates of insulin resistance and beta-cell function. A Danish study proposed three T2D phenotypes (insulinopenic, hyperinsulinemic, and classical) based on HOMA2 measures only. We examined these two new T2D classifications using the Danish Centre for Strategic Research in Type 2 Diabetes cohort.

RESEARCH DESIGN AND METHODS

In 3529 individuals, we first performed a k-means cluster analysis with a forced k-value of four to replicate the Swedish clusters: severe insulin deficient (SIDD), severe insulin resistant (SIRD), mild age-related (MARD), and mild obesity-related (MOD) diabetes. Next, we did an analysis open to alternative k-values (ie, data determined the optimal number of clusters). Finally, we compared the data-driven clusters with the three Danish phenotypes.

RESULTS

Compared with the Swedish findings, the replicated Danish SIDD cluster included patients with lower mean HbA1c (86 mmol/mol vs 101 mmol/mol), and the Danish MOD cluster patients were less obese (mean BMI 32 kg/m² vs 36 kg/m²). Our data-driven alternative k-value analysis suggested the optimal number of T2D clusters in our data to be three, rather than four. When comparing the four replicated Swedish clusters with the three proposed Danish phenotypes, 81%, 79%, and 69% of the SIDD, MOD, and MARD patients, respectively, fitted the classical T2D phenotype, whereas 70% of SIRD patients fitted the hyperinsulinemic phenotype. Among the three alternative data-driven clusters, 60% of patients in the most insulin-resistant cluster constituted 76% of patients with a hyperinsulinemic phenotype.

CONCLUSION

Different HOMA2-based approaches did not classify patients with T2D in a consistent manner. The T2D classes characterized by high insulin resistance/hyperinsulinemia appeared most distinct.

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.

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.

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.

Abstract P3-12-22: Socioeconomic position and prognosis in premenopausal breast cancer: A population-based cohort study in Denmark

Background: To investigate how socioeconomic position (SEP) influences the effectiveness of cancer-directed treatment in premenopausal breast cancer patients in terms of breast cancer recurrence and mortality.Methods: Our cohort included all premenopausal women aged 18-55 years diagnosed with non-metastatic breast cancer and prescribed docetaxel-based chemotherapy in Denmark during 2007-2011. Population-based administrative registries provided data on SEP: marital status (married including registered partnership or single including divorced or widowed), cohabitation (cohabiting or living alone), education (low, intermediate or high), income (low, medium or high), and employment status (employed, unemployed or health-related absenteeism). For each SEP measure, we computed incidence rates, cumulative incidence proportions (CIPs) and used Poisson regression to compute incidence rate ratios and 95% confidence intervals (95% CIs) of recurrence and death. We stratified on ER status/tamoxifen to evaluate interaction.Results: Our cohort included 2,616 women; 286 (CIP: 13%) experienced recurrence and 223 (CIP: 11%) died during follow-up (median 6.6 and 7.2 years, respectively). Single women had both increased risks of recurrence (IRR: 1.45, 95% CI: 1.11-1.89) and mortality (IRR: 1.83, 95% CI: 1.32-2.52). Furthermore, we observed increased mortality in women with low education (IRR: 1.49, 95% CI: 0.95-2.33), low income (IRR: 1.37, 95% CI: 0.83-2.28), unemployment (IRR: 1.61, 95% CI: 0.83-3.13) or health-related work absenteeism (IRR: 1.80, 95% CI: 1.14-2.82), but smaller or no increased risk of recurrence. These findings were especially evident among women with ER+ tumors prescribed tamoxifen.Conclusions: Low SEP in premenopausal women with non-metastatic breast cancer was associated with increased mortality, but not always recurrence. This suggests underdetection of recurrences in certain groups. Poor prognosis in women with low SEP, especially single women, may partly be explained by tamoxifen adherence.

Citation Format: Cathrine Hjorth, Per Damkier, Bent Ejlertsen, Timothy L Lash, Henrik T Sørensen, Deirdre Cronin-Fenton. Socioeconomic position and prognosis in premenopausal breast cancer: A population-based cohort study in Denmark [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-22.

Abstract P3-13-06: Single nucleotide polymorphisms and mortality after docetaxel-based chemotherapy in premenopausal breast cancer: A population-based cohort study in Denmark

Background Taxane-based chemotherapy is first line treatment in various cancers, including premenopausal breast cancer, but the inter-individual effectiveness is unpredictable. Differences in expression and activity of docetaxel-metabolizing enzymes and transporters (DMETs) may modify docetaxel effectiveness. Although reported data are inconsistent, some findings suggests that variant alleles that reduce the function of 1) SLC-transporters reduce drug influx into hepatocytes; 2) CYP-450 enzymes hamper drug metabolism; and 3) ABC-transporters decrease docetaxel clearance. The net effect is hypothesized to be increased docetaxel exposure and effectiveness. In contrast, GSTP1 variants have been associated with poorer docetaxel effectiveness. We investigated whether single nucleotide polymorphisms (SNPs) in drug metabolizing enzymes and transporters were associated with mortality in premenopausal breast cancer patients. Materials and methods Using the Danish Breast Cancer Group (DBCG) clinical database, we identified data on premenopausal women aged 18–55 years, diagnosed with non–metastatic breast cancer during 2007–2011. All women were recommended epirubicin, cyclophosphamide and docetaxel-based adjuvant chemotherapy, and tamoxifen if the disease was estrogen receptor (ER) positive. From DBCG and other Danish administrative and medical registries we retrieve data on death, emigration, and tumor characteristics. We collected archived formalin-fixed paraffin-embedded primary tumor tissue from Danish pathology departments. We genotyped 17 candidate SNPs using TaqMan SNP genotyping assays and, for each SNP, categorized the women as having two normal alleles (wildtype) or at least one variant allele. We followed the women from six months after breast cancer diagnosis until death, emigration or 30th June 2019, whichever came first. Comparing variant carriers with wildtype, we computed cumulative incidence proportions (CIPs) and used Poisson regression models to calculate unadjusted incidence rate ratios (IRRs) and associated 95% confidence intervals (CIs) of all–cause mortality. We stratified by ER status to evaluate interaction. Analyses were repeated for breast cancer specific mortality. Results Our cohort included 2,262 women. During follow–up (median 9.6 years, interquartile range: 8.4–11.0), 250 women died (CIP: 14%); 219 due to breast cancer (CIP: 11%). Genotyping was successful for ≥95% of the study cohort, with exception of two SNPs, which were excluded from analyses. We detected decreased mortality in variant carriers of SLCO1B1 rs2306283 (IRR: 0.75, 95% CI 0.58–0.97), and ABCB1 rs1128503 (IRR: 0.81, 95% CI: 0.63–1.05), ABCB1 rs2032582 (IRR: 0.80, 95% CI: 0.62–1.04) and ABCC2 rs12762549 (IRR: 0.80, 95% CI: 0.62–1.04). In contrast, mortality was increased in carriers of GSTP1 rs1138272 (IRR: 1.28, 95% CI: 0.93–1.76) and, unexpectedly, in carriers of CYP3A rs10273424 (IRR: 1.36, 95% CI: 0.99–1.86) variant carriers. Sensitivity analyses yielded similar findings. ER status did not modify the associations. Conclusions In this study, mortality may be associated with SNPs in ABCB1, ABCC2, SLCO1B1, CYP3A and GSTP1 in premenopausal women with non-metastatic breast cancer receiving docetaxel. The mechanisms underlying our findings remains unclear but may be related to docetaxel pharmacokinetics.

Citation Format: Cathrine F Hjorth, Per Damkier, Tore B Stage, Søren Feddersen, Bent Ejlertsen, Timothy L Lash, Stephen Hamilton-Dutoit, Thomas P Ahern, Mikael Rørth, Henrik T Sørensen, Deirdre Cronin-Fenton. Single nucleotide polymorphisms and mortality after docetaxel-based chemotherapy in premenopausal breast cancer: A population-based cohort study in Denmark [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-13-06.

Sex Differences in Long-term Outcomes After Group B Streptococcal Infections During Infancy in Denmark and the Netherlands: National Cohort Studies of Neurodevelopmental Impairments and Mortality

BACKGROUND

Male infants have a higher incidence of invasive group B Streptococcus disease (iGBS) compared with female infants; however, data on sex differences in mortality and long-term outcomes after iGBS are lacking. We assessed whether a child's sex influences the effects of iGBS on mortality and risk of neurodevelopmental impairments (NDIs).

METHODS

We used Danish and Dutch registry data to conduct a nationwide cohort study of infants with a history of iGBS. A comparison cohort, children without a history of iGBS, was randomly selected and matched on relevant factors. Effect modification by sex was assessed on additive and multiplicative scales.

RESULTS

Our analyses included data from children with a history of iGBS in Denmark (period 1997 -2017; n = 1432) and the Netherlands (2000 -2017; n = 697) and from 21 172 children without iGBS. There was no clear evidence of between-sex heterogeneity in iGBS-associated mortality. Boys had a higher risk of NDI, with evidence for effect modification on additive scale at the age of 5 years for any NDI (relative excess risk due to interaction = 1.28; 95% confidence interval [CI], -0.53 to 3.09 in Denmark and 1.14; 95% CI, -5.13 to 7.41 in the Netherlands). A similar pattern was observed for moderate/severe NDI at age 5 years in Denmark and age 10 years in the Netherlands.

CONCLUSION

Boys are at higher risk of NDI ; our results suggest this is disproportionally increased in those who develop iGBS. Future studies should investigate mechanisms of this effect modification by sex.

Air pollution and fecundability: Results from a Danish preconception cohort study

BACKGROUND

Animal and epidemiologic studies indicate that air pollution may adversely affect fertility. Epidemiologic studies have been restricted largely to couples undergoing fertility treatment or have retrospectively ascertained time-to-pregnancy among pregnant women.

OBJECTIVES

We examined the association between residential ambient air pollution and fecundability, the per-cycle probability of conception, in a large preconception cohort of Danish pregnancy planners.

METHODS

During 2007-2018, we used the Internet to recruit and follow women who were trying to conceive without the use of fertility treatment. Participants completed an online baseline questionnaire eliciting socio-demographic characteristics, lifestyle factors, and medical and reproductive histories and follow-up questionnaires every 8 weeks to ascertain pregnancy status. We determined concentrations of ambient nitrogen oxides (NOx ), nitrogen dioxide (NO2 ), carbon monoxide (CO), ozone (O3 ), particulate matter <2.5 µm (PM2.5 ) and <10 µm (PM10 ), and sulphur dioxide (SO2 ) at each participant's residential address. We calculated average exposure during the year before baseline, during each menstrual cycle over follow-up and during the entire pregnancy attempt time. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders and co-pollutants. The analysis was restricted to the 10,183 participants who were trying to conceive for <12 cycles at study entry whose addresses could be geocoded.

RESULTS

During 12 months of follow-up, 73% of participants conceived. Higher concentrations of PM2.5 and PM10 were associated with small reductions in fecundability. For example, the FRs for a one interquartile range (IQR) increase in PM2.5 (IQR = 3.2 µg/m3 ) and PM10 (IQR = 5.3 µg/m3 ) during each menstrual cycle were 0.93 (95% CI: 0.87, 0.99) and 0.91 (95% CI: 0.84, 0.99), respectively. Other air pollutants were not appreciably associated with fecundability.

CONCLUSIONS

In this preconception cohort study of Danish women, residential exposures to PM2.5 and PM10 were associated with reduced fecundability.

SARS-CoV-2 vaccination and myocarditis or myopericarditis: population based cohort study

OBJECTIVE

To investigate the association between SARS-CoV-2 vaccination and myocarditis or myopericarditis.

DESIGN

Population based cohort study.

SETTING

Denmark.

PARTICIPANTS

4 931 775 individuals aged 12 years or older, followed from 1 October 2020 to 5 October 2021.

MAIN OUTCOME MEASURES

The primary outcome, myocarditis or myopericarditis, was defined as a combination of a hospital diagnosis of myocarditis or pericarditis, increased troponin levels, and a hospital stay lasting more than 24 hours. Follow-up time before vaccination was compared with follow-up time 0-28 days from the day of vaccination for both first and second doses, using Cox proportional hazards regression with age as an underlying timescale to estimate hazard ratios adjusted for sex, comorbidities, and other potential confounders.

RESULTS

During follow-up, 269 participants developed myocarditis or myopericarditis, of whom 108 (40%) were 12-39 years old and 196 (73%) were male. Of 3 482 295 individuals vaccinated with BNT162b2 (Pfizer-BioNTech), 48 developed myocarditis or myopericarditis within 28 days from the vaccination date compared with unvaccinated individuals (adjusted hazard ratio 1.34 (95% confidence interval 0.90 to 2.00); absolute rate 1.4 per 100 000 vaccinated individuals within 28 days of vaccination (95% confidence interval 1.0 to 1.8)). Adjusted hazard ratios among female participants only and male participants only were 3.73 (1.82 to 7.65) and 0.82 (0.50 to 1.34), respectively, with corresponding absolute rates of 1.3 (0.8 to 1.9) and 1.5 (1.0 to 2.2) per 100 000 vaccinated individuals within 28 days of vaccination, respectively. The adjusted hazard ratio among 12-39 year olds was 1.48 (0.74 to 2.98) and the absolute rate was 1.6 (1.0 to 2.6) per 100 000 vaccinated individuals within 28 days of vaccination. Among 498 814 individuals vaccinated with mRNA-1273 (Moderna), 21 developed myocarditis or myopericarditis within 28 days from vaccination date (adjusted hazard ratio 3.92 (2.30 to 6.68); absolute rate 4.2 per 100 000 vaccinated individuals within 28 days of vaccination (2.6 to 6.4)). Adjusted hazard ratios among women only and men only were 6.33 (2.11 to 18.96) and 3.22 (1.75 to 5.93), respectively, with corresponding absolute rates of 2.0 (0.7 to 4.8) and 6.3 (3.6 to 10.2) per 100 000 vaccinated individuals within 28 days of vaccination, respectively. The adjusted hazard ratio among 12-39 year olds was 5.24 (2.47 to 11.12) and the absolute rate was 5.7 (3.3 to 9.3) per 100 000 vaccinated individuals within 28 days of vaccination.

CONCLUSIONS

Vaccination with mRNA-1273 was associated with a significantly increased risk of myocarditis or myopericarditis in the Danish population, primarily driven by an increased risk among individuals aged 12-39 years, while BNT162b2 vaccination was only associated with a significantly increased risk among women. However, the absolute rate of myocarditis or myopericarditis after SARS-CoV-2 mRNA vaccination was low, even in younger age groups. The benefits of SARS-CoV-2 mRNA vaccination should be taken into account when interpreting these findings. Larger multinational studies are needed to further investigate the risks of myocarditis or myopericarditis after vaccination within smaller subgroups.

Use of negative control outcomes to assess the comparability of patients initiating lipid-lowering therapies

PURPOSE

Clinical trials have demonstrated efficacy of proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) in reducing risk of cardiovascular disease events, but effectiveness in routine clinical care has not been well-studied. We used negative control outcomes to assess potential confounding in an observational study of PCSK9i versus ezetimibe or high-intensity statin.

METHODS

Using commercial claims, we identified U.S. adults initiating PCSK9i, ezetimibe, or high-intensity statin in 2015-2018, with other lipid-lowering therapy (LLT) use in the year prior (LLT cohort) or atherosclerotic cardiovascular disease (ASCVD) in the past 90 days (ASCVD cohort). We compared initiators of PCSK9i to ezetimibe and high-intensity statin by estimating one-year risks of negative control outcomes influenced by frailty or health-seeking behaviors. Inverse probability of treatment and censoring weighted estimators of risk differences (RDs) were used to evaluate residual confounding after controlling for covariates.

RESULTS

PCSK9i initiators had lower one-year risks of negative control outcomes associated with frailty, such as decubitus ulcer in the ASCVD cohort (PCSK9i vs. high-intensity statin RD = -3.5%, 95% confidence interval (CI): -4.6%, -2.5%; PCSK9i vs. ezetimibe RD = -1.3%, 95% CI: -2.1%, -0.6%), with similar but attenuated associations in the LLT cohort. Lower risks of accidents and fractures were also observed for PCSK9i, varying by cohort. Risks were similar for outcomes associated with health-seeking behaviors, although trended higher for PCSK9i in the ASCVD cohort.

CONCLUSIONS

Observed associations suggest lower frailty and potentially greater health-seeking behaviors among PCSK9i initiators, particularly those with a recent ASCVD diagnosis, with the potential to bias real-world analyses of treatment effectiveness.

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

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

Stress Disorders and the Risk of Nonfatal Suicide Attempts in the Danish Population

Accurate documentation of the associations between stress disorders and suicide attempts provides important information about a high-risk population and target group for preventative interventions. In this case-cohort study, cases were all individuals born or residing in Denmark who made a nonfatal suicide attempt during 1995-2015 (n = 22,974). The comparison subcohort included a 5% random sample of the Danish population on January 1, 1995 (n = 265,183). Stress disorder diagnoses and suicide attempts were identified using ICD-10 codes from national medical registries. The presence of any stress disorder substantially increased the rate of suicide attempts versus the comparison subcohort, rate per 100,000 person-years (PYs) = 604 vs. 13. We observed associations between each type of stress disorder and suicide attempts, hazard ratios (HRs) = 10.1-37.6, even after adjustment for potential confounders, adjusted HRs = 1.8-8.3, with the strongest associations for adjustment disorder relative to other diagnoses. After adjusting for demographic and health variables, the rate of suicide attempts among individuals with any stress disorder diagnosis was nearly 13 times the suicide attempt rate in the comparison cohort. A bias analysis demonstrated that associations remained robust despite potential differential misclassification of suicide attempts. Study strengths included the use of individual-level data linked across administrative and medical registries in the setting of universal health care and the use of longitudinal analyses capturing data over 20 years. The study demonstrated associations between the full range of stress disorders and suicide attempts, extending research specific to posttraumatic stress disorder.

Irritable bowel syndrome and risk of glaucoma: An analysis of two independent population-based cohort studies

OBJECTIVE

Irritable bowel syndrome (IBS) is a chronic disorder associated with an abnormal gastrointestinal microbiome. Microbiome-host interactions are known to influence organ function including in the central nervous system; thus, we sought to identify whether IBS may be a risk factor for the development of glaucoma.

DESIGN

Two prospective cohort studies.

SUBJECTS

The 1958 United Kingdom Birth Cohort (UKBC; 9091 individuals) and the Danish National Registry of Patients (DNRP; 62,541 individuals with IBS and 625,410 matched general population cohort members).

METHODS

In the UKBC, participants were surveyed throughout life (including at ages 42 and 50). The DNRP contains records of hospital-based contacts and prescription data from the national prescription database.

MAIN OUTCOME MEASURE

The main outcome measure was incidence of glaucoma. In the UKBC, incident glaucoma at age 50 (n = 48) was determined through comparison of survey responses at ages 42 and 50 years. In the DNRP, glaucoma was assessed by hospital diagnosis (n = 1510), glaucoma surgery (n = 582) and initiation of glaucoma medications (n = 1674).

RESULTS

In the UKBC, the odds ratio (OR) of developing glaucoma between ages 42 and 50 in persons with a chronic IBS diagnosis was increased [OR: 5.84, 95% confidence interval (CI): 2.26-15.13]. People with an IBS diagnosis in the DNRP had a hazard ratio (HR) of 1.35 for developing physician-diagnosed glaucoma (95% CI: 1.16-1.56), an HR of 1.35 for undergoing glaucoma surgery (95% CI: 1.06-1.70) and an HR of 1.19 for initiating glaucoma medication (95% CI: 1.03-1.38).

CONCLUSIONS

In two large European cohort studies, IBS is a risk factor for glaucoma.

Kidney disease and risk of dementia: a Danish nationwide cohort study

OBJECTIVES

It is unclear whether kidney disease is a risk factor for developing dementia. We examined the association between kidney disease and risk of future dementia.

DESIGN AND SETTING

Nationwide historical registry-based cohort study in Denmark based on data from 1 January 1995 until 31 December 2016.

PARTICIPANTS

All patients diagnosed with kidney disease and matched general population cohort without kidney disease (matched 1:5 on age, sex and year of kidney disease diagnosis).

PRIMARY AND SECONDARY OUTCOME MEASURES

All-cause dementia and its subtypes: Alzheimer's disease, vascular dementia and other specified or unspecified dementia. We computed 5-year cumulative incidences (risk) and hazard ratios (HRs) for outcomes using Cox regression analyses.

RESULTS

The study cohort comprised 82 690 patients with kidney disease and 413 405 individuals from the general population. Five-year and ten-year mortality rates were twice as high in patients with kidney disease compared with the general population. The 5-year risk for all-cause dementia was 2.90% (95% confidence interval: 2.78% to 3.08%) in patients with kidney disease and 2.98% (2.92% to 3.04%) in the general population. Compared with the general population, the adjusted HRs for all-cause dementia in patients with kidney disease were 1.06 (1.00 to 1.12) for the 5-year follow-up and 1.08 (1.03 to 1.12) for the entire study period. Risk estimates for dementia subtypes differed substantially and were lower for Alzheimer's disease and higher for vascular dementia.

CONCLUSIONS

Patients diagnosed with kidney disease have a modestly increased rate of dementia, mainly driven by vascular dementia. Moreover, patients with kidney disease may be underdiagnosed with dementia due to high mortality and other comorbidities of higher priority.

Suicide prediction among men and women with depression: A population-based study

BACKGROUND

Accurate identification of persons at risk of suicide is challenging because suicide is a rare outcome with a multifactorial origin. The purpose of this study was to predict suicide among persons with depression using machine learning methods.

METHODS

A case-cohort study was conducted in Denmark between January 1, 1995 and December 31, 2015. Cases were all persons who died by suicide and had an incident depression diagnosis in Denmark (n = 2,774). The comparison subcohort was a 5% random sample of all individuals in Denmark at baseline, restricted to persons with an incident depression diagnosis during the study period (n = 11,963). Classification trees and random forests were used to predict suicide.

RESULTS

In men with depression, there was a high risk of suicide among those who were prescribed other analgesics and antipyretics (i.e., non-opioid analgesics such as acetaminophen), prescribed hypnotics and sedatives, and diagnosed with a poisoning (n = 96; risk = 81%). In women with depression, there was an elevated risk of suicide among those who were prescribed other analgesics and antipyretics, anxiolytics, and hypnotics and sedatives, but were not diagnosed with poisoning nor cerebrovascular diseases (n = 338; risk = 58%).

DISCUSSION

Psychiatric disorders and their associated medications were strongly indicative of suicide risk. Notably, anti-inflammatory medications (e.g., acetaminophen) prescriptions, which are used to treat chronic pain and illnesses, were associated with suicide risk in persons with depression. Machine learning may advance our ability to predict suicide deaths.

Lessons Learned Using Real-World Data to Emulate Randomized Trials: A Case Study of Treatment Effectiveness for Newly Diagnosed Immune Thrombocytopenia

Regulatory agencies are increasingly considering real-world evidence (RWE) to support label expansions of approved medicines. We conducted a comparative effectiveness study to emulate a proposed randomized trial of romiplostim vs. standard-of-care (SOC) therapy among patients with recently diagnosed (≤12 months) immune thrombocytopenia (ITP), that could support expansion of the romiplostim label. We discuss challenges that we encountered and solutions that were developed to address those challenges. Study size was a primary concern, particularly for romiplostim initiators, given the rarity of ITP and the stringent trial eligibility criteria. For this reason, we leveraged multiple data sources (Nordic Country Patient Registry for Romiplostim; chart review study of romiplostim initiators in Europe; Flatiron Health EMR linked with MarketScan claims). Additionally, unlike the strictly controlled clinical trial setting, platelet counts were not measured at regular intervals in the observational data sources, and therefore the end point of durable platelet response often used in trials could not be reliably measured. Instead, the median platelet count was chosen as the primary end point. Ultimately, while we observed a slightly higher median platelet count in the romiplostim group vs. SOC, precision was limited because of small study size (median difference was 11 × 10⁹ /L (95% CI: -59, 81)). We underscore the importance of conducting comprehensive feasibility assessments to identify fit-for-purpose data sources with sufficient sample size, data elements, and follow-up. Beyond technical challenges, we also discuss approaches to increase the credibility of RWE, including systematic incorporation of clinical expertise into study design decisions, and separation between decision makers and the data.

Nationwide Trends in Cardiac Risk and Mortality in Patients With Incident Type 2 Diabetes: A Danish Cohort Study

OBJECTIVE

Trends in cardiac risk and death have not been examined in patients with incident type 2 diabetes and no prior cardiovascular disease. Therefore, we aimed to examine trends in cardiac risk and death in relation to the use of prophylactic cardiovascular medications in patients with incident type 2 diabetes without prior cardiovascular disease.

RESEARCH DESIGN AND METHODS

In this population-based cohort study, we included patients with incident type 2 diabetes between 1996 and 2011 through national health registries. Each patient was matched by age and sex with up to five individuals without diabetes from the general population. All individuals were followed for 7 years.

RESULTS

We identified 209,311 patients with incident diabetes. From 1996-1999 to 2008-2011, the 7-year risk of myocardial infarction decreased from 6.9 to 2.8% (adjusted hazard ratio [aHR] 0.39 [95% CI 0.37-0.42]), cardiac death from 7.1 to 1.6% (aHR 0.23 [95% CI 0.21-0.24]), and all-cause death from 28.9 to 16.8% (aHR 0.68 [95% CI 0.66-0.69]). Compared with the general population, 7-year risk differences decreased from 3.3 to 0.8% for myocardial infarction, from 2.7 to 0.5% for cardiac death, and from 10.6 to 6.0% for all-cause death. Use of cardiovascular medications within ±1 year of diabetes diagnosis, especially statins (5% of users in 1996-1999 vs. 60% in 2008-2011), increased during the study period.

CONCLUSIONS

From 1996 to 2011, Danish patients with incident type 2 diabetes and no prior cardiovascular disease experienced major reductions in cardiac risk and mortality. The risk reductions coincided with increased use of prophylactic cardiovascular medications.

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

BACKGROUND

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

AIMS

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Global epidemiology of hip fractures: a study protocol using a common analytical platform among multiple countries

INTRODUCTION

Hip fractures are associated with a high burden of morbidity and mortality. Globally, there is wide variation in the incidence of hip fracture in people aged 50 years and older. Longitudinal and cross-geographical comparisons of health data can provide insights on aetiology, risk factors, and healthcare practices. However, systematic reviews of studies that use different methods and study periods do not permit direct comparison across geographical regions. Thus, the objective of this study is to investigate global secular trends in hip fracture incidence, mortality and use of postfracture pharmacological treatment across Asia, Oceania, North and South America, and Western and Northern Europe using a unified methodology applied to health records.

METHODS AND ANALYSIS

This retrospective cohort study will use a common protocol and an analytical common data model approach to examine incidence of hip fracture across population-based databases in different geographical regions and healthcare settings. The study period will be from 2005 to 2018 subject to data availability in study sites. Patients aged 50 years and older and hospitalised due to hip fracture during the study period will be included. The primary outcome will be expressed as the annual incidence of hip fracture. Secondary outcomes will be the pharmacological treatment rate and mortality within 12 months following initial hip fracture by year. For the primary outcome, crude and standardised incidence of hip fracture will be reported. Linear regression will be used to test for time trends in the annual incidence. For secondary outcomes, the crude mortality and standardised mortality incidence will be reported.

ETHICS AND DISSEMINATION

Each participating site will follow the relevant local ethics and regulatory frameworks for study approval. The results of the study will be submitted for peer-reviewed scientific publications and presented at scientific conferences.