The Danish health care system and epidemiological research: from health care contacts to database records

How follow-up rates in cervical cancer screening depend on organizational factors: A comparison of two population-based organized screening programmes

OBJECTIVES

This study compares the follow-up rates of non-normal cervical screening samples between Denmark and Flanders (Belgium) to illuminate whether organizational differences between the health systems might affect the follow-up rates, e.g. sending of reminders in Denmark since 2012 compared to Flanders with no such system in place.

METHODS

The study population included 48,082 Danish women and 22,271 Flemish women who received abnormal or inadequate primary screening results from 2014 to 2016. The participants were followed for 24 months, and the timeliness and appropriateness of the recommended follow-up, according to national guidelines, were evaluated.

RESULTS

After 18 months over 90% of the Danish women had received some form of follow-up, while in Flanders, this level is achieved only for those who test positive for human papillomavirus. The analysis also revealed that 10-28% of follow-ups were performed too early, with Danish women showing the highest proportions. In both regions, general practitioners (GPs) exhibited better follow-up rates compared to gynaecologists, with gynaecologists displaying a tendency towards earlier re-testing than recommended.

CONCLUSIONS

An important factor influencing the follow-up rate may be the sending of reminders in Denmark since 2012, as the follow-up rates in general were higher in this period. It is noteworthy that a reminder system is currently being implemented in Flanders and further studies on the potential effects should be studied. Additionally, the organization of the health system might influence the follow-up rate, as engaging the GP for screening in Denmark may have had a positive effect.

Blood laboratory analyses preceding in-hospital cardiac arrest: A matched case-control study

BACKGROUND

Whether blood laboratory analyses differ in patients who later suffer in-hospital cardiac arrest (IHCA) compared to other hospitalised patients remains unknown. The aim of this study was to describe pre-arrest sampling frequencies, results, and trends in blood laboratory analyses in patients with IHCA compared to controls.

METHODS

This study was a matched case-control study using national registries in Denmark. Cases were defined as patients with IHCA from 2017 to 2021. Controls were defined as hospitalised patients and were matched on age, sex, and date and length of admission. Data on a total of 51 different blood laboratory analyses were obtained. The laboratory analyses of primary interest were lactate, sodium, potassium, and haemoglobin. The index time for cases was defined as the time of cardiac arrest, and a corresponding index time was defined for controls based on the time to cardiac arrest for their corresponding case. Blood sampling frequencies were reported for blood laboratory analyses obtained either within the last 24 h before the index time or between the time of hospital admission and the index time. Blood sampling results were reported for blood laboratory analyses obtained within the last 24 h before the index time.

RESULTS

A total of 9268 cases and 92,395 controls were included in this study. Cases underwent more frequent sampling of all blood laboratory analyses compared to controls. This higher sampling frequency was more pronounced for lactate compared to sodium, potassium, or haemoglobin. The last measured lactate was higher in cases (median [IQR]: 2.3 [1.3, 4.9]) compared to controls (median [IQR]: 1.3 [0.9, 2.0]). Differences in sodium, potassium, and haemoglobin were negligible. The proportion of abnormally elevated levels of lactate and potassium increased as time to cardiac arrest decreased; no such effect was seen in controls. No temporal trend was evident for sodium or haemoglobin.

CONCLUSIONS

Patients with IHCA undergo more frequent blood sampling prior to IHCA and have higher levels of lactate compared to matched controls.

Low smoking exposure and development and prognosis of COPD over four decades: a population-based cohort study

BACKGROUND

A diagnosis of COPD is mainly considered in individuals with >10 pack-years of smoking. We tested the hypothesis that low smoking exposure, below the critical threshold of 10 pack-years, increases risk of COPD and leads to poor prognosis.

METHODS

We followed non-obstructed adult smokers from the Copenhagen City Heart Study for COPD, defined as a forced expiratory volume in 1 s (FEV1)/forced vital capacity <0.70 and FEV1 <80% predicted, and for related clinical outcomes. First, we followed individuals for 5 years according to baseline smoking for risk of developing COPD, and thereafter for up to four decades for severe exacerbations and death.

RESULTS

In 6098 non-obstructed smokers, 1781 (29%) developed COPD after 5 years of follow-up: 23% of individuals with <10 pack-years of smoking at baseline, 26% of those with 10-19.9 pack-years, 30% of those with 20-39.9 pack-years and 39% of those with ≥40 pack-years. During four decades of follow-up, we recorded 620 exacerbations and 5573 deaths. Compared to individuals without COPD with <10 pack‑years of smoking, multivariable adjusted hazard ratios (HRs) for exacerbations were 1.94 (95% CI 1.36-2.76) in those without COPD and ≥10 pack-years, 2.83 (95% CI 1.72-4.66) in those with COPD and <10 pack-years, 4.34 (95% CI 2.93-6.43) in those with COPD and 10-19.9 pack-years, 4.39 (95% CI 2.98-6.46) in those with COPD and 20-39.9 pack-years and 4.98 (95% CI 3.11-7.97) in those with COPD and ≥40 pack-years. Corresponding HRs for all-cause mortality were 1.20 (95% CI 1.10-1.32), 1.31 (95% CI 1.13-1.53), 1.59 (95% CI 1.40-1.79), 1.81 (95% CI 1.62-2.03) and 1.81 (95% CI 1.55-2.10).

CONCLUSION

Low smoking exposure below the critical threshold of 10 pack-years increases risk of COPD in middle-aged adults within 5 years, and these individuals have increased risk of severe exacerbation and early death over four decades.

Overall and cause-specific mortality in anorexia nervosa; impact of psychiatric comorbidity and sex in a 40-year follow-up study

OBJECTIVE

This study investigates the overall and cause-specific mortality in males and females with anorexia nervosa (AN) from 1977 to 2018, focusing on the impact of psychiatric comorbidity on mortality risk, a less explored aspect despite a high prevalence in patients with AN.

METHOD

We conducted a nationwide population-based cohort study in Denmark including all patients with AN (n = 14,774) with a median follow-up time of 9.1 years and a 1:10 age- and sex-matched general population comparison cohort. Using Cox proportional hazard model, we calculated adjusted hazard ratios (aHR) for death stratified by psychiatric comorbidity, sex, and age at AN onset and evaluated the causes of death using Fine and Gray sub-distribution hazard ratios (SHR).

RESULTS

In patients with AN, the weighted average aHR for all-cause mortality was 4.5 [95% CI 4.1-4.9] with up to 40 years follow-up. Psychiatric comorbidity was present in 47% of patients with AN at index date, which was associated with a 1.9-fold increase in 10-year mortality compared with patients without comorbidity and a notably four-fold increase, when diagnosed at age 6-25 years. The mortality risk was similar according to sex. 13.9% of all deaths in patients with AN were due to suicide (SHR 10.7 [8.1-14.2]). The risk of dying of natural causes was increased with a SHR of 3.8 [95% CI 3.4-4.2].

DISCUSSION

The increased mortality risk in both males and females with AN and psychiatric comorbidity, particularly when diagnosed at young age, underscores the need for comprehensive treatment addressing both AN and coexisting psychiatric conditions.

PUBLIC SIGNIFICANCE

The mortality in patients with anorexia nervosa (AN) is high and we show in our study that the mortality is doubled in the presence of psychiatric comorbidity particularly the first 10 years after diagnosis seen in both sexes and with suicide as a major cause of death. These findings stress the importance of detection and treatment of psychiatric comorbidities alongside the eating disorder to prevent fatal outcome.

Incidence and survival of multiply revised knee arthroplasties in Denmark 1998-2021: a nationwide register-based study

PURPOSE

The primary aim of our study was to identify the absolute incidence and implant survival of multiply revised knee arthroplasties based on nationwide register data. The secondary aim was to determine the change in the absolute incidence and implant survival of multiply revised knee arthroplasties Methods: We performed a retrospective observational study of primary knee arthroplasties using several nationwide Danish registers. All primary knee arthroplasties performed in Denmark from 1998 to 2021 were identified. From these primary arthroplasties, revision procedures were identified. Kaplan-Meier plots were used in survival analysis to estimate the likelihood of implant survival.

RESULTS

161,384 primary knee arthroplasties and their revisions performed between 1998 and 2021 were identified; of 13,786 (8.5%) revisions there were 10,638 1st revisions, 2,148 2nd revisions, 624 3rd revisions, 223 4th revisions, and 153 procedures that had been revised more than 4 times. The 10-year revision-free survival of primary arthroplasties was 92.3% (95% confidence interval [CI] 92.2-92.5). First-time revisions had a 10-year revision-free survival of 75.9% (CI 74.9-76.9). The 10-year survival of second- and third-time revisions was 65.1% (CI 62.6-67.6) and 57.8% (CI 53.4-62.5), respectively. The 10-year implant survival probabilities of primary knee arthroplasties were 91.4% in 1998-2009 and 93.3% in 2010-2021 (difference 2.2%). The 10-year implant survival probabilities of 1st revisions were 77% in 1998-2009 and 75% in 2010-2021 (difference -2.4%).

CONCLUSION

We found that 0.3% of all primary knee arthroplasties resulted in 3 or more revisions. The implant survival decreased for each consecutive revision, with almost half of the 3rd revisions being re-revised within 10 years. The 10-survival of the primary implant was higher in 2010-2021, and the 10-year survival of the 1st revision was higher in 1998-2009.

Evaluating the comparability of osteoporosis treatments using propensity score and negative control outcome methods in UK and Denmark electronic health record databases

Evidence on the comparative effectiveness of osteoporosis treatments is heterogeneous. This may be attributed to different populations and clinical practice, but also to differing methodologies ensuring comparability of treatment groups before treatment effect estimation and the amount of residual confounding by indication. This study assessed the comparability of denosumab vs oral bisphosphonate (OBP) groups using propensity score (PS) methods and negative control outcome (NCO) analysis. A total of 280 288 women aged ≥50 yr initiating denosumab or OBP in 2011-2018 were included from the UK Clinical Practice Research Datalink (CPRD) and the Danish National Registries (DNR). Balance of observed covariates was assessed using absolute standardized mean difference (ASMD) before and after PS weighting, matching, and stratification, with ASMD >0.1 indicating imbalance. Residual confounding was assessed using NCOs with ≥100 events. Hazard ratio (HR) and 95%CI between treatment and NCO were estimated using Cox models. Presence of residual confounding was evaluated with 2 approaches (1) >5% of NCOs with 95% CI excluding 1, (2) >5% of NCOs with an upper CI <0.75 or lower CI >1.3. The number of imbalanced covariates before adjustment (CPRD 22/87; DNR 18/83) decreased, with 2%-11% imbalance remaining after weighting, matching, or stratification. Using approach 1, residual confounding was present for all PS methods in both databases (≥8% of NCOs), except for stratification in DNR (3.8%). Using approach 2, residual confounding was present in CPRD with PS matching (5.3%) and stratification (6.4%), but not with weighting (4.3%). Within DNR, no NCOs had HR estimates with upper or lower CI limits beyond the specified bounds indicating residual confounding for any PS method. Achievement of covariate balance and determination of residual bias were dependent upon several factors including the population under study, PS method, prevalence of NCO, and the threshold indicating residual confounding.

Machine Learning-Driven Prediction of Comorbidities and Mortality in Adults With Type 1 Diabetes

BACKGROUND

Comorbidities such as cardiovascular disease (CVD) and diabetic kidney disease (DKD) are major burdens of type 1 diabetes (T1D). Predicting people at high risk of developing comorbidities would enable early intervention. This study aimed to develop models incorporating socioeconomic status (SES) to predict CVD, DKD, and mortality in adults with T1D to improve early identification of comorbidities.

METHODS

Nationwide Danish registry data were used. Logistic regression models were developed to predict the development of CVD, DKD, and mortality within five years of T1D diagnosis. Features included age, sex, personal income, and education. Performance was evaluated by five-fold cross-validation with area under the receiver operating characteristic curve (AUROC) and the precision-recall area under the curve (PR-AUC). The importance of SES was assessed from feature importance plots.

RESULTS

Of the 6572 included adults (≥21 years) with T1D, 379 (6%) developed CVD, 668 (10%) developed DKD, and 921 (14%) died within the five-year follow-up. The AUROC (±SD) was 0.79 (±0.03) for CVD, 0.61 (±0.03) for DKD, and 0.87 (±0.01) for mortality. The PR-AUC was 0.18 (±0.01), 0.15 (±0.03), and 0.49 (±0.02), respectively. Based on feature importance plots, SES was the most important feature in the DKD model but had minimal impact on models for CVD and mortality.

CONCLUSIONS

The developed models showed good performance for predicting CVD and mortality, suggesting they could help in the early identification of these outcomes in individuals with T1D. The importance of SES in individual prediction within diabetes remains uncertain.

Colorectal cancer and association with anaerobic bacteraemia: A Danish nationwide population-based cohort study

OBJECTIVES

We aimed to identify specific anaerobic bacteria causing bacteraemia and a subsequent diagnosis of colorectal cancer.

METHODS

A nationwide population-based cohort study, which included all episodes of defined specific anaerobic bacteraemia from 2010 (5,534,738 inhabitants) through 2020 (5,822,763 inhabitants) and all cases of colorectal cancer diagnosed from 2010 through 2021 in Denmark. We calculated the incidence and risk of colorectal cancer after bacteraemia with specific anaerobic bacteria using Escherichia coli bacteraemia as reference.

RESULTS

Nationwide data on colorectal cancer and specific anaerobic bacteraemia (100% complete, representing 11,124 episodes). The frequencies of colorectal cancer within one year following anaerobic bacteraemia were higher for species, which almost exclusively reside in the colon, such as Phocaeicola vulgatus/dorei (5.5%), Clostridium septicum (24.2%), and Ruminococcus gnavus (4.6%) compared to 0.6% in 50,650 E. coli bacteraemia episodes. Bacteroides spp. had a subhazard ratio for colorectal cancer of 3.9 (95% confidence interval [CI], 3.0 to 5.1) and for Clostridium spp. it was 8.9 (95% CI, 6.7 to 11.8, with C. septicum 50.0 [95% CI, 36.0 to 69.5]) compared to E. coli (reference).

CONCLUSION

This nationwide study identified specific colorectal cancer-associated anaerobic bacteria, which almost exclusively reside in the colon. Bacteraemia with these bacteria could be an indicator of colorectal cancer.

Children born preterm or small for gestational age to mothers with multiple sclerosis: Do these children have an increased risk of infections in early life?

BACKGROUND

Mothers with multiple sclerosis are at increased risk of preterm birth and small for gestational age infants. Both conditions pose a risk of morbidity, including early-life infections.

OBJECTIVE

This study aimed to assess the risk of infections in the first 3 years of life among children born preterm or small for gestational age to mothers with multiple sclerosis.

METHODS

We used Danish national health registers to establish the study cohort of all births by women with MS born from 1995 to 2023. In Cox regression models, we estimated hazard ratios (HRs) of infections in preterm or small for gestational age children.

RESULTS

Preterm children had an adjusted HR of 1.49 (95% confidence interval (95% CI) 1.15-1.93) for hospital-diagnosed infection and 0.88 (95% CI 0.72-1.06) for antibiotic prescriptions. Small for gestational age children had an adjusted HR of 0.81 (95% CI 0.54-1.22) for hospital-diagnosed infection and 1.07 (95% CI 0.82-1.38) for antibiotic prescriptions.

CONCLUSION

Children born preterm to mothers with multiple sclerosis had an increased risk of hospital-diagnosed infections in the first 3 years of life, but not of mild-to-moderate infections evaluated on prescriptions. Children born small for gestational age did not have an increased risk of infections.

Socio-economic position, multimorbidity, and health care utilization among Danish left ventricular assist device patients

AIMS

Increasing numbers of patients with advanced heart failure and significant comorbidity and social barriers are considered for left ventricular assist devices (LVADs). We sought to examine health care utilization post-LVAD implantation, including the influence of individual-level socio-economic position and multimorbidity.

METHODS AND RESULTS

We conducted a Danish nationwide cohort study linking individual-level data from clinical LVAD databases, the Scandiatransplant Database, and Danish national medical and administrative registries. Socio-economic position included cohabitation status, educational level, and employment status. Multimorbidity was defined as two or more chronic conditions from at least two chronic disease groups. Health care utilization (hospital activity, general practice activity, and redeemed medical prescriptions) within 2 years post-discharge after LVAD implantation was evaluated using descriptive statistics at 0.5 year intervals. We identified 119 patients discharged alive with first-time LVAD implanted between 2006 and 2018. The median age of the patients was 56.1 years, and 88.2% were male. Patients were followed until heart transplantation, LVAD explantation, death, 31 December 2018, or for 2 years. The median follow-up was 0.8 years. The highest median use of health care services was observed 0-0.5 years post-LVAD discharge compared with the subsequent follow-up intervals: 0.5-1, 1-1.5, and 1.5-2 years, respectively. The median (interquartile range) number of hospitalizations was 10 (7-14), bed days 14 (9-28), outpatient visits 8 (5-12), telephone contacts with a general practitioner 4 (2-8), and total redeemed medical prescriptions 26 (19-37) within 0-0.5 years post-LVAD discharge compared with the median utilization within the consecutive follow-up periods [e.g. within 0.5-1 year: hospitalizations 5 (3-8), bed days 8 (4-14), outpatient visits 5 (3-8), telephone contacts 2 (0-5), and redeemed medical prescriptions 24 (18-30)]. The median use of health care services was stable from 0.5 years onwards. The median number of hospitalizations and bed days was slightly higher in patients living alone with a low educational level or low employment status within 0-0.5 years post-LVAD implantation. Finally, the median number of in-hospital days and redeemed prescriptions was higher among patients with pre-existing multimorbidity.

CONCLUSIONS

Among patients who underwent LVAD implantation, health care utilization was high in the early post-LVAD discharge phase and was influenced by socio-economic position. Multimorbidity influenced the number of in-hospital days and redeemed prescriptions during the 2 year follow-up.

Survival among people with HIV and their families in Denmark 1995-2021: a nationwide population-based cohort study

Background

Survival among people with HIV (PWH) has vastly improved globally over the last few decades but remains lower than among the general population. We aimed to estimate time trends of survival among PWH and their families from 1995 to 2021.

Methods

We conducted a registry-based, nationwide, population-based, matched cohort study. We included all Danish-born PWH from 1995 to 2021 who had been on antiretroviral therapy for 90 days, did not report intravenous drug use, and were not co-infected with hepatitis C (n = 4168). We matched population controls from the general population 10:1 to PWH by date of birth and sex (n = 41,680). For family cohorts, we identified siblings, mothers, and fathers of PWH and population controls. From Kaplan-Meier tables with age as time scale, we estimated survival from age 25. We compared PWH with population controls and families of PWH with families of population controls to calculate mortality rate ratios adjusted for sex, age, comorbidities, and education (aMRR).

Findings

The median age of death among PWH increased from 27.5 years in 1995-1997 to 73.9 years (2010-2014), but thereafter survival increased only marginally. From 2015 to 2021, mortality was increased among PWH (aMRR 1.87 (95% CI: 1.65-2.11)) and siblings (aMRR: 1.25 (95% CI: 1.07-1.47)), mothers (aMRR: 1.30 (95% CI: 1.17-1.43)), and fathers (aMRR: 1.15 (95% CI: 1.03-1.29)) of PWH compared to their respective control cohorts. Mortality among siblings of PWH who reported heterosexual route of HIV transmission (aMRR: 1.51 (95% CI: 1.16-1.96)) was higher than for siblings of PWH who reported men who have sex with men as route of HIV transmission (aMRR 1.19 (95% CI: 0.98-1.46)).

Interpretation

Survival among PWH improved substantially until 2010, after which it increased only marginally. This may partly be due to social and behavioural factors as PWH families also had higher mortality.

Funding

Preben and Anna Simonsen's Foundation and Independent Research Fund Denmark.

Increasing coverage in cervical and colorectal cancer screening by leveraging attendance at breast cancer screening: A cluster-randomised, crossover trial

BACKGROUND

Screening participation remains suboptimal in cervical cancer (CC) and colorectal cancer (CRC) screening despite their effectiveness in reducing cancer-related morbidity and mortality. We investigated the effectiveness of an intervention by leveraging the high participation rate in breast cancer (BC) screening as an opportunity to offer self-sampling kits to nonparticipants in CC and CRC screening.

METHODS AND FINDINGS

A pragmatic, unblinded, cluster-randomised, multiple period, crossover trial was conducted in 5 BC screening units in the Central Denmark Region (CDR) between September 1, 2021 and May 25, 2022. On each of 100 selected weekdays, 1 BC screening unit was randomly allocated as the intervention unit while the remaining units served as controls. Women aged 50 to 69 years attending BC screening at the intervention unit were offered administrative check-up on their CC screening status (ages 50 to 64 years) and CRC screening status (aged 50 to 69), and women with overdue screening were offered self-sampling. Women in the control group received only standard screening offers according to the organised programmes. The primary outcomes were differences between the intervention group and the control group in the total screening coverage for the 2 programmes and in screening participation among women with overdue screening, measured 6 months after the intervention. These were assessed using intention-to-treat analysis, reporting risk differences with 95% confidence intervals (CIs). A total of 27,116 women were included in the trial, with 5,618 (20.7%) in the intervention group and 21,498 (79.3%) in the control group. Six months after the intervention, total coverage was higher in the intervention group as compared with the control group in CC screening (88.3 versus 83.5, difference 4.8 percentage points, 95% CI [3.6, 6.0]; p < 0.001) and in CRC screening (79.8 versus 76.0, difference 3.8 percentage points, 95% CI [2.6, 5.1]; p < 0.001). Among women overdue with CC screening, participation in the intervention group was 32.0% compared with 6.1% in the control group (difference 25.8 percentage points, 95% CI [22.0, 29.6]; p < 0.001). In CRC screening, participation among women overdue with screening in the intervention group was 23.8% compared with 8.9% in the control group (difference 14.9 percentage points, 95% CI [12.3, 17.5]; p < 0.001). Women who did not participate in BC screening were not included in this study.

CONCLUSIONS

Offering self-sampling to women overdue with CC and CRC screening when they attend BC screening was a feasible intervention, resulting in an increase in participation and total coverage. Other interventions are required to reach women who are not participating in BC screening.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05022511. The record of processing activities for research projects in the Central Denmark Region (R. No.: 1-16-02-217-21).

Characteristics and outcomes for general anesthesia in Denmark

BACKGROUND

General anesthesia is common, but concerns regarding post-operative complications and mortality remain. No study has described the Danish patient population undergoing general anesthesia on a national level. The aim of this study was to describe the characteristics and outcomes of patients undergoing general anesthesia in Denmark.

METHODS

This study was a registry-based observational cohort study of adult patients (≥18 years) undergoing general anesthesia in Denmark during 2020 and 2021. Data from nationwide registries covering patient characteristics, anesthesia and procedure information, and patient outcomes were combined. Descriptive statistics were used to present findings, both overall and in subgroups based on the American Society of Anesthesiologists (ASA) classification.

RESULTS

We identified 453,133 cases of general anesthesia in 328,951 unique patients. The median age was 57 years (quartiles: 41, 71), and 242,679 (54%) were females. Data on ASA classification were missing for less than 1% of the population, and ASA II was the most prevalent ASA classification (49%). Among cases of general anesthesia, 0.1% experienced a stroke, 0.2% had in-hospital cardiac arrest, and 3.9% had a stay in the intensive care unit within 30 days. Mortality at 30 days and 1 year were 1.8% and 6.3%, respectively, increasing with a higher ASA classification.

CONCLUSION

This study offers the first comprehensive overview of adult patients undergoing general anesthesia in Denmark. Post-anesthesia complications were few and increased with ASA classification.

School Well-Being and Academic Performance of Children With Juvenile Idiopathic Arthritis: A National Register-Based Study

OBJECTIVE

We aimed to investigate how school well-being (SWB) and academic performance of children with juvenile idiopathic arthritis (JIA) compare to their peers on a national level using the Danish national registers. Further, we investigated the potential influence of socioeconomic status (SES).

METHODS

A population-wide, register-based, cross-sectional study was performed. We compared the results of children with and without JIA in the Danish National Well-Being Questionnaire (DNWQ), the National Danish School Testing (NDST), and their ninth grade (aged approximately 16 yrs) final school marks in Danish and mathematics. The results were analyzed using adjusted ordinal logistic regression (SWB) and linear regression (tests and marks).

RESULTS

In separate cohorts, we included a total of 505,340 children answering the DNWQ, 812,461 children with NDST results, and the ninth-grade final marks of 581,804 children. Of these children, 1042, 1541, and 1410, respectively, fulfilled the criteria of JIA. Children with JIA reported SWB comparable to their peers, except for the question "Do you perform well in school?" (odds ratio 0.89, 95% CI 0.81-0.99). In the NDST, the children with JIA in general did just as well as their peers. We found no differences in the ninth-grade final marks in either Danish or mathematics. Stratifying the analyses on SES showed no significant differences in the associations.

CONCLUSION

Overall, children with JIA report SWB comparable to that of children without JIA and perform equally well in school as children without JIA.

Confounding and Negative Control Methods in Observational Study of SARS-CoV-2 Vaccine Effectiveness: A Nationwide, Population-Based Danish Health Registry Study

Background

Observational studies of SARS-CoV-2 vaccine effectiveness are prone to confounding, which can be illustrated using negative control methods.

Methods

Nationwide population-based cohort study including two cohorts of Danish residents 60-90 years of age matched 1:1 on age and sex: A vaccinated and a non-vaccinated cohort, including 61052 SARS-CoV-2 vaccinated individuals between 1 March and 1 July 2021 and 61052 individuals not vaccinated preceding 1 July 2021. From these two cohorts, we constructed negative control cohorts of individuals diagnosed with SARS-CoV-2 infection or acute myocardial infarction, stroke, cancer, low energy fracture, or head-trauma. Outcomes were SARS-CoV-2 infection, negative control outcomes (eg, mammography, prostate biopsy, operation for cataract, malignant melanoma, examination of eye and ear), and death. We used Cox regression to calculate adjusted incidence and mortality rate ratios (aIRR and aMRR).

Results

Risks of SARS-CoV2 infection and all negative control outcomes were elevated in the vaccinated population, ranging from an aIRR of 1.15 (95% CI: 1.09-1.21) for eye examinations to 3.05 (95% CI: 2.24-4.14) for malignant melanoma. Conversely, the risk of death in the SARS-CoV-2 infected cohort and in all negative control cohorts was lower in vaccinated individuals, ranging from an aMRR of 0.23 (95% CI: 0.19-0.26) after SARS-CoV-2 infection to 0.50 (95% CI: 0.37-0.67) after stroke.

Conclusion

Our findings indicate that observational studies of SARS-CoV-2 vaccine effectiveness may be subject to substantial confounding. Therefore, randomized trials are essential to establish vaccine efficacy after the emergence of new SARS-CoV-2 variants and the rollout of multiple booster vaccines.

Impact of the pre-biologic treatment journey on biologic drug survival in psoriasis: A nationwide cohort study

BACKGROUND

It is unknown whether the pre-biologic treatment journey affects subsequent biologic drug survival.

OBJECTIVE

To examine the potential impact of a complex treatment journey on subsequent biologic drug survival in patients with psoriasis.

METHODS

The study utilized longitudinal data from Danish national registries and included all patients who, for the first time, initiated a biological treatment for psoriasis. Maximum follow-up was 5 years and patients were included from 1 January 2010 to 30 June 2021. The study used three definitions of exposure to a complex treatment journey and the following conventional systemic treatments: acitretin, cyclosporine, dimethyl fumarate and methotrexate. The first definition was the cumulative number of treatment series. The second definition comprised the number of unique treatments. The third definition was time from the first conventional systemic treatment to biological therapy. Drug survival for the three definitions were illustrated using Kaplan-Meier curves and compared using log-rank test. The sensitivity analysis largely confirmed these findings by grouping patients according to pharmacotherapy.

RESULTS

A total of 2496 patients were included in the study, with 1380 (55.3%) receiving adalimumab, 608 (24.4%) receiving ustekinumab, 271 (10.9%) receiving secukinumab, 166 (6.7%) receiving etanercept and 71 (2.8%) receiving infliximab. The mean age at initiation of biologics was 43.6 years (standard deviation (SD) 15.2 years), and most patients were male (62.9%). During the follow-up of 5477 patient years, 1953 patients (78.2%) reached the main endpoint of discontinuation. Using a log-rank test, the probability of remaining on treatment was unaffected by the three definitions of complexity of the treatment journey.

CONCLUSION

None of the three exposures used to assess the complexity of the pre-biologic treatment journey appeared to impact drug survival. As long as patients experience adequate disease control, these results suggest that conventional systemic treatment do not negatively impact the drug survival of subsequent biologics.

Prevalence of ichthyoses in Denmark: a nationwide registry-based study

The results demonstrate a prevalence of 1.6 per 10 000 for all types of ichthyoses, based on large Danish national patient registries, including all patients with relevant diagnoses alive on 31 December 2021. A study of this size and depth has not been completed before but may still underestimate the prevalence and potential burden of the diseases.

The association of demographic and socioeconomic variables with cancer screening participation: A national cross-sectional study of three cancer screening programs in Denmark

Objective

To analyze the demographic and socioeconomic determinants of non-participation in cervical, colorectal and breast cancer screening programs in Denmark.

Study design and setting

We conducted a cross-sectional study involving all women aged 53-65 years residing in Denmark on March 31, 2018, utilizing comprehensive individual data from population registries. Logistic regression models were employed to assess associations between demographic and socioeconomic factors and non-participation compared with participating in one, two, and three cancer screening programs, presenting odds ratios (ORs) with 95 % confidence intervals (CIs). Both unadjusted and adjusted models were applied for each level of screening participation.

Results

Significant associations with non-participation in the three cancer screening programs were observed across all demographic and socioeconomic covariates considered. Women with low incomes demonstrated the highest likelihood of non-participation (none vs. three programs attended, OR: 2.95, 95 % CI: 2.82-3.08). Similarly, increased odds of non-participation were noted among immigrants (Western immigrants: OR: 2.08, 95 % CI: 1.96-2.21; non-Western immigrants OR 1.26 95 % CI: 1.20-1.32), women living alone (OR: 2.08, 95 % CI: 2.02-2.14), women outside the labor force (OR: 1.92, 95 % CI: 1.86-1.99), and women with lower educational levels (OR: 1.44, 95 % CI: 1.39-1.50) in the model comparing non-participation to participating in three screening programs. A progressive intensification of the association with non-participation was noted with each incremental increase in screening participation (from one to two to three programs).

Conclusions

Demographic and socioeconomic variables are significantly associated with non-participation in all three Danish cancer screening programs, particularly affecting women from vulnerable demographic and socioeconomic backgrounds. Future research should prioritize strategies to enhance participation within this subgroup, aiming to alleviate social inequities in cancer screening.

Prognosis and antithrombotic practice patterns in patients with recurrent and transient atrial fibrillation following acute coronary syndrome: A nationwide study

BACKGROUND

First-time detected atrial fibrillation (AF) is associated with aggravated prognosis in patients admitted with acute coronary syndrome (ACS). Yet, among patients surviving beyond one year after ACS, it remains unclear how the recurrence of AF within the initial year after ACS affects the risk of stroke.

METHODS

With Danish nationwide data from 2000 to 2021, we identified all patients with first-time ACS who were alive one year after discharge (index date). Patients were categorized into: i) no AF; ii) first-time detected AF during ACS admission without a recurrent hospital contact with AF (transient AF); and iii) first-time detected AF during ACS admission with a subsequent recurrent hospital contact with AF (recurrent AF). From index date, two-year rates of ischemic stroke were compared using multivariable adjusted Cox regression analysis. Treatment with antithrombotic therapy was assessed as filled prescriptions between 12 and 15 months following ACS discharge.

RESULTS

We included 139,137 patients surviving one year post ACS discharge: 132,944 (95.6%) without AF, 3920 (2.8%) with transient AF, and 2273 (1.6%) with recurrent AF. Compared to those without AF, the adjusted two-year hazard ratios of ischemic stroke were 1.45 (95% CI, 1.22-1.71) for patients with transient AF and 1.47 (95% CI: 1.17-1.85) for patients with recurrent AF. Prescription rates of oral anticoagulation increased over calendar time, reaching 68.3% and 78.7% for transient and recurrent AF, respectively, from 2019 to 2021.

CONCLUSION

In patients surviving one year after ACS with first-time detected AF, recurrent and transient AF were associated with a similarly increased long-term rate of ischemic stroke.

Diagnostic accuracy of dipsticks for urinary tract infections in acutely hospitalised patients: a prospective population-based observational cohort study

OBJECTIVE

To determine the added diagnostic value of dipsticks for urinary tract infections (UTI) in acutely hospitalised individuals.

DESIGN

Prospective population-based cohort study.

SETTING

North Denmark.

PARTICIPANTS

All adults (≥18 years) examined with dipsticks at emergency departments in North Denmark Region from September 20 through 23 October 2021.

MAIN OUTCOME MEASURES

UTI was defined as ≥1 symptom of new-onset frequency, dysuria or suprapubic tenderness combined with a positive urine culture. Positive dipsticks were defined as any reaction for leucocyte esterase and/or nitrite.

RESULTS

Dipsticks were used in 1052/2495 (42%) of acutely hospitalised patients with a median age of 73 years (IQR 57-82) and 540 (51%) were female. Overall, 89/1052 (8%) fulfilled the UTI criteria and urine cultures were done in 607/1052 (58%) patients. Among patients examined with both dipstick and urine culture, sensitivity and specificity for UTI were 87% (95% CI 78% to 93%) and 45% (95% CI 41% to 50%). Positive and negative predictive values were 21% (95% CI 17% to 26%) and 95% (95% CI 92% to 98%), whereas positive and negative likelihood ratios were 1.58 (95% CI 1.41 to 1.77) and 0.30 (95% CI 0.18 to 0.51). Pretest probabilities of UTI ranged from 29% to 60% in participants with specific UTI symptoms with corresponding post-test probabilities of 35-69% if dipsticks were positive and 12-27% if dipsticks were negative. Results remained comparable if final clinical diagnosis was used as outcome among all patients examined with dipsticks. Modified Poisson regression yielded an adjusted relative risk of 4.41 (95% CI 2.40 to 8.11) for empirical antibiotics for UTI in participants without specific UTI symptoms and a positive dipstick.

CONCLUSIONS

Dipsticks yielded limited clinical decision support compared with a symptom-driven approach in this study and were independently associated with excess antibiotics for UTI.

Lipid Levels and Risk of Diabetic Polyneuropathy in 2 Danish Type 2 Diabetes Cohorts

BACKGROUND AND OBJECTIVES

Reduction of blood lipids may aid in preventing diabetic polyneuropathy (DPN), but evidence remains conflicting. We investigated the association between lipid parameters and DPN risk in individuals with type 2 diabetes mellitus (T2DM).

METHODS

We conducted a population-based cohort study of individuals with newly diagnosed T2DM and a cross-sectional study using a clinically recruited T2DM cohort. Triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and non-HDL cholesterol were measured in routine diabetes care. Each lipid parameter was categorized according to the latest cutoffs in clinical guidelines on dyslipidemia. DPN was assessed with validated hospital diagnosis codes in the population-based cohort and with the Michigan Neuropathy Screening Instrument questionnaire in the clinical cohort. We calculated hazard ratios (HRs) using Cox regression and prevalence ratios (PRs) using Poisson regression.

RESULTS

We included 61,853 individuals in the population-based cohort (median age 63 [quartiles 54-72] years) and 4,823 in the clinical cohort (median age 65 [quartiles 57-72] years). The incidence rate of hospital-diagnosed DPN in the population-based cohort was 3.6 per 1000 person-years during a median follow-up of 7.3 years. Achieving guideline targets for HDL, LDL, and non-HDL cholesterol showed no association with DPN risk. By contrast, adjusted HRs (95% CI) for DPN were 1.02 (0.89-1.18) for triglyceride levels between 150 and 204 mg/dL (1.7-2.3 mmol/L) and 1.28 (1.13-1.45) for levels >204 mg/dL (2.3 mmol/L). In the clinical cohort with a DPN prevalence of 18%, DPN associated strongly with triglycerides >204 mg/dL (2.3 mmol/L) with an adjusted PR (95% CI) of 1.40 (1.21-1.62). The prevalence of DPN was modestly elevated for individuals with HDL cholesterol <39 mg/dL (1.0/1.3 mmol/L) in men and <50 mg/dL (1.3 mmol/L) in women (PR 1.13 [0.99-1.28]) and for individuals with non-HDL cholesterol >131 mg/dL (3.4 mmol/L) (PR 1.27 [1.05-1.52]). In both cohorts, spline models showed an increasing risk of DPN starting from triglyceride levels >124 mg/dL (1.4 mmol/L). All results were similar among statin users.

DISCUSSION

High triglyceride levels are a strong DPN risk factor. Future intervention studies shall determine whether triglyceride reduction is more important for DPN prevention than reduction of other lipids.

Healthcare-seeking behaviour preceding diagnosis of Lyme neuroborreliosis: population-based nationwide matched nested case-control study

OBJECTIVES

To identify diagnostic opportunities, we investigated healthcare-seeking behaviour among patients with Lyme neuroborreliosis (LNB) within 28 weeks before diagnosis.

METHODS

We conducted a population-based, nationwide matched nested case-control study (Denmark, 2009-2021). As cases, we included all Danish residents with LNB (positive Borrelia burgdorferi intrathecal antibody index test and cerebrospinal fluid pleocytosis). We randomly selected controls from the general population and matched 10:1 on date of birth and sex. Exposures were assignment of diagnostic codes for symptoms, contact to medical specialties, medical wandering, and undergoing diagnostic procedures. We calculated the weekly and 3-month proportions of individuals with exposures and calculated absolute risk differences with corresponding 95% CI.

RESULTS

We included 1056 cases with LNB and 10 560 controls. Within 3 months before diagnosis, the most frequent assigned symptoms were pain (difference: 13.0%, 95% CI: 10.9-15.1). Cases with LNB exhibited increased contact with most specialties, particularly general practitioners (difference: 48.7%, 95% CI: 46.0-51.4), neurology (difference: 14.3%, 95% CI: 11.7-16.8), and internal medicine (difference: 11.1%, 95% CI: 8.7-13.5), and medical wandering (difference: 17.1%, 95% CI: 14.3-20.0). Common diagnostic procedures included imaging of the brain (difference: 10.2, 95% CI: 8.3-12.1), the spine (difference: 8.8%, 85% CI: 7.0-10.6), and the abdomen (difference: 7.2%, 95% CI: 5.4-9.1). The increase in healthcare-seeking behaviour was observed ≤12 weeks preceding diagnosis.

DISCUSSION

Pain appears to be an ambiguous symptom of LNB, potentially contributing to delays in establishing the correct diagnosis. It would be difficult to identify patients with LNB more effectively as the increased healthcare-seeking behaviour preceding diagnosis is distributed across many medical specialties.

Risk of fractures following bariatric surgery with Roux-en-Y gastric bypass or sleeve gastrectomy: a Danish population-based cohort study

OBJECTIVE

We examined the association between Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) and fracture risk, including major osteoporotic fractures (MOF), and the use of anti-osteoporosis medication (AOM). While RYGB is associated with impaired bone health and increased fracture risk, it remains uncertain whether SG has a similar impact and whether this risk is primarily due to MOF or any fracture.

DESIGN

We conducted a nationwide cohort study covering patients treated with RYGB (n = 16 121, 10.2-year follow-up) or SG (n = 1509, 3.7-year follow-up), from 2006 to 2018, comparing them with an age- and sex-matched cohort (n = 407 580).

METHODS

We computed incidence rates and adjusted hazard ratios (HRs) with 95% CIs, using Cox regression for any fracture, MOF, and use of AOM with adjustment for comorbidities.

RESULTS

Compared with the general population cohort, RYGB was associated with an increased risk of any fracture (HR 1.56 [95% CI, 1.48-1.64]) and MOF (HR 1.49 [1.35-1.64]). Sleeve gastrectomy was associated with an increased risk of any fracture (HR 1.38 [1.13-1.68]), while the HR of MOF was 1.43 (0.97-2.12). The use of AOM was low but similar in all cohorts (approximately 1%).

CONCLUSIONS

Bariatric surgery increased the risk of any fracture and MOF to similar extend. Risks were similar for RYGB and SG. However, SG had a shorter follow-up than RYGB, and the cohort size was rather small. More research is needed for long-term SG fracture risk assessment. The use of AOM was low in all cohorts.

Impact of diabetes on the risk of subsequent fractures in 92,600 patients with an incident hip fracture: A Danish nationwide cohort study 2004-2018

PURPOSE

We investigated the incidence rates of a subsequent hip fracture (HF) and other subsequent fractures than HF after first incident HF, comparing patients with and without diabetes.

METHODS

Using Danish medical databases, we identified 92,600 incident HF patients in the period 2004-2018. Diabetes exposure was examined overall, by type of diabetes (T2D and T1D), and by presence of diabetes complications. We estimated cumulative incidence of subsequent HFs and fractures other than HF within two years of the incident HF. Using Cox regression, adjusted hazard ratios (aHRs) with 95 % confidence interval (CI) were calculated.

RESULTS

Among incident HF patients, 11,469 (12 %) had diabetes, of whom 10,253 (89 %) had T2D and 1216 (11 %) had T1D. The 2-year incidence rates for a new subsequent HF were 4.8 % (95 % CI: 4.6-4.9) for patients without diabetes (reference group), 4.1 % (95 % CI: 3.8-4.6) for T2D, and 4.3 % (95 % CI: 3.3-5.6) for T1D. Corresponding aHRs were 1.01 (95 % CI 0.90-1.14) for T2D and 1.17 (95 % CI 0.87-1.58) for T1D. There was effect modification by sex, as women with T1D had an aHR of 1.52 (95 % CI: 1.09-2.11) for subsequent HF, and by specific diabetes complications (for example, patients with T2D and prior hypoglycemia had an aHR of 1.75 (95 % CI: 1.24-2.42) for subsequent HF, while patients with T1D and neuropathy had an aHR of 1.73 (95 %: 1.09-2.75), when compared with patients without diabetes). For fractures other than HF, the 2-year incidence rates were 7.3 % (95 % CI: 7.2-7.5) for patients without diabetes, 6.6 % (95 % CI: 6.1-7.1) for T2D, and 8.5 % (95 % CI: 7.0-10.1) for T1D, with corresponding aHRs of 1.01 (95 % CI 0.92-1.11) for T2D and 1.43 (95 % CI: 1.16-1.78) for T1D. T2D was only a risk factor for other subsequent fractures among HF patients of high age (age 86-89 years: aHR 1.22 (95 % CI 0.99-1.55), age 90+ years: aHR 1.37 (95 % CI 1.08-1.74)), whereas T1D was robustly associated with increased risk of fractures other than HF in all subgroups.

CONCLUSION

Among HF patients, we found no strong overall association of T2D or T1D with increased risk of subsequent HF, but diabetes patients with prior hypoglycemic events or neuropathy were at increased risk. In contrast, patients with T1D had a clearly increased risk of subsequent fractures other than HF.

Direct factor Xa inhibitors and the risk of cancer and cancer mortality: A Danish population-based cohort study

BACKGROUND

Preclinical animal studies have suggested that myeloid cell-synthesized coagulation factor X dampens antitumor immunity and that rivaroxaban, a direct factor Xa inhibitor, can be used to promote tumor immunity. This study was aimed at assessing whether patients with atrial fibrillation taking direct factor Xa inhibitors have lower risk of cancer and cancer-related mortality than patients taking the direct thrombin inhibitor dabigatran.

METHODS AND FINDINGS

This nationwide population-based cohort study in Denmark included adult patients with atrial fibrillation and without a history of cancer, who started taking a factor Xa inhibitor or dabigatran between 2011 and 2015. Data on medical history, outcomes, and drug use were acquired through Danish healthcare registries. The primary outcome was any cancer. Secondary outcomes were cancer-related mortality and all-cause mortality. Outcome events were assessed during 5 years of follow-up in an intention-to-treat analysis. The propensity score-based inverse probability of treatment weighting was used to compute cumulative incidence and subdistribution hazard ratios (SHRs) and corresponding 95% confidence intervals (CIs), with death as a competing event. Propensity scores were estimated using logistic regression and including in the model sex, age group at index date, comorbidities, and use of comedications. A total of 11,742 patients with atrial fibrillation starting a factor Xa inhibitor and 11,970 patients starting dabigatran were included. Mean age was 75.2 years (standard deviation [SD] 11.2) in the factor Xa cohort and 71.7 years (SD 11.1) in the dabigatran cohort. On the basis of the propensity score-weighted models, after 5 years of follow-up, no substantial difference in the cumulative incidence of cancer was observed between the factor Xa inhibitor (2,157/23,711; 9.11%, 95% CI [8.61%,9.63%]) and dabigatran (2,294/23,715; 9.68%, 95% CI [9.14%,10.25%]) groups (SHR 0.94, 95% CI [0.89,1.00], P value 0.0357). We observed no difference in cancer-related mortality (factor Xa inhibitors cohort 1,028/23,711; 4.33%, 95% CI [4.02%,4.68%]. Dabigatran cohort 1,001/23,715; 4.22%, 95% CI [3.83%,4.66%]; SHR 1.03, 95% CI [0.94,1.12]), but all-cause mortality was higher in the factor Xa inhibitor cohort (factor Xa inhibitors cohort 7,416/23,711; 31.31%, 95% CI [30.37%,32.29%]. Dabigatran cohort 6,531/23,715; 27.56%, 95% CI [26.69%,28.45%]; HR 1.17, 95% CI [1.13,1.21]). The main limitations of the study were the possibility of residual confounding and the short follow-up period.

CONCLUSIONS

In this population based cohort study, factor Xa inhibitor use was not associated with an overall lower incidence of cancer or cancer-related mortality when compared to dabigatran. We did observe an increase in all-cause mortality in the factor Xa inhibitor cohort.

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.

Autoimmune blistering disorders and cardiovascular risks: A population-based cohort study

BACKGROUND

Autoimmune blistering disorders (ABDs) might elevate cardiovascular risk, but studies are lacking.

OBJECTIVE

The objective of this study was to examine if ABDs elevate the risk of atherosclerotic cardiovascular disease, heart failure, arrhythmia, venous thromboembolism, and cardiovascular death.

METHODS

A population-based cohort of Danish patients with ABD (≥18 years of age) diagnosed during 1996-2021 (n = 3322) was compared with an age- and sex-matched comparison cohort from the general population (n = 33,195).

RESULTS

Compared with the general population, patients with ABDs had higher 1-year risks of atherosclerotic cardiovascular disease (3.4% vs 1.6%), heart failure (1.9% vs 0.7%), arrhythmia (3.8% vs 1.3%), venous thromboembolism (1.9% vs 0.3%), and cardiovascular death (3.3% vs 0.9%). The elevated risk persisted after 10 years for all outcomes but arrhythmia. The hazard ratios associating ABDs with the outcomes during the entire follow-up were 1.24 (1.09-1.40) for atherosclerotic cardiovascular disease, 1.48 (1.24-1.77) for heart failure, 1.16 (1.02-1.32) for arrhythmia, 1.87 (1.50-2.34) for venous thromboembolism, and 2.01 (1.76-2.29) for cardiovascular death. The elevated cardiovascular risk was observed for both pemphigus and pemphigoid.

LIMITATIONS

Our findings might only generalize to patients with ABDs without prevalent cardiovascular diseases.

CONCLUSION

Patients with ABDs had an elevated cardiovascular risk compared with age- and sex-matched controls.

Risk of heart failure among individuals tested for Borrelia burgdorferi sensu lato antibodies, and serum Borrelia burgdorferi sensu lato seropositive individuals; a nationwide population-based, registry-based matched cohort study

BACKGROUND

Lyme borreliosis is a tick-borne disease caused by the bacterium Borrelia burgdorferi (Bb) sensu lato complex. Previous studies have suggested an association between Lyme borreliosis and heart failure, which have been suggested to be a possible manifestation of Lyme carditis. We aimed to investigate the risk of heart failure among individuals tested for serum Bb antibodies, and serum Bb seropositive individuals.

METHODS

We performed a matched nationwide cohort study (Denmark, 1993-2020) and included 52,200 Bb seropositive individuals, and two age- and sex-matched comparison cohorts: 1) 104,400 Bb seronegative comparison cohort members, and 2) 261,000 population controls. We investigated the risk associated with 1) being tested for serum Bb antibodies, and 2) being Bb seropositive. Outcomes were: 1) a composite of heart failure, cardiomyopathy, and/or myocarditis diagnosis, and 2) redemption of cardiovascular medicine used for treatment of heart failure. We calculated short-term odds ratios (aOR) (within 1 month) and long-term hazard rates (aHR) (after 1 month) adjusted for age, sex, diabetes, pre-existing heart failure, and kidney disease.

RESULTS

Compared with the population controls, individuals tested for Bb antibodies, regardless of the test result, had increased short-term risk of heart failure, cardiomyopathy, and myocarditis (aOR 8.3, 95 %CI: 6.7-10.2), and both increased short- and long-term risk of redemption of cardiovascular medicine (aOR 4.3, 95 %CI: 3.8-4.8, aHR 1.13, 95 % CI: 1.11-1.15). The Bb seropositive individuals had no increased short- or long-term risk of any outcome compared with Bb seronegative comparison cohort members.

CONCLUSIONS

In conclusion, Bb antibody tests seemed to be performed in the diagnostic work-up of heart failure, but Bb seropositivity was not associated with heart failure.

Type 2 diabetes mellitus and post-colonoscopy colorectal cancer: clinical and molecular characteristics and survival

PURPOSE

Studies suggest that patients with type two diabetes mellitus (T2D) may be at increased risk of post-colonoscopy colorectal cancer (PCCRC). We investigated clinical and molecular characteristics and survival of T2D patients with PCCRC to elucidate how T2D-related PCCRC may arise.

METHODS

We identified T2D patients with colorectal cancer (CRC) from 1995 to 2015 and computed prevalence ratios (PRs) comparing clinical and molecular characteristics of CRC in T2D patients with PCCRC vs. in T2D patients with colonoscopy-detected CRC (dCRC). We also followed T2D patients from the diagnosis of PCCRC/dCRC until death, emigration, or study end and compared mortality using Cox-proportional hazards regression models adjusted for sex, age, year of CRC diagnosis, and CRC stage.

RESULTS

Compared with dCRC, PCCRC was associated with a higher prevalence of proximal CRCs (54% vs. 40%; PR: 1.43, 95% confidence interval [CI] 1.27-1.62) in T2D patients. We found no difference between PCCRC vs. dCRC for CRC stage, histology, and mismatch repair status. The proportion of CRCs that could be categorized as PCCRC decreased over time. Within one year after CRC, 63% of PCCRC vs. 78% of dCRC patients were alive (hazard ratio [HR] 1.85 [95% CI 1.47-2.31]). Within five years after CRC, 44% of PCCRC vs. 54% of dCRC patients were still alive (HR 1.44 [95% CI 1.11-1.87]).

CONCLUSION

The increased prevalence of proximally located PCCRCs and the poorer survival may suggest overlooked colorectal lesions as a predominant explanation for T2D-related PCCRC, although altered tumor progression cannot be ruled out.

Risk of a post-colonoscopy colorectal cancer in patients with diverticular disease: a population-based cohort study

BACKGROUND

Post-colonoscopy colorectal cancers (PCCRCs) may account for up to 30% of all colorectal cancers (CRCs) diagnosed in patients with diverticular disease; however, absolute and relative risks of PCCRC among these patients undergoing colonoscopy remain unknown.

METHODS

We performed a cohort study (1995-2015) including patients with and without diverticular disease who underwent colonoscopy. We calculated 7-36-month cumulative incidence proportions (CIPs) of PCCRC. We used Cox proportional hazards regression models to compute hazard ratios (HRs) of PCCRC, comparing patients with and without diverticular disease, as a measure of relative risk. We calculated 3-year PCCRC rates, as per World Endoscopy Organization recommendations, to estimate the proportion of CRC patients with and without diverticular disease who were considered to have PCCRC. We stratified all analyses by PCCRC location.

RESULTS

We observed 373 PCCRCs among 56 642 patients with diverticular disease and 1536 PCCRCs among 306 800 patients without diverticular disease. The PCCRC CIP after first-time colonoscopy was 0.45% (95%CI 0.40%-0.51%) for patients with and 0.36% (95%CI 0.34%-0.38%) for patients without diverticular disease. Comparing patients with and without diverticular disease undergoing first-time colonoscopy, the adjusted HR was 0.84 (95%CI 0.73-0.97) for PCCRC and 1.23 (95%CI 1.01-1.50) for proximal PCCRCs. The 3-year PCCRC rate was 19.0% (22.3% for proximal PCCRCs) for patients with and 6.5% for patients without diverticular disease.

CONCLUSIONS

Although the absolute risk was low, the relative risk of proximal PCCRCs may be elevated in patients with diverticular disease undergoing colonoscopy compared with patients without the disease.

Landmark analysis of the risk of recurrence after resection or ablation for HCC: A nationwide study

BACKGROUND

The risk of HCC recurrence at particular landmarks since the initial treatment is unknown. With this registry-based study, we aimed to provide a nuanced description of the prognosis following resection or ablation for HCC, including landmark analyses.

METHODS

Using the Danish nationwide health care registries, we identified all patients who received resection or ablation in 2000-2018 as the first HCC treatment. HCC recurrence was defined as a new HCC treatment > 90 days after the first treatment. We conducted competing risk landmark analyses of the cumulative risk of recurrence and death.

RESULTS

Among 4801 patients with HCC, we identified 426 patients who received resection and 544 who received ablation. The 2 treatment cohorts differed in cirrhosis prevalence and tumor stage. The 5-year recurrence risk was 40.7% (95% CI 35.5%-45.8%) following resection and 60.7% (95% CI: 55.9%-65.1%) following ablation. The 1-year recurrence risk decreased over the landmarks from 20.4% (95% CI: 16.6%-24.6%) at the time of resection to 4.7% (95% CI: 0.9%-13.9%) at the 5-year landmark. For ablation, the risk decreased from 36.1% (95% CI: 31.9%-40.4%) at the time of treatment to 5.3% (95% CI: 0.4%-21.4%) at the 5-year landmark. The risk of death without recurrence was stable over the landmarks following both resection and ablation.

CONCLUSIONS

In conclusion, the risk of recurrence or death following resection or ablation for HCC is high from the treatment date, but the risk of recurrence decreases greatly over the survival landmarks. This information is valuable for clinicians and their patients.

Regional variation in incidence and prognosis of acute kidney injury

BACKGROUND

Examining regional variation in acute kidney injury (AKI) and associated outcomes may reveal inequalities and possibilities for optimization of the quality of care. Using the Danish medical databases, we examined regional variation in the incidence, follow-up and prognosis of AKI in Denmark.

METHODS

Patients with one or more AKI episodes in 2017 were identified using population-based creatinine measurements covering all Danish residents. Crude and sex-and-age-standardized incidence rates of AKI were estimated using census statistics for each municipality. Adjusted hazard ratios (aHR) of chronic kidney disease (CKD), all-cause death, biochemical follow-up and outpatient contact with a nephrology department after AKI were estimated across geographical regions and categories of municipalities, accounting for differences in demographics, comorbidities, medication use, lifestyle and social factors, and baseline kidney function.

RESULTS

We identified 63 382 AKI episodes in 58 356 adults in 2017. The regional standardized AKI incidence rates ranged from 12.9 to 14.9 per 1000 person-years. Compared with the Capital Region of Denmark, the aHRs across regions ranged from 1.04 to 1.25 for CKD, from 0.97 to 1.04 for all-cause death, from 1.09 to 1.15 for biochemical follow-up and from 1.08 to 1.49 for outpatient contact with a nephrology department after AKI. Similar variations were found across municipality categories.

CONCLUSIONS

Within the uniform Danish healthcare system, we found modest regional variation in AKI incidence. The mortality after AKI was similar; however, CKD, biochemical follow-up and nephrology follow-up after AKI varied across regions and municipality categories.

Risk factor analysis for a rapid progression of chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a growing global health concern. Identifying individuals in routine clinical care with new-onset CKD at high risk of rapid progression of the disease is imperative to guide allocation of prophylactic interventions, but community-based data are limited. We aimed to examine the risk of rapid progression, kidney failure, hospitalization and death among adults with incident CKD stage G3 and to clarify the association between predefined risk markers and rapid CKD progression.

METHODS

Using plasma creatinine measurements for the entire Danish population from both hospitals and primary care, we conducted a nationwide, population-based cohort study, including adults in Denmark with incident CKD stage G3 in 2017-2020. We estimated 3-year risks of rapid progression (defined by a confirmed decline in estimated glomerular filtration rate of ≥5 mL/min/1.73 m2/year), kidney failure, all-cause hospitalization and death. To examine risk markers, we constructed a heat map showing the risk of rapid progression based on predefined markers: albuminuria, sex, diabetes and hypertension/cardiovascular disease.

RESULTS

Among 133 443 individuals with incident CKD stage G3, the 3-year risk of rapid progression was 14.6% [95% confidence interval (CI) 14.4-14.8]. The 3-year risks of kidney failure, hospitalization and death were 0.3% (95% CI 0.3-0.4), 53.3% (95% CI 53.0-53.6) and 18.1% (95% CI 17.9-18.4), respectively. In the heat map, the 3-year risk of rapid progression ranged from 7% in females without albuminuria, hypertension/cardiovascular disease or diabetes, to 46%-47% in males and females with severe albuminuria, diabetes and hypertension/cardiovascular disease.

CONCLUSION

This population-based study shows that CKD stage G3 is associated with considerable morbidity in a community-based setting and underscores the need for optimized prophylactic interventions among such patients. Moreover, our data highlight the potential of using easily accessible markers in routine clinical care to identify individuals who are at high risk of rapid progression.

Potential medicine waste in the process of outpatients receiving cost-free medicines from medicine pick-up lockers in the North Denmark region

OBJECTIVES

In the Danish healthcare system, restructuring is an ongoing process to accommodate the rising number of patients and to optimise resource allocation. To ease departmental burdens at hospitals in the North Denmark Region, outpatients are empowered to collect their cost-free medicines from medication pick-up lockers. The lockers function similarly to a package box, thereby enhancing patient freedom. Due to lack of evidence within the published literature regarding cost-free medicines and medicine waste, the aim of our study was to identify the common medications delivered to medicine pick-up lockers and secondly, to evaluate potential medicine waste.

METHODS

Data from ApoVision provided insights into medications delivered to medicine pick-up lockers from March to October 2023 in the North Denmark Region. To estimate unused medicines we obtained data on the number of medications returned from medicine pick-up lockers.

RESULTS

From 2020 to 2023, the number of patients receiving cost-free medicines at medication pick-up lockers increased. In total, approximately 30 000 packages of medicine were delivered to medicine pick-up lockers from March to October 2023 in the North Denmark Region; 1.7% were returned. Methotrexate, adalimumab, and omalizumab were among the most common deliveries and were also the three most returned from the medicine pick-up lockers.

CONCLUSIONS

This study is an initial attempt to investigate potential medicine waste in cost-free medicines dispensed to outpatients via pick-up lockers. Antineoplastic and immunomodulating agents were the most common medicines delivered to medication pick-up lockers in the North Denmark Region from March to October 2023. In this period, approximately 2% of all delivered medicine packages were returned to the hospital pharmacy. Our analysis solely focuses on waste associated with medications left uncollected from medicine pick-up lockers. Addressing the impact of medicine waste in a hospital setting requires a comprehensive approach, thus future studies should also focus on other sites relevant for medication waste as, for example, the patient's household.

Obtainment of prescribed analgesics among patients with Lyme neuroborreliosis; a nationwide, population-based matched cohort study

BACKGROUND

Radicular pain is the most predominant symptom among adults with Lyme neuroborreliosis (LNB) but the duration preceding and following diagnosis remains unknown. We aimed to investigate whether patients with LNB have increased obtainment of analgesics before and after diagnosis and for how long.

METHODS

We performed a nationwide, population-based, matched cohort study (2009-2021). all Danish residents with LNB (positive Borrelia burgdorferi intrathecal antibody index test and cerebrospinal fluid pleocytosis) were included. To form a comparison cohort, individuals from the general population were randomly extracted and matched 10:1 to patients with LNB on age and sex. Outcomes were obtainment of simple analgesics, antiepileptics, tricyclic antidepressants, serotonin and noradrenaline reuptake inhibitors, tramadol, and other opioids. We calculated monthly and six-monthly proportions of individuals with obtainment of analgesics and absolute risk differences.

RESULTS

1,056 patients with LNB and 10,560 comparison cohort members were included. An increased proportion of patients with LNB obtained analgesics from 3 months before study inclusion, especially simple analgesics, tramadol, and other opioids. Within the 0-1-month period after study inclusion, patients with LNB most frequently obtained simple analgesics (15 %), antiepileptics (11 %), and tramadol (10 %). Thereafter, obtainment of analgesics declined within a few months. A slightly larger proportion of patients with LNB obtained antiepileptics up to 2.5 years after diagnosis.

CONCLUSIONS

Up to 3 months preceding diagnosis, LNB was preceded by increased obtainment of analgesics, which suggests diagnostic delay. Importantly, most patients with LNB did not obtain analgesics after the immediate disease course, although obtainment remained more frequent up to 2.5 years after.

Association of Antithrombotic Drug Use With Incident Intracerebral Hemorrhage Location

BACKGROUND AND OBJECTIVES

Few population-based studies have assessed associations between the use of antithrombotic (platelet antiaggregant or anticoagulant) drugs and location-specific risks of spontaneous intracerebral hemorrhage (s-ICH). In this study, we estimated associations between antithrombotic drug use and the risk of lobar vs nonlobar incident s-ICH.

METHODS

Using Danish nationwide registries, we identified cases in the Southern Denmark Region of first-ever s-ICH in patients aged 50 years or older between 2009 and 2018. Each verified case was classified as lobar or nonlobar s-ICH and matched to controls in the general population by age, sex, and calendar year. Prior antithrombotic use was ascertained from a nationwide prescription registry. We calculated odds ratios (aORs) for associations between the use of clopidogrel, aspirin, direct oral anticoagulants (DOACs) or vitamin K antagonists (VKA), and lobar and nonlobar ICH in conditional logistic regression analyses that were adjusted for potential confounders.

RESULTS

A total of 1,040 cases of lobar (47.9% men, mean age [SD] 75.2 [10.7] years) and 1,263 cases of nonlobar s-ICH (54.2% men, mean age 73.6 [11.4] years) were matched to 41,651 and 50,574 controls, respectively. A stronger association with lobar s-ICH was found for clopidogrel (cases: 7.6%, controls: 3.5%; aOR 3.46 [95% CI 2.45-4.89]) vs aspirin (cases: 22.9%, controls: 20.4%; aOR 2.14 [1.74-2.63; p = 0.019). Corresponding estimates for nonlobar s-ICH were not different between clopidogrel (cases: 5.4%, controls: 3.4%; aOR 2.44 [1.71-3.49]) and aspirin (cases: 20.7%, controls: 19.2%; aOR 1.77 [1.47-2.15]; p = 0.12). VKA use was associated with higher odds of both lobar (cases: 14.3%, controls: 6.1%; aOR 3.66 [2.78-4.80]) and nonlobar (cases: 15.4%, controls: 5.5%; aOR 4.62 [3.67-5.82]) s-ICH. The association of DOAC use with lobar s-ICH (cases: 3.5%, controls: 2.7%; aOR 1.66 [1.02-2.70]) was weaker than that of VKA use (p = 0.006). Corresponding estimates for nonlobar s-ICH were not different between DOACs (cases: 5.1%, controls: 2.4%; aOR 3.44 [2.33-5.08]) and VKAs (p = 0.20).

DISCUSSION

Antithrombotics were associated with higher risks of s-ICH, but the strength of the associations varied by s-ICH location and drug, which may reflect differences in the cerebral microangiopathies associated with lobar vs nonlobar hemorrhages and the mechanisms of drug action.

Association of Autoimmune Diseases With Coronary Atherosclerosis Severity and Ischemic Events

BACKGROUND

Some autoimmune diseases carry elevated risk for atherosclerotic cardiovascular disease (ASCVD), yet the underlying mechanism and the influence of traditional risk factors remain unclear.

OBJECTIVES

This study sought to determine whether autoimmune diseases independently correlate with coronary atherosclerosis and ASCVD risk and whether traditional cardiovascular risk factors modulate the risk.

METHODS

The study included 85,512 patients from the Western Denmark Heart Registry undergoing coronary computed tomography angiography. A diagnosis of 1 of 18 autoimmune diseases was assessed. Adjusted OR (aOR) for any plaque, any coronary artery calcification (CAC), CAC of >90th percentile, and obstructive coronary artery disease as well as adjusted HR (aHR) for ASCVD were calculated.

RESULTS

During 5.3 years (Q1-Q3: 2.8-8.2 years) of follow-up, 3,832 ASCVD events occurred. A total of 4,064 patients had a diagnosis of autoimmune disease, which was associated with both presence of any plaque (aOR: 1.29; 95% CI: 1.20-1.40), any CAC (aOR: 1.28; 95% CI: 1.19-1.37), and severe CAC of >90th percentile (aOR: 1.53; 95% CI: 1.39-1.68), but not with having obstructive coronary artery disease (aOR: 1.04; 95% CI: 0.91-1.17). Patients with autoimmune diseases had a 46% higher risk (aHR: 1.46; 95% CI: 1.29-1.65) for ASCVD. Traditional cardiovascular risk factors were strongly associated with future ASCVD events, and a favorable cardiovascular risk factor profile in autoimmune patients was associated with ∼54% lower risk compared to patients with presence of risk factors (aHR: 0.46; 95% CI: 0.27-0.81).

CONCLUSIONS

Autoimmune diseases were independently associated with higher burden of coronary atherosclerosis and higher risk for future ASCVD events, with risk accentuated by traditional cardiovascular risk factors. These findings suggest that autoimmune diseases increase risk through accelerated atherogenesis and that cardiovascular risk factor control is key for improving prognosis in patients with autoimmune diseases.

Risk of mortality and recurrence after first-time stroke among patients with type 2 diabetes: A Danish nationwide cohort study

INTRODUCTION

The prognosis for stroke patients with type 2 diabetes mellitus (T2DM) remains poorly understood. We examined the risk of mortality and stroke recurrence in stroke patients with T2DM and stroke patients without diabetes.

PATIENTS AND METHODS

We conducted a population-based cohort study including all patients diagnosed with a first-time ischemic stroke (n = 131,594) or intracerebral hemorrhage (ICH, n = 15,492) in Denmark, 2005-2021. Patients with T2DM were identified using hospital diagnosis codes and glucose-lowering drug prescriptions. We calculated risks, risk differences, and risk ratios, standardized by age, sex, and calendar year of stroke admission.

RESULTS

Following ischemic stroke, the 5-year standardized mortality was 46.1% for patients with T2DM and 35.4% for patients without diabetes (standardized risk difference: 10.7% [95% CI 9.9-11.6]; risk ratio: 1.3 [95% CI 1.3-1.3]). The 5-year risk of recurrence following ischemic stroke was 12.7% for patients with T2DM and 11.3% for those without diabetes (risk difference: 1.4% [95% CI 0.9-2.0]; risk ratio: 1.1 [95% CI 1.1-1.2]). Following ICH, the 5-year mortality was 62.8% for patients with T2DM and 53.0% for patients without diabetes (risk difference: 9.8% [95% CI 7.2-12.4)]; risk ratio: 1.2 [95% CI 1.1-1.2]). The 5-year risk of recurrence after ICH was 9.1% for patients with T2DM and 9.7% for patients without diabetes.

DISCUSSION AND CONCLUSION

Stroke patients with T2DM were at increased risk of mortality. The risk of stroke recurrence was slightly higher for ischemic stroke patients with T2DM than patients without diabetes, while no difference was observed among ICH patients.

Registration of Amyotrophic Lateral Sclerosis: Validity in the Danish National Patient Registry

Purpose

Health care databases are a valuable source for epidemiological research on amyotrophic lateral sclerosis (ALS) if diagnosis codes are valid. We evaluated the validity of the diagnostic codes for ALS in the Danish National Patient Registry (DNPR).

Patients and Methods

We obtained data from the DNPR for all adult (>17 years) patients registered with ALS in Denmark between 1987 and 2022 (median population of 4.2 million during the study period). We randomly selected adult patients living in the North Denmark Region and Central Denmark Region (median population 1.4 million), with a primary discharge diagnosis code of ALS, diagnosed at three departments of neurology. We retrieved and reviewed medical records and estimated the positive predictive value (PPV) of the ALS diagnosis.

Results

Over 36 years, we identified 5679 patients. From the validation cohort of 300 patients, we were able to retrieve 240 (80%) medical records, and 215 ALS diagnoses were confirmed. The overall positive predictive value was 89.6% (95% confidence interval (CI): 85.1-92.8). The highest PPV was achieved for diagnoses registered for patients aged ≥70 years (93.8; 95% CI: 86.2-97.3) compared to patients <60 years (83.4; 95% CI: 73.3-90.7).

Conclusion

We found a high PPV of primary diagnostic codes for ALS from Danish departments of neurology, demonstrating high validity. Thus, the DNPR is a well-suited data source for large-scale epidemiological research on ALS.

Pediatric health service utilization at tertiary hospitals in Denmark 2000-2018

Pediatric health service differs between and within countries. To prioritize limited resources, data-driven studies on pediatric tertiary hospital contacts are warranted. This population-based register study identified all contacts with four Danish tertiary hospitals 2000-2018 by 0-17-year-old patients. During 2000-2018, 2,496,001 individuals resided in Denmark while 0-17 years old, and the study described 829,562 inpatient and 3,932,744 outpatient contacts at tertiary hospitals by hospital, sex, age, diagnosis, department, and residence. Male patients accounted for more contacts overall (inpatient 55.51%, outpatient 52.40%) and more contacts with severe chronic disease (inpatient 56.24%, outpatient 54.41%). Median (interquartile range) patient age was 3.09 (0.26-9.96) and 8.48 (2.78-13.70) years for in- and outpatient contacts. Overall, 28.23% and 21.02% of in- and outpatient contacts included a diagnosis of a severe chronic disease, but the proportions differed across hospitals. A pattern of pediatric healthcare directed towards less severe diseases was observed: While the total number of outpatient visits at tertiary hospitals increased from 2000 to 2018, the proportion of these contacts which had a diagnosis of a severe chronic disease decreased. Future comparisons between hospitals regarding pediatric outcomes should consider potential differences in terms of uptake and diagnosis severity. Such findings may have implications for future pediatric organization, nationally and internationally.

Risk of post-injection endophthalmitis peaks within the first three injections of anti-vascular endothelial growth factor therapy: A nationwide registry-based study

PURPOSE

To report the incidence of post-injection endophthalmitis (PIE) and the cumulative risk associated with repeated injections of intravitreal anti-vascular endothelial growth factor (anti-VEGF).

METHODS

We employed nationwide registries in Denmark to include all individuals aged ≥40 years who received at least one intravitreal anti-VEGF injection in 2007-2022. Our primary endpoint PIE was identified using specific diagnostic codes for endophthalmitis and procedure codes for vitreous biopsy within 10 days prior to and 120 days post-injection. Patients were stratified according to the underlying diagnoses for which they received the treatment. The relative risk (RR) for PIE was calculated between groups based on the number of injections received by the patients.

RESULTS

We identified 60 825 patients who received intravitreal anti-VEGF treatment during study time, with a median age of 77.2 years and females constituting 58.1%. We identified 232 cases of PIE after 1 051 549 injections during follow-up, resulting in an incidence of 0.022% [95% CI 0.019%-0.025%]. Despite a linear growth in annual anti-VEGF use, the incidence remained stable at 0.020% [95% CI 0.017%-0.023%] from 2013 to 2022. Compared to patients receiving 1-3 injections, RR for patients receiving 4-20, 21-40, and >40 injections were 0.46 [95% CI 0.34-0.63], 0.32 [95% CI 0.21-0.50], and 0.54 [95% CI 0.36-0.81], respectively. Findings were similar across the different diagnoses.

CONCLUSIONS

Based on 16 years of nationwide registry data, this study identified a low and stable incidence of PIE. Notably, the highest risk of endophthalmitis was within the first three anti-VEGF injections.

Follow-Up Study of Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against All-Type and Serotype-Specific Invasive Pneumococcal Disease, Denmark

As a follow-up to a previous study, we investigated vaccine effectiveness (VE) of 23-valent pneumococcal polysaccharide vaccine (PPSV23) against invasive pneumococcal disease (IPD) among 1,254,498 persons >65 years of age as part of a vaccination program in Denmark during April 2020-January 2023. We assessed VE by using a Cox regression model and adjusted for age, sex, and underlying conditions. Using nationwide data, we estimated a VE of PPSV23 against all-type IPD of 32% and against PPSV23-serotype IPD of 41%. Because this follow-up study had more statistical power than the original study, we also estimated VE against IPD caused by PPSV23-serotypes excluding serotype 3; serotype 3; serotype 8; serotype 22F; PPSV23 non-PCV15 serotypes; PPSV23 non-PCV20 serotypes; and IPD over time. Our findings suggest PPSV23 vaccination can protect persons >65 years of age against IPD caused by all serotypes or serotype groupings, except serotype 3.

Trends in cause-specific mortality among people with type 2 and type 1 diabetes from 2002 to 2019: a Danish population-based study

Background

Despite advances in primary and secondary prevention of cardiovascular disease, excess mortality persists within the diabetes population. This study explores the components of this excess mortality and their interaction with sex.

Methods

Using Danish registries (2002-2019), we identified residents aged 18-99 years, their diabetes status, and recorded causes of death. Applying Lexis-based methods, we computed age-standardized mortality rates (asMRs), mortality relative risks (asMRRs), and log-linear trends for cause-specific mortality.

Findings

From 2002 to 2019, 958,278 individuals died in Denmark (T2D: 148,620; T1D: 7830) during 84.4 M person-years. During the study period, overall asMRs declined, driven by reducing cardiovascular mortality, notably in men with T2D. Conversely, cancer mortality remained high, making cancer the leading cause of death in individuals with T2D. Individuals with T2D faced an elevated mortality risk from nearly all cancer types, ranging from 9% to 257% compared to their non-diabetic counterparts. Notably, obesity-related cancers exhibited the highest relative risks: liver cancer (Men: asMRR 3.58 (3.28; 3.91); Women: asMRR 2.49 (2.14; 2.89)), pancreatic cancer (Men: asMRR 3.50 (3.25; 3.77); Women: asMRR 3.57 (3.31; 3.85)), and kidney cancer (Men: asMRR 2.10 (1.84; 2.40); Women: asMRR 2.31 (1.92; 2.79)). In men with type 2 diabetes, excess mortality remained stable, except for dementia. In women, diabetes-related excess mortality increased by 6-17% per decade across all causes of death, except cardiovascular disease.

Interpretation

In the last decade, cancer has emerged as the leading cause of death among individuals with T2D in Denmark, emphasizing the need for diabetes management strategies incorporating cancer prevention. A sex-specific approach is crucial to address persistently higher relative mortality in women with diabetes.

Funding

Supported by Steno Diabetes Center Aarhus, which is partially funded by an unrestricted donation from the Novo Nordisk Foundation, and by The Danish Diabetes Academy.

Towards more comprehensive nationwide familial aggregation studies in Denmark: The Danish Civil Registration System versus the lite Danish Multi-Generation Register

AIM

Linking information on family members in the Danish Civil Registration System (CRS) with information in Danish national registers provides unique possibilities for research on familial aggregation of diseases, health patterns, social factors and demography. However, the CRS is limited in the number of generations that it can identify. To allow more complete familial linkages, we introduce the lite Danish Multi-Generation Register (lite MGR) and the future full Danish MGR that is currently being developed.

METHODS

We generated the lite MGR by linking the current version of the CRS with historical versions stored by the Danish National Archives in the early 1970s, which contain familial links not saved in the current CRS. We describe and compare the completeness of familial links in the lite MGR and the current version of the CRS. We also describe planned procedures for generating the full MGR by linking the current CRS with scanned archived records from Parish Registers.

RESULTS

Among people born in Denmark in 1960 or later, the current CRS contains information on both parents. However, it has limited parental information for people born earlier. Among the 732,232 people born in Denmark during 1950-1959, 444,084 (60.65%) had information on both parents in the CRS. In the lite MGR, it was 560,594 (76.56%).

CONCLUSIONS

The lite MGR offers more complete information on familial relationships than the current CRS. The lite and full MGR will offer an infrastructure tying together existing research infrastructures, registers and biobanks, raising their joint research value to an unparalleled level.

Disparities in prehospital and emergency surgical care among patients with perforated ulcers and a history of mental illness: a nationwide cohort study

PURPOSE

To compare patients with and without a history of mental illness on process and outcome measures in relation to prehospital and emergency surgical care for patients with perforated ulcer.

METHODS

A nationwide registry-based cohort study of patients undergoing emergency surgery for perforated ulcer. We used data from the Danish Prehospital Database 2016-2017 and the Danish Emergency Surgery Registry 2004-2018 combined with data from other Danish databases. Patients were categorized according to severity of mental health history.

RESULTS

We identified 4.767 patients undergoing emergency surgery for perforated ulcer. Among patients calling the EMS with no history of mental illness, 51% were identified with abdominal pain when calling the EMS compared to 31% and 25% among patients with a history of moderate and major mental illness, respectively. Median time from hospital arrival to surgery was 6.0 h (IQR: 3.6;10.7). Adjusting for age, sex and comorbidity, patients with a history of major mental illness underwent surgery 46 min (95% CI: 4;88) later compared to patients with no history of mental illness. Median number of days-alive-and-out-of-hospital at 90-day follow-up was 67 days (IQR: 0;83). Adjusting for age, sex and comorbidity, patients with a history of major mental illness had 9 days (95% CI: 4;14) less alive and out-of-hospital at 90-day follow-up.

CONCLUSION

One-third of the population had a history of mental illness or vulnerability. Patients with a history of major mental illness were less likely to be identified with abdominal pain if calling the EMS prior to arrival. They had longer delays from hospital arrival to surgery and higher mortality.

Homelessness, psychiatric disorders, and violence in Denmark: a population-based cohort study

BACKGROUND

Homelessness is associated with adverse health and social outcomes. People experiencing homelessness have been found to have a high risk of violent crime victimisation as well as high prevalence of psychiatric disorders. It is poorly understood whether experiencing homelessness is associated with additional risks of violent offending and whether psychiatric disorders contribute to these risks. We examined the association between homelessness, psychiatric disorders, and first violence offence leading to conviction.

METHODS

We did a nationwide, register-based cohort study of all Danish residents who were alive at least 1 day during the study period, born between Jan 1, 1980, and Dec 31, 2006, and aged 15 years or older retrieved from the Danish Civil Registration System, which was linked to registers with information on homelessness, health care, and criminality. The exposure was any experience of homelessness, which was defined as having at least one contact with a homeless shelter during the study period. The outcome was first violent offence leading to a conviction. We calculated incidence rates per 10 000 person-years, incidence rate ratios (IRRs) using Poisson regression analysis, and probability of conviction of a violent offence using an Aalen-Johansen estimator. Analyses were stratified by sex and adjusted for calendar year of the study period, age, other sociodemographic factors, and psychiatric disorders.

FINDINGS

The study cohort included 1 786 433 Danish residents aged 15-42 years living in Denmark at some point from Jan 1, 2001, to Dec 31, 2021, contributing to 21 336 322 person-years at risk, of whom 57 084 (3·2%) individuals had their first violent offence leading to conviction during follow-up. 10 years after their first contact with a homeless shelter, 22·9% (95% CI 21·6-24·2) of men and 7·7% (6·8-8·7) of women had committed at least one violent crime leading to conviction. The fully adjusted IRRs of a violent offence leading to conviction were 4·8 (4·5-5·1) in men and 6·3 (5·6-7·2) in women experiencing homelessness compared with individuals who had not experienced homelessness. The IRR for a violent offence leading to conviction was highest in individuals experiencing homelessness and having co-occurring psychiatric disorders compared with those not experiencing homelessness and without co-occurring psychiatric disorders, especially drug use disorders (IRR in those experiencing homelessness and having a drug use disorder: 15·3 [14·1-16·7] in men and 40·1 [33·9-47·5] in women compared with individuals not experiencing homelessness and having no drug use disorder).

INTERPRETATION

Individuals experiencing homelessness had higher risks of a violent offence leading to conviction than those who had not experienced homelessness. In addition to preventing homelessness, public health and policy should consider how to reduce the risk of adverse outcomes in people experiencing homelessness.

FUNDING

Lundbeck Foundation.

Parous women perform less moderate to vigorous physical activity than their nulliparous peers: a population-based study in Denmark

OBJECTIVES

The World Health Organization (WHO) highlights parous women as a key population for monitoring trends of physical activity (PA). We aimed to estimate the proportion of Danish women non-adhering to WHO PA guidelines in parous women compared with nulliparous women and to describe leisure-time PA intensity in each of these groups.

STUDY DESIGN

Cross-sectional study.

METHODS

This population-based study builds on a sample of 27,668 women aged 16-40 years from the Danish National Health Survey 2021. These data were linked with childbirth data from the Danish National Birth Registry. The primary outcome was self-reported weekly hours of moderate to vigorous leisure-time PA (MVPA) dichotomized into: (i) adhering to WHO guidelines for MVPA or (ii) not adhering to WHO guidelines for MVPA. Binomial regression analysis was used to calculate prevalence proportions (PP) and prevalence proportion ratios (PPR).

RESULTS

Of the 27,668 women, a total of 20,022 were included; 9338 (46.6%) parous women and 10,684 (53.4%) nulliparous women. The PP of women non-adhering to WHO PA guidelines was 63.8% (95% CI 62.9-64.8) for parous and 51.3% (95% CI 50.4-52.3) for nulliparous women, corresponding to a PPR of 1.24 (95% CI 1.21; 1.27).

CONCLUSIONS

The proportion of parous women who did not adhere to WHO PA guidelines for MVPA was 24% higher than that of nulliparous women. This highlights parous women as a subgroup of the adult population at increased risk of non-adherence to WHO PA guidelines. These findings call for future research to inform new strategies aiming to promote PA in parous women.

Longitudinal HbA1c patterns before the first treatment of diabetes in routine clinical practice: A latent class trajectory analysis

AIMS

To examine the longitudinal heterogeneity of HbA1c preceding the initiation of diabetes treatment in clinical practice.

METHODS

In this population-based study, we used HbA1c from routine laboratory and healthcare databases. Latent class trajectory analysis was used to classify individuals according to their longitudinal HbA1c patterns before first glucose-lowering drug prescription irrespective of type of diabetes.

RESULTS

Among 21,556 individuals initiating diabetes treatment during 2017-2018, 20,733 (96 %) had HbA1c measured (median 4 measurements [IQR 2-7]) in the 5 years preceding treatment initiation. Four classes with distinct HbA1c trajectories were identified, with varying steepness of increase in HbA1c. The largest class (74 % of the individuals) had mean HbA1c above the 48 mmol/mol threshold 9 months before treatment initiation. Mean HbA1c was 52 mmol/mol (95 % CI 52-52) at treatment initiation. In the remaining three classes, mean HbA1c exceeded 48 mmol/mol almost 1.5 years before treatment initiation and reached 79 mmol/mol (95 % CI 78-80), 105 mmol/mol (95 % CI 104-106), and 137 mmol/mol (95 % CI 135-140) before treatment initiation.

CONCLUSION

We identified four distinct longitudinal HbA1c patterns before initiation of diabetes treatment in clinical practice. All had mean HbA1c levels exceeding the diagnostic threshold many months before treatment initiation, indicating therapeutic inertia.