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

Prognostic Accuracy of SOFA, qSOFA, and SIRS for Mortality Among Emergency Department Patients with Infections

Objective

This study aimed to determine the prognostic accuracy of SOFA in comparison to quick-SOFA (qSOFA) and systemic inflammatory response syndrome (SIRS) in predicting 28-day mortality in the emergency department (ED) patients with infections.

Methods

A secondary analysis of data from a prospective study of adult patients with documented or suspected infections admitted to an ED in Denmark from Oct-2017 to Mar-2018. The SOFA scores were calculated after adjustment for chronic diseases. The prognostic accuracy was assessed by analysis of sensitivity, specificity, predictive values, likelihood ratios, and area under the receiver operating characteristic curve (AUROC) with 95% confidence intervals (CI).

Results

A total of 2045 patients with a median age of 73.2 (IQR: 60.9-82.1) years were included. The overall 28-day mortality was 7.7%. In patients meeting a SOFA score ≥2, qSOFA score ≥2, and SIRS criteria ≥2 the 28-day mortality was 13.6% (11.2-16.3), 17.8% (12.4-24.3) and 8.3% (6.7-10.2), respectively. SOFA ≥2 had a sensitivity of 61.4% (53.3-69.0) and specificity of 67.3% (65.1-69.4), qSOFA ≥2 had a sensitivity of 19.6% (13.7-26.7) and specificity of 92.4% (91.1-93.6), and SIRS ≥2 had a sensitivity of 52.5% (44.4-60.5) and specificity of 51.5% (49.2-53.7). The AUROC for SOFA compared to SIRS was: 0.68 vs 0.52; p<0.001 and compared to qSOFA: 0.68 vs 0.63; p=0.018.

Conclusion

A SOFA score of at least two had better prognostic accuracy for 28-day mortality than SIRS and qSOFA. However, the overall accuracy of SOFA was poor for the prediction of 28-day mortality.

Nordic Health Registry-Based Research: A Review of Health Care Systems and Key Registries

The Nordic countries are Denmark, Finland, Iceland, Norway, and Sweden and comprise a total population of approximately 27 million. The countries provide unique opportunities for joint health registry-based research in large populations with long and complete follow-up, facilitated by shared features, such as the tax-funded and public health care systems, the similar population-based registries, and the personal identity number as unique identifier of all citizens. In this review, we provide an introduction to the health care systems, key registries, and how to navigate the practical and ethical aspects of setting up such studies. For each country, we provide an overview of population statistics and health care expenditures, and describe the operational and administrative organization of the health care system. The Nordic registries provide population-based, routine, and prospective data on individuals lives and health with virtually complete follow-up and exact censoring information. We briefly describe the total population registries, birth registries, patient registries, cancer registries, prescription registries, and causes of death registries with a focus on period of coverage, selected key variables, and potential limitations. Lastly, we discuss some practical and legal perspectives. The potential of joint research is not fully exploited, mainly due to legal and practical difficulties in, for example, cross-border sharing of data. Future tasks include clear and transparent legal pathways and a framework by which practical aspects are facilitated.

Maternal education before childbirth and cardiovascular diseases in offspring during early adulthood: a Danish population-based cohort study

BACKGROUND

Cardiovascular disease (CVD) is increasing in youths, but there is limited knowledge about the etiology of early-onset CVD. We aimed to examine the association between maternal education before childbirth and CVD risk in offspring during early adulthood (20-40 years old).

METHODS AND RESULTS

This population-based cohort study included 1123600 individuals born in Denmark during 1977-1996. Compared to offspring born to mothers with high education, offspring born to mothers with low or medium education had 27% (hazard ratio, 1.27; 95% confidence interval, 1.23-1.30) or 12% (1.12; 1.09-1.15) increased overall risk of early-onset CVD, respectively. Increased risks were observed for most type-specific CVDs, in particular for myocardial infarction low [2.03; 1.55-2.65] or medium education [1.52; 1.16-1.99]), heart failure (low [1.59; 1.24-2.03] or medium education [1.51; 1.19-1.92]), and ischemic stroke (low [1.50; 1.28-1.76] or medium education [1.29; 1.10-1.51]). We observed high incidences of CVD in offspring of mothers with comorbid CVD (low [1.67; 1.51-1.86] or medium education [1.46; 1.29-1.64]), compared with those of mothers with high education and no CVD history.

CONCLUSIONS

Low maternal education before childbirth, especially with maternal comorbid CVD, is significantly associated with increased risk of overall CVD and most type-specific CVDs in offspring in early adulthood. The influence of maternal education on future offspring CVD should be taken into consideration in the assessment of CVD risks from early decades of life.

The Validity of Danish Prescription Data to Measure Use of Aspirin and Other Non-Steroidal Anti-Inflammatory Drugs and Quantification of Bias Due to Non-Prescription Drug Use

Purpose

To evaluate the potential of Danish prescription registries to capture aspirin and non-aspirin non-steroidal anti-inflammatory drug (NSAID) use and to quantitatively evaluate the magnitude of bias from misclassification of true NSAID and aspirin use as apparent non-use in drug outcome studies.

Patients and Methods

In a population-based cohort study, we retrieved sales statistics for NSAIDs and aspirins based on nationwide data from the Danish Health Data Authority and the Danish National Prescription Registry. We estimated prevalence of recorded and non-recorded NSAID use in the prescription registry and resulting proportions of true NSAID and aspirin use misclassified as apparent non-use from 1999 to 2019 at population and patient levels.

Results

The prevalence of true use misclassified as non-use (mainly due to over-the-counter use) peaked at 4.7% in 2012 for NSAIDs overall, 5.5% in 2012 for ibuprofen, and at 5.9% in 2002 for high-dose aspirin. Misclassification of other individual NSAIDs was near null. Misclassification of true low-dose aspirin use as non-use declined during the study period but remained around 1% since 2005. In subgroups of cardiac patients, the highest prevalence of true NSAID use misclassified as non-use was 5.0% in 2002 and 4.3% in 2017. Quantitative bias analyses showed how such misclassification of true NSAID and aspirin use as non-use remained minimal both at population and patient levels. In hypothetical examples simulating real study populations with differing exposure prevalence and prevalence of true NSAID and aspirin use misclassified as apparent non-use, the approximate percentage change due to misclassification of use as non-use did not exceed 5% and in most scenarios stayed around 1%.

Conclusion

The Danish prescription registries are valid data sources for assessing the effects of aspirin and NSAID use. The influence of non-recorded NSAID and aspirin use on estimates of association is virtually negligible.

Pharmacoepidemiological methods for computing the duration of pharmacological prescriptions using secondary data sources

PURPOSE

In pharmacoepidemiology, correctly defining the exposure period of pharmacological treatment is a challenging step when information on the time in treatment is missing or incomplete.

METHODS

In this review, we describe several methods for defining exposure to pharmacological treatments using secondary data sources that lack such information.

RESULTS AND CONCLUSION

Several methods for assessing the duration of redeemed prescriptions and combining them into temporal sequences are available. We present a set of considerations to make researchers aware of the potentials and pitfalls of these methods that may aid in minimizing biases in research using these methods. Additionally, we highlight that, to date, there is no one-size-fits-all solution. Thus, the choice of method should be based on their area of applicability combined with a careful mapping to the research scenario under investigation.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants and warfarin in atrial fibrillation: a Scandinavian population-based cohort study

AIMS

Using Scandinavian population-based registries, we assessed risk of stroke/systemic embolism (SE) and bleeding with non-vitamin K antagonist oral anticoagulants compared with warfarin in anticoagulation-naïve patients with atrial fibrillation (AF).

METHODS AND RESULTS

This historical cohort study included 219 545 AF patients [median age 74 years; 43% women; mean CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischaemic attack, vascular disease, age 65-74 years, sex category) score 3.3] initiating apixaban, dabigatran, rivaroxaban, or warfarin in Denmark, Norway, and Sweden (1 January 2013 to 31 December 2016). The primary endpoints were stroke/SE and major bleeding. The median follow-up times were 9.7 (3.9-21.5) months for stroke/SE and 9.6 (3.8-21.3) months for bleeding. Apixaban and warfarin initiators were older and had higher CHA2DS2-VASc scores compared with dabigatran and rivaroxaban initiators. After 1:1 propensity score matching, three cohorts were created: apixaban-warfarin (n = 111 162), dabigatran-warfarin (n = 56 856), and rivaroxaban-warfarin (n = 61 198). Adjusted hazard ratios (HRs) were estimated using a Cox regression. For stroke/SE, adjusted HRs against warfarin were 0.96 [95% confidence interval (CI): 0.87-1.06] for apixaban, 0.89 (95% CI: 0.80-1.00) for dabigatran, and 1.03 (95% CI: 0.92-1.14) for rivaroxaban. For major bleeding, the HRs against warfarin were 0.73 (95% CI: 0.67-0.78) for apixaban, 0.89 (95% CI: 0.82-0.97) for dabigatran, and 1.15 (95% CI: 1.07-1.25) for rivaroxaban. The results in the dabigatran cohort did not hold in all dose-defined subgroups.

CONCLUSION

In this large Scandinavian study among AF patients initiating oral anticoagulation, those initiating dabigatran, apixaban, and rivaroxaban had similar rates of stroke/SE to patients initiating warfarin. Rates of major bleeding were lower with apixaban and dabigatran and higher with rivaroxaban, each compared with warfarin.

Hyperhidrosis and the risk of being treated for skin infections

BACKGROUND

A few studies have described an increased prevalence of skin infections in individuals with hyperhidrosis compared to others. However, it remains uncertain whether hyperhidrosis is an independent risk factor for skin infections.

OBJECTIVE

To compare the risk of skin infections in individuals with and without hyperhidrosis.

METHODS

In this retrospective cohort study, data on hyperhidrosis were collected from the Danish Blood Donor Study. Blood donors included in 2010-2019 were followed from inclusion until December 2019. Data on redeemed prescriptions against skin infections were collected from the National Prescription Register. The intensity of prescription-use by hyperhidrosis status was assessed in Andersen-Gill models.

RESULTS

Overall, 4,176 (9.6%) of 43,477 blood donors had self-reported hyperhidrosis and 437 (0.34%) of 127,823 blood donors had hospital diagnosed hyperhidrosis. Self-reported hyperhidrosis was associated with the use of antibiotic prescriptions (adjusted hazard ratio = 1.21; 95% confidence interval 1.00-1.45, p = 0.047). Hospital diagnosed hyperhidrosis was associated with the use of antibiotic (adjusted hazard ratio = 1.33; 95% confidence interval 1.03-1.68, p = 0.028) and topical antifungal prescriptions (adjusted hazard ratio = 1.43; 95% confidence interval 1.04-1.97, p = 0.027).

CONCLUSIONS

Hyperhidrosis is associated with the use of prescriptions for antibiotics and topical antifungals. This suggests a clinically relevant association between hyperhidrosis and skin infections.

Mortality of older acutely admitted medical patients after early discharge from emergency departments: a nationwide cohort study

Background

The mortality of older patients after early discharge from hospitals is sparsely described. Information on factors associated with mortality can help identify high-risk patients who may benefit from preventive interventions. The aim of this study was to examine whether demographic factors, comorbidity and admission diagnoses are predictors of 30-day mortality among acutely admitted older patients discharged within 24 h after admission.

Methods

All medical patients aged ≥65 years admitted acutely to Danish hospitals between 1 January 2013 and 30 June 2014 surviving a hospital stay of ≤24 h were included. Demographic factors, comorbidity, discharge diagnoses and mortality within 30 days were described using data from the Danish National Patient Registry and the Civil Registration System. Cox regression was used to estimate adjusted hazard ratios (aHR) with 95% confidence intervals (CI) for all-cause mortality.

Results

A total of 93,295 patients (49.4% men) with a median age of 75 years (interquartile range: 69–82 years), were included. Out of these, 2775 patients (3.0%; 95% CI 2.9–3.1%) died within 30 days after discharge. The 30-day mortality was increased in patients with age 76–85 years (aHR 1.59; 1.45–1.75) and 86+ years (aHR 3.35; 3.04–3.70), male gender (aHR 1.22; 1.11–1.33), a Charlson Comorbidity Index of 1–2 (aHR 2.15; 1.92–2.40) and 3+ (aHR 4.07; 3.65–4.54), and unmarried status (aHR 1.17; 1.08–1.27). Discharge diagnoses associated with 30-day mortality were heart failure (aHR 1.52; 1.17–1.95), respiratory failure (aHR 3.18; 2.46–4.11), dehydration (aHR 2.87; 2.51–3.29), constipation (aHR 1.31; 1.02–1.67), anemia (aHR 1.45; 1.27–1.66), pneumonia (aHR 2.24; 1.94–2.59), urinary tract infection (aHR 1.33; 1.14–1.55), dyspnea (aHR 1.57; 1.32–1.87) and suspicion of malignancy (aHR 2.06; 1.64–2.59).

Conclusions

Three percent had died within 30 days. High age, male gender, the comorbidity burden, unmarried status and several primary discharge diagnoses were identified as independent prognostic factors of 30-day all-cause mortality.

Severe mental illness is associated with increased mortality and severe course of COVID-19

OBJECTIVE

Psychiatric disorders have been associated with unfavourable outcome following respiratory infections. Whether this also applies to coronavirus disease 2019 (COVID-19) has been scarcely investigated.

METHODS

Using the Danish administrative databases, we identified all patients with a positive real-time reverse transcription-polymerase chain reaction test for COVID-19 in Denmark up to and including 2 January 2021. Multivariable cox regression was used to calculate 30-day absolute risk and average risk ratio (ARR) for the composite end point of death from any cause and severe COVID-19 associated with psychiatric disorders, defined using both hospital diagnoses and redemption of psychotropic drugs.

RESULTS

We included 144,321 patients with COVID-19. Compared with patients without psychiatric disorders, the standardized ARR of the composite outcome was significantly increased for patients with severe mental illness including schizophrenia spectrum disorders 2.43 (95% confidence interval [CI], 1.79-3.07), bipolar disorder 2.11 (95% CI, 1.25-2.97), unipolar depression 1.70 (95% CI, 1.38-2.02), and for patients who redeemed psychotropic drugs 1.70 (95% CI, 1.48-1.92). No association was found for patients with other psychiatric disorders 1.13 (95% CI, 0.86-1.38). Similar results were seen with the outcomes of death or severe COVID-19. Among the different psychiatric subgroups, patients with schizophrenia spectrum disorders had the highest 30-day absolute risk for the composite outcome 3.1% (95% CI, 2.3-3.9%), death 1.2% (95% CI, 0.4-2.0%) and severe COVID-19 2.7% (95% CI, 1.9-3.6%).

CONCLUSION

Schizophrenia spectrum disorders, bipolar disorder, unipolar depression and psychotropic drug redemption are associated with unfavourable outcomes in patients with COVID-19.

Loss of pre-fracture basic mobility status at hospital discharge for hip fracture is associated with 30-day post-discharge risk of infections - a four-year nationwide cohort study of 23,309 Danish patients

BACKGROUND

The loss of pre-fracture basic mobility status is associated with increased mortality and any readmission after hip fracture. However, it is less known if the loss of pre-fracture mobility has impact on acquiring a post-discharge infection.

PURPOSE

To examine if the loss of pre-fracture basic mobility status at hospital discharge was associated with hospital-treated or community-treated infections within 30-days of hospital discharge after hip fracture.

METHODS

Using the nationwide Danish Multidisciplinary Hip Fracture Registry from January 2014 through November 2017, we included 23,309 patients undergoing surgery for a first-time hip fracture. The Cumulated Ambulation Score (CAS, 0-6 points) was recorded using questionnaire at admission (pre-fracture CAS) and objectively assessed at discharge. The loss of any CAS-points at discharge compared with pre-fracture CAS was calculated and dichotomized (yes/no). Using Cox regression analyses, we estimated the hazard ratio (HR) with 95% confidence interval (CI) of any hospital-treated infection, hospital-treated pneumonia or community-treated infection adjusted for sex, age, body mass index, Charlson Comorbidity Index, residential status, type of fracture, and length of hospital stay (LOS).

RESULTS

Total of 12,046 (62%) patients lost their pre-fracture CAS status at discharge. Among patients who had lost their pre-fracture CAS, 6.0% developed a hospital-treated infection compared to 4% of those who did not lose their pre-fracture CAS. Correspondingly, 9.2% versus 6.2% developed a community-treated infection. The risk of 30-day post-discharge infection increased with increasing loss of any CAS points. The adjusted HRs for patients who had lost their pre-fracture CAS status, compared to patients who did not, was 1.34 (CI: 1.16-1.54) for hospital-treated infection, 1.35 (CI: 1.09 - 1.67) for pneumonia and 1.36 (CI: 1.21-1.52) for community-treated infection.

CONCLUSION

In this large national cohort study, we found that loss of pre-fracture basic mobility status upon hospital discharge was strongly associated with 30-day post-discharge risk of developing infection. These findings suggest a clinical importance of carefully focusing on regaining the pre-fracture basic mobility before discharging the patient.

Increased vulnerability to COVID-19 in chronic kidney disease

BACKGROUND

The significance of chronic kidney disease on susceptibility to COVID-19 and subsequent outcomes remains unaddressed.

OBJECTIVE

To investigate the association of estimated glomerular filtration rate (eGFR) on risk of contracting COVID-19 and subsequent adverse outcomes.

METHODS

Rates of hospital-diagnosed COVID-19 were compared across strata of eGFR based on conditional logistic regression using a nested case-control framework with 1:4 matching of patients diagnosed with COVID-19 with controls from the Danish general population on age, gender, diabetes and hypertension. Risk of subsequent severe COVID-19 or death was assessed in a cohort study with comparisons across strata of eGFR based on adjusted Cox regression models with G-computation of results to determine 60-day risk standardized to the distribution of risk factors in the sample.

RESULTS

Estimated glomerular filtration rate was inversely associated with rate of hospital-diagnosed COVID-19: eGFR 61-90 mL/min/1.73m² HR 1.13 (95% CI 1.03-1.25), P = 0.011; eGFR 46-60 mL/min/1.73m²   HR 1.26 (95% CI 1.06-1.50), P = 0.008; eGFR 31-45 mL/min/1.73m² HR 1.68 (95% CI 1.34-2.11), P < 0.001; and eGFR ≤ 30 mL/min/1.73m² 3.33 (95% CI 2.50-4.42), P < 0.001 (eGFR > 90 mL/min/1.73m² as reference), and renal impairment was associated with progressive increase in standardized 60-day risk of death or severe COVID-19; eGFR > 90 mL/min/1.73m² 13.9% (95% CI 9.7-15.0); eGFR 90-61 mL/min/1.73m² 16.1% (95% CI 14.5-17.7); eGFR 46-60 mL/min/1.73m² 17.8% (95% CI 14.7-21.2); eGFR 31-45 mL/min/1.73m² 22.6% (95% CI 18.2-26.2); and eGFR ≤ 30 mL/min/1.73m² 23.6% (95% CI 18.1-29.1).

CONCLUSIONS

Renal insufficiency was associated with progressive increase in both rate of hospital-diagnosed COVID-19 and subsequent risk of adverse outcomes. Results underscore a possible vulnerability associated with impaired renal function in relation to COVID-19.

Sodium-glucose cotransporter 2 inhibitors and risk of nephrolithiasis

AIMS/HYPOTHESIS

Sodium-glucose cotransporter 2 inhibitors (SGLT2Is) may reduce nephrolithiasis risk by increasing urine flow. We aimed to investigate whether initiation of SGLT2I was associated with reduced nephrolithiasis risk.

METHODS

We conducted an active-comparator new-user cohort study using the Danish health registries in the period 11 November 2012 to 31 December 2018. Individuals aged ≥40 years initiating SGLT2Is or glucagon-like peptide-1 receptor agonists (GLP1 RAs) were followed from treatment initiation until an inpatient or outpatient diagnosis of nephrolithiasis, death, emigration or end of study. New users of SGLT2Is were matched 1:1 on propensity scores to new users of GLP1 RAs. In supplementary analyses, risk of recurrent nephrolithiasis was assessed in individuals with a history of nephrolithiasis before treatment initiation.

RESULTS

We identified 24,290 and 19,576 eligible users of SGLT2Is and GLP1 RAs, respectively. After matching, 12,325 patient pairs remained. The median age was 61 years and median follow-up was 2.0 years. The nephrolithiasis rate was 2.0 per 1000 person-years in SGLT2I initiators compared with 4.0 per 1000 person-years in GLP1 RA initiators, with a rate difference of -1.9 per 1000 person-years (95% CI -2.8, -1.0) and an HR of 0.51 (95% CI 0.37, 0.71). For recurrent nephrolithiasis (n = 731 patient pairs), the rate difference was -17 per 1000 person-years (95% CI -33, -1.5) and the HR was 0.68 (95% CI 0.48, 0.97).

CONCLUSIONS/INTERPRETATION

Initiation of treatment with SGLT2Is was associated with a clinically significant reduced risk of incident and recurrent nephrolithiasis.

Low-dose aspirin for primary and secondary prevention of cardiovascular events in Denmark 1998-2018

Randomised controlled trials have shown a neutral or even unfavourable risk–benefit balance of aspirin for primary prevention of cardiovascular events. Using Danish nationwide registries, we investigated aspirin use and associated risks during the past two decades (1998–2018). We linked individual patient data on repeated aspirin redemptions with registered hospital ICD-10 diagnoses of atherosclerotic cardiovascular disease and bleedings. The prevalence of aspirin use among 1.1 million Danish adults fluctuated over the 20-year study period peaking in 2008 with 8.5% (5.4% primary prevention) and dropping to 5.1% (3.1% primary prevention) in 2018. Aspirin use showed strong age dependency, and 21% of individuals > 80 years were treated with aspirin for primary prevention in 2018. Medication adding to bleeding risk was used concurrently by 21% of all aspirin users in 2018. The incidence of major bleedings were similar with primary and secondary prevention aspirin use and highest in elderly (2 per 100 patient years among individuals > 80 years in 2018). In conclusion, low-dose aspirin use for primary prevention of cardiovascular events remains prevalent. The widespread use of aspirin, especially among older adults, and substantial concomitant use of medications adding to bleeding risk warrant increased focus on discontinuation of inappropriate aspirin use.

No difference in antidepressant prescription in rheumatoid arthritis and controls. Results from a population-based, matched inception cohort

Objective: Depression occurs at least two times more often in rheumatoid arthritis (RA) patients than in controls, but little is known about the treatment of depression in RA. The primary objective of this study was to compare the 1 year period prevalence of antidepressant prescription in patients with RA versus controls.Method: We included a retrospective inception cohort of 509 patients with incident RA and 2545 frequency-matched population controls ascertained from 1995 to 2002. The cohort was followed until 31 December 2017 and linked with nationwide Danish registers. From the Danish National Prescription Register, we obtained information on redeemed prescriptions of antidepressants (Anatomical Therapeutic Chemical code N06A).Results: We did not demonstrate significant differences in the 1 year period prevalence ratios and the incidence rate ratios for either antidepressant prescription or the frequency of hospital admissions with depressive episode. The most frequent indication for antidepressant prescription in patients with RA was depression. Cox regression analyses showed no association between RA and antidepressant prescription.Conclusion: We found no significant differences in the occurrence of antidepressant prescription in patients with RA versus matched controls. The main indication for antidepressant prescription in RA was depression.

Risk of lower gastrointestinal bleeding and colorectal neoplasms following initiation of low-dose aspirin: a Danish population-based cohort study

OBJECTIVE

Aspirin may increase the risk of lower gastrointestinal bleeding (LGIB) from precursors of colorectal cancer (CRC). We investigated whether use of low-dose aspirin, through initiation of LGIB, may lead patients to undergo colonoscopy and polypectomy before manifest CRC.

DESIGN

We conducted a historical cohort study (2005-2013) of all Danish residents who initiated low-dose aspirin treatment (n=412 202) in a setting without screening for CRC. Each new aspirin user was matched with three non-users (n=1 236 560) by age, sex and region of residence on the date of their matched new user's first-time aspirin prescription (index date). We computed absolute risks (ARs), risk differences and relative risks (RRs) of LGIB, lower gastrointestinal endoscopy, colorectal polyps and CRC, comparing aspirin users with non-users.

RESULTS

The ARs were higher for new users than non-users for LGIB, lower gastrointestinal endoscopy, colorectal polyps and CRC within 3 months after index. Comparing new users with non-users, the RRs were 2.79 (95% CI 2.40 to 3.24) for LGIB, 1.73 (95% CI 1.63 to 1.84) for lower gastrointestinal endoscopy, 1.56 (95% CI 1.42 to 1.72) for colorectal polyps and 1.73 (95% CI 1.51 to 1.98) for CRC. The RRs remained elevated for more than 12 months after the index date, with the exception of CRC where the RRs were slightly decreased during the 3-5 years (RR 0.90, 95% CI 0.83 to 0.98) and more than 5 years (RR 0.91, 95% CI 0.82 to 1.00) following the index date.

CONCLUSION

These findings indicate that aspirin may contribute to reduce CRC risk by causing premalignant polyps to bleed, thereby expediting colonoscopy and polypectomy before CRC development.

Risk of primary gastrointestinal cancers following incident non-metastatic breast cancer: a Danish population-based cohort study

Objective

We examined the risk of primary gastrointestinal cancers in women with breast cancer and compared this risk with that of the general population.

Design

Using population-based Danish registries, we conducted a cohort study of women with incident non-metastatic breast cancer (1990–2017). We computed cumulative cancer incidences and standardised incidence ratios (SIRs).

Results

Among 84 972 patients with breast cancer, we observed 2340 gastrointestinal cancers. After 20 years of follow-up, the cumulative incidence of gastrointestinal cancers was 4%, driven mainly by colon cancers. Only risk of stomach cancer was continually increased beyond 1 year following breast cancer. The SIR for colon cancer was neutral during 2–5 years of follow-up and approximately 1.2-fold increased thereafter. For cancer of the oesophagus, the SIR was increased only during 6–10 years. There was a weak association with pancreas cancer beyond 10 years. Between 1990–2006 and 2007–2017, the 1–10 years SIR estimate decreased and reached unity for upper gastrointestinal cancers (oesophagus, stomach, and small intestine). For lower gastrointestinal cancers (colon, rectum, and anal canal), the SIR estimate was increased only after 2007. No temporal effects were observed for the remaining gastrointestinal cancers. Treatment effects were negligible.

Conclusion

Breast cancer survivors were at increased risk of oesophagus and stomach cancer, but only before 2007. The risk of colon cancer was increased, but only after 2007.

Age and sex differences in outcomes after in-hospital cardiac arrest

INTRODUCTION

While specific factors have been associated with outcomes after in-hospital cardiac arrest, the association between sex and outcomes remains debated. Moreover, age-specific sex differences in outcomes have not been fully characterized in this population.

METHODS

Adult patients (≥18 years) with an index in-hospital cardiac arrest were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST) from January 1st, 2017 to December 31st, 2018. Population-based registries were used to obtain data on patient characteristics, cardiac arrest characteristics, and outcomes. Unadjusted and adjusted estimates for return of spontaneous circulation (ROSC), survival to 30 days, survival to one year, duration of resuscitation, and post-cardiac arrest time-to-death were computed.

RESULTS

A total of 3266 patients were included, of which 2041 (62%) patients were male with a median age of 73 years (quartiles: 64, 80). Among 1225 (38%) female patients, the median age was 76 years (quartiles: 67, 83). Younger age was associated with higher odds of ROSC and survival. Sex was not associated with ROSC and survival in the unadjusted analyses. In the adjusted analyses, women had 1.32 (95%CI: 1.12, 1.54) times the odds of survival to 30 days and 1.26 (95%CI: 1.02, 1.57) times the odds of survival to one year compared to men. The overall association between sex and survival did not vary substantially across age categories, although female sex was associated with a higher survival within certain age categories. Among patients who did not achieve ROSC, female sex was associated with a shorter duration of resuscitation, which was more pronounced in younger age categories.

CONCLUSIONS

In this study of patients with in-hospital cardiac arrest, female sex was associated with a shorter duration of resuscitation among patients without ROSC but a higher survival to 30 days and one year. While the overall association between sex and outcomes did not vary substantially across age categories, female sex was associated with a higher survival within certain age categories.

Priapism in patients with hemolytic disorders: a nationwide retrospective cohort study

Priapism is a persistent, painful erection, which can lead to permanent penile damage and reduced quality of life. Patients with sickle cell disease have an increased risk of priapism which has been related to chronic hemolysis. This study investigates the prevalence of priapism in all major hereditary and acquired forms of hemolytic disorders. Patients with hemolytic disorders were identified in the nationwide Danish Hemolysis Cohort. Each patient was age-sex-matched with 50 comparisons from the general population without hemolysis. We identified the episodes of hospital-registered priapism events for both patients with hemolysis disorders and comparisons in the Danish National Patient Register between 1977 and 2016. We identified 4181 male patients with hemolytic disorders and 205,994 male comparisons, with 2,294,027 person-years of total observation time. Totally, 101 episodes of priapism occurred during follow-up period. Six episodes of priapism were recorded in three patients with a hemolytic disorder, all affected by sickle cell disease. Two of these patients had verified genotype HbSS. The incidence rate for first priapism in sickle cell disease was 432.8 per 100,000 person-years [95% CI: 139.6; 1341.8] versus 0.84 per 100,000 person-years [95% CI 0.54; 1.32] in comparisons. Using a large nationwide cohort, we found that only sickle cell disease is associated with priapism among patients with hemolytic disorders. The incidence rate of priapism in patients with sickle cell disease was lower than previously reported.

The Danish Myelodysplastic Syndromes Database: Patient Characteristics and Validity of Data Records

Background

The Danish Myelodysplastic Syndromes Database (DMDSD) comprises nearly all patients diagnosed with myelodysplastic syndromes (MDS) in Denmark since 2010. The DMDSD has not yet been used for epidemiological research and the quality of registered variables remains to be investigated.

Objective

To describe characteristics of the patients registered in the DMDSD and to calculate predictive values and the proportion of missing values of registered data records.

Methods

We performed a nationwide cross-sectional validation study of recorded disease and treatment data on MDS patients during 2010-2019. Patient characteristics and the proportion of missing values were tabulated. A random sample of 12% was drawn to calculate predictive values with 95% confidence intervals (CIs) of 48 variables using information from medical records as a reference standard.

Results

Overall, 2284 patients were identified (median age: 76 years, men 62%). Of these, 10% had therapy-related MDS, and 6% had an antecedent hematological disease. Hemoglobin level was less than 6.2 mmol/L for 59% of patients. Within the first two years of treatment, 59% received transfusions, 35% received erythropoiesis-stimulating agents, and 15% were treated with a hypomethylating agent. For the majority of variables (around 80%), there were no missing data. A total of 260 medical records were available for validation. The positive predictive value of the MDS diagnosis was 92% (95% CI: 88-95). Predictive values ranged from 64% to 100% and exceeded 90% for 36 out of 48 variables. Stratification by year of diagnosis suggested that the positive predictive value of the MDS diagnosis improved from 88% before 2015 to 95% after.

Conclusion

In this study, there was a high accuracy of recorded data and a low proportion of missing data. Thus, the DMDSD serves as a valuable data source for future epidemiological studies on MDS.

Pulseless electrical activity vs. asystole in adult in-hospital cardiac arrest: Predictors and outcomes

AIM

This observational cohort study aimed to identify factors associated with pulseless electrical activity (PEA) and asystole in in-hospital cardiac arrest (IHCA) patients and to determine whether differences in outcome based on the initial rhythm were explained by patient- and cardiac arrest characteristics.

METHODS

Adults with IHCA from 2017 to 2018 were included from the Danish IHCA Registry (DANARREST). Additional data came from population-based registries. Unadjusted (RRs) and adjusted risk ratios (aRRs) were estimated for predictors of initial rhythm, return of spontaneous circulation (ROSC), and survival.

RESULTS

We included 1495 PEA and 1285 asystole patients. The patients did not differ substantially in patient characteristics. Female sex, age>90 years, pulmonary disease, and obesity were associated with initial asystole. Ischemic heart disease and witnessed and monitored cardiac arrest were associated with initial PEA. In unadjusted and adjusted analyses, PEA was associated with increased ROSC (aRR = 1.21, 95% confidence interval [CI] 1.10; 1.33). PEA was also associated with increased 30-day and 1-year survival in the unadjusted analysis, while there was no clear association between the initial rhythm and 30-day (aRR = 0.88, 95% CI 0.71; 1.11) and 1-year (aRR = 0.85, 95% CI 0.69; 1.04) survival when patient- and cardiac arrest characteristics were adjusted for.

CONCLUSION

In patients with IHCA presenting with PEA or asystole, there were no major differences in patient demographics and comorbidities. The patients differed substantially in cardiac arrest characteristics. Initial PEA was associated with higher risk of ROSC, but there was no difference in 30-day and 1-year survival.

Drug-related challenges following primary total hip and knee arthroplasty

We aimed to characterize the in-hospital analgesic use among total hip or knee arthroplasty (THA or TKA) patients, and to identify possible drug-related challenges. We identified 15 263 patients operated with a THA or TKA between 1 January 2012 and 30 April 2016. The prevalence of analgesic users and patients with potential clinically relevant drug-drug interactions (DDIs), along with the prevalence of readmission among patients with vs. without a DDI, were calculated. A DDI was defined as the combination of (A) a diuretic, an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, and an non-steroidal anti-inflammatory Drug (NSAID); (B) warfarin and an NSAID; and (C) a benzodiazepine or a benzodiazepine-related drug and an opioid. The prevalence of analgesics administered in THA and TKA patients was 99.3% and 99.1% for paracetamol and 93.8% and 98.8% for opioids, respectively. The prevalence of patients who received interaction A, B or C was 8.4%, 2.5% and 40.7%, respectively. Patients with vs. without a DDI had a higher prevalence of 30-day readmission. In conclusion, most THA and TKA patients were administered paracetamol or opioids. The prevalence of 30-day readmission was higher in patients with than in patients without a potential clinically relevant DDI.

High-dose corticosteroid use and risk of hospitalization for infection in patients treated with immune checkpoint inhibitors--A nationwide register-based cohort study

High‐dose corticosteroids have been associated with increased risk of serious infection in patients with metastatic melanoma treated with immune checkpoint inhibitors targeting cytotoxic T‐lymphocyte antigen 4. This potential association needs to be examined further among patients with other cancer types and for other immune checkpoint inhibitors. We examined whether receipt of high‐dose corticosteroids was associated with increased rates of hospitalization for infection among 981 Danish renal, urothelial, and lung cancer patients followed from first administration of programmed death receptor 1 (PD‐1)/programmed death ligand 1 (PD‐L1) immune checkpoint inhibitors. Our cohort analysis was based on the information from national medical registries. During follow‐up, 522 patients (53.2%) initiated treatment with high‐dose corticosteroids and 317 patients (32.3%) experienced at least one hospitalization for infection. In analyses adjusted for age, sex, and previous use of chemotherapy/targeted therapy, initiation of high‐dose systemic corticosteroids was associated with increased rate of hospitalization for infections (hazard ratio (HR) = 2.96, 95% confidence interval (CI) = 2.41–3.65) even in patients not receiving any chemotherapy/targeted therapy (HR = 3.66, 95% CI = 2.25–5.96). Our findings showed that high‐dose corticosteroid initiation is associated with hospitalization for infection in patients treated with PD‐1/PD‐L1 immune checkpoint inhibitors. Clinicians and patients should be aware of this risk of infection when initiating treatment with high‐dose corticosteroids.

Comparison of Patients with Hospital-Recorded Nephrotic Syndrome and Patients with Nephrotic Proteinuria and Hypoalbuminemia: A Nationwide Study in Denmark

Background

Registry-based studies of nephrotic syndrome (NS) may only include a subset of patients with biochemical features of NS. To address this, we compared patients with laboratory-recorded nephrotic proteinuria and hypoalbuminemia to patients with hospital-recorded NS.

Methods

We identified adult patients with first-time hospital-recorded NS (inpatients, outpatients, or emergency-room visitors) in the Danish National Patient Registry and compared them with adults with first-time recorded nephrotic proteinuria and hypoalbuminemia in Danish laboratory databases during 2004-2018, defining the date of admission or laboratory findings as the index date. We characterized these cohorts by demographics, comorbidity, medication use, and laboratory and histopathologic findings.

Results

We identified 1139 patients with hospital-recorded NS and 5268 patients with nephrotic proteinuria and hypoalbuminemia; of these, 760 patients were identified in both cohorts. Within 1 year of the first record of nephrotic proteinuria and hypoalbuminemia, 18% had recorded hospital diagnoses indicating the presence of NS, and 87% had diagnoses reflecting any kind of nephropathy. Among patients identified with nephrotic proteinuria and hypoalbuminemia, their most recent eGFR was substantially lower (median of 35 versus 61 ml/min per 1.73 m²), fewer underwent kidney biopsies around the index date (34% versus 61%), and the prevalence of thromboembolic disease (25% versus 17%) and diabetes (39% versus 18%) was higher when compared with patients with hospital-recorded NS.

Conclusions

Patients with nephrotic proteinuria and hypoalbuminemia are five-fold more common than patients with hospital-recorded NS, and they have a lower eGFR and more comorbidities. Selective and incomplete recording of NS may be an important issue when designing and interpreting studies of risks and prognosis of NS.

Cardiovascular events in cancer patients with bone metastases-A Danish population-based cohort study of 23,113 patients

INTRODUCTION

The incidence of cardiovascular events among cancer patients with bone metastases is poorly understood. We examined rates of cardiovascular events among cancer patients with bone metastases and mortality following such events.

METHODS

Using Danish health registries, we identified all Danish cancer patients diagnosed with bone metastases (1994-2013) and followed them from bone metastasis diagnosis. We computed incidence rates (IR) per 100 person-years and cumulative incidence for first-time inpatient hospitalization or outpatient clinic visit for cardiovascular events, defined as myocardial infarction, ischemic stroke, or venous thromboembolism (VTE). We also analyzed all-cause mortality rates including cardiovascular events as time-varying exposure with adjustment for age, sex, and Charlson Comorbidity Index score. All analyses were performed overall and stratified by cancer type (prostate, breast, lung, and other).

RESULTS

We included 23,113 cancer patients with bone metastases. The cumulative incidence of cardiovascular events was 1.3% at 30 days, 3.7% at 1 year, and 5.2% at 5 years of follow-up. The highest IR was observed for VTE, followed by ischemic stroke and myocardial infarction, both overall and by cancer types. Lung cancer patients with bone metastases had the highest incidence of cardiovascular events followed by prostate and breast cancer. Occurrence of any cardiovascular event was a strong predictor of death (5 years following the event, the adjusted hazard ratio was 1.8 [95% confidence interval: 1.7-1.9]).

CONCLUSION

Cancer patients with bone metastases had a substantial risk of developing cardiovascular events, and these events were associated with a subsequent increased mortality. Our findings underscore the importance of continuous optimized prevention of and care for cardiovascular disease among cancer patients with bone metastases.

The association between water hardness and xerosis-Results from the Danish Blood Donor Study

BACKGROUND

The pathophysiology of xerosis depends on extrinsic and intrinsic exposures. Residential hard water may constitute such an exposure.

OBJECTIVES

To estimate the prevalence of xerosis and to compare water hardness exposure in blood donors with and without xerosis.

METHODS

In this retrospective cohort study in 2018-2019, blood donors with self-reported moderately or severely dry skin were compared to blood donors without dry skin. Blood donors with ichthyosis, lichen planus and psoriasis were excluded. Water hardness data was collected from the Geology Survey of Denmark and Greenland.

RESULTS

Overall, 4,748 of 30,721 (15.5%; 95% confidence interval 15.1-15.9%) blood donors had xerosis. After excluding blood donors with ichthyosis, lichen planus and psoriasis, 4,416 blood donors (2,559 females; median age 38.4 years [interquartile range 28.0-49.8]; 700 smokers) remained in this study. Water softer than 12-24 degrees Deutsche härte was associated with decreased probability of xerosis (odds ratio 0.83; 95% confidence interval 0.74-0.94) and water harder than 12-24 degrees Deutsche härte was associated with increased probability of xerosis (odds ratio 1.22; 95% confidence interval 1.03-1.45). The association between water hardness and xerosis remained significant after excluding blood donors with dermatitis.

CONCLUSIONS

Water hardness is associated with xerosis independent of other dermatoses.

Comorbidities, socioeconomic status, drug use, and health care consumption in Danish women with psoriasis: A nationwide cross-sectional study

BACKGROUND

Psoriasis is a disease that extends beyond the skin, with profound medical, social, and mental health implications. To our knowledge, no previous studies have specifically investigated the medical and socioeconomic characteristics of women with versus without psoriasis.

OBJECTIVE

We investigated whether women with psoriasis differed from women without psoriasis with respect to comorbidities, socioeconomic status, healthcare consumption, and drug use, as well as how these characteristics differed according to psoriasis severity.

METHODS

In this nationwide, register-based, cross-sectional study, data were collected from Danish registries from 1977 to 2017, linked at the individual level, and identified by International Classification of Diseases codes, prescription data, income and educational information, and contact with public health care services. Psoriasis was defined by either a hospital International Classification of Diseases code for psoriasis or calcipotriol prescription data. Psoriasis severity was stratified based on psoriasis treatment. Age-adjusted logistic regression models were used to estimate the odds ratios (ORs) of outcomes compared with those of women without psoriasis.

RESULTS

A total of 77,143 women (3%) met the criteria for psoriasis. Psoriasis was significantly associated with all investigated outcomes. Women with psoriasis were less likely to have a high income (OR: 0.89; 95% confidence interval [CI], 0.87-0.91), more likely to visit their general practitioner more often (OR: 3.82; 95% CI, 3.70-3.95), and received pain medication more often (OR: 1.57; 95% CI, 1.52-1.62) compared with women without psoriasis.

CONCLUSION

Psoriasis was significantly associated with all investigated adverse medical and socioeconomic outcomes. Risk of outcomes increased with psoriasis severity. Our study highlights the need for a multidisciplinary collaboration to optimize medical care for women with (especially moderate and severe) psoriasis.

Time to administration of antibiotics and mortality in sepsis

OBJECTIVE

To examine the association between delay of antibiotic treatment and 28-day mortality in a study of septic patients identified by the Sepsis-3 criteria.

METHODS

A prospective observational cohort study of patients (≥ 18 years) with sepsis admitted to a Danish emergency department between October 2017 and March 2018. The interval between arrival to the ED and first delivery of antibiotics was used as time to antibiotic treatment (TTA). Logistic regression was used in the analysis of the association between TTA and mortality adjusted for potential confounding.

RESULTS

A total of 590 patients, median age 74.2 years, were included. Overall 28-day mortality was 14.6% (95% confidence interval [CI], 11.8-17.7). Median TTA was 4.7 hours (interquartile range 2.7-8.1). The mortality in patients with TTA ≤1 hour was 26.5% (95% CI, 12.8-44.4), and 15.3% (95% CI, 9.8-22.5), 10.5% (95% CI, 6.6-15.8), and 12.8 (95% CI, 7.3-20.1) in the timespans 1-3, 3-6, and 6-9 hours, respectively, and 18.8% (95% CI, 12.0-27.2) in patients with TTA >9 hours. With patients with lowest mortality (TTA timespan 3-6 hours) as reference, the adjusted odds ratio of mortality was 4.53 (95% CI, 1.67-3.37) in patients with TTA ≤1 hour, 1.67 (95% CI, 0.83-3.37) in TTA timespan 1-3 hours, 1.17 (95% CI, 0.56-2.49) in timespan 6-9 hours, and 1.91 (95% CI, 0.96-3.85) in patient with TTA >9 hours.

CONCLUSIONS

The adjusted odds of 28-day mortality were lowest in emergency department (ED) patients with sepsis who received antibiotics between 1 and 9 hours and highest in patients treated within 1 and >9 hours after admission to the ED.

Antidepressant use in pregnancy and severe cardiac malformations: Danish register-based study

OBJECTIVE

Studies restricted to live births may underestimate severe teratogenic effects. We address the limitation by including data from both prenatal and postnatal diagnoses of cardiac malformations.

DESIGN

Register-based study.

SETTING

Denmark.

POPULATION

364 012 singleton pregnancies from 2007 to 2014.

METHODS

We used data from five nationwide registries. Exposure to antidepressants was measured using redeemed prescriptions.

MAIN OUTCOME MEASURES

Pregnancies with cardiac malformations that end in miscarriage, termination, stillbirth, postnatal death or cardiac surgery <1 year of birth were classified as severe cardiac malformations (SCM). Propensity scores with adjusted prevalence ratios (PRs) were calculated.

RESULTS

SCM were reported in 972 of 364 012 pregnancies overall and in 16 of 4105 exposed. For venlafaxine, the PR for SCM was 2.13 (95% confidence interval [CI] 0.89-5.13), 1.73 (95% CI 1.08-2.77) for other cardiac malformations, and there was a cluster of hypoplastic left heart syndromes (HLHS) (crude PR 17.4 [95% CI 6.41-47.2]), none of which ended in a live birth. For HLHS, the absolute risk increase was 4.4/1000 and the number needed to harm was 225. For selective serotonin reuptake inhibitors, the PRs were 1.09 (95% CI 0.52-2.30) and 1.38 (95% CI 1.00-1.92) for SCM and other cardiac malformations, respectively.

CONCLUSIONS

Pregnancy exposure to venlafaxine is associated with an increased risk of severe cardiac malformations but with a low absolute risk. Potential mechanisms include direct effects or confounding by indication. Venlafaxine exposure is a marker for risk pregnancies for which fetal echocardiography may be considered.

TWEETABLE ABSTRACT

Exposure to venlafaxine is associated with an increased risk of cardiac malformations but with a low absolute risk. TWEETABLE ABSTRACT.

Positive Predictive Value of ICD-10 Diagnosis Codes for COVID-19

Purpose

To examine the positive predictive value (PPV) of International Classification version 10 (ICD-10) diagnosis codes for Coronavirus disease 2019 (COVID-19).

Patients and Methods

Medical record review of all patients assigned a diagnosis code of COVID-19 (DB342A or DB972A) at six Danish departments of infectious diseases from February 27 through May 4, 2020. Confirmed COVID-19 diagnosis was defined as either: 1) definite, a positive polymerase chain reaction (PCR) for severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) on a respiratory sample combined with symptoms suggestive of COVID-19: 2) probable, clinical presentation of COVID-19 without detection of SARS-CoV-2 and no alternative diagnoses considered more likely; or 3) possible, clinical presentation of COVID-19 without detection of SARS-CoV-2, and the patient was discharged or deceased before further investigations were carried out. We computed the PPV with 95% confidence intervals (CI) as the number of patients with confirmed (i.e., definite, probable, and possible) COVID-19 divided by the number of patients assigned a diagnosis code for COVID-19.

Results

The study included 710 patients with a median age of 61 years (interquartile range [IQR] 47–74) and 285/710 (40%) were female. COVID-19 was confirmed in 706/710 (99%) with 705/710 (99%) categorized as definite, 1/710 (0.1%) as probable, and 0 patients as possible COVID-19. The diagnosis was disproven in 4/710 (0.6%) patients who were hospitalized due to bacterial pneumonia (n = 2), influenza (n = 1), and urinary tract infection (n = 1). The overall PPV for COVID-19 was 99% (95% CI 99–100) and remained consistently high among all subgroups including sex, age groups, calendar period, and stratified by diagnosis code and department of infectious diseases (range 97–100%).

Conclusion

The overall PPV of diagnosis codes for COVID-19 in Denmark was high and may be suitable for future registry-based prognosis studies of COVID-19.

Symptom presentation of SARS-CoV-2-positive and negative patients: a nested case-control study among patients calling the emergency medical service and medical helpline

OBJECTIVE

Currently effective symptom-based screening of patients suspected of COVID-19 is limited. We aimed to investigate age-related differences in symptom presentations of patients tested positive and negative for SARS-CoV-2.

DESIGN

SETTING: Calls to the medical helpline (1-8-1-3) and emergency number (1-1-2) in Copenhagen, Denmark. At both medical services all calls are recorded.

PARTICIPANTS

We included calls for patients who called for help/guidance at the medical helpline or emergency number prior to receiving a test for SARS-CoV-2 between April 1^st and 20^th 2020 (8423 patients). Among these calls, we randomly sampled recorded calls from 350 patients who later tested positive and 250 patients tested negative and registered symptoms described in the call.

OUTCOME

RESULTS: After exclusions, 544 calls (312 SARS-CoV-2 positive and 232 negative) were included in the analysis. Fever and cough remained the two most common of COVID-19 symptoms across all age groups and approximately 42% of SARS-CoV-2 positive and 20% of negative presented with both fever and cough. Symptoms including nasal congestion, irritation/pain in throat, muscle/joint pain, loss of taste and smell, and headache were common symptoms of COVID-19 for patients younger than 60 years; whereas loss of appetite and feeling unwell were more commonly seen among patients over 60 years. Headache and loss of taste and smell were rare symptoms of COVID-19 among patients over 60 years.

CONCLUSION

Our study identified age-related differences in symptom presentations of SARS-CoV-2-positive patients calling for help or medical advice. The specific symptoms of loss of smell or taste almost exclusively reported by patients younger than 60 years. Differences in symptom presentation across age groups must be considered when screening for COVID-19.

Positive Predictive Value of Diagnostic Codes for Inflammatory Bowel Disease in the Danish National Patient Registry Among Individuals 50+ Years, Using Patient Records as Reference Standard

Purpose

Inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are chronic diseases. The aim was to validate diagnoses of IBD among patients aged 50+ years in the Danish National Patient Registry (NPR) by comparison with patient medical records.

Patients and Methods

Men and women in the Diet, Cancer and Health (DCH) cohort were linked to NPR, and cases with a diagnosis of IBD and their respective hospital records were identified. Validation was performed by comparing patient medical records with information on discharge diagnoses of IBD from the NPR.

Results

Of 57,053 individuals in the DCH-cohort, 339 were registered with an IBD diagnosis in NPR, with 277 (82%) records available for review. Among 277 patients, the positive predictive values (PPVs) of one CD or UC registration in NPR were 78% for IBD overall, 51% for CD and 54% for UC. One hundred fifty-seven patients had at least two CD and/or UC registrations with PPVs of 90% for IBD overall, 65% for CD and 73% for UC. One hundred and two patients had at least three registrations with PPVs of 97% for IBD overall, 75% for CD and 88% for UC. 96% were diagnosed at a specialized department. Other diagnoses coded as IBD mostly included microscopic colitis, irritable bowel syndrome and cancer.

Conclusion

Validity of IBD diagnoses in the registry of individuals aged 50+ years increased with the number of registrations. It is recommended that these results are taken into consideration in future studies, especially in epidemiology research using NPR as a data source for patients diagnosed with IBD.

Hospital admission and mortality rates for non-covid diseases in Denmark during covid-19 pandemic: nationwide population based cohort study

OBJECTIVE

To determine the incidence of hospital admissions and associated mortality rates for non-covid medical conditions during the covid-19 pandemic.

DESIGN

Nationwide, population based cohort study.

SETTING

Denmark from 13 March 2019 to 27 January 2021.

PARTICIPANTS

All Danish residents >1 year of age.

MAIN OUTCOMES MEASURES

Population based healthcare registries that encompass the entire Danish population were used to compare hospital admission and mortality rates during the covid-19 pandemic (from 11 March 2020 to 27 January 2021) with the prepandemic baseline data (from 13 March 2019 to 10 March 2020). Hospital admissions were categorised as covid-19 when patients were assigned a diagnosis code for covid-19 within five days of admission. All patients were followed until migration, death, or end of follow-up, whichever came first. Rate ratios for hospital admissions were computed using Poisson regression and were directly standardised using the Danish population on 1 January 2019 as reference. 30 day mortality rate ratios were examined by Cox regression, adjusted for age and sex, and covid-19 diagnosis was used as a competing risk.

RESULTS

5 753 179 residents were identified during 567.8 million person weeks of observation, with 1 113 705 hospital admissions among 675 447 people. Compared with the prepandemic baseline period (mean hospital admission rate 204.1 per 100 000/week), the overall hospital admission rate for non-covid-19 conditions decreased to 142.8 per 100 000/week (rate ratio 0.70, 95% confidence interval 0.66 to 0.74) after the first national lockdown, followed by a gradual return to baseline levels until the second national lockdown when it decreased to 158.3 per 100 000/week (0.78, 0.73 to 0.82). This pattern was mirrored for most major diagnosis groups except for non-covid-19 respiratory diseases, nervous system diseases, cancer, heart failure, sepsis, and non-covid-19 respiratory infections, which remained lower throughout the study period. Overall 30 day mortality rates were higher during the first national lockdown (mortality rate ratio 1.28, 95% confidence interval 1.23 to 1.32) and the second national lockdown (1.20, 1.16 to 1.24), and these results were similar across most major diagnosis groups. For non-covid-19 respiratory diseases, cancer, pneumonia, and sepsis, the 30 day mortality rate ratios were also higher between lockdown periods.

CONCLUSIONS

Hospital admissions for all major non-covid-19 disease groups decreased during national lockdowns compared with the prepandemic baseline period. Additionally, mortality rates were higher overall and for patients admitted to hospital with conditions such as respiratory diseases, cancer, pneumonia, and sepsis. Increased attention towards management of serious non-covid-19 medical conditions is warranted.

Sodium-glucose cotransporter-2 inhibitors and the risk of gout: A Danish population based cohort study and symmetry analysis

PURPOSE

Sodium-glucose cotransporter-2 inhibitors (SGLT2-I) are frequently used in type 2 diabetes and have recently been associated with lower rates of gout compared to glucagon-like peptide-1 receptor agonists (GLP1-RA). Our objective was to assess the association between SGLT2-I initiation and gout using a cohort study design and a symmetry analysis.

METHODS

Using the Danish nationwide health registries, we conducted an active comparator, new user cohort study comparing the 3-year risk of gout among SGLT2-I users with propensity score matched GLP1-RA users. Individuals were followed according to the intention-to-treat, and incidence rate differences (IRD) and hazard ratios (HR) were obtained. To address unmeasured confounding that is stable over time, a corresponding symmetry analysis was performed.

RESULTS

11 047 pairs of SGLT2-I and GLP1-RA users were identified, contributing 42 201 person-years of follow-up. The incidence rate of gout was 4.1 and 7.0 events per 1000 person years among SGLT2-I and GLP1-RA users, yielding an IRD of -3.0 (95% confidence interval: -4.4 to -1.5) and HR of 0.58 (0.44 to 0.75). In the symmetry analysis, 80 individuals initiated SGLT2-Is prior to gout; 118 patients initiated treatment after gout. The trend adjusted SR was 0.63 (0.47 to 0.84) and the active comparator adjusted estimate was 0.67 (0.44 to 0.86).

CONCLUSIONS

Initiation of SGLT2-Is was associated with a markedly decreased risk of gout compared to initiation of GLP1-RAs. The findings are comparable to prior studies addressing this association.

Arterial events, venous thromboembolism, thrombocytopenia, and bleeding after vaccination with Oxford-AstraZeneca ChAdOx1-S in Denmark and Norway: population based cohort study

OBJECTIVE

To assess rates of cardiovascular and haemostatic events in the first 28 days after vaccination with the Oxford-AstraZeneca vaccine ChAdOx1-S in Denmark and Norway and to compare them with rates observed in the general populations.

DESIGN

Population based cohort study.

SETTING

Nationwide healthcare registers in Denmark and Norway.

PARTICIPANTS

All people aged 18-65 years who received a first vaccination with ChAdOx1-S from 9 February 2021 to 11 March 2021. The general populations of Denmark (2016-18) and Norway (2018-19) served as comparator cohorts.

MAIN OUTCOME MEASURES

Observed 28 day rates of hospital contacts for incident arterial events, venous thromboembolism, thrombocytopenia/coagulation disorders, and bleeding among vaccinated people compared with expected rates, based on national age and sex specific background rates from the general populations of the two countries.

RESULTS

The vaccinated cohorts comprised 148 792 people in Denmark (median age 45 years, 80% women) and 132 472 in Norway (median age 44 years, 78% women), who received their first dose of ChAdOx1-S. Among 281 264 people who received ChAdOx1-S, the standardised morbidity ratio for arterial events was 0.97 (95% confidence interval 0.77 to 1.20). 59 venous thromboembolic events were observed in the vaccinated cohort compared with 30 expected based on the incidence rates in the general population, corresponding to a standardised morbidity ratio of 1.97 (1.50 to 2.54) and 11 (5.6 to 17.0) excess events per 100 000 vaccinations. A higher than expected rate of cerebral venous thrombosis was observed: standardised morbidity ratio 20.25 (8.14 to 41.73); an excess of 2.5 (0.9 to 5.2) events per 100 000 vaccinations. The standardised morbidity ratio for any thrombocytopenia/coagulation disorders was 1.52 (0.97 to 2.25) and for any bleeding was 1.23 (0.97 to 1.55). 15 deaths were observed in the vaccine cohort compared with 44 expected.

CONCLUSIONS

Among recipients of ChAdOx1-S, increased rates of venous thromboembolic events, including cerebral venous thrombosis, were observed. For the remaining safety outcomes, results were largely reassuring, with slightly higher rates of thrombocytopenia/coagulation disorders and bleeding, which could be influenced by increased surveillance of vaccine recipients. The absolute risks of venous thromboembolic events were, however, small, and the findings should be interpreted in the light of the proven beneficial effects of the vaccine, the context of the given country, and the limitations to the generalisability of the study findings.

Association of Low-Dose Quetiapine and Diabetes

IMPORTANCE

Quetiapine has been associated with increased risk of type 2 diabetes when used in medium or high doses for the treatment of severe mental disorders. It is not known whether low doses, commonly used off-label for sedative-hypnotic purposes, are also associated with increased risk of type 2 diabetes.

OBJECTIVE

To investigate whether there is an association between prescription of low-dose quetiapine and the risk of type 2 diabetes.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study examined nationwide Danish health registers for data regarding new users of quetiapine (n = 185 938) or selective serotonin reuptake inhibitors (SSRIs) (n = 1 031 920) who were aged 18 years or older between January 1, 1998, and December 31, 2018. Individuals with schizophrenia or bipolar disorder were excluded. Quetiapine-initiators were matched 1:1 with initiators of SSRIs, using a high-dimensional propensity score (hdPS). Maximum follow-up was 5 years. Association with cumulative dose was investigated, using a case-control approach nested among quetiapine users. Data analysis was performed from May to September 2020.

EXPOSURES

Dispensing of quetiapine or SSRIs. Quetiapine prescriptions were limited to tablet strengths of 25 mg and 50 mg to focus on low-dose use.

MAIN OUTCOMES AND MEASURES

Incident type 2 diabetes was defined as first filling of an antidiabetic medication, first register diagnosis of type 2 diabetes or first hemoglobin A1C measurement greater than or equal to 6.4% (≥48 mmol/mol). Incidence rates (IRs), incidence rate ratios (IRRs), and number-needed-to-harm (NNH) were calculated for full and matched cohorts using as-treated and intention-to-treat approaches. Odds ratios (ORs) were calculated for the association with cumulative quetiapine dose.

RESULTS

Altogether, 896 285 patients were included in the full cohort; 538 164 (60%) were female and the median (interquartile range) age was 47 (33-67) years. There were 57 701 low-dose quetiapine initiators and 838 584 SSRI initiators. The matched cohort consisted of 54 616 pairs. In as-treated analyses, the incidence of type 2 diabetes during treatment with low-dose quetiapine (425 cases) was 9.59 cases/1000 person-years (PY) (95% CI, 8.72-10.5/1000 PY), which was slightly higher than for SSRI users (8462 cases; IR, 8.13/1000 PY; 95% CI, 7.96-8.30/1000 PY), resulting in a significant IRR of 1.18 (95% CI, 1.07-1.30) and NNH of 684 (95% CI, 418-1873). However, the between-group difference was nonsignificant in the hdPS-matched cohort (IR, 9.49 vs IR, 9.58; IRR, 0.99; 95% CI, 0.87-1.13). The case-control analysis found no dose-response association of low-dose quetiapine with diabetes (OR for doubling of the cumulative dose: 1.02; 95% CI, 0.95-1.09; P = .54), but in sensitivity analyses higher daily doses were associated with diabetes (all tablet strengths: OR, 1.08; 95% CI, 1.03-1.13).

CONCLUSIONS AND RELEVANCE

In this cohort study, use of low-dose quetiapine was not associated with excess risk of type 2 diabetes in comparison with SSRIs.

Is the risk of cardiovascular disease increased in living kidney donors? A Danish population-based cohort study

Reduced renal function is associated with cardiovascular disease (CVD); however, how living donor nephrectomy affects the risk of CVD remains controversial. We conducted a nationwide cohort study including living kidney donors in Denmark from 1996 to 2018 to assess the risk of hypertension, atrial fibrillation/flutter (AF), major adverse cardiovascular events (MACE; composite of myocardial infarction, ischemic stroke, and death) and death after living kidney donation. As comparisons we identified: a cohort of healthy individuals from the general population and an external blood donor cohort. We followed kidney donors (1,103 when compared with the general population cohort; 1,007 when compared with blood donors) for a median of 8 years. Kidney donors had an increased risk of initiating treatment for hypertension when compared with blood donors (standardized incidence ratio [SIR], 1.40; 95% confidence interval [CI], 1.17-1.66) but they did not have increased risk of MACE neither when compared with the general population cohort (hazard ratio, 0.68; 95% CI, 0.52-0.89) nor with blood donors (SIR, 1.17; 95% CI, 0.88-1.55). Neither did they have increased risks of AF and death. Thus, living kidney donation may be associated with increased risk of hypertension; however, we did not identify increased risks of CVD or death.

Mannose-binding lectin and risk of infections in type 2 diabetes: A Danish cohort study

AIMS

In individuals at increased risk of infections, e.g., patients with type 2 diabetes, low MBL may have detrimental effects. We used the Mendelian randomization principle to examine whether genetically low MBL is a risk factor for developing infections in patients with type 2 diabetes.

METHODS

Serum MBL (n = 7305) and MBL genotype (n = 3043) were determined in a nationwide cohort of patients with new type 2 diabetes and up to 8 years follow-up for hospital-treated infections and community-based antimicrobial prescriptions. The associations were examined in spline and Cox regression analyses.

RESULTS

1140 patients (16%) were hospitalized with an infection and 5077 patients (70%) redeemed an antimicrobial prescription. For low (≤100 μg/L) versus intermediate (101-1000 μg/L) serum MBL concentration, the adjusted hazard ratios (aHRs) were 1.13(95% confidence interval, 0.96-1.33) for any hospital-treated infections and 1.19(1.01-1.41) for bacterial infections. Low MBL expression genotype was not associated with risk of any hospital-treated infections except for diarrheal diseases (aHR 2.23[1.04-4.80]). Low MBL expression genotype, but not low serum MBL, was associated with increased risk for antimicrobial prescriptions (aHR 1.18[1.04-2.34] and antibacterial prescriptions 1.20[1.05-1.36]).

CONCLUSIONS

Low MBL is a weak causal risk factor for developing infections in patients with type 2 diabetes.

Mortality Among Parents of Children With Major Congenital Anomalies

BACKGROUND

A mother whose child has a chronic condition, such as a major congenital anomaly, often experiences poorer long-term health, including earlier mortality. Little is known about the long-term health of fathers of infants with a major congenital anomaly.

METHODS

In this population-based prospective cohort study, we used individual-linked Danish registry data. Included were all mothers and fathers with a singleton infant born January 1, 1986, to December 31, 2015. Cox proportional hazards regression was used to generate hazard ratios for all-cause and cause-specific mortality among mothers and fathers whose infant had an anomaly and fathers of unaffected infants, relative to mothers of unaffected infants (referent), adjusted for child's year of birth, parity, parental age at birth, parental comorbidities, and sociodemographic characteristics.

RESULTS

In total, 20 952 of 965 310 mothers (2.2%) and 20 655 of 951 022 fathers (2.2%) had an infant with a major anomaly. Median (interquartile range) of parental follow-up was 17.9 (9.5 to 25.5) years. Relative to mothers of unaffected infants, mothers of affected infants had adjusted hazard ratios (aHRs) of death of 1.20 (95% confidence interval [CI]: 1.09 to 1.32), fathers of unaffected infants had intermediate aHR (1.62, 95% CI: 1.59 to 1.66), and fathers of affected infants had the highest aHR (1.76, 95% CI: 1.64 to 1.88). Heightened mortality was primarily due to cardiovascular and endocrine/metabolic diseases.

CONCLUSIONS

Mothers and fathers of infants with a major congenital anomaly experience an increased risk of mortality, often from preventable causes. These findings support including fathers in interventions to support the health of parental caregivers.

Predictors for and outcomes after bone marrow biopsy in Scandinavian patients with chronic immune thrombocytopenia

OBJECTIVES

To examine predictors for bone marrow biopsy (BMB) and the outcome following BMB in patients with chronic immune thrombocytopenia (cITP).

METHODS

We identified patients diagnosed with cITP during 2009-2017 and obtained information on BMB, cITP treatment and subsequent thrombotic events, hospitalized bleeding, hematological cancer, and death using data from population-based healthcare databases and medical records in Denmark, Norway, and Sweden.

RESULTS

Among 4471 adults (≥18 years) with cITP, 1683 (37.6%) underwent BMB before cITP diagnosis, while cumulative BMB incidence after cITP diagnosis date was 3.1% at 1 year and 7.5% at 5 years. Predictors of having a BMB after cITP diagnosis included older age, male sex, low baseline platelet count, splenectomy, and number of cITP treatments. Compared with patients without BMB, patients with BMB had higher rates of thrombotic events (1 year adjusted hazard ratio [HR] 1.53 [95% CI, 0.92-2.54]), hospitalized bleeding episodes (1 year adjusted HR 1.72 [95% CI, 1.15-2.58]), hematological cancer (1 year adjusted HR 35.26 [95% CI 17.67-70.34]), and all-cause mortality (1 year adjusted HR 1.97 [95% CI, 1.44-2.68]).

CONCLUSION

Patients who undergo BMB after cITP diagnosis represent a subset of patients with more severe disease and increased rates of complications as well as hematological malignancies.

Household exposure to SARS-CoV-2 and association with COVID-19 severity: a Danish nationwide cohort study

Background

Households are high-risk settings for the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Severity of Coronavirus disease 2019 (COVID-19) is likely associated with the infectious dose of SARS-CoV-2 exposure. We therefore aimed to assess the association between SARS-CoV-2 exposure within households and COVID-19 severity.

Methods

We performed a Danish nationwide register-based cohort study including laboratory-confirmed SARS-CoV-2 infected individuals from 22 February to 6 October 2020. Household exposure to SARS-CoV-2 was defined as having one individual tested positive for SARS-CoV-2 within the household. Cox proportional-hazards models were used to estimate the association between ‘critical COVID-19’ within and between households with and without secondary cases.

Results

From 15,063 multi-person households, 19,773 SARS-CoV-2 positive individuals were included; 11,632 were categorized as index cases without any secondary household cases, 3,431 as index cases with secondary cases, i.e. 22.8% of multi-person households, and 4,710 as secondary cases. ‘Critical COVID-19’ occurred in 2.9 % of index cases living with no secondary cases, 4.9 % of index cases with secondary cases, and 1.3 % of secondary cases. The adjusted hazard ratio for ‘critical COVID-19’ among index cases versus secondary cases within the same household was 2.50 (95%CI=1.88-3.34), 2.27 (95%CI=1.77-2.93) for index cases in households with no secondary cases versus secondary cases, and 1.1 (95%CI=0.93-1.30) for index cases with secondary cases versus index cases without secondary cases.

Conclusion

We found no increased hazard ratio of ‘critical COVID-19’ among household members of infected SARS-CoV-2 index cases.

Sex-Specific Prevalence, Incidence, and Mortality Associated With Atrial Fibrillation in Heart Failure

OBJECTIVES

This study sought to investigate the mortality associated with atrial fibrillation (AF) in men and women with heart failure (HF) according to the sequence of presentation and rhythm versus rate control.

BACKGROUND

The sex-specific epidemiology of AF in HF is sparse.

METHODS

Using the Danish nationwide registries, all first-time cases of HF were identified and followed for all-cause mortality from 1998 to 2018.

RESULTS

Among 252,988 patients with HF (mean age: 74 ± 13 years, 45% women), AF presented before HF in 54,064 (21%) and on the same day in 27,651 (11%) individuals, similar in women and men. Among patients without AF, the cumulative 10-year incidence of AF was 18.7% (95% confidence interval [CI]: 18.2% to 19.1%) in women and 21.3% (95% CI: 21.0% to 21.6%) in men. On follow-up (mean: 6.2 ± 5.8 years), adjusted mortality rate ratios were 3.33 (95% CI: 3.25 to 3.41) in women and 2.84 (95% CI: 2.78 to 2.90) in men if AF antedated HF, 3.45 (95% CI: 3.37 to 3.56) in women versus 2.76 (95% CI: 2.69 to 2.83) in men when AF and HF were diagnosed concomitantly, and 4.85 (95% CI: 4.73 to 4.97) in women versus 3.89 (95% CI: 3.80 to 3.98) in men when AF developed after HF. Compared with rate control for AF, a rhythm-controlling strategy was associated with lowered mortality in inverse probability-weighted models across all strata and in both sexes (hazard ratios: 0.75 to 0.83), except for women who developed AF after HF onset (hazard ratio: 1.03).

CONCLUSIONS

More than half of all men and women with HF will develop AF during their clinical course, with prognosis associated with AF being worse in women than men. Further studies are needed to understand the underlying mechanisms.

Arterial Thromboembolism in Cancer Patients: A Danish Population-Based Cohort Study

Background

The relation between cancer and arterial thromboembolism (ATE) remains unclear.

Objectives

The purpose of this study was to evaluate ATE risk in cancer patients.

Methods

Danish registries were used to identify all cancer patients between 1997 and 2017, each matched to three cancer-free comparator individuals. ATE was defined as the composite of myocardial infarction, ischemic/unspecified stroke, and peripheral arterial occlusion. A competing risk approach was used to compute cumulative incidences and subdistribution hazard ratios (SHRs). Cause-specific hazard ratios (HRs) were calculated using Cox regression. Among cancer patients, mortality risk was estimated in Cox regression analysis by treating ATE as a time-varying exposure. Patients were followed for 12 months.

Results

The study included 458,462 cancer patients and 1,375,386 comparator individuals. In the 6-month period following cancer diagnosis/index date, the cumulative incidence for ATE was 1.50% (95% confidence interval [CI]: 1.47% to 1.54%) in cancer patients and 0.76% (95% CI: 0.75% to 0.77%) in comparator individuals (HR: 2.36; 95% CI: 2.28 to 2.44). Among cancer patients age <65 years, 65 to 75 years, and >75 years, this was 0.79% (95% CI: 0.74% to 0.83%), 1.61% (95% CI: 1.55% to 1.67%), and 2.30% (95% CI: 2.22% to 2.38%), respectively. Other predictors for ATE among cancer patients were prior ATE (SHR: 2.96; 95% CI: 2.77 to 3.17), distant metastasis (adjusted SHR: 1.21; 95% CI: 1.12 to 1.30), and chemotherapy (SHR: 1.47; 95% CI: 1.33 to 1.61). Among cancer patients, ATE was associated with an increased risk of mortality (HR: 3.28; 95% CI: 3.18 to 3.38).

Conclusions

Cancer patients are at increased risk of ATE. Clinicians should be aware of this risk, which is associated with mortality.

Association Between Atopic Dermatitis and Educational Attainment in Denmark

IMPORTANCE

Atopic dermatitis (AD) may affect academic performance through multiple pathways, including poor concentration associated with itching, sleep deprivation, or adverse effects of medications. Because educational attainment is associated with health and well-being, any association with a prevalent condition such as AD is of major importance.

OBJECTIVE

To examine whether a childhood diagnosis of AD is associated with lower educational attainment.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used linked routine health care data from January 1, 1977, to June 30, 2017 (end of registry follow-up), in Denmark. The study population included all children born in Denmark on June 30, 1987, or earlier with an inpatient or outpatient hospital clinic diagnosis of AD recorded before their 13th birthday (baseline) and a comparison cohort of children from the general population matched by birth year and sex. A secondary analysis included exposure-discordant full siblings as a comparison cohort to account for familial factors. Data were analyzed from September 11, 2019, to January 21, 2021.

EXPOSURES

Hospital-diagnosed AD.

MAIN OUTCOMES AND MEASURES

Estimated probability or risk of not attaining specific educational levels (lower secondary, upper secondary, and higher) by 30 years of age among children with AD compared with children in the matched general population cohort. Corresponding risk ratios (RRs) were computed using Poisson regression that was conditioned on matched sets and adjusted for age. The sibling analysis was conditioned on family and adjusted for sex and age.

RESULTS

The study included a total of 61 153 children, 5927 in the AD cohort (3341 male [56.4%]) and 55 226 from the general population (31 182 male [56.5%]). Compared with matched children from the general population, children with AD were at increased risk of not attaining lower secondary education (150 of 5927 [2.5%] vs 924 of 55 226 [1.7%]; adjusted RR, 1.50; 95% CI, 1.26-1.78) and upper secondary education (1141 of 5777 [19.8%] vs 8690 of 52 899 [16.4%]; RR, 1.16; 95% CI, 1.09-1.24), but not higher education (2406 of 4636 [51.9%] vs 18 785 of 35 408 [53.1%]; RR, 0.95; 95% CI, 0.91-1.00). The absolute differences in probability were less than 3.5%. The comparison of 3259 children with AD and 4046 of their full siblings yielded estimates that were less pronounced than those in the main analysis (adjusted RR for lower secondary education, 1.29 [95% CI, 0.92-1.82]; adjusted RR for upper secondary education, 1.05 [95% CI, 0.93-1.18]; adjusted RR for higher education, 0.94 [95% CI, 0.87-1.02]).

CONCLUSIONS AND RELEVANCE

This population-based cohort study found that hospital-diagnosed AD was associated with reduced educational attainment, but the clinical importance was uncertain owing to small absolute differences and possible confounding by familial factors in this study. Future studies should examine for replicability in other populations and variation by AD phenotype.

Long-term risk of epilepsy, cerebral palsy and attention-deficit/hyperactivity disorder in children affected by a threatened abortion in utero

BACKGROUND

The birth of a child affected by a threatened abortion (TAB) in utero is associated with autism spectrum disorder; association with other neurological disorders is unknown.

METHODS

This nationwide registry-based cohort study included singletons live-born in Denmark (1979-2010), followed through 2016. The outcomes were epilepsy, cerebral palsy (CP) and attention-deficit/hyperactivity disorder (ADHD). We used Cox regression to compute hazard ratios (HRs), adjusted for birth year, birth order, parental age, morbidity, medication use and maternal socio-economic factors. To remove time-invariant family-shared confounding, we applied sibling analyses.

RESULTS

The study population included 1 864 221 singletons live-born in 1979-2010. Among the TAB-affected children (N = 59 134) vs TAB-unaffected children, at the end of follow-up, the cumulative incidence was 2.2% vs 1.6% for epilepsy, 0.4% vs 0.2% for CP and 5.5% vs 4.2% for ADHD (for children born in 1995-2010). The adjusted HRs were 1.25 [95% confidence interval (CI) 1.16-1.34] for epilepsy, 1.42 (95% CI 1.20-1.68) for CP and 1.21 (95% CI 1.14-1.29) for ADHD. In the sibling design, the adjusted HRs were unity for epilepsy (full siblings: 0.96, 95% CI 0.82-1.12; maternal: 1.04, 95% CI 0.90-1.20; paternal: 1.08, 95% CI 0.93-1.25) and ADHD (full: 1.08, 95% CI 0.92-1.27; maternal: 1.04, 95% CI 0.90-1.20; paternal: 1.08, 95% CI 0.93-1.25). For CP, HRs shifted away from unity among sibling pairs (full: 2.92, 95% CI 1.33-6.39; maternal: 2.03, 95% CI 1.15-3.57; paternal: 3.28, 95% CI 1.36-7.91).

CONCLUSIONS

The birth of a child affected by TAB in utero was associated with a greater risk of CP, but not epilepsy or ADHD.

Family involvement and patient-experienced improvement and satisfaction with care: a nationwide cross-sectional study in Danish psychiatric hospitals

BACKGROUND

Randomised controlled trials suggest that family therapy has a positive effect on the course of depression, schizophrenia and anorexia nervosa. However, it is largely unknown whether a positive link also exists between caregiver involvement and patient outcome in everyday psychiatric hospital care, using information reported directly from patients, i.e. patient-reported experience measures (PREM), and their caregivers. The objective of this study is to examine whether caregiver-reported involvement is associated with PREM regarding patient improvement and overall satisfaction with care.

METHODS

Using data from the National Survey of Psychiatric Patient Experiences 2018, we conducted a nationwide cross-sectional study in Danish psychiatric hospitals including patients and their caregivers who had been in contact with the hospital (n = 940 patients, n = 1008 caregivers). A unique patient identifier on the two distinct questionnaires for the patient and their caregiver enabled unambiguous linkage of data. In relation to PREM, five aspects of caregiver involvement were analysed using logistic regression with adjustment for patient age, sex and diagnosis.

RESULTS

We consistently find that high caregiver-reported involvement is statistically significantly associated with high patient-reported improvement and overall satisfaction with care with odds ratios (OR) ranging from 1.69 (95% confidence interval (CI) 0.95-2.99) to 4.09 (95% CI 2.48-6.76). This applies to the following aspects of caregiver-reported involvement: support for the patient-caregiver relationship, caregiver information, consideration for caregiver experiences and the involvement of caregivers in decision making. No statistically significant association is observed regarding whether caregivers talk to the staff about their expectations for the hospital contact.

CONCLUSION

This nationwide study implies that caregiver involvement focusing on the patient-caregiver relationship is positively associated with patient improvement and overall satisfaction with care in everyday psychiatric hospital care.

The impact of changed treatment patterns in multiple myeloma on health-care utilisation and costs, myeloma complications, and survival: A population-based comparison between two time periods in Denmark

OBJECTIVES

To evaluate health-care utilisation and costs, myeloma complications and survival in Danish patients with multiple myeloma (MM) before and after implementation of new early-line treatments in 2009.

METHODS

Based on data from the Danish National Health Registers, 3518 patients diagnosed with MM during 2002-2005 or 2010-2013 and randomly matched control individuals were identified, and health-care utilisation and costs were estimated.

RESULTS

Health-care utilisation showed a marked shift from inpatient admissions towards outpatient visits. From early to late period, the mean annual number of outpatient visits increased by 22% and 28% in patients <65 years and ≥65 years, respectively. Additionally, the mean annual outpatient service costs increased correspondingly from 17 001€ to 23 643€ in younger patients and from 11 317€ to 16 144€ in the elderly. Increasing outpatient costs were outbalanced by lower inpatient admission costs and the adjusted total mean annual costs decreased in younger patients, probably partly due to fewer myeloma complications. The five-year survival rates increased markedly in both younger (HR = 0.51) and elderly (HR = 0.69) patients.

CONCLUSION

Despite the introduction of new expensive early-line MM treatments in 2009, health-care costs remained stable due to a shift in health-care utilisation towards outpatient clinic care and fewer complications.

Venous thromboembolism in cancer patients: a population-based cohort study

The incidence of venous thromboembolism (VTE) in cancer patients may have changed in the past decade, possibly due to novel cancer therapies, improved survival, and high-resolution imaging. Danish medical registries were used to identify 499 092 patients with a first-time cancer diagnosis between 1997 and 2017, who were matched to 1 497 276 comparison individuals without cancer from the general population. We computed cumulative incidences of VTE 6 and 12 months after the diagnosis/index date. Hazard ratios (HRs) were calculated using Cox regression. Risk factors were examined by computing subdistribution hazard ratios (SHRs) in a competing-risk analysis. Cumulative incidence of VTE 12 months after the cancer diagnosis/index date was 2.3% (95% confidence interval [CI], 2.2% to 2.3%) in the cancer cohort and 0.35% (95% CI, 0.34% to 0.36%) in the comparison cohort (HR, 8.5; 95% CI, 8.2-8.8). Important risk factors for cancer patients were prior VTE (SHR, 7.6; 95% CI, 7.2-8.0), distant metastasis (SHR, 3.2; 95% CI, 2.9-3.4), and use of chemotherapy (SHR, 3.4; 95% CI, 3.1-3.7), protein kinase inhibitors (SHR, 4.1; 95% CI, 3.4-4.9), antiangiogenic therapy (SHR, 4.4; 95% CI, 3.8-5.2), and immunotherapy (SHR, 3.6; 2.8-4.6). Twelve-month incidence in the cancer cohort increased from 1.0% (95% CI, 0.9% to 1.2%) in 1997 to 3.4% (95% CI, 2.9% to 4.0%) in 2017, which was paralleled by improved 12-month survival and increased use of computed tomography scans, chemotherapy, and targeted therapies. In conclusion, the risk of VTE in cancer patients is increasing steadily and is ninefold higher than in the general population.

Identification of Patients with CKD in Medical Databases: A Comparison of Different Algorithms

BACKGROUND AND OBJECTIVES

Despite CKD consensus definitions, epidemiologic studies use multiple different algorithms to identify CKD. We aimed to elucidate if this affects the patient characteristics and the estimated prevalence and prognosis of CKD by applying six different algorithms to identify CKD in population-based medical databases and compare the cohorts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with CKD in Northern Denmark (2009-2016) were identified using six different algorithms: five were laboratory based defined by (1) one measured outpatient eGFR <60 ml/min per 1.73 m2 (single test, n=103,435), (2) two such findings ≥90 days apart (Kidney Disease Improving Global Outcomes, n=84,688), (3) two such findings ≥90 days apart with no eGFR >60 ml/min per 1.73 m2 observed in-between (Kidney Disease Improving Global Outcomes, persistent, n=68,994), (4) two such findings ≥90 and <365 days apart (Kidney Disease Improving Global Outcomes, time limited, n=75,031), and (5) two eGFRs <60 ml/min per 1.73 m2 or two urine albumin-creatinine ratios >30 mg/g ≥90 days apart (Kidney Disease Improving Global Outcomes, eGFR/albuminuria, n=100,957). The sixth included patients identified by reported in- and outpatient hospital International Classification of Diseases diagnoses of CKD (hospital-diagnosed, n=27,947). For each cohort, we estimated baseline eGFR, CKD prevalence, and 1-year mortality using the Kaplan-Meier method.

RESULTS

The five different laboratory-based algorithms resulted in large differences in the estimated prevalence of CKD from 4637-8327 per 100,000 population. In contrast, 1-year mortality varied only slightly (7%-9%). Baseline eGFR levels at diagnosis were comparable (53-56 ml/min per 1.73 m2), whereas median time since first recorded eGFR <60 ml/min per 1.73 m2 varied from 0 months (single-test) to 17 months (Kidney Disease Improving Global Outcomes, persistent). The hospital-diagnosed algorithm yielded markedly lower CKD prevalence (775 per 100,000 population), a lower baseline eGFR (47 ml/min per 1.73 m2), longer time since first eGFR <60 ml/min per 1.73 m2 (median 70 months), and much higher 1-year mortality (22%).

CONCLUSIONS

Population prevalence of CKD identified in medical databases greatly depends on the applied algorithm to define CKD. Despite these differences, laboratory-based algorithms produce cohorts with similar prognosis.

PODCAST

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Independent predictors for 90-day readmission of emergency department patients admitted with sepsis: a prospective cohort study

Background

The primary objective of our study was to examine predictors for readmission in a prospective cohort of sepsis patients admitted to an emergency department (ED) and identified by the new Sepsis-3 criteria.

Method

A single-center observational population-based cohort study among all adult (≥18 years) patients with sepsis admitted to the emergency department of Slagelse Hospital during 1.10.2017–31.03.2018. Sepsis was defined as an increase in the sequential organ failure assessment (SOFA) score of ≥2. The primary outcome was 90-day readmission. We followed patients from the date of discharge from the index admission until the end of the follow-up period or until the time of readmission to hospital, emigration or death, whichever came first. We used competing-risks regression to estimate adjusted subhazard ratios (aSHRs) with 95% confidence intervals (CI) for covariates in the regression models.

Results

A total of 2110 patients were admitted with infections, whereas 714 (33.8%) suffered sepsis. A total of 52 patients had died during admission and were excluded leaving 662 patients (44.1% female) with a median age of 74.8 (interquartile range: 66.0–84.2) years for further analysis. A total of 237 (35,8%; 95% CI 32.1–39.6) patients were readmitted within 90 days, and 54(8.2%) had died after discharge without being readmitted. We found that a history of malignant disease (aSHR 1,61; 1.16–2.23), if previously admitted with sepsis within 1 year before the index admission (aSHR; 1.41; 1.08–1.84), and treatment with diuretics (aSHR 1.51; 1.17–1.94) were independent predictors for readmission. aSHR (1.49, 1.13–1.96) for diuretic treatment was almost unchanged after exclusion of patients with heart failure, while aSHR (1.47, 0.96–2.25) for malignant disease was slightly attenuated after exclusion of patients with metastatic tumors.

Conclusions

More than one third of patients admitted with sepsis, and discharged alive, were readmitted within 90 days. A history of malignant disease, if previously admitted with sepsis, and diuretic treatment were independent predictors for 90-day readmission.