Use of antibiotics for urinary tract infections up to and after care home admission in Denmark: a nationwide study

PURPOSE

Older people have the highest use of antibiotics for acute and chronic urinary tract infection (UTI), despite diagnostic uncertainty and the growing problem of antibiotic resistance. We aim to describe use-patterns of UTI antibiotics two years prior to and following care home admission in Denmark.

METHODS

This was a register-based nationwide drug-utilization study. In a cohort comprising all Danish residents admitted into a care home from 2015 to 2021, we described the use of UTI antibiotics, and examined differences between regions and individual care homes in rates of UTI antibiotic use. Further, we described trends in UTI-related contacts with hospitals in the two years prior to and following care home admission.

RESULTS

The cohort comprised 101,297 residents (61% female; median age 84 years). UTI antibiotic use doubled from 7 to 14 treatments/100 residents/month two months prior to care home admission and remained at 10 treatments/100 residents/month the following two years. Prescription of pivmecillinam (55%) was most common. Primary care practitioners prescribed the majority (92%) of UTI antibiotics. UTI-related hospital contacts peaked at two months prior to care home admission, with 6 admissions/100 residents/month, subsequently dropping to 2 admission/100 residents/month. We found considerable variation in UTI antibiotic use, with 10% of care homes responsible for 20% of treatments in 2021.

CONCLUSION

Use of UTI antibiotics increased prior to and remained at a stable high level following care home admission in Denmark. Despite variation in use across regions and individual care homes, an overall decrease was seen throughout the years 2016-2021.

Semaglutide (Ozempic®) Use in Denmark 2018 Through 2023 ‒ User Trends and off-Label Prescribing for Weight Loss

Purpose

A surge in the use of semaglutide injection (Ozempic®) approved to treat type 2 diabetes (T2D) has led to a global supply shortage. We investigated contemporary user rates and clinical characteristics of semaglutide (Ozempic®) users in Denmark, and the extent of "off-label" prescribing for weight loss.

Patients and Methods

Nationwide population-based cross-sectional study based on linked health registries January 2018 through December 2023. All adults who received a first prescription of semaglutide once weekly (Ozempic®) were included. We examined quarterly rates of new users and total user prevalences, using other glucagon-like peptide-1 receptor agonists and weight loss medications as comparison. We also investigated user characteristics including T2D, glucose control, comedications, and cardiorenal disease.

Results

The new user rate of semaglutide (Ozempic®) remained stable at approximately 4 per 1000 adult person-years between 2019 and 2021 and then accelerated, peaking at 10 per 1000 in the first quarter of 2023 after which it declined sharply. User prevalence increased to 91,626 users in Denmark in 2023. The proportion of semaglutide (Ozempic®) new users who had a record of T2D declined from 99% in 2018 to only 67% in 2022, increasing again to 87% in 2023. Among people with T2D who initiated semaglutide (Ozempic®) in 2023, 52% received antidiabetic polytherapy before initiation, 39% monotherapy, and 8% no antidiabetic therapy. Most T2D initiators had suboptimal glucose control, with 83% having an HbA1c ≥48 mmol/mol and 68% ≥53 mmol/mol despite use of antidiabetic medication, and 29% had established atherosclerotic cardiovascular disease or kidney disease.

Conclusion

The use of semaglutide (Ozempic®) in Denmark has increased dramatically. Although not approved for weight loss without T2D, one-third of new users in 2022 did not have T2D. Conversely, most initiators with T2D had a clear medical indication for treatment intensification, and "off-label" use can only explain a minor part of the supply shortage.

Risk of fractures and use of bisphosphonates in adult patients with immune thrombocytopenia-A nationwide population-based study

Corticosteroids remain the first-line treatment of immune thrombocytopenia (ITP), but increase the risk of osteoporosis and fractures. Bisphosphonates are used for the treatment of osteoporosis, but their usage among patients with ITP has not been systemically described. We investigated the risk of fractures and the use of bisphosphonates in adult patients with primary (pITP) and secondary ITP (sITP) compared with matched comparators in a nationwide registry-based cohort study. We identified 4030 patients with pITP (median age 60 years [IQR, 40-74]), 550 with sITP (median age 59 years [IQR, 43-74]) and 182 939 age-sex-matched general population comparators. All individuals were followed for incident fractures. Bisphosphonate use was estimated for calendar-years and in temporal relation to the ITP diagnosis. Adjusted cause-specific hazard ratio (csHR) for any fracture was 1.37 (95% confidence interval [CI] 1.23; 1.54) for pITP and 1.54 (1.17; 2.03) for sITP. The first-year csHR was 1.82 (1.39; 2.40) for pITP and 2.78 (1.58; 4.91) for sITP. Bisphosphonate use over calendar-years and in the early years following ITP diagnosis was higher among patients with ITP diagnosis compared with the general population. In conclusion, the risk of fractures and the use of bisphosphonates are higher in patients with ITP compared with the general population.

Considerations for the use of biochemical laboratory registry data in clinical and public health research

OBJECTIVES

To inform researchers of central considerations and limitations when applying biochemical laboratory-generated registry data in clinical and public health research.

STUDY DESIGN AND SETTING

After review of literature on registry-based studies and the utilization of clinical laboratory registry data, relevant paragraphs and their applicability toward the creation of considerations for the use of biochemical registry data in research were evaluated. This led to the creation of an initial ten considerations. These were elaborated, edited, and merged after several read-throughs by all authors and discussed thoroughly under influence by the authors' personal experiences with laboratory databases and research registries in Denmark, leading to the formulation of five central considerations with corresponding items and illustrative examples.

RESULTS

We recommend that the following considerations should be addressed in studies relying on biochemical laboratory-generated registry data: why are biochemical laboratory data relevant to examine the hypothesis, and how were the variable(s) utilized in the study? What were the primary indications for specimen collection in the study population of interest? Were there any pre-analytical circumstances that could influence the test results? Are data comparable between producing laboratories and within the single laboratory over time? Is the database representative in terms of completeness of study populations and key variables?

CONCLUSION

It is crucial to address key errors in laboratory registry data and acknowledge potential limitations.

Critical evaluation of cohort study results

Being able to critically evaluate modern cohort studies is important when being presented with claims based on observational evidence. In this review article, key aspects of the cohort design are presented using an example of a cohort study investigating the association between the use of SGLT2 inhibitors and gout. We describe the active comparator, new user design, modern methods used to address confounding, how to identify the most common sources of bias, and how to interpret study results appropriately.

Impact of immunosuppressive therapy on SARS-CoV-2 mRNA vaccine effectiveness in patients with immune-mediated inflammatory diseases: a Danish nationwide cohort study

OBJECTIVE

Patients receiving immunosuppressives have been excluded from trials for SARS-CoV-2 vaccine efficacy. Investigation of immunosuppressants' impact on effectiveness of vaccines, particularly in patients with immune-mediated inflammatory diseases (IMID), is therefore required.

DESIGN

We performed a nationwide cohort study to assess the risk of COVID-19 infection in vaccinated patients with IMID exposed to immunosuppressives compared with IMID unexposed to immunosuppressives. Exposure to immunosuppressives in the 120 days before receiving the second SARS-CoV-2 mRNA vaccination was assessed. Patients were followed from date of second vaccination and weighted Cox models were used to estimate the risk of infection associated with immunosuppressives. Secondary outcomes included hospitalisation and death associated with a positive SARS-CoV-2 test. Risk of infection by immunosuppressant drug class was also analysed.

SETTING

This study used population-representative data from Danish national health registries in the period from 1 January to 30 November 2021.

RESULTS

Overall, 152 440 patients were followed over 19 341 person years. Immunosuppressants were associated with a significantly increased risk of infection across IMID (HR: 1.4, 95% CI 1.2 to 1.5), in inflammatory bowel disease (IBD) (HR: 1.6, 95% CI 1.4 to 1.9) and arthropathy (HR: 1.3, 95% CI 1.1 to 1.4) but not psoriasis (HR: 1.1, 95% CI 0.9 to 1.4). Immunosuppressants were also associated with an increased risk of hospitalisation across IMID (HR: 1.4, 95% CI 1.1 to 2.0), particularly in IBD (HR: 2.1, 95% CI 1.0 to 4.1). No significantly increased risk of death in immunosuppressant exposed patients was identified. Analyses by immunosuppressant drug class showed increased COVID-19 infection and hospitalisation with anti-tumour necrosis factor (TNF), systemic corticosteroid, and rituximab and other immunosuppressants in vaccinated patients with IMID.

CONCLUSION

Immunosuppressive therapies reduced effectiveness of mRNA SARS-CoV-2 vaccination against infection and hospitalisation in patients with IMID. Anti-TNF, systemic corticosteroids, and rituximab and other immunosuppressants were particularly associated with these risks.

Validation of Obstetric Diagnosis and Procedure Codes in the Danish National Patient Registry in 2017

Purpose

This study aimed to systematically evaluate the validity of variables related to pregnancy, delivery, and key characteristics of the infant in the Danish National Patient Register using maternal medical records as the reference standard.

Patients and Methods

We reviewed medical records of 1264 women giving birth in the Region of Southern Denmark during 2017. We calculated positive (PPV) and negative (NPV) predictive values, sensitivity, and specificity to estimate the validity of 49 selected variables.

Results

The PPV was ≥0.90 on most pregnancy-related variables including parity, pre-gestational BMI, diabetes disorders, and previous cesarean section, while it was lower for hypertensive disorders, especially mild to moderate preeclampsia (0.49, 95% CI 0.32-0.66). Sensitivity ranged from 0.80 to 1.00 on all pregnancy-related variables, except hypertensive disorders (sensitivity 0.38-0.71, lowest for severe preeclampsia). On most delivery-related variables including obstetric surgical procedures (eg cesarean section and induction of labor), pharmacological pain-relief, and gestational age at delivery, PPV's ranged from 0.98 to 1.00 and the corresponding sensitivities from 0.87 to 1.00. Regarding infant-related variables, both the APGAR score registered five minutes after delivery and birthweight yielded a PPV of 1.00.

Conclusion

Obstetric coding in the Danish National Patient Register shows very high validity and completeness making it a valuable source for epidemiologic research.

Critical evaluation of articles on case-control studies

The case-control design is one of the key designs used in observational research. In this review, we discuss common pitfalls of case-control studies and describe how case-control studies can be critically evaluated. We further assert that a well-conducted case-control study provides the same results, precision, and level of evidence as a corresponding cohort study.

Use of prescribed analgesics before and after exercise therapy and patient education in patients with knee or hip osteoarthritis

The aim of this study was to investigate utilisation patterns of prescribed analgesics before, during, and after an exercise therapy and patient education program among patients with knee or hip osteoarthritis. This cohort study is based on data from the nationwide Good Life with osteoarthritis in Denmark (GLA:D®) patient-register linked with national health registries including data on prescribed analgesics. GLA:D® consists of 8-12 weeks of exercise and patient education. We included 35,549 knee/hip osteoarthritis patients starting the intervention between January 2013 and November 2018. Utilisation patterns the year before, 3 months during, and the year after the intervention were investigated using total dispensed defined daily doses (DDDs) per month per 1000 population as outcome. During the year before the intervention, use of prescribed paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), and opioids increased with 85%, 79% and 22%, respectively. During the intervention, use of paracetamol decreased with 16% with a stable use the following year. Use of NSAIDs and opioids decreased with 38% and 8%, respectively, throughout the intervention and the year after. Sensitivity analyses indicated that the prescription of most analgesics changed over time. For paracetamol, NSAIDs, and opioids, 10% of analgesic users accounted for 45%, 50%, and 70%, respectively, of the total DDDs dispensed during the study period. In general, analgesic use increased the year before the intervention followed by a decrease during the intervention and the year after. A small proportion of analgesic users accounted for half or more of all paracetamol, NSAIDs, and opioids dispensed during the study period.

Validation of the "Indication for Use" (INDO) Variable in the Danish National Prescription Registry

BACKGROUND

Despite its potential value in register-based pharmacoepidemiologic research, recorded information on "indication for use" (INDO) in the Danish National Prescription Registry has rarely been used, likely because of questions about the variable's validity, which to our knowledge no study has systematically assessed.

METHODS

We extracted data on 80,814 prescriptions from the software systems (PharmaNet and C2) of five Danish community pharmacies filled between 4 and 16 February 2019 and 2020. Using the indication information recorded in the pharmacy software systems as the gold standard, we evaluated the extent and quality of the corresponding information from the Prescription Registry.

RESULTS

Of all prescriptions identified, we captured >99% in the Prescription Registry. The proportion of prescriptions with recorded indication codes in the Prescription Registry was 82% (n = 66,164) but was lower for C2 than PharmaNet. Correcting for the overrepresentation of C2 data in our sample, the estimated proportion of registration was ≈88%. Almost 100% (66,158 of 66,164) of the prescriptions with recorded indication codes in the Prescription Registry had correctly recorded indication codes. Nonspecific indication codes were present in 5.6%-36% of selected drugs and drug classes.

CONCLUSIONS

Prescriptions filled at Danish community pharmacies are accurately captured by the Danish National Prescription Registry, and the recorded information on indication is generally valid and usable in research. However, minor concerns remain about missingness, nonspecific recorded indication codes, and lower validity, and a higher proportion of missingness of recorded indication codes is expected before 2017.A supplementary digital video by the article's co-author, Hanin Harbi, is available at http://links.lww.com/EDE/C89.

Attitudes towards deprescribing in geriatric psychiatry: A survey among older psychiatric outpatients

Understanding the patient perspective is a significant part of the deprescribing process. This study aimed to explore the attitudes of older patients with psychiatric disorders towards deprescribing. A total of 72 of psychiatric outpatients (68% women; median age 76 years) completed the validated Danish version of the revised Patients' Attitudes Towards Deprescribing (rPATD) questionnaire. Patients used a median of eight medications (interquartile range 6-12), with 88%, 49% and 24% using antidepressants, antipsychotics and anxiolytics, respectively. Fifty-one percent of patients reported an intrinsic desire to stop one of their medications, while 92% would be willing to stop one on their physician's advice. Seventy-five percent of patients would be worried about missing out on future benefits following deprescribing and 37% had previous bad deprescribing experiences. Use of ≥8 regular medications was associated with more concerns about stopping medication and greater perceived burden of using medication, while use of antipsychotics was not associated with any differences in rPATD factor scores. It is crucial for health care professionals to be aware of patients' specific concerns and past experiences to promote a patient-centred deprescribing approach that takes into account the needs and preferences of older patients with psychiatric disorders.

Effectiveness of the quadrivalent live attenuated influenza vaccine against influenza-related hospitalisations and morbidity among children aged 2 to 6 years in Denmark: a nationwide cohort study emulating a target trial

BACKGROUND

Scant evidence exists on the real-world effectiveness of quadrivalent live attenuated influenza vaccines (LAIV-4) in younger children. We aimed to assess the real-world effectiveness of LAIV-4 against influenza-related hospital contacts and admission and morbidity.

METHODS

Using nationwide Danish health-care registries, we designed a cohort study that emulates a target trial, comparing LAIV-4 to no vaccination in children aged 2-6 years. Eligible children vaccinated from Oct 1, 2021, to Jan 15, 2022, were matched to unvaccinated controls in a 1:1 ratio according to demographic characteristics and risk groups for influenza, and followed-up until May 31, 2022. Primary study outcomes any hospital contact for influenza and influenza-related hospital admissions more than 12 h in duration, while hospital admission for respiratory tract infections, or for wheezing or asthma, and antibiotic prescriptions were evaluated as secondary outcomes. We estimated incidence rate ratios (IRRs) and 95% CIs using Poisson regression for each outcome. Vaccine effectiveness was calculated as 1 - IRR.

FINDINGS

Among 308 520 Danish children aged 2-6 years, 95 434 vaccinated children were matched with 95 434 unvaccinated children who acted as controls. Receipt of LAIV-4 compared with no vaccination was associated with a reduced IRR of 0·36 (95% CI 0·27 to 0·46) and estimated vaccine effectiveness of 64·3% (53·6 to 72·6) against influenza-related hospital contacts (76 vs 210 events). The corresponding IRR and vaccine effectiveness against influenza-related hospital admissions were 0·63 (0·38 to 1·05) and 36·9% (-5·2 to 62·1; 24 vs 38 events), respectively. LAIV-4 was not associated with reductions in admission rates for respiratory tract infections (IRR 1·14, 95% CI 0·94 to 1·38), wheezing or asthma (1·04, 0·83 to 1·31), or antibiotic prescriptions for respiratory tract infections (0·97, 0·93 to 1·00). Vaccine effectiveness assessed across risk groups for influenza showed similar effectiveness in children with and without coexisting risk factors for severe influenza.

INTERPRETATION

LAIV-4 offered moderate protection in younger children against influenza-related hospital contacts during a season dominated by influenza A(H3N2); however vaccination was not associated with reductions in secondary outcomes. This real-world study thereby supports trial evidence of moderate vaccine effectiveness of LAIV-4 against influenza-related outcomes when implementing broad vaccination schedules in younger children.

FUNDING

Beckett-Fonden.

Methodological Considerations for Describing Medication Changes in Relation to Clinical Events and Death: An Applied Example in Patients with Type 2 Diabetes and Cancer

INTRODUCTION

Certain clinical events reduce life expectancy and necessitate a reassessment of patient treatment.

OBJECTIVE

To describe medication changes in relation to a cancer diagnosis and the end of life and to highlight challenges and limitations with such descriptions.

METHODS

From a cohort with all Danish patients with type 2 diabetes, we matched patients with incident cancer during 2000-2021 (n = 41,745) with patients without cancer (n = 166,994) using propensity scores. We described their medication usage from cancer diagnosis until death.

RESULTS

The 1- and 5-year mortality were 51% and 86%, respectively, in the cancer group, and 13% and 59% in the non-cancer group. In relation to cancer diagnosis and death, the use of symptomatic medications (e.g., opioids, benzodiazepines) increased (10-60 incident medications per 100 patient-months), and the use of preventive medications (e.g., antihypertensives, statins) decreased (5-30% fewer users). The changes in relation to the diagnosis were driven by patients with short observed lengths of survival (< 2 years). In contrast, changes occurring within a year before death were less dependent on survival strata, and > 60% used preventive medications in their last months.

CONCLUSIONS

Medication changes in relation to a cancer diagnosis were frequent and correlated to the length of survival. The results showcase the challenges and limited clinical utility of anchoring analyses on events or death. While the former diluted the results by averaging changes across patients with vastly different clinical courses, the latter leveraged information unavailable to the treating clinicians. While medication changes were common near death, preventive medications were often used until death.

Heterogeneity after harmonisation: A retrospective cohort study of bleeding and stroke risk after the introduction of direct oral anticoagulants in four Western European countries

PURPOSE

Database heterogeneity can impact effect estimates. Harmonisation provided by common protocols and common data models (CDMs) can increase the validity of pharmacoepidemiologic research. In a case study measuring the changes in the safety and effectiveness of stroke prevention therapy after the introduction of direct oral anticoagulants (DOACs), we performed an international comparison.

METHODS

Using data from Stockholm, Denmark, Scotland and Norway, harmonised with a common protocol and CDM, two calendar-based cohorts were created: 2012 and 2017. Patients with a diagnosis code of atrial fibrillation 5 years preceding the 1-year cohort window were included. DOAC, vitamin K antagonist and aspirin treatment were assessed in the 6 months prior to the start of each year while strokes and bleeds were assessed during the year. A Poisson regression generated incidence rate ratios (IRRs) to compare outcomes from 2017 to 2012 adjusted for changes in individual-level baseline characteristics.

RESULTS

In 280 359 patients in the 2012 cohort and 356 779 in the 2017 cohort, treatment with OACs increased on average from 45% to 65%, while treatment with aspirin decreased from 30% to 10%. In all countries except Scotland, there were decreases in the risk of stroke and no changes in bleeding risk, after adjustment for changes in baseline characteristics. In Scotland, major bleeding (IRR 1.09, 95% confidence interval [CI] [1.00; 1.18]) and intracranial haemorrhage (IRR 1.31, 95% CI [1.13; 1.52]) increased from 2012 to 2017.

CONCLUSIONS

Stroke prevention therapy improved from 2012 to 2017 with a corresponding reduction in stroke risk without increasing the risk of bleeding in all countries, except Scotland. The heterogeneity that remains after methodological harmonisation can be informative of the underlying population and database.

Melatonin use among children, adolescents, and young adults: a Danish nationwide drug utilization study

We aimed to provide a detailed description of the use of melatonin in Danish children, adolescents, and young adults during 2012-2019. We identified melatonin users 0-24 years of age (n = 43,652; median age 16 years) via the Danish nationwide health registers. Melatonin is a prescription drug in Denmark. The incidence of melatonin use increased from 2.4 to 3.9/1000 person-years during 2012 to 2019. Among 6,557 incident users in 2019, 53% filled only a single prescription within the first 6 months. Long-term use was most common among the younger age groups, with 17% of 5-9-year-olds and 14% of 10-13-year-olds being in continued treatment (no treatment breaks) 12 months after their first melatonin prescription. Disregarding treatment breaks, 3 in 10 were using melatonin 12 months after their first melatonin prescription and this proportion was also highest among 5-9-year-olds (63%) and 10-13-year-olds (51%). Psychopathology was common among melatonin users with 75% registered with either a psychiatric disorder diagnosis (54%), a filled prescription for another psychotropic (58%), or a contact to a private practice psychiatrist (15%) within ± 12 months of treatment initiation. General practitioners authorized melatonin prescriptions to almost half of all new users (48%), while psychiatric specialists authorized 37% of first prescriptions. In conclusion, the incidence of melatonin use increased in Denmark from 2012 to 2019. A substantial proportion of users had concurrent psychopathology most likely explaining their use of melatonin. Long-term melatonin use was more common among the youngest age groups, which should be a focus of interest due to limited safety data.

Cardiovascular risks of continuing vs. initiating NSAIDs after first-time myocardial infarction or heart failure: a nationwide cohort study

AIMS

It is unknown whether the cardiovascular risks associated with the use of non-steroidal anti-inflammatory drugs (NSAIDs) shortly after first-time myocardial infarction (MI) or heart failure (HF) differ between patients continuing and initiating use.

METHODS AND RESULTS

Using nationwide health registries, we conducted a cohort study of all patients with first-time MI or HF during 1996-2018 (n = 273 682). NSAID users (n = 97 966) were categorized as continuing (17%) and initiating (83%) users according to prescription fillings < 60 days before index diagnosis. The primary outcome was a composite of new MI, HF admission, and all-cause death. Follow-up started 30 days after the index discharge date. We used Cox regression to compute hazard ratios (HRs) with 95% confidence intervals (CIs) comparing NSAID users vs. non-users. The most commonly filled NSAIDs were ibuprofen (50%), diclofenac (20%), etodolac (8.5%), and naproxen (4.3%). The composite outcome HR of 1.25 (CI: 1.23-1.27) was driven by initiators (HR = 1.39, 1.36-1.41) and not continuing users (HR = 1.03, 1.00-1.07). The lack of association among continuing users was also observed for individual NSAIDs (ibuprofen and naproxen), except diclofenac (HR = 1.11, 95% CI: 1.05-1.18). Among initiators, the HR was 1.63 (CI: 1.57-1.69) for diclofenac, 1.31 (CI: 1.27-1.35) for ibuprofen, and 1.19 (CI: 1.08-1.31) for naproxen. The results were consistent for both MI and HF patients, the individual components of the composite outcome, and various sensitivity analyses.

CONCLUSION

NSAID initiators were more susceptible to adverse cardiovascular outcomes after first-time MI or HF than continuing users.

Neurofilament light chain as a biomarker of axonal damage in sensory neurons and paclitaxel-induced peripheral neuropathy in patients with ovarian cancer

ABSTRACT

Paclitaxel-induced peripheral neuropathy (PIPN) is a barrier to effective cancer treatment and impacts quality of life among patients with cancer. We used a translational approach to assess the utility of neurofilament light chain (NFL) as a biomarker of PIPN in a human cell model and in patients with ovarian cancer. We measured NFL in medium from human induced pluripotent stem cell-derived sensory neurons (iPSC-SNs) exposed to paclitaxel. Serum NFL (sNFL) levels were quantified in 190 patients with ovarian cancer receiving paclitaxel/carboplatin chemotherapy at baseline and after each of the following 2 or 6 cycles. Adverse outcomes related to PIPN were retrospectively obtained, and Cox regression model was performed with different sNFL cut-offs after first cycle. The apparent elimination half-life of sNFL was estimated in patients who discontinued paclitaxel. Paclitaxel neurotoxicity in iPSC-SNs was accompanied by NFL release in a concentration-dependent manner ( P < 0.001, analysis of variance). Serum NFL levels increased substantially in patients during paclitaxel/carboplatin chemotherapy with considerable interindividual variability. Patients with sNFL >150 pg/mL after first cycle had increased risk to discontinue paclitaxel early (unadjusted HR: 2.47 [95% CI 1.16-5.22], adjusted HR: 2.25 [95% CI: 0.88-5.79]). Similar trends were shown for risk of severe PIPN and paclitaxel dose reduction because of PIPN. The median elimination half-life of sNFL was 43 days (IQR 27-82 days). Neurofilament light chain constitutes an objective biomarker of neurotoxicity in iPSC-SNs and in ovarian cancer patients with high sNFL predicting PIPN-related adverse outcomes. If prospectively validated, NFL can be used to study PIPN and may guide clinical decision making and personalize treatment with paclitaxel.

Prenatal antidepressant exposure and emotional disorders until age 22: a danish register study

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are the most frequently prescribed antidepressants in pregnancy. Animal and some clinical studies have suggested potential increases in depression and anxiety following prenatal SSRI exposure, but the extent to which these are driven by the medication remains unclear. We used Danish population data to test associations between maternal SSRI use during pregnancy and children outcomes up to age 22.

METHODS

We prospectively followed 1,094,202 single-birth Danish children born 1997-2015. The primary exposure was ≥ 1 SSRI prescription filled during pregnancy; the primary outcome, first diagnosis of a depressive, anxiety, or adjustment disorder, or redeemed prescription for an antidepressant medication. We used propensity score weights to adjust potential confounders, and incorporated data from the Danish National Birth Cohort (1997-2003) to further quantify potential residual confounding by subclinical factors.

RESULTS

The final dataset included 15,651 exposed and 896,818 unexposed, children. After adjustments, SSRI-exposed had higher rates of the primary outcome than those of mothers who either did not use an SSRI (HR = 1.55 [95%CI:1.44,1.67] or discontinued the SSRI use ≥ 3 months prior to conception (HR = 1.23 [1.13,1.34]). Age of onset was earlier among exposed (9 [IQR:7-13] years) versus unexposed (12 [IQR:12-17] years) children (p < 0.01). Paternal SSRI use in the absence of maternal use during the index pregnancy (HR = 1.46 [1.35,1.58]) and maternal SSRI use only after pregnancy (HR = 1.42 [1.35,1.49]) were each also associated with these outcomes.

CONCLUSIONS

While SSRI exposure was associated with increased risk in the children, this risk may be driven at least partly by underlying severity of maternal illness or other confounding factors.

Tranexamic acid use is not associated with the risk of melanoma in Danish women: A nested case-control study using Danish health registries

BACKGROUND

Repurposing already approved drugs in a cancer setting has gained increasing interest in recent years. Tranexamic acid is an anti-fibrinolytic drug that has recently been suggested as an anti-cancer drug due to its anti-inflammatory and anti-carcinogenic effects in animal studies. In this study, we aimed to investigate the possible melanoma-preventive role of tranexamic acid in Danish women.

METHOD

In this nested case-control study, we identified female cases 18-60 years with first-time melanoma during 2000-2015 and age-matched them with 10 female controls. The odds ratio (OR) of melanoma with tranexamic acid ever- or high use (≥ 100,000 mg) was estimated using conditional logistic regression.

RESULTS

A total of 7986 women with incident melanoma were eligible for study inclusion and were matched to 79,860 controls. Most exposed cases and controls were exposed to low cumulative doses of tranexamic acid corresponding to around 5 days of continuous treatment (1000 mg 3 times daily) for the presumed main indication, i.e., menorrhagia. The crude OR associating tranexamic ever use with melanoma was 1.04 (95% CI 0.98-1.11, p = 0.20), and the adjusted OR was 1.03 (0.97-1.10, p = 0.32). We found no dose-response pattern or effect measure modification by age, histologic type, localization, or clinical stage. However, prolonged use with cumulative doses of tranexamic acid (≥ 100,000 mg) was associated with an increased risk of melanoma (adjusted OR 1.23,95 %, CI 0.96-1.56), compared with non-use.

CONCLUSION

We found no association between tranexamic acid use and the risk of melanoma in Danish women. This could be explained by underlying dose- or biological factors, and sporadic use patterns. A higher risk of melanoma was seen among prolonged users which could be due to surveillance bias.

The Application of Lag Times in Cancer Pharmacoepidemiology: A Narrative Review

With the increasing utilization of medications worldwide, coupled with the increasing availability of long-term data, there is a growing opportunity and need for robust studies evaluating drug-cancer associations. One methodology of importance in such studies is the application of lag times. In this review, we discuss the main reasons for using lag times. Namely, we discuss the typically long latency period of cancer concerning both tumor promoter and initiator effects and outline why cancer latency is a key consideration when choosing a lag time. We also discuss how the use of lag times can help reduce protopathic and detection bias. Finally, we present practical advice for implementing lag periods. In general, we recommend that researchers consider the information that generated the hypothesis as well as clinical and biological knowledge to inform lag period selection. In addition, given that latency periods are usually unknown, we also advocate that researchers examine multiple lag periods in sensitivity analyses as well as duration analyses and flexible modeling approaches.

Dicloxacillin-Warfarin Drug-Drug Interaction - A Register-Based Study and In Vitro Investigations in 3D Spheroid Primary Human Hepatocytes

AIM

Dicloxacillin is used to treat staphylococcal infections and we have previously shown that dicloxacillin is an inducer of cytochrome P450 enzymes (CYPs). Here, we employed a translational approach to investigate the effect of a treatment with dicloxacillin on warfarin efficacy in Danish registries. Furthermore, we assessed dicloxacillin as an inducer of CYPs in vitro.

METHODS

We conducted a register-based study and analyzed international normalized ratio (INR) levels in chronic warfarin users before and after short- and long-term use of dicloxacillin (n=1023) and flucloxacillin (n=123). Induction of CYPs were investigated in a novel liver model of 3D spheroid primary human hepatocytes (PHHs) at the level of mRNA, and protein and enzyme activity.

RESULTS

Short- and long-term dicloxacillin treatments decreased INR levels by -0.65 (95% CI: -0.57 to -0.74) and -0.76 (95% CI: -0.50 to -1.02), respectively. More than 90% of individuals experienced subtherapeutic INR levels (below 2) after long-term dicloxacillin treatment. Flucloxacillin decreased INR levels by -0.37 (95% CI: -0.14 to -0.60). In 3D spheroid PHHs, the maximal induction of CYP3A4 mRNA, protein and enzyme activity by dicloxacillin were 4.9-, 2.9- and 2.4-fold, respectively. Dicloxacillin also induced CYP2C9 mRNA by 1.7-fold.

CONCLUSION

Dicloxacillin induces CYP enzymes and reduces the clinical efficacy of warfarin in patients. This effect is substantially exacerbated during long-term treatment with dicloxacillin. The in vitro results corroborated this drug-drug interaction and correlated to the clinical findings. Caution is warranted for warfarin patients that initiate dicloxacillin or flucloxacillin, especially for a long-term treatment of endocarditis.

Antiplatelet drugs and breast cancer risk in a large nationwide Danish case-control study

Low-dose aspirin has been hypothesized to prevent cancer risk by inhibiting platelet aggregation. However, the anti-cancer effect of low-dose aspirin has recently been questioned and its effect on breast cancer development remains unclear. The impact of other antiplatelet drugs on breast cancer risk has rarely been evaluated. Thus, this study aimed to investigate the associations between breast cancer risk and antiplatelet drug use in a nationwide nested case-control study. From the Danish healthcare registries, we identified as cases all women with invasive breast cancer diagnosis between 2001 and 2018 (n = 68 852). The date of diagnosis corresponded to the index date. We matched cases to 10 population controls on age and calendar time, using risk set sampling. Controls were assigned the same index date as their matched case. We used the prescription registry to identify exposure to low-dose aspirin, clopidogrel and dipyridamole. We defined ever use of antiplatelet drugs as at least two prescriptions filled up to 1 year before the index date. We applied conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals for breast cancer associated with the use of antiplatelet drugs, overall, by breast cancer subtype and by cumulative dose. Twelve percent of women had ever been exposed to low-dose aspirin, 2% to clopidogrel and 2% to dipyridamole. In multivariable models, breast cancer risk was not associated with ever use of low-dose aspirin (OR = 1.00 [0.97-1.03]), clopidogrel (OR = 0.93 [0.87-1.00]), and dipyridamole (OR = 1.02 [0.94-1.10]), compared with never use, and there was no evidence of a dose-response relation. However, we found an inverse association between dipyridamole use and breast cancer risk among women aged <55 years old, with suggestion of a dose-response relationship (OR per 1000 Defined Daily Doses = 0.72 [0.54-0.95]). Associations did not differ by breast cancer histological type, estrogen receptor status or clinical stage at diagnosis. Overall, the findings from this study do not support the use of antiplatelet drugs for breast cancer prevention.

Use of analgesics in Denmark: A national survey

People suffering from pain constitute a sizeable and heterogeneous patient group. Conventional oral analgesics are considered a cheap and safe first-line treatment. These drugs are used on both a regular and 'as needed' basis and are often obtained over-the-counter (OTC). We explored patient-reported patterns of use and adverse effects of analgesics in a community pharmacy questionnaire. Eight pharmacies invited persons aged ≥18 years requesting analgesics via prescription or OTC to complete an electronic questionnaire. A total of 2410 participants completed the questionnaire (68% female; 50% ≥ 60 years). Most participants filled a prescription for paracetamol (61%; n = 842) and non-steroidal analgesics (n = 363; 26%). Among OTC users, most obtained paracetamol (61%). Among prescription users, 73% (n = 1114) had their analgesic prescribed for daily use; however, of these only 61% (n = 630) reported using it daily, while 35% (n = 363) reported 'as needed' use. Of all prescriptions, 80% (n = 898) were labelled with the standardized indication 'against pain'. Self-reported indications showed that back pain and muscle/joint pain were the most common indications. Among non-new users of OTC analgesics (n = 841), 17% (n = 141) used their medication daily. Finally, 90% (n = 1658) of all participants reported not experiencing adverse effects. Our findings suggest a need for continuous assessment of analgesic patterns of use after treatment initiation to inform counselling in community pharmacies and elsewhere.

Changes in the use of glucose-lowering drugs: A Danish nationwide study

AIM

To investigate changes in the pattern of drugs used to treat type 2 diabetes in Denmark from 2005 to 2021.

MATERIALS AND METHODS

A nationwide, population-based drug utilization study based on medical databases covering the Danish population was conducted. We assessed incident and prevalent use patterns among all 441 205 individuals initiating at least one non-insulin, glucose-lowering drug.

RESULTS

The rate of new users of non-insulin, glucose-lowering drugs increased from 2005, peaked in 2011, decreased to stable levels during 2013 to 2019, then increased dramatically during 2020-2021. The prevalence of use increased from 2.1% (in 2005) to 5.0% (in 2021) of the entire adult population. In 2021, metformin comprised 39% of all glucose-lowering drug consumption, followed by insulin (17%), sodium-glucose co-transporter-2 inhibitors (SGLT-2is) (17%), glucagon-like peptide-1 receptor agonists (GLP-1RAs) (16%) and dipeptidyl peptidase-4 inhibitors (7.5%). Overall, 56% of users were on monotherapy, 28% used dual therapy, while 13% and 2.8% used three and four drug classes, respectively. Both the intensity and diversity of therapies increased substantially over time, with 15 different treatment regimens each covering more than 1% of users in 2021. General practitioners prescribed 88% of all glucose-lowering drugs. Marked shifts towards GLP-1RA initiation by general practitioners and SGLT-2i initiation by specialists were observed, and changing user profiles suggested increasing use for non-diabetes indications.

CONCLUSIONS

The rate of new users of non-insulin, glucose-lowering drugs has increased in recent years and the prevalence of glucose-lowering drug use increases steadily. Glucose-lowering drugs are mainly prescribed by general practitioners, and the intensity, diversity and indications of glucose-lowering treatment are increasing.

Opioid prescriber responsibility: A Danish drug utilization study

AIMS

We describe the distribution of prescribers responsible for opioid initiation and maintenance (general practice, hospital prescribers and other prescribers) in Denmark.

METHODS

We leveraged data on opioid fills from a 20% sample of all Danes alive during 2000-2021.

RESULTS

Overall, general practitioners were responsible for most treatment initiation (74% during 2000-2021) and maintenance treatment (92%). However, while hospital prescribers initiated ≈20% of treatments during 2001-2012, this increased to 35% in 2021. Similarly, hospital prescriber's share of maintenance treatment increased from 5.9% during 2000-2012 to 13% in 2021. This change was particularly pronounced for morphine initiation (48% hospital prescribers in 2021 up from 38% during 2000-2010) and oxycodone initiation (78% up from 41%). Regarding choice of opioids, codeine use dropped markedly, in particular among hospital prescribers. Tramadol was consistently the most common first choice opioid in general practice (33% in 2021), whereas its use among hospital prescribers decreased (54% during 2000-2015 to 15% in 2021). Conversely, the proportion of treatment initiation by hospital prescribers composed of morphine and oxycodone increased to 38% and 42% in 2021, respectively.

CONCLUSIONS

General practice prescribes most opioids; however, hospital prescribers are increasingly responsible for opioid prescribing, in particular initiation of morphine and oxycodone.

Initiation of glucose-lowering drugs reduces the anticoagulant effect of warfarin-But not through altered drug metabolism in patients with type 2 diabetes

AIMS

Drug metabolism might be altered in patients with type 2 diabetes. We aimed to evaluate if initiation of glucose-lowering drugs impacts warfarin efficacy and drug metabolism.

METHODS

First, we conducted a register-based self-controlled cohort study on Danish and Scottish warfarin users. Warfarin efficacy (international normalized ratio [INR]) was compared before and after initiation of glucose-lowering drugs. Second, we conducted a clinical pharmacokinetic trial comprising treatment-naïve type 2 diabetes patients. Patients ingested probe drugs for drug-metabolizing enzymes (the Basel Cocktail) before initiating glucose-lowering treatment, and after 3 and 12 weeks of treatment. Drug metabolism, glycaemic control, and inflammation were assessed on each visit.

RESULTS

In the Danish and Scottish cohorts (n = 982 and n = 44, respectively), initiating glucose-lowering drugs reduced warfarin efficacy. INR decreased from 2.47 to 2.21 in the Danish cohort (mean difference -0.26; 95% CI -0.35; -0.17) and from 2.33 to 2.13 in the Scottish cohort (-0.21; 95% CI -0.52; 0.11) after initiation of glucose-lowering treatment. This impact on INR was more pronounced among individuals with stronger effects of glucose-lowering treatment. In the clinical pharmacokinetic trial (n = 10), initiating metformin did not affect drug metabolism after 3 weeks (geometric mean ratio of CYP3A metabolic ratio: 1.12 [95% CI: 0.95; 1.32]) or 12 weeks of metformin treatment. Glycaemic control improved during treatment, while inflammation remained low and unchanged during treatment.

CONCLUSIONS

In conclusion, initiation of glucose-lowering drugs among chronic warfarin users seems associated with a reduction in INR, particularly among individuals with a large decrease in HbA_1c . This effect seems unrelated to CYP enzyme activity and warfarin drug metabolism.

Cox regression using a calendar time scale was unbiased in simulations of COVID-19 vaccine effectiveness & safety

BACKGROUND

Observational studies on corona virus disease 2019 (COVID-19) vaccines compare event rates in vaccinated and unvaccinated person time using Poisson or Cox regression. In Cox regression, the chosen time scale needs to account for the time-varying incidence of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infection and COVID-19 vaccination.We aimed to quantify bias in person-time based methods, with and without adjustment for calendar time, using simulations and empirical data analysis.

METHODS

We simulated 500,000 individuals who were followed for 365 days, and a point exposure resembling COVID-19 vaccination (cumulative incidence 80%). We generated an effectiveness outcome, emulating the incidence of severe acute respiratory syndrome corona virus 2 infection in Denmark during 2021 (risk 10%), and a safety outcome with seasonal variation (myocarditis, risk 1/5,000). Incidence rate ratios (IRRs) were set to 0.1 for effectiveness and 5.0 for safety outcomes. IRRs and hazard ratios (HRs) were estimated using Poisson and Cox regression with a time under observation scale, and a calendar time scale. Bias was defined as estimated IRR or HR-true IRR. Further, we obtained estimates for both outcomes using data from the Danish health registries.

RESULTS

Unadjusted IRRs (bias_effectivenes +0.16; bias_safety -2.09) and HRs estimated using a time-under-observation scale (+0.28;-2.15) were biased. Adjustment for calendar time reduced bias in Cox (+0.03; +0.33) and Poisson regression (0.00; -0.28). Cox regression using a calendar time scale was least biased (0.00, +0.12). When analyzing empirical data, adjusted Poisson and Cox regression using a calendar time scale yielded estimates in accordance with existing evidence.

CONCLUSION

Lack of adjustment for the time-varying incidence of COVID-19 related outcomes may severely bias estimates.

Perspectives on medication safety from vulnerable older migrants and their relatives-A qualitative explorative study

Little is known about the combined effect of several risk factors occurring simultaneously, and the perspectives of patients with language barriers or dementia are lacking because these patients are often excluded as research participants. This study aimed at investigating medication safety among older migrants with cognitive disorders who use five or more medications daily from the perspective of older patients and their relatives. Eight semi-structured interviews with patients and relatives were conducted in their homes. The study adopted an inductive hermeneutic phenomenological approach and used both "Analyzing the present" and "Systematic text condensation" as inspiration for the analysis. Three main themes were identified: (i) potential medication safety and threats, (ii) communication and missing medication information and (iii) everyday life with medication. Threats to medication safety included medication perceptions, health perceptions, and cognitive impairment of the patient as well as miscommunication among departments, wrong diagnosis and medication, and unlocked medication cabinets. However, most families expressed having no problems concerning medication, which could be a result of limited engagement of the patient and relatives in the medical treatment and limited medication information provided to the families by healthcare professionals.

Use of methotrexate and risk of skin cancer: a nationwide case-control study

BACKGROUND

Methotrexate (MTX) use has been suspected of increasing the risk of skin cancer. The aim of this investigation was to examine the association between the use of MTX and the risk of basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC) and cutaneous malignant melanoma (CMM).

METHODS

In a nationwide Danish case-control study, we identified incident, histologically verified cases of BCC (n = 131,447), cSCC (n = 18,661) or CMM (26,068) from 2004 to 2018. We matched 10 controls to each case on sex and birth year using risk-set sampling and computed crude and adjusted odds ratios (ORs) using conditional logistic regression for the use of MTX (≥2.5 g) compared with never-use.

RESULTS

Use of MTX was associated with increased risk of BCC, cSCC and CMM with adjusted ORs of (95% confidence interval) 1.29 (1.20-1.38), 1.61 (1.37-1.89) and 1.35 (1.13-1.61), respectively. For BCC and cSCC, ORs increased with higher cumulative doses. When restricting the study population to patients with psoriasis, the ORs were 1.43 (1.23-1.67), 1.18 (0.80-1.74) and 1.15 (0.77-1.72), respectively.

CONCLUSIONS

We observed an increased risk of BCC and cSCC associated with the use of MTX with evidence of a dose-response pattern; however, the association was not consistent when restricting the study population to patients with psoriasis.

Survival in adult patients with chronic primary and secondary immune thrombocytopenia: A population-based study

BACKGROUND

Few studies have investigated long-term survival in patients with primary immune thrombocytopenia (pITP). Further, changes in prognosis over the past decades and prognosis of secondary immune thrombocytopenia (sITP) are largely unstudied. Our objectives were to study comorbidity-adjusted prognostic changes and causes of death in chronic pITP and sITP patients.

STUDY DESIGN/METHODS

Using nationwide Danish health registries 1980-2016, we identified 1762 patients with chronic pITP (median age 58 (IQR, 37-73) years) and 128 with chronic sITP (median age 59 (IQR, 40-73) years). Patients were age-sex-matched to 74,781 general population comparators. Comorbidity was assessed using Charlson Comorbidity Index (CCI).

RESULTS

Overall median survival was reduced by 5.1 years (95% CI, 0.7-9.4) (p < .001) for pITP and 11.1 years (95% CI, 5.8-16.4) (p < .001) for sITP. 5-year survival increased from 69% (95% CI, 59-78) in 1980-89 to 80% (95% CI, 75-83) in 2010-16 for pITP, and decreased from 100% (95% CI, 89-98) to 64% (95% CI, 87-91) for sITP. However, numbers were small for sITP. 5-year survival for pITP with high CCI was 41% (95% CI, 32-49), and 85% (95% CI, 83-87) for low CCI. Bleeding, infection and hematological cancer were relatively frequent causes of death with adjusted subhazard ratios of 3.25 (95% CI, 2.33-4.52), 1.53 (95% CI, 1.08-2.16) and 2.16 (95% CI, 1.12-4.16) in pITP respectively, and 10.52 (95% CI, 1.43-77.36) for hematological cancer in sITP.

CONCLUSIONS

Long-term survival is reduced in chronic ITP but seems to be improving. Comorbidity and sITP are associated with a poor prognosis.

Psychotropic Medication Use and Psychiatric Disorders During the COVID-19 Pandemic Among Danish Children, Adolescents, and Young Adults

Importance

The direct and indirect implications of the COVID-19 pandemic have been associated with the mental health of children and adolescents, but it is uncertain whether these implications have been associated with changes in prescribing and diagnosis patterns.

Objective

To examine psychotropic medication use and rates of psychiatric disorders in Danish children, adolescents, and young adults during the COVID-19 pandemic.

Design, Setting, and Participants

This population-based, descriptive register-based cohort study included all Danish individuals aged 5 to 24 years from January 1, 2017, until June 30, 2022.

Main Outcomes and Measures

Rates of filled prescriptions of psychotropic medications, including antipsychotics, anxiolytics, hypnotics, sedatives, antidepressants, and psychostimulants, and all inpatient and outpatient contacts with mental and behavioral disorders. Rates of new (incident) and total (prevalent) psychotropic medication use and psychiatric diagnoses were estimated. Rate ratios (RRs) were assessed between observed and expected numbers of incident psychotropic medication use or psychiatric diagnoses from March 2020 to June 30, 2022, comparing observed numbers with expected numbers predicted from the modeled prepandemic trend.

Results

The study identified 108 840 (58 856 female individuals [54%]; median [IQR] age, 18 [14-22] years) incident psychotropic medication users. From March 2020 (first national lockdown) to June 2022, the rate of incident users of any psychotropic medication showed a relative increase of 18% (RR, 1.18; CI, 1.17-1.20) compared with expected numbers, which was primarily associated with an increase among those aged 12 to 17 years of 37% (RR, 1.37; 95% CI, 1.34-1.41). Similarly, there was an overall relative increase of incident psychiatric disorders of 5% (incidence rate, 1.05; CI, 1.04-1.07) (incident cases, 114 048 [58 708 female individuals (51%)]), which was associated with an increase in hyperkinetic disorders (RR, 1.13; CI, 1.09-1.18) and anxiety disorders (RR, 1.04; CI, 1.02-1.06). Prevalence patterns showed similar trends of an overall increase in psychotropic medication use and psychiatric disorders. One of 3 new users of an individual drug group had filled a prescription for a drug from another psychotropic medication group within the prior 6 months.

Conclusions and Relevance

The results of this cohort study suggest that Danish youths experienced an increase in rates of psychotropic treatment and psychiatric disorder diagnoses during the COVID-19 pandemic, which was most pronounced among those aged 12 to 17 years. The increase was observed for children and adolescents with and without a psychiatric history within the last 5 years.

High-dimensional propensity scores for empirical covariate selection in secondary database studies: Planning, implementation, and reporting

Real-world evidence used for regulatory, payer, and clinical decision-making requires principled epidemiology in design and analysis, applying methods to minimize confounding given the lack of randomization. One technique to deal with potential confounding is propensity score (PS) analysis, which allows for the adjustment for measured preexposure covariates. Since its first publication in 2009, the high-dimensional propensity score (hdPS) method has emerged as an approach that extends traditional PS covariate selection to include large numbers of covariates that may reduce confounding bias in the analysis of healthcare databases. hdPS is an automated, data-driven analytic approach for covariate selection that empirically identifies preexposure variables and proxies to include in the PS model. This article provides an overview of the hdPS approach and recommendations on the planning, implementation, and reporting of hdPS used for causal treatment-effect estimations in longitudinal healthcare databases. We supply a checklist with key considerations as a supportive decision tool to aid investigators in the implementation and transparent reporting of hdPS techniques, and to aid decision-makers unfamiliar with hdPS in the understanding and interpretation of studies employing this approach. This article is endorsed by the International Society for Pharmacoepidemiology.

Identifying diabetogenic drugs using real world health care databases: A Danish and Australian symmetry analysis

AIMS

Drug-induced diabetes is underreported in conventional drug safety monitoring and may contribute to the increasing incidence of type 2 diabetes. Therefore, we used routinely collected prescription data to screen all commonly used drugs for diabetogenic effects.

METHODS

Leveraging the Danish nationwide health registries, we used a case-only symmetry analysis design to evaluate all possible associations between drug initiation and subsequent diabetes. The study was conducted among individuals aged ≥40 years with a first-ever prescription for any antidiabetic drug 1996-2018 (n = 348 996). Sequence ratios (SRs) and 95% confidence intervals (CIs) were obtained for all possible drug class-diabetes combinations. A lower bound of the 95% CI >1.00 was considered a signal. Signals generated in Denmark were replicated using the Services Australia, Pharmaceutical Benefits Scheme 10% data extract.

RESULTS

Overall, 386 drug classes were investigated, of which 70 generated a signal. In total, 43 were classified as previously known based on the SIDER database or a literature review, for example, glucocorticoids (SR 1.67, 95% CI 1.62-1.72) and β-blockers (SR 1.20, 95% CI 1.16-1.23). Of 27 new signals, three drug classes yielded a signal in both the Danish and Australian data source: digitalis glycosides (SR 2.15, 95% CI 2.04-2.27, and SR 1.76, 95% CI 1.50-2.08), macrolides (SR 1.20, 95% CI 1.16-1.24, and SR 1.11, 95% CI 1.06-1.16) and inhaled β2-agonists combined with glucocorticoids (SR 1.35, 95% CI 1.28-1.42, and SR 1.14, 95% CI 1.06-1.22).

CONCLUSION

We identified 70 drug-diabetes associations, of which 27 were classified as hitherto unknown. Further studies evaluating the hypotheses generated by this work are needed, particularly for the signal for digitalis glycosides.

HARmonized Protocol Template to Enhance Reproducibility of hypothesis evaluating real-world evidence studies on treatment effects: A good practices report of a joint ISPE/ISPOR task force

PROBLEM

Ambiguity in communication of key study parameters limits the utility of real-world evidence (RWE) studies in healthcare decision-making. Clear communication about data provenance, design, analysis, and implementation is needed. This would facilitate reproducibility, replication in independent data, and assessment of potential sources of bias.

WHAT WE DID

The International Society for Pharmacoepidemiology (ISPE) and ISPOR-The Professional Society for Health Economics and Outcomes Research (ISPOR) convened a joint task force, including representation from key international stakeholders, to create a harmonized protocol template for RWE studies that evaluate a treatment effect and are intended to inform decision-making. The template builds on existing efforts to improve transparency and incorporates recent insights regarding the level of detail needed to enable RWE study reproducibility. The overarching principle was to reach for sufficient clarity regarding data, design, analysis, and implementation to achieve 3 main goals. One, to help investigators thoroughly consider, then document their choices and rationale for key study parameters that define the causal question (e.g., target estimand), two, to facilitate decision-making by enabling reviewers to readily assess potential for biases related to these choices, and three, to facilitate reproducibility.

STRATEGIES TO DISSEMINATE AND FACILITATE USE

Recognizing that the impact of this harmonized template relies on uptake, we have outlined a plan to introduce and pilot the template with key international stakeholders over the next 2 years.

CONCLUSION

The HARmonized Protocol Template to Enhance Reproducibility (HARPER) helps to create a shared understanding of intended scientific decisions through a common text, tabular and visual structure. The template provides a set of core recommendations for clear and reproducible RWE study protocols and is intended to be used as a backbone throughout the research process from developing a valid study protocol, to registration, through implementation and reporting on those implementation decisions.

Flecainide and risk of skin neoplasms: Results of a large nested case-control study in Spain and Denmark

Background: A previous study in Denmark suggested an increased melanoma risk associated with the use of flecainide. Objective: To study the association between flecainide use and the risk of melanoma and non-melanoma skin cancer in Spain and Denmark. Methods: We conducted a multi-database case-control study in (database/study period) Spain (SIDIAP/2005-2017 and BIFAP/2007-2017) and Denmark (Danish registries/2001-2018). We included incident cases of melanoma or non-melanoma skin cancer (NMSC) aged ≥18 with ≥2 years of previous data (≥10 years for Denmark) before the skin cancer and matched them to controls (10:1 by age and sex). We excluded persons with immunosuppression or previous cancer. We defined ever-use as any prescription fill and high-use as a cumulative dose of at least 200 g (reference: never-use). We categorized a cumulative dose for a dose-response assessment. We used conditional logistic regression to compute ORs (95% CI) adjusted for photosensitizing, anti-neoplastic, disease-specific drugs and comorbidities. Results: The total numbers of melanoma/NMSC cases included were 7,809/64,230 in SIDIAP, 4,661/31,063 in BIFAP, and 27,978/152,821 in Denmark. In Denmark, high-use of flecainide was associated with increased adjusted ORs of skin cancer compared with never-use [melanoma: OR 1.97 (1.38-2.81); NMSC: OR 1.34 (1.15-1.56)]. In Spain, an association between high-use of flecainide and NMSC was also observed [BIFAP: OR 1.42 (1.04-1.93); SIDIAP: OR 1.19 (0.95-1.48)]. There was a non-significant dose-response pattern for melanoma in Denmark and no apparent dose-response pattern for NMSC in any of the three databases. We found similar results for ever-use of flecainide. Conclusion: Flecainide use was associated with an increased risk of melanoma (Denmark only) and NMSC (Denmark and Spain) but without substantial evidence of dose-response patterns. Further studies are needed to assess for possible unmeasured confounders.

Chronic opioid use before and after exercise therapy and patient education among patients with knee or hip osteoarthritis

OBJECTIVE

To investigate changes in opioid use after supervised exercise therapy and patient education among knee or hip osteoarthritis patients with chronic opioid use.

METHOD

In this cohort study, we linked data from the Good Life with osteoArthritis in Denmark register (GLA:D®; standardised treatment program for osteoarthritis; January 2013 to November 2018) with national health registries. Among 35,549 patients, 1,262 were classified as chronic opioid users based on amount and temporal distribution of dispensed opioids the year before the intervention. We investigated changes in opioid use, measured as mg oral morphine equivalents (OMEQs), from the year before the intervention to the year after using generalized estimating equations.

RESULTS

We found a 10% decrease in mg OMEQs from the year before to the year after the intervention (incidence rate ratio [IRR]: 0.90, 95% confidence interval [CI]: 0.86, 0.94). Additional analyses suggested this decrease to be mainly attributable to regulatory actions targeting opioid prescribing during the study period (IRR among patients participating in the intervention before: 0.98 [95% CI: 0.89, 1.07] vs after: 0.83 [0.74, 0.93] regulatory actions). In a random general population sample of matched chronic opioid users, a similar opioid use pattern was observed over time, further supporting the impact of regulatory actions on the opioid use in the study population.

CONCLUSION

Among patients with knee or hip osteoarthritis and chronic opioid use, a standardised treatment program did not change opioid use when regulatory changes in opioid prescribing were taken into account.

Drug metabolism and drug transport of the 100 most prescribed oral drugs

Safe and effective use of drugs requires an understanding of metabolism and transport. We identified the 100 most prescribed drugs in six countries and conducted a literature search on in vitro data to assess contribution of Phase I and II enzymes and drug transporters to metabolism and transport. Eighty-nine of the 100 drugs undergo drug metabolism or are known substrates for drug transporters. Phase I enzymes are involved in metabolism of 67 drugs, while Phase II enzymes mediate metabolism of 18 drugs. CYP3A4/5 is the most important Phase I enzyme involved in metabolism of 43 drugs followed by CYP2D6 (23 drugs), CYP2C9 (23 drugs), CYP2C19 (22 drugs), CYP1A2 (14 drugs) and CYP2C8 (11 drugs). More than half of the drugs (54 drugs) are known substrates for drug transporters. P-glycoprotein (P-gp) is known to be involved in transport of 30 drugs, while breast cancer resistance protein (BCRP) facilitates transport of 11 drugs. A considerable proportion of drugs are subject to a combination of Phase I metabolism, Phase II metabolism and/or drug transport. We conclude that the majority of the most frequently prescribed drugs depend on drug metabolism or drug transport. Thus, understanding variability of drug metabolism and transport remains a priority.

Use of benzodiazepines and benzodiazepine‐related drugs in the Nordic Countries between 2000 and 2020

Use of benzodiazepines (BZ) and related drugs is subject to considerable debate due to problems with dependency and adverse events. We aimed to describe and compare their use across the Nordic countries. Data on the use of clonazepam, BZ-sedatives, BZ-hypnotics, and benzodiazepine-related drugs (BZRD) in adults (≥20 years) were obtained from nationwide registers in Denmark, Finland, Iceland, Norway, and Sweden, 2000-2020. Main measures were therapeutic intensity (TI:DDD/1000 inhabitants [inhab.]/day) and annual prevalence (users/1000 inhab./year). Overall, TI of BZ and related drugs decreased in all Nordic countries from 2004 to 2020. However, there were considerable differences between countries in TI. In 2020, the TI of BZ and related drugs ranged from 17 DDD/1000 inhab./day in Denmark to 93 DDD/1000 inhab./day in Iceland. BZRD accounted for 55-78% of BZ use in 2020, followed by BZ sedatives at 20-44%, BZ-hypnotics at <1-5%, and clonazepam at <1-2%. Annual prevalence of BZ use increased with age in all countries, and the highest annual prevalence was observed among people ≥80 years. Overall, the use of BZ and related drugs has decreased in all Nordic countries from 2004 to 2020, however, with considerable differences in their use between countries. The highest prevalence was observed among the oldest age groups-despite warnings against their use in this population.

HARmonized Protocol Template to Enhance Reproducibility of Hypothesis Evaluating Real-World Evidence Studies on Treatment Effects: A Good Practices Report of a Joint ISPE/ISPOR Task Force

OBJECTIVES

Ambiguity in communication of key study parameters limits the utility of real-world evidence (RWE) studies in healthcare decision-making. Clear communication about data provenance, design, analysis, and implementation is needed. This would facilitate reproducibility, replication in independent data, and assessment of potential sources of bias.

METHODS

The International Society for Pharmacoepidemiology (ISPE) and ISPOR-The Professional Society for Health Economics and Outcomes Research (ISPOR) convened a joint task force, including representation from key international stakeholders, to create a harmonized protocol template for RWE studies that evaluate a treatment effect and are intended to inform decision-making. The template builds on existing efforts to improve transparency and incorporates recent insights regarding the level of detail needed to enable RWE study reproducibility. The over-arching principle was to reach for sufficient clarity regarding data, design, analysis, and implementation to achieve 3 main goals. One, to help investigators thoroughly consider, then document their choices and rationale for key study parameters that define the causal question (e.g., target estimand), two, to facilitate decision-making by enabling reviewers to readily assess potential for biases related to these choices, and three, to facilitate reproducibility.

STRATEGIES TO DISSEMINATE AND FACILITATE USE

Recognizing that the impact of this harmonized template relies on uptake, we have outlined a plan to introduce and pilot the template with key international stakeholders over the next 2 years.

CONCLUSION

The HARmonized Protocol Template to Enhance Reproducibility (HARPER) helps to create a shared understanding of intended scientific decisions through a common text, tabular and visual structure. The template provides a set of core recommendations for clear and reproducible RWE study protocols and is intended to be used as a backbone throughout the research process from developing a valid study protocol, to registration, through implementation and reporting on those implementation decisions.

Core Concepts in Pharmacoepidemiology: Measures of drug utilization based on individual-level drug dispensing data

Background

Drug utilization studies are essential to facilitate rational drug use in the society.

Aim

In this review, we provide an overview of drug utilization measures that can be used with individual‐level drug dispensing data, referencing additional reading on the individual analysis. This is intended to serve as a primer for those new to drug utilization research and a shortlist from which researchers can identify useful analytical approaches when designing their drug utilization study.

Results and Discussion

We provide an overview of: (1) basic measures of drug utilization which are used to describe changes in drug use over time or compare drug use in different populations; (2) treatment adherence measures with specific focus on persistence and implementation; (3) how to measure drug combinations which is useful when assessing drug–drug interactions, concomitant treatment, and polypharmacy; (4) prescribing quality indicators and measures to assess variations in drug use which are useful tools to assess appropriate use of drugs; (5) proxies of prescription drug misuse and skewness in drug use; and (6) considerations when describing the characteristics of drug users or prescribers.

Changing characteristics over time of individuals receiving COVID-19 vaccines in Denmark: A population-based descriptive study of vaccine uptake

AIMS

The Danish authorities implemented a differential rollout of the COVID-19 vaccines where individuals at high risk of COVID-19 were prioritized. We describe the temporal uptake and characteristics of COVID-19 vaccine recipients in Denmark.

METHODS

Using nationwide healthcare registries, we identified all Danish residents ⩾5 years of age who received at least one dose of a COVID-19 vaccine from 27 December 2020-29 January 2022. We charted the daily number of newly vaccinated individuals and the cumulative vaccine coverage over time, stratified by vaccine type, age groups and vaccination priority groups, and described characteristics of vaccine recipients during two-month-intervals and in vaccination priority groups.

RESULTS

By 29 January 2022, 88%, 86% and 64% of Danish residents ⩾5 years (n=5,562,008) had received a first, second and third dose, respectively, of a COVID-19 vaccine, most commonly the BNT162b2 vaccine (84%). Uptake ranged from 48% in 5-11-year-olds to 98% in 65-74-year-olds. Individuals vaccinated before June 2021 were older (median age 61-70 years vs 10-35 years in later periods) and had more comorbidities such as hypertension (22-28% vs 0.77-2.8% in later periods), chronic lung disease (9.4-15% vs 3.7-4.6% in later periods) and diabetes (9.3-12% vs 0.91-2.4% in later periods).

CONCLUSIONS

We document substantial changes over time in, for example, age, sex and medical history of COVID-19 vaccine recipients. Though these results are related to the differential vaccine rollout in Denmark, similar findings are probable in other countries and should be considered when designing and interpreting studies on the effectiveness and safety of COVID-19 vaccines.

[Deprescribing in Danish clinical treatment guidelines]

Lack of clinical guidance constitutes a significant barrier to deprescribing. Within Danish clinical guidelines on treatment of dementia, type 2 diabetes, hypertension, and osteoporosis, only limited attention was given to deprescribing. For dementia, type 2 diabetes, and osteoporosis, guidance was primarily focused on when to consider and implement deprescribing, with limited practical guidance on how to deprescribe. No guidance for deprescribing antihypertensives was identified. This highlights a need to consider deprescribing more broadly when developing and updating clinical guidelines, as argued in this review.

Trends and predictors of specialist assessments in oral corticosteroid treated asthma among young adults

Background

Repeated oral corticosteroid use indicates uncontrolled disease among asthma patients and referral for asthma specialist assessment is recommended. We aimed to describe trends and predictors associated with specialist contacts among young adults with asthma and repeated oral corticosteroid use.

Methods

Individuals aged 18–45 years with ≥2 dispensed asthma medication prescriptions and two dispended oral corticosteroid prescriptions (including short-term and long-term treatments) within 12 months during 1999–2018 were identified by use of Danish healthcare registers. The frequency of specialist contacts within 1 year of follow-up was assessed among individuals without previous specialist contacts within 5 years of inclusion. Factors associated with specialist contact were identified by logistic regression models. Furthermore, oral corticosteroid prescriber sources were assessed.

Results

For the 11 223 individuals included, 2444 (22%) had previous specialist contacts care within 5 years prior of inclusion and additionally 926 (8.3%) within 1 year of follow-up. Among those without previous specialist contacts (n 8779), the frequency of incident specialist contacts within 1 year of follow-up increased from 6.3% in 1999 to 18% in 2017. Factors associated with incident specialist contacts included dispensing ≥12 SABA canisters and previous asthma-related emergency department visits and hospitalisations. The majority of oral corticosteroid prescriptions at baseline (71%) were prescribed by general practitioners, though with decreasing proportions from 1999–2018.

Conclusions

The majority (70%) of young adults with asthma and repeated oral corticosteroid use do not seem to receive specialist assessment in Denmark. This highlights a potential room for improvement in the patient referral pathway for at-risk asthma patients.

Prescription rates for drugs used in treatment of benign prostatic hyperplasia and erectile dysfunction before and after prostate cancer diagnosis

BACKGROUND

Symptoms and treatment of benign prostatic hyperplasia (BPH) or erectile dysfunction (ED) may lead to prostate cancer workup, and patterns of prescriptions before diagnosis may affect findings of pharmacoepidemiological studies. Usage of BPH and ED drugs after diagnosis may be related to prostate cancer treatment. We investigated differences in prescription rates of BPH and ED drugs among prostate cancer patients and cancer-free comparisons and between patients with localized and non-localized disease.

MATERIAL AND METHODS

A nationwide register-based study, including all Danish men aged 50-85 years diagnosed with prostate cancer during 1998-2015 and an age-matched comparison cohort without cancer. We calculated rates of new and total prescriptions in 1-month intervals from 3 years before to 3 years after cancer diagnosis for drugs used to treat BPH and ED, overall and stratified by clinical stage.

RESULTS

We identified 54,286 men with prostate cancer and a comparison cohort of 249,645 age-matched men. The new prescription rate for BPH drugs increased for men with prostate cancer in the year before diagnosis and peaked 1 month before diagnosis with an 18-fold higher rate. Men with prostate cancer had a higher total prescription rate of BPH drugs 3 years before diagnosis, notably among men with localized disease. Before diagnosis, the new prescription rates for ED drugs were similar among men with prostate cancer and comparisons. After diagnosis, men with prostate cancer had a 7-fold higher rate of new prescriptions for ED drugs. Among men with localized disease, the total prescription rate of ED drugs increased in the months following diagnosis.

CONCLUSION

Differences in prescription rates suggest increased prostate cancer surveillance among men receiving BPH drugs, whereas the post-diagnostic increase in ED drugs among men with localized disease is compatible with the increased risk of ED following prostate cancer treatment.

Use of hypnotic drugs among Scandinavian children, adolescents, and young adults

Introduction

Hypnotic drug use in children and adolescents is widely debated.

Objectives

To describe use of hypnotic drugs (melatonin, z-drugs and sedating antihistamines) among 5-24-year-old Scandinavians during 2012 to 2018.

Methods

Aggregate-level data from public data sources in Sweden, Norway and Denmark. We calculated annual prevalence (users/1000 inhabitants) stratified by sex, age group and country. Quantity of use (Defined Daily Dose (DDD)/user/day) was estimated for Norway and Denmark.

Results

Melatonin was most frequently used, with an increase from 2012 to 2018 in all countries. Sweden presented the highest rise (7 to 25/1,000) compared to Denmark (6 to 12/1,000) and Norway (10 to 20/1,000). The increase was strongest for females and 15-24-year-olds. Melatonin use was twice as common for males under age 15 years, and slightly more common for females thereafter. The annual prevalence of sedating antihistamine use doubled from 7 to 13/1,000 in Sweden, whereas it was more stable in Norway and Denmark, reaching 8/1,000 and 3/1,000, respectively. Z-drug use decreased in all countries, lowering to 4/1,000 in Sweden and Norway in 2018 and 2/1,000 in Denmark. The quantity of hypnotic use in Norway and Denmark was 1 DDD/user/day for melatonin, as compared to 0.1-0.3 for z-drugs and antihistamines.

Conclusions

There is an increasing use of melatonin and sedating antihistamines among Scandinavian children, adolescents and young adults. The increase is more pronounced in Sweden compared to Norway and Denmark. This Scandinavian discrepancy could reflect variation in frequency of sleep problems or national variation in clinical practice or health care access.

Disclosure

No significant relationships.

Identification of Drug-Cancer Associations: A Nationwide Screening Study

The main tool in drug safety monitoring, spontaneous reporting of adverse effects, is unlikely to detect delayed adverse drug effects including cancer. Hypothesis-free screening studies based on administrative data could improve ongoing drug safety monitoring. Using Danish health registries, we conducted a series of case-control studies by identifying individuals with incident cancer in Denmark from 2001 to 2018, matching each case with 10 population controls on age, sex, and calendar time. ORs were estimated using conditional logistic regression accounting for matching factors, educational level, and selected comorbidities. A total of 13,577 drug-cancer associations were examined for individual drugs and 8,996 for drug classes. We reviewed 274 drug-cancer pairs where an association with high use and a cumulative dose-response pattern was present. We classified 65 associations as not readily attributable to bias of which 20 were established as carcinogens by the International Agency for Research on Cancer and the remaining 45 associations may warrant further study. The screening program identified drugs with known carcinogenic effects and highlighted a number of drugs that were not established as carcinogens and warrant further study. The effect estimates in this study should be interpreted cautiously and will need confirmation targeted epidemiologic and translational studies.

Significance

This study provides a screening tool for drug carcinogenicity aimed at hypothesis generation and explorative purposes. As such, the study may help to identify drugs with unknown carcinogenic effects and, ultimately, improve drug safety as part of the ongoing safety monitoring of drugs.

Risk of Appendicitis After mRNA COVID-19 Vaccination in a Danish Population

This cohort study used data from Danish registers to assess whether recipients of mRNA COVID-19 vaccines had a higher risk of appendicitis after receiving the shot compared with individuals who did not receive the vaccine.

Core Concepts in Pharmacoepidemiology: Fundamentals of the cohort and case-control study designs

In this review paper, I outline the principles of the cohort as a sampling frame and provide a basic introduction to the cohort study design and the case–control study design, two of the most important designs in the pharmacoepidemiologist's toolbox. Further, I discuss when to prefer one design over the other. The paper is intended as a primer for people new to the field of pharmacoepidemiology and contains a range of suggestions for additional reading regarding the study designs and related epidemiological topics.

Who prescribes quetiapine in Denmark?

The second‐generation antipsychotic quetiapine is commonly used off‐label for its anxiolytic and hypnotic properties. However, quetiapine is associated with problematic side‐effects. We used Danish Medicinal Product Statistics and a 20% random sample of the Danish population's prescription fills (2001–2020) to describe the utilization of quetiapine and proportion of various prescriber types (general practitioner [GP], specialist in private practice, hospital physician and other prescribers) both in connection to first‐time and subsequent prescriptions. In 2020, 92% of all quetiapine was dispensed outside hospitals and the average daily dispensed quantity of quetiapine per user corresponded to 100 mg/user/d. A GP issued 53% of first‐time prescriptions and 75% of subsequent prescriptions for quetiapine in 2020. The proportion of quetiapine prescriptions issued by GPs varied by age group—from 14% among 0–17‐year‐olds to 93% among the ≥80‐year‐olds. Future initiatives on the rational use of quetiapine and related drugs, especially among adults, should target GPs.