Screening of dermatology drugs for aberrant use-patterns: An application of epidemiologic estimates and measures of inequality in drug use.

AIMS: Dermatology treatments require adherence for safe and effective use. Real-world healthcare databases can reveal drug utilization patterns and uncover inappropriate or unexpected use. This study aimed to analyse dermatology drug utilization patterns using epidemiological and inequality measures, leveraging Danish nationwide registries. It also assessed the feasibility of this method for detecting aberrant drug use. METHODS: We formed a 2019 cohort of all patients treated for skin conditions through Danish healthcare registries. We calculated prevalence, incidence rates and treatment duration for dermatological drugs. Inequality in drug utilization was assessed using Lorenz curves, Gini coefficients and other measures. RESULTS: The study encompassed 1 021 255 patients using 94 dermatology drugs. Most usage aligned with 'expected clinical use', but we detected inequality, with some drugs having high Gini coefficients and disproportionate consumption by the top percentile of users. Notable findings included potential inappropriate antibiotic use, excessive topical corticosteroid use and unexpected drug use duration. CONCLUSIONS: In Denmark, dermatology drugs are used primarily as anticipated, with minimal unexpected patterns. Specific follow-up is required to draw conclusions about inappropriate use. This approach demonstrates broad applicability for screening aberrant drug utilization.

Risk and timing of postpartum depression in parents of twins compared to parents of singletons.

BACKGROUND: Parents of twins appear to be at increased risk of postpartum depression (PPD), yet little is known about the magnitude and timing of onset in the postpartum period compared to singleton parents. METHODS: We conducted a cohort study using the Danish nationwide health registers. We defined a study population of parents that is, mothers and fathers of all twin and singleton livebirths between 1997 and 2019. Postpartum depression was defined as incident depression diagnosis or a redeemed antidepressant prescription from childbirth through 365 days postpartum. We performed a parametric time-to-event analysis based on Poisson regression. The time scale was time since birth, modeled using restricted cubic splines. From this we estimated the hazard ratio (HR) representing the momentary risk, and the cumulative risk ratio (RR) over the first year postpartum, in twin compared to singleton parents. RESULTS: The study population was based on 27,095 twin and 1,350,046 singleton births. In adjusted analyses, the HR of twins compared to singletons was highest around 2 months postpartum (HR 1.28, 95% CI 1.10-1.49) for mothers, and around 6 months (1.20, 95% CI 1.02-1.42) for fathers. The 6 months adjusted cumulative RR of PPD in twins compared to singletons was 1.24 (95% CI 1.10-1.40) for mothers and 1.11 (95% CI 0.95-1.30) for fathers. CONCLUSIONS: Twin mothers had increased risk of PPD compared to singleton mothers, which was driven by an immediate increase after childbirth. The risk among twin fathers was not increased immediately after childbirth, but we found slightly elevated risk around 6 months postpartum. This could suggest diverse patterns of PPD symptomatology in twin parents compared to singleton parents and between mothers and fathers. Our findings underline parents of twins as a potentially vulnerable group to PPD and emphasize the need for increased awareness of their mental health.

A case for screening real-world data for collateral drug benefits: Glucagon-like peptide 1 receptor agonists and bile acid diarrhea.

PURPOSE: Collateral drug benefits are hitherto unknown beneficial effects that might lead to repurposing of already marketed drugs. A randomized controlled trial has found liraglutide to be non-inferior to colesevelam in reducing bile acid diarrhea. We hypothesized that this collateral drug benefit of liraglutide could have been detected using observational data. METHODS: We performed a sequence symmetry analysis (SSA). In the SSA, we indexed individuals on the date of the first prescription of GLP1-RA and restricted the analysis to all individuals who had a first prescription of bile acid sequestrants between 365 days prior to until 365 days after the index date. Sequence ratios (SR), that is, the ratio between counts of persons initiating GLP1-RA first versus last, were calculated, and 95% confidence intervals were obtained. We adjusted for prescribing trends using null-effect SR adjustment. RESULTS: We included 158 individuals, with a median age of 58 years. The trend-adjusted SR was 0.96 (95% confidence interval 0.70-1.31). When stratifying on the type of GLP1-RA (liraglutide or semaglutide), we found results compatible with the previous trial (SRliraglutide 0.75, 0.51-1.10 and SRsemagltuide 1.23, 0.80-1.89). Since BAS also can be used as a cholesterol lowering drug, we repeated the main analysis while excluded statin users, resulting in a stronger association (SR 0.56, 0.33-0.96). CONCLUSION: Using the SSA methodology, we obtained estimates of a collateral drug benefit that were compatible with trial results. These results support the use of epidemiological analyses of observational data as instrument for detecting collateral drug benefits.

Application of the waiting time distribution in a nationwide screening of real-world dermatology drug utilization for aberrant use patterns.

BACKGROUND: Inappropriate use of medicines may have critical consequences from individual, public health, and economic perspectives. Discovering wrongful medicine use may require intentional surveillance or screening. OBJECTIVES: The objectives of this study were to: (i) apply and evaluate the waiting time distribution (WTD) method as a screening tool for identifying aberrant drug use and (ii) evaluate the nationwide use of Dermatology drugs in Denmark for signals of aberrant drug use. METHOD: Dermatology drug use data from the Danish nationwide healthcare registries from 2018 to 2020 were used to produce WTDs that were analyzed for drug use patterns. The method provides estimates of the prevalence and incidence and enables estimation of mean treatment duration, drug relapse, and unexpected drug prescribing. RESULTS: The study included 2 027 889 individual drug users and analyzed 6 141 449 prescriptions. The analysis included approximately 100 dermatology drugs and drug categories and produced 56 WTD drug curves. The WTD patterns and epidemiological estimates confirmed that most drugs are used as intended and revealed few unexpected patterns for further investigation. Three unexpected findings were identified concerning (i) short-term use that would entail suboptimal clinical efficiency for minoxidil, (ii) sub-optimal use of topical tacrolimus, and (iii) potential undesirable increase in short-course doxycycline treatments. CONCLUSION: In Denmark, dermatology drugs are predominantly used as expected, with few unexpected use patterns identified. Targeted specific follow-up on the identified signals is necessary for conclusions about inappropriate use. The findings suggest that the WTD method is applicable for screening for aberrant drug use.

Is the sequence ratio an unbiased estimate of the incidence rate ratio? A simulation study.

PURPOSE: We aimed to evaluate the conditions under which the sequence ratio (SR) obtained from a sequence symmetry analysis is an unbiased estimate of the true incidence rate ratio (IRR). METHODS: We simulated cohorts of 1 million individuals who could initiate an exposure drug and experience a very rare, rare, common, or frequent outcome of interest. The outcome rate among exposed individuals was modified by a true incidence rate ratio of 0.2, 0.5, 1.0, 2.0, and 5.0. We further evaluated scenarios where the outcome was fatal and led to immediate censoring or the outcome reduced the rate of initiation of the exposure drug. RESULTS: We found the SR to be close to unbiased for rare, common, and frequent events, except when the true IRR was 5.0 (mean SR 4.94 and 3.74 for common and frequent events). The SR was slightly biased when the outcome was very rare. When the outcome was potentially fatal, the SR was increasingly biased with an increasing probability of death. Likewise, when the outcome reduced the probability of future exposure, the SR was upwards biased. CONCLUSION: The SR is a biased estimate of the incidence rate ratio, when the true IRR is high, the outcome has a high mortality, or when the outcome reduces the probability of future exposure.

Mortality and clinical outcomes following SARS-CoV-2 infection among individuals with haematological malignancies: A Danish population-based cohort study.

OBJECTIVES: We aimed to quantify the risk of death following a positive test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among individuals with haematological malignancies, stratified by virus variants and type of malignancy. METHODS: Using the Danish nationwide registries, we conducted a population-based cohort study among individuals who received a discharge diagnosis of haematological malignancies during the 5 years prior to testing positive for SARS-CoV-2 (February 2020-April 2023). All individuals were followed for 30 days after a positive test, and overall and time-stratified case fatality risks (CFR) were estimated. RESULTS: We identified 7154 individuals with a history of haematological malignancies who tested positive for SARS-CoV-2. Among these, we observed 223 deaths, yielding a CFR of 3.1%. The CFR was highest at the beginning of the pandemic (10%) and gradually declined to 1.9% during the period of Omicron BA1/BA2 predominance. The highest CFR was observed among individuals with acute leukaemia (CFR 6.2%, adjusted relative risk 1.95, 95% confidence interval 1.33-2.88) compared to individuals with lymphoma (CFR 3%). CONCLUSIONS: We observed a reduction in the CFR over time, which may be attributed to new treatments, COVID-19 vaccination and the emergence of less aggressive variants.

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 ß-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 ß2-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.

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.

Venous Thromboembolism and Major Bleeding in Patients With Coronavirus Disease 2019 (COVID-19): A Nationwide, Population-Based Cohort Study.

BACKGROUND: Venous thromboembolism (VTE) is a potentially fatal complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and thromboprophylaxis should be balanced against risk of bleeding. This study examined risks of VTE and major bleeding in hospitalized and community-managed SARS-CoV-2 patients compared with control populations. METHODS: Using nationwide population-based registries, 30-day risks of VTE and major bleeding in SARS-CoV-2 positive patients were compared with those of SARS-CoV-2 test-negative patients and with an external cohort of influenza patients. Medical records of all COVID-19 patients at 6 departments of infectious diseases in Denmark were reviewed in detail. RESULTS: The overall 30-day risk of VTE was 0.4% (40/9460) among SARS-CoV-2 patients (16% hospitalized), 0.3% (649/226 510) among SARS-CoV-2 negative subjects (12% hospitalized), and 1.0% (158/16 281) among influenza patients (59% hospitalized). VTE risks were higher and comparable in hospitalized SARS-CoV-2 positive (1.5%), SARS-CoV-2 negative (1.8%), and influenza patients (1.5%). Diagnosis of major bleeding was registered in 0.5% (47/9460) of all SARS-CoV-2 positive individuals and in 2.3% of those hospitalized. Medical record review of 582 hospitalized SARS-CoV-2 patients observed VTE in 4% (19/450) and major bleeding in 0.4% (2/450) of ward patients, of whom 31% received thromboprophylaxis. Among intensive care patients (100% received thromboprophylaxis), risks were 7% (9/132) for VTE and 11% (15/132) for major bleeding. CONCLUSIONS: Among people with SARS-CoV-2 infection in a population-based setting, VTE risks were low to moderate and were not substantially increased compared with SARS-CoV-2 test-negative and influenza patients. Risk of severe bleeding was low for ward patients, but mirrored VTE risk in the intensive care setting.

SARS-CoV-2 infection and adverse outcomes in users of ACE inhibitors and angiotensin-receptor blockers: a nationwide case-control and cohort analysis.

OBJECTIVE: To examine the impact of ACE inhibitor (ACE-I)/angiotensin receptor blocker (ARB) use on rate of SARS-CoV-2 infection and adverse outcomes. METHODS: This nationwide case-control and cohort study included all individuals in Denmark tested for SARS-CoV-2 RNA with PCR from 27 February 2020 to 26 July 2020. We estimated confounder-adjusted ORs for a positive test among all SARS-CoV-2 tested, and inverse probability of treatment weighted 30-day risk and risk ratios (RRs) of hospitalisation, intensive care unit (ICU) admission and mortality comparing current ACE-I/ARB use with calcium channel blocker (CCB) use and with non-use. RESULTS: The study included 13 501 SARS-CoV-2 PCR-positive and 1 088 695 PCR-negative individuals. Users of ACE-I/ARB had a marginally increased rate of a positive PCR when compared with CCB users (aOR 1.17, 95% CI 1.00 to 1.37), but not when compared with non-users (aOR 1.00 95% CI 0.92 to 1.09).Among PCR-positive individuals, 1466 (11%) were ACE-I/ARB users. The weighted risk of hospitalisation was 36.5% in ACE-I/ARB users and 43.3% in CCB users (RR 0.84, 95% CI 0.70 to 1.02). The risk of ICU admission was 6.3% in ACE-I/ARB users and 5.4% in CCB users (RR 1.17, 95% CI 0.64 to 2.16), while the 30-day mortality was 12.3% in ACE-I/ARB users and 13.9% in CCB users (RR 0.89, 95% CI 0.61 to 1.30). The associations were similar when ACE-I/ARB users were compared with non-users. CONCLUSIONS: ACE-I/ARB use was associated neither with a consistently increased rate nor with adverse outcomes of SARS-CoV-2 infection. Our findings support the current recommendation of continuing use of ACE-Is/ARBs during the SARS-CoV-2 pandemic. TRIAL REGISTRATION NUMBER: EUPAS34887.

Use of dipeptidyl peptidase-4 inhibitors and risk of splanchnic vein thrombosis: A Danish nationwide new-user active comparator cohort study.

Use of dipeptidyl peptidase-4 (DPP-4) inhibitors, on the basis of spontaneous adverse event reports, has recently been suspected of causing splanchnic vein thrombosis. Here, we report the results of a population-based new-user active comparator cohort study addressing this hypothesis, comparing DPP-4 inhibitor initiators (n = 75 042) with initiators of glucagon-like-peptide-1 receptor agonists (GLP-1RAs) or sodium-glucose co-transporter-2 (SGLT2) inhibitors (n = 38 718). We estimated the hazard ratio (HR) associating DPP-4 inhibitor use with risk of splanchnic vein thrombosis using Cox regression. In a crude analysis, the incidence rate of splanchnic vein thrombosis was 0.22/1000 person-years among DPP-4 inhibitor initiators, compared to 0.17 among GLP-1RA/SGLT2 inhibitor initiators, corresponding to an unadjusted absolute incidence rate difference of 0.05 (95% confidence interval [CI] -0.04 to 0.14) and an HR of 1.29 (95% CI 0.78 to 2.15). Adjusting for potential confounders using stabilized inverse probability of treatment weighing, we obtained an absolute incidence rate difference of 0.03/1000 person-years (95% CI -0.07 to 0.14) and an HR of 1.18 (95% CI 0.62 to 2.26). No evidence of increased risk of splanchnic vein thrombosis was found in supplementary analyses, including an absence of any dose-response patterns. As such, we found no association between DPP-4 inhibitor use and splanchnic vein thrombosis risk.

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.

Adverse outcomes and mortality in users of non-steroidal anti-inflammatory drugs who tested positive for SARS-CoV-2: A Danish nationwide cohort study.

BACKGROUND: Concerns over the safety of non-steroidal anti-inflammatory drug (NSAID) use during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been raised. We studied whether use of NSAIDs was associated with adverse outcomes and mortality during SARS-CoV-2 infection. METHODS AND FINDINGS: We conducted a population-based cohort study using Danish administrative and health registries. We included individuals who tested positive for SARS-CoV-2 during the period 27 February 2020 to 29 April 2020. NSAID users (defined as individuals having filled a prescription for NSAIDs up to 30 days before the SARS-CoV-2 test) were matched to up to 4 non-users on calendar week of the test date and propensity scores based on age, sex, relevant comorbidities, and use of selected prescription drugs. The main outcome was 30-day mortality, and NSAID users were compared to non-users using risk ratios (RRs) and risk differences (RDs). Secondary outcomes included hospitalization, intensive care unit (ICU) admission, mechanical ventilation, and acute renal replacement therapy. A total of 9,236 SARS-CoV-2 PCR-positive individuals were eligible for inclusion. The median age in the study cohort was 50 years, and 58% were female. Of these, 248 (2.7%) had filled a prescription for NSAIDs, and 535 (5.8%) died within 30 days. In the matched analyses, treatment with NSAIDs was not associated with 30-day mortality (RR 1.02, 95% CI 0.57 to 1.82, p = 0.95; RD 0.1%, 95% CI -3.5% to 3.7%, p = 0.95), risk of hospitalization (RR 1.16, 95% CI 0.87 to 1.53, p = 0.31; RD 3.3%, 95% CI -3.4% to 10%, p = 0.33), ICU admission (RR 1.04, 95% CI 0.54 to 2.02, p = 0.90; RD 0.2%, 95% CI -3.0% to 3.4%, p = 0.90), mechanical ventilation (RR 1.14, 95% CI 0.56 to 2.30, p = 0.72; RD 0.5%, 95% CI -2.5% to 3.6%, p = 0.73), or renal replacement therapy (RR 0.86, 95% CI 0.24 to 3.09, p = 0.81; RD -0.2%, 95% CI -2.0% to 1.6%, p = 0.81). The main limitations of the study are possible exposure misclassification, as not all individuals who fill an NSAID prescription use the drug continuously, and possible residual confounding by indication, as NSAIDs may generally be prescribed to healthier individuals due to their side effects, but on the other hand may also be prescribed for early symptoms of severe COVID-19. CONCLUSIONS: Use of NSAIDs was not associated with 30-day mortality, hospitalization, ICU admission, mechanical ventilation, or renal replacement therapy in Danish individuals who tested positive for SARS-CoV-2. TRIAL REGISTRATION: The European Union electronic Register of Post-Authorisation Studies EUPAS34734.

Selective serotonin reuptake inhibitors and the risk of restless legs syndrome: a symmetry analysis.

PURPOSE: Largely based on case series, several drugs have been implicated in drug-induced restless legs syndrome (RLS) including selective serotonin reuptake inhibitors (SSRI). We aimed to assess the association between initiation of SSRIs and RLS in a self-controlled design. METHODS: We conducted a symmetry analysis, including Danish adults who filled in their first prescription of an SSRI in the period of 1997-2017 and initiated an RLS drug (quinine, ropinirole, pramipexole or rotigotine) 1 year prior to or after this date. A symmetrical distribution of prescriptions before and after SSRI initiation is expected if there is no association between SSRI and RLS (a sequence ratio (SR) of 1.0). The symmetry analysis design is robust to confounders that are stable over time. Subgroup analyses were conducted, restricting the population on sex, age, selected diagnoses and concurrent medication. RESULTS: A total of 10,875 patients filled in their first-ever prescription of both an SSRI and an RLS drug within a 1-year interval; 5341 patients filled their prescription of SSRI prior to their prescription of an RLS drug, and 5534 patients redeemed their prescriptions in the opposite order (SR 0.97, 95% CI 0.93-1.00). Restricting the outcome to dopamine agonist initiation revealed a slightly increased sequence ratio (SR 1.34, 95% CI 1.24-1.46), which was reduced when adjusting for trends in prescription (adjusted SR 1.21, 95% CI 1.12-1.32). Restricting the outcome to quinine initiation showed no association. CONCLUSION: We found no association between the initiation of an SSRI and the development of RLS assessed by the prescription of an RLS drug.