Estrogen-modulating treatment among mid-life women and COVID-19 morbidity and mortality: a multiregister nationwide matched cohort study in Sweden.

BACKGROUND: It has been repeatedly shown that men infected by SARS-CoV-2 face a twofold higher likelihood of dying, being hospitalized or admitted to the intensive care unit compared to women, despite taking into account relevant confounders. It has been hypothesized that these discrepancies are related to sex steroid hormone differences with estrogens being negatively correlated with disease severity. The objective of this study was therefore to evaluate COVID-19-related mortality and morbidity among peri- and postmenopausal women in relation to estrogen-containing menopause hormonal treatments (MHT). METHODS: This is a national register-based matched cohort study performed in Sweden between January 1 to December 31, 2020. Study participants comprised women over the age of 53 years residing in Sweden. Exposure was defined as prescriptions of local estrogens, systemic estrogens with and without progestogens, progestogens alone, or tibolone. MHT users were then compared with a matched cohort of non-users. The primary outcome consisted of COVID-19 mortality, whereas the secondary outcomes included inpatient hospitalizations/outpatient visits and confirmed SARS-CoV-2 infection. Multivariable adjusted Cox regression-derived hazard ratios (HRs) were calculated. RESULTS: Use of systemic estrogens alone is associated with increased COVID-19 mortality among older women (aHR 4.73, 1.22 to 18.32), but the association is no longer significant when discontinuation of estrogen use is accounted for. An increased risk for COVID-19 infection is further observed for women using combined systemic estrogens and progestogens (aHR 1.06, 1.00 to 1.13) or tibolone (aHR 1.21, 1.01 to 1.45). Use of local estrogens is associated with an increased risk for COVID-19-related death (aHR 2.02,1.45 to 2.81) as well as for all secondary outcomes. CONCLUSIONS: Systemic or local use of estrogens does not decrease COVID-19 morbidity and mortality to premenopausal background levels. Excess risk for COVID-19 morbidity and mortality was noted among older women and those discontinuing systemic estrogens. Higher risk for death was also noted among women using local estrogens, for which non-causal mechanisms such as confounding by comorbidity or frailty seem to be the most plausible underlying explanations. TRIAL REGISTRATION DETAILS: Not applicable.

Consistency between the National Patient Register and the Swedish Cancer Register.

PURPOSE: The Swedish National Patient Register (NPR) is widely used as a data source in epidemiological studies, but the consistency of all cancer diagnoses compared to the Swedish Cancer Register (SCR) remains unclear. Using NPR supplementary for detecting safety signals is beneficial due to shorter data extraction delays compared to using SCR alone. This study aims to evaluate the consistency of NPR for cancer diagnoses compared to SCR and its potential use in pharmacoepidemiology. METHODS: Patients with a cancer diagnosis recorded in SCR during 2018-2020 were included. To measure the consistency of NPR diagnoses with SCR as the gold standard, positive predictive value (PPV), and sensitivity were calculated. As an empirical example showing differences in identification of cancer diagnoses in NPR and SCR, two nested case-control studies for the association between antidiabetic medications and pancreatic cancer were repeated using the two registers. Conditional logistic regression was performed and the 95% confidence intervals (CIs) for the odds ratios (ORs) were checked for overlaps. RESULTS: For breast, male genital organs, and oral cancers consistency was high (PPV: 87.5%-97.4%, sensitivity: 82.2%-91.0%), while for female genital organs, thyroid, and ill-defined, secondary, and unspecified sites cancers it was low (PPV: 8.8%-90.0%, sensitivity: 19.9%-32.3%). All the CIs for the ORs from the nested case-control studies overlapped when pancreatic cancer was identified in NPR or SCR. CONCLUSION: Consistency of cancer diagnoses in NPR when compared to SCR depends on cancer type with higher consistency for some cancers and lower for others. Differences in diagnostic processes for different cancer types and coding of cancer in the two registers may explain part of the inconsistent results.

Lessons learned from a multi-data source research collaboration: The mirabegron post-authorization safety study program.

BACKGROUND: Many factors contribute to developing and conducting a successful multi-data source, non-interventional, post-authorization safety study (NI-PASS) for submission to multiple health authorities. Such studies are often large undertakings; evaluating and sharing lessons learned can provide useful insights to others considering similar studies. OBJECTIVES: We discuss challenges and key methodological and organizational factors that led to the delivery of a successful post-marketing requirement (PMR)/PASS program investigating the risk of cardiovascular and cancer events among users of mirabegron, an oral medication for the treatment of overactive bladder. RESULTS: We provide context and share learnings, including sections on research program collaboration, scientific transparency, organizational approach, mitigation of uncertainty around potential delays, validity of study outcomes, selection of data sources and optimizing patient numbers, choice of comparator groups and enhancing precision of estimates of associations, potential confounding and generalizability of study findings, and interpretation of results. CONCLUSIONS: This large PMR/PASS program was a long-term commitment from all parties and benefited from an effective coordinating center and extensive scientific interactions across research partners, scientific advisory board, study sponsor, and health authorities, and delivered useful learnings related to the design and organization of multi-data source NI-PASS.

Comparison of rivaroxaban and low molecular weight heparin in the treatment of cancer-associated venous thromboembolism: a Swedish national population-based register study.

BACKGROUND: Treating cancer-associated venous thromboembolism (CAT) with anticoagulation prevents recurrent venous thromboembolism (rVTE), but increases bleeding risk. OBJECTIVES: To compare incidence of rVTE, major bleeding, and all-cause mortality for rivaroxaban versus low molecular weight heparin (LMWH) in patients with CAT. METHODS: We developed a cohort study using Swedish national registers 2013-2019. Patients with CAT (venous thromboembolism within 6 months of cancer diagnosis) were included. Those with other indications or with high bleeding risk cancers were excluded (according to guidelines). Follow-up was from index-CAT until outcome, death, emigration, or end of study. Incidence rates (IR) per 1000 person-years with 95% confidence interval (CI) and propensity score overlap-weighted hazard ratios (HRs) for rivaroxaban versus LMWH were estimated. RESULTS: We included 283 patients on rivaroxaban and 5181 on LMWH. The IR for rVTE was 68.7 (95% CI 40.0-109.9) for rivaroxaban, compared with 91.6 (95% CI 81.9-102.0) for LMWH, with adjusted HR 0.77 (95% CI 0.43-1.35). The IR for major bleeding was 23.5 (95% CI 8.6-51.1) for rivaroxaban versus 49.2 (95% CI 42.3-56.9) for LMWH, with adjusted HR 0.62 (95% CI 0.26-1.49). The IR for all-cause mortality was 146.8 (95% CI 103.9-201.5) for rivaroxaban and 565.6 (95% CI 541.8-590.2) for LMWH with adjusted HR 0.48 (95% CI 0.34-0.67). CONCLUSIONS: Rivaroxaban performed similarly to LMWH for patients with CAT for rVTE and major bleeding. An all-cause mortality benefit was observed for rivaroxaban which potentially may be attributed to residual confounding. TRIAL REGISTRATION NUMBER: NCT05150938 (Registered 9 December 2021).

Bleeding events among patients concomitantly treated with direct oral anticoagulants and macrolide or fluoroquinolone antibiotics.

Fluoroquinolones and macrolides may, due to a potential drug-drug interaction, increase the concentration of any concomitantly administered direct oral anticoagulant (DOAC) and thereby increase the risk of severe bleeding. However, clinical evidence for such an effect is scarce. The present study aimed to evaluate the association between the use of fluoroquinolones or macrolides and bleeding events in patients with concomitant DOAC use. This was a nationwide cohort study including 19 288 users of DOACs in 2008-2018 using information from Swedish national health registers. We compared the incidence of bleeding events associated with use of fluoroquinolones or macrolides using doxycycline as a negative control. Cox regression was used to calculate crude and adjusted hazard ratios (aHRs) in time windows of various length of follow-up after the start of antibiotic use. The incidence rates for fluoroquinolones and macrolides ranged from 12 to 24 and from 12 to 53 bleeding events per 100 000 patients in the investigated time windows. The aHRs (95% confidence interval) for use of fluoroquinolones and macrolides were 1.29 (0.69-2.44) and 2.60 (0.74-9.08) at the concomitant window, 1.31 (0.84-2.03) and 1.79 (0.75-4.29) at 30 days, and 1.34 (0.99-1.82) and 1.28 (0.62-2.65) at 150 days, respectively. With regard to fluoroquinolones, the present study suggests that the risk of bleeding when combined with DOACs, if any, is small. Codispensation of macrolides in patients on DOACs was not associated with an increased risk of bleeding. However, due to the small number of macrolide users, the results must be interpreted with caution.

Identification of irritable bowel syndrome in the Swedish National Patient Register: a validation study.

BACKGROUND AND OBJECTIVE: National patient registers are valuable in epidemiological studies. To ensure high-quality data for studies of irritable bowel syndrome (IBS), this study aimed to validate the ICD-10 code for IBS in the Swedish National Patient Register. METHODS: The positive predictive values (PPV) for IBS defined by the Rome criteria were calculated based on a review of medical records of randomly selected individuals with a first-ever diagnostic listing of IBS in the Swedish National Patient register in the year 2005 (Rome II criteria) or 2010 (Rome III criteria). KEY RESULTS: 340 medical records were reviewed (172 from 2005 and 168 from 2010). The majority of patients were females (74%), and the mean age was 42 years. IBS used in any type of department had a PPV of 76% (95% confidence interval 71-80%), which increased to 80% (76-84%) when we included individuals likely to have IBS but where information about some aspects of the Rome criteria was lacking in the medical record. Two highly specialized gastroenterological departments had the best PPV, 96%, while departments of internal medicine in general had a PPV of 82% (80-95%). The PPV for the IBS subtype was 62% (55-67%). The PPVs were not significantly different comparing the two time periods investigated. CONCLUSION AND INFERENCES: The validity of a register-based definition of IBS in the Swedish National Patient register is high and can be used to identify patients with IBS in observational research. The data source, i.e., type of hospital and department, influences reliability.

COVID-19 and comedications in atrial fibrillation-a case-control study in Stockholm.

To test the main hypothesis that anticoagulation reduces risk of hospitalization, intensive care unit (ICU) admission and death in COVID-19. Nested case-control study among patients with atrial fibrillation (AF) in Stockholm. COVID-19 cases were matched to five disease-free controls with same sex, born within ± 1 years. Source population was individuals in Stockholm with AF 1997-2020. Swedish regional and national registers are used. National registers cover hospitals and outpatient clinics, local registers cover primary care. Records were linked through the personal identity number assigned to each Swedish resident. Cases were individuals with COVID-19 (diagnosis, ICU admission, or death). The AF source population consisted of 179,381 individuals from which 7548 cases were identified together with 37,145 controls. The number of cases (controls) identified from hospitalization, ICU admission or death were 5916 (29,035), 160 (750) and 1472 (7,360). The proportion of women was 40% for hospitalization and death, but 20% and 30% for admission to ICU in wave one and two, respectively. Primary outcome was mortality, secondary outcome was hospitalization, tertiary outcome was ICU admission, all with COVID-19. Odds ratios (95% confidence interval) for antithrombotics were 0.79 (0.66-0.95) for the first wave and 0.80 (0.64-1.01) for the second wave. Use of anticoagulation among patients with arrythmias infected with COVID-19 is associated with lower risk of hospitalization and death. If further COVID-variants emerge, or other infections with prothrombotic properties, this emphasize need for physicians to ensure compliance among vulnerable patients.

Patient characteristics and safety outcomes in new users of ticagrelor and clopidogrel-An observational cohort study in Sweden.

PURPOSE: We aimed to describe characteristics of new users of ticagrelor or clopidogrel following a recent coronary event, and to compare incidences of selected safety outcomes. METHODS: This observational cohort study used data from national Swedish registers. Patients first dispensed ticagrelor or clopidogrel (June 2011-December 2013) were identified from the Prescribed Drug Register and followed until censoring or 31 December 2014. Cohorts were restricted to patients with a recent coronary event-related hospital contact identified in the Patient Register. RESULTS: The study included 45 987 unique, naïve users of ticagrelor (73% men; mean age 66 years) or clopidogrel (69% men; mean age 69 years). Corresponding to indication, diagnoses before initiation were acute coronary syndrome (93%), myocardial infarction (76%), and percutaneous coronary intervention (69%). The most common medications used in the year before initiation of study therapy were antithrombotic agents (clopidogrel 62%, ticagrelor 43%), mainly low-dose acetylsalicylic acid. Ticagrelor users had a higher incidence (per 1000 person-years) of respiratory bleeding (24.6 [95% confidence interval (CI): 22.1-27.3]; vs clopidogrel users: 14.4 [13.1-15.8]) and dyspnea (25.9 [23.3-28.7]; vs clopidogrel users: 16.8 [15.4-18.4]). Epistaxis accounted for 83-93% of respiratory bleeds. Adjusted analyses found increased risks of gout and acute renal failure with ticagrelor. CONCLUSIONS: Clopidogrel users were older with a higher prevalence of concomitant medications than ticagrelor users. Our study showed increased incidences of dyspnea and respiratory bleeding (mainly epistaxis) among current ticagrelor users compared with clopidogrel users, and increased risks of gout and acute renal failure after adjustment.

The use of uncertain exposure-A method to define switching and add-on in pharmacoepidemiology.

PURPOSE: When defining exposure to pharmacological treatments in pharmacoepidemiology, register data often do not provide information regarding if a pharmacological treatment is a switch or an add-on. This study aims to compare two methods defining switching and add-on therapies and their impact on exposure-outcome associations. Additionally, to guide bias reduction, it aims to describe how the methods relate to immortal time bias and selection bias. METHODS: Cohort study using Swedish population-based health registers to identify antidepressant (AD) prescriptions as exposures while hospitalizations for psychiatric reasons were used as an empirical outcome example. The first method for exposure definition used conditioning on future exposure (FE), the second used the concept of uncertain exposure (UE). To estimate associations between outcome and exposure categories "Use of one AD," "Use of two or more ADs", and "UE" compared to "Unexposed," hazard ratios (HRs) and 95% confidence intervals were estimated using Cox regression adjusted for age and sex. RESULTS: Using the UE method, 7.2% of time periods were classified as "UE" with a notable proportion of psychiatric hospitalizations (7.7%) occurring during this time, while when using the FE method these hospitalizations were distributed over unexposed time and AD use time. The FE method resulted in slightly higher associations than the UE method. The highest HR was found during "UE": HR (95% CI) 5.54 (5.06-6.07). CONCLUSIONS: This study suggests that to reduce the potential immortal time bias, selection bias, and exposure misclassification inherent to the FE method, the UE method could be used for identifying switching and add-on therapies. If not used as a main exposure definition, the UE method may be used to investigate the impact of UE time in a sensitivity analysis.

Risk factors of hospitalisation for thrombosis in adults with primary immune thrombocytopenia, including disease-specific treatments: a French nationwide cohort study.

We aimed to assess the risk factors of venous thrombosis (VT) and arterial thrombosis (AT) in adults with primary immune thrombocytopenia (ITP), particularly in relation to treatments. The population comprised all incident primary ITP adults in France between 2009 and 2017 (FAITH cohort; NCT03429660) built in the national health database. Outcomes were the first hospitalisation for VT and AT. Multivariable Cox regression models included baseline risk factors, time-varying exposure to ITP drugs, splenectomy and to cardiovascular drugs. The cohort included 10 039 patients. A higher risk of hospitalisation for VT was observed with older age, history of VT, history of cancer, splenectomy [hazard ratio (HR) 3·23, 95% confidence interval (CI) 2·26-4·61], exposure to corticosteroids (HR 3·55, 95% CI 2·74-4·58), thrombopoietin-receptor agonists (TPO-RAs; HR 2·28, 95% CI 1·59-3·26) and intravenous immunoglobulin (IVIg; HR 2·10, 95% CI 1·43-3·06). A higher risk of hospitalisation for AT was observed with older age, male sex, a history of cardiovascular disease, splenectomy (HR 1·50, 95% CI 1·12-2·03), exposure to IVIg (HR 1·85, 95% CI 1·36-2·52) and TPO-RAs (HR 1·64, 95% CI 1·26-2·13). Rituximab was not associated with an increased risk. These findings help to estimate the risk of thrombosis in adult patients with ITP and to select treatment.

Use of non-insulin antidiabetic drugs in children and young adults - A Scandinavian drug utilization study from 2010-2019.

Knowledge on utilization patterns of non-insulin antidiabetic drugs in childhood and youth is limited. Therefore, we conducted a population-based drug utilization study using publicly available aggregate data on use of non-insulin antidiabetics from 2010 to 2019 in Scandinavia (Denmark, Norway and Sweden) in individuals aged up to 24 years. For each non-insulin antidiabetic drug, we calculated the annual prevalence proportion of users, overall and for specific age groups. From 2010 to 2019, the prevalence of non-insulin antidiabetic users in Scandinavia increased 37% from 0.43 to 0.59/1000 individuals. The prevalence proportions were highest among female adolescents and young adults, but the largest relative increase in use was seen among 10-14-year-olds (78%). Metformin was by far the most widely used non-insulin antidiabetic drug with a prevalence proportion of 0.51/1000 in 2019, followed by glucagon-like peptide-1 (GLP-1) analogues, which, however, showed an eight-fold relative increase during the study period.

Influence of statin-potency on the risk of kidney disease - A nationwide cohort study using laboratory data.

PURPOSE: To estimate the risk of kidney disease in high-potency statin users compared to those treated with low-potency statins without history of kidney disease at statin initiation, linking the Swedish national healthcare registers and laboratory data. METHODS: Incident users of statins, ≥40 years of age, with estimated Glomerular Filtration Rate (eGFR) >60 ml/min/1.73 m2 and no diagnosis of kidney disease at treatment initiation were identified between 2006 and 2007 and then followed for 2-years. The outcome was the incidence of kidney disease identified by the presence of the diagnostic code in the healthcare registers or eGFR <60 ml/min/1.73 m2 . We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) with adjusted and propensity score (PS)-matched Cox proportional hazards models. RESULTS: A total of 27 385 patients were identified, 25.2% of which treated with a high-potency statin. During the follow-up, 68 (0.25%) patients were identified with a diagnosis of kidney disease from the registers. The number increased to 2498 (9.1%) when the criteria of eGFR <60 ml/min/1.73 m2 was added. The adjusted HR of kidney disease in high-potency statin users was 1.14 (95%CI 1.03-1.25) compared to low-potency users; the result was unchanged after the PS approach. CONCLUSIONS: Adding information from laboratory data to those from the national health registers, a slightly increased risk for kidney disease was found in high-potency statin users without pre-existing kidney disease at treatment initiation compared to those treated with low-potency statins.

Use of intravenous iron and risk of anaphylaxis: A multinational observational post-authorisation safety study in Europe.

PURPOSE: This post-authorisation safety study estimated the risk of anaphylaxis in patients receiving intravenous (IV) iron in Europe, with interest in iron dextran and iron non-dextrans. Studies conducted in the United States have reported risk of anaphylaxis to IV iron ranging from 2.0 to 6.8 per 10 000 first treatments. METHODS: Cohort study of IV iron new users, captured mostly through pharmacy ambulatory dispensing, from populations covered by health and administrative data sources in five European countries from 1999 to 2017. Anaphylaxis events were identified through an algorithm that used parenteral penicillin as a positive control. RESULTS: A total of 304 210 patients with a first IV iron treatment (6367 iron dextran), among whom 13-16 anaphylaxis cases were identified and reported as a range to comply with data protection regulations. The pooled unadjusted incidence proportion (IP) ranged from 0.4 (95% confidence interval [CI], 0.2-0.9) to 0.5 (95% CI, 0.3-1.0) per 10 000 first treatments. No events were identified at first dextran treatments. There were 231 294 first penicillin treatments with 30 potential cases of anaphylaxis (IP = 1.2; 95% CI, 0.8-1.7 per 10 000 treatments). CONCLUSION: We found an IP of anaphylaxis from 0.4 to 0.5 per 10 000 first IV iron treatments. The study captured only a fraction of IV iron treatments administered in hospitals, where most first treatments are likely to happen. Due to this limitation, the study could not exclude a differential risk of anaphylaxis between iron dextran and iron non-dextrans. The IP of anaphylaxis in users of penicillin was consistent with incidences reported in the literature.

Risk factors for severe bleeding events during warfarin treatment: the influence of sex, age, comorbidity and co-medication.

PURPOSE: To investigate risk factors for severe bleeding during warfarin treatment, including the influence of sex, age, comorbidity and co-medication on bleeding risk. METHODS: Patients initiating warfarin treatment between 2007 and 2011 were identified in the nationwide Swedish Prescribed Drug Register, and diagnoses of severe bleeding were retrieved from the National Patient Register. Hazard ratios (HR) with 95% confidence intervals (CI) for severe bleeding were estimated using multiple Cox regression adjusting for indications and including covariates age, sex, comorbidities and co-medications. Interactions between sex and other covariates were investigated. RESULTS: The study cohort included 232,624 patients ≥ 18 years (101,011 women and 131,613 men). The incidence rate of severe bleeding was 37 per 1000 person-years, lower among women than men with an adjusted HR (95% CI) of 0.84 (0.80-0.88). Incidence of bleeding increased with age, HR 2.88 (2.37-3.50) comparing age ≥ 80 to < 40 years, and comorbidities associated with the highest risk of severe bleeding were prior bleeding, HR 1.85 (1.74-1.97); renal failure, HR 1.82 (1.66-2.00); and alcohol dependency diagnosis, HR 1.79 (1.57-2.05). Other comorbidities significantly associated with bleeding events were hypertension, diabetes, peripheral vascular disease, congestive heart failure, liver failure, stroke/TIA, COPD and cancer. CONCLUSION: Most of the well-established risk factors were found to be significantly associated with bleeding events in our study. We additionally found that women had a lower incidence of bleeding. Potential biases are selection effects, residual confounding and unmeasured frailty.

Methods for constructing treatment episodes and impact on exposure-outcome associations.

PURPOSE: To assess the impact on exposure time and outcome misclassifications, and consequent impact on exposure-outcome associations from treatment episode construction. We investigated the dosage assumptions of 1 unit per day, and 1 DDD per day, versus actual prescribed dosage under different handling of gaps and overlaps of prescriptions. METHODS: Data on mirtazapine and citalopram exposure (years 2006-2014) from the Swedish Prescribed Drug register were used. Via a within individuals design we compared method A, based on actual dosage, with methods B and C based on 1 unit of drug per day and 1 DDD per day assumptions, respectively, including consideration of gaps and overlaps. Four outcomes were used, hospitalizations and outpatient visits for all and for psychiatric causes. RESULTS: Relative to method A, both alternative methods lead to misclassification of exposure time. With regard to outcome misclassifications, method B overestimates the effect of the exposure on the outcome in 77% and 100% of exposure definition comparisons for mirtazapine and citalopram respectively, while 23% of the comparisons for mirtazapine results in underestimation of exposure-outcome associations. Conversely, treatment episodes based on DDD (method C) result in underestimation of the exposure-outcome association in 100% and 87.5% of exposure definition comparisons for mirtazapine and citalopram respectively, while 12.5% of the comparisons for citalopram results in overestimation of the exposure-outcome associations. CONCLUSIONS: The study provides results that have consistent clinical relevance. We have showed that a non-accurate construction of exposure time may lead to errors on outcome detection during exposed time, and consequently affect conclusions on safety or efficacy profile of a treatment.

Risk of common infections among individuals with psoriasis in Sweden: A nationwide cohort study comparing secukinumab to ustekinumab.

PURPOSE: To determine risk of respiratory tract infections, urinary tract infections and candidiasis in secukinumab users compared to ustekinumab users among individuals with psoriasis in Sweden. METHODS: This was a Swedish population-based register-linked new-user cohort study on individuals with psoriasis and psoriasis arthritis treated with secukinumab (2015-2017) and ustekinumab (2009-2017). Ever-never exposure definition was used, that is, each individual's follow-up time was attributed to the drug they were first exposed to. Risk of severe respiratory and urinary tract infections and candidiasis (diagnosis codes from out-patient specialist visits and in-patient hospitalisations) and respiratory and urinary tract infections treated in primary care (proxied by dispensation of antibiotics) was determined by adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox regression. We also give crude incidence rates and rate ratios. RESULTS: In total, 1955 new users of secukinumab (n = 848) and ustekinumab (n = 1107) were identified. There was a slightly increased risk of respiratory and urinary tract infections treated in primary care among secukinumab users compared to ustekinumab users (HR: 1.22, 95% CI: 1.03-1.43). Non-significant differences in estimated risk of severe respiratory and urinary tract infections (HR: 0.96, 95% CI: 0.57-1.61) and candidiasis (HR: 1.80, 95% CI: 0.84-3.84) treated in the hospital setting were observed. CONCLUSION: We observed a slightly increased risk of respiratory and urinary tract infections treated in primary care among secukinumab users compared to ustekinumab users. Larger studies with longer follow-up are needed to draw conclusions on relative safety.

Classification and characteristics of on-label and off-label apixaban use in Denmark and Sweden.

PURPOSE: To estimate the proportion of apixaban users who received the drug for on-label indications and characterise the patients using apixaban for on-label and off-label indications. METHODS: We report results from two independently conducted studies in Denmark and Sweden, with 19,709 Danish and 17,592 Swedish patients, who received at least one outpatient dispensing of apixaban as identified through nationwide prescription registries. Indications, inferred from inpatient and hospital diagnoses recorded at the initial apixaban dispensing, were classified as on-label, off-label, or unclassified according to the Summary of Product Characteristics. All diagnoses were retrieved using inpatient or outpatient hospital diagnoses at the first outpatient dispensing during the study period. RESULTS: Men comprised 52% of the users in both Denmark and Sweden. The median age was 76 years (interquartile range [IQR]: 68-83 years) among Danish patients and 74 years (IQR: 67-82 years) among Swedish patients. An on-label indication could be assigned to 82.6% (95% confidence interval [CI]: 82.1%-83.1%) of the Danish patients and 86.4% (95% CI: 85.9%-86.9%) of the Swedish patients. The main on-label indication for apixaban was non-valvular atrial fibrillation (NVAF), which accounted for 76.1% of the indications in Denmark and 69.1% of the indications in Sweden. Off-label indications were assigned to 10.8% (95% CI: 10.3-11.2) of the Danish patients (main indication possible mechanical heart valve) and 7.7% (95% CI: 7.3-8.1) of the Swedish patients (main indication off-label atrial fibrillation). CONCLUSION: The majority of apixaban initiators in Denmark and Sweden received apixaban for an on-label indication, primarily for NVAF.

Methods for time-varying exposure related problems in pharmacoepidemiology: An overview.

PURPOSE: Lack of control for time-varying exposures can lead to substantial bias in estimates of treatment effects. The aim of this study is to provide an overview and guidance on some of the available methodologies used to address problems related to time-varying exposure and confounding in pharmacoepidemiology and other observational studies. The methods are explored from a conceptual rather than an analytical perspective. METHODS: The methods described in this study have been identified exploring the literature concerning to the time-varying exposure concept and basing the search on four fundamental pharmacoepidemiological problems, construction of treatment episodes, time-varying confounders, cumulative exposure and latency, and treatment switching. RESULTS: A correct treatment episodes construction is fundamental to avoid bias in treatment effect estimates. Several methods exist to address time-varying covariates, but the complexity of the most advanced approaches-eg, marginal structural models or structural nested failure time models-and the lack of user-friendly statistical packages have prevented broader adoption of these methods. Consequently, simpler methods are most commonly used, including, for example, methods without any adjustment strategy and models with time-varying covariates. The magnitude of exposure needs to be considered and properly modelled. CONCLUSIONS: Further research on the application and implementation of the most complex methods is needed. Because different methods can lead to substantial differences in the treatment effect estimates, the application of several methods and comparison of the results is recommended. Treatment episodes estimation and exposure quantification are key parts in the estimation of treatment effects or associations of interest.

Effectiveness of risk minimization measures for the use of cilostazol in United Kingdom, Spain, Sweden, and Germany.

PURPOSE: The purpose of the study is to evaluate the effectiveness of risk minimization measures-labeling changes and communication to health care professionals-recommended by the European Medicines Agency for use of cilostazol for the treatment of intermittent claudication in Europe. METHODS: Observational study of cilostazol in The Health Improvement Network (United Kingdom), EpiChron Cohort (Spain), SIDIAP (Spain), Swedish National Databases, and GePaRD (Germany). Among new users of cilostazol, we compared the prevalence of conditions targeted by the risk minimization measures in the periods before (2002-2012) and after (2014) implementation. Conditions evaluated were prevalence of smoking, cardiovascular conditions, concurrent use of ≥2 antiplatelet agents, concurrent use of potent CYP3A4/CYP2C19 inhibitors and high-dose cilostazol, early monitoring of all users, and continuous monitoring of users at high cardiovascular risk. RESULTS: We included 22 593 and 1821 new users of cilostazol before and after implementation of risk minimization measures, respectively. After implementation, the frequency of several conditions related to the labeling changes improved in all the study populations: prevalence of use decreased between 13% (EpiChron) and 57% (SIDIAP), frequency of cardiovascular contraindications decreased between 8% (GePaRD) and 84% (EpiChron), and concurrent use of high-dose cilostazol and potent CYP3A4/CYP2C19 inhibitors decreased between 6% (Sweden) and 100% (EpiChron). The frequency of other conditions improved in most study populations, except smoking, which decreased only in EpiChron (48% reduction). CONCLUSIONS: This study indicates that the risk minimization measures implemented by the EMA for the use of cilostazol have been effective in all European countries studied, except for smoking cessation before initiating cilostazol, which remains an area of improvement.

Characterization of new users of cilostazol in the UK, Spain, Sweden, and Germany.

PURPOSE: To describe the characteristics of new users of cilostazol in Europe with the aim to support the evaluation of its benefit/risk as used in regular clinical practice before the implementation of labeling changes recommended by the European Medicines Agency. METHODS: New users of cilostazol were identified in populations enrolled in five European health automated databases in the UK (The Health Improvement Network [THIN]), Spain (EpiChron cohort and Information System for the Improvement of Research in Primary Care [SIDIAP]), Sweden (National Registers), and Germany (German Pharmacoepidemiological Research Database [GePaRD]) between 2002 and 2012. New users were characterized according to the prevalence of cardiovascular disease and other comorbidities, concurrent use of interacting medications, new contraindications, duration of use, and potential off-label prescribing. RESULTS: We identified 22 593 new users of cilostazol. The median age was between 68.0 (THIN) and 73.7 (Sweden) years. More than 78% of users had concomitant cardiovascular disease, and between 78.8% (GePaRD) and 91.6% (THIN) were treated with interacting medications. Prevalence of new cardiovascular contraindications ranged from 1.5% (THIN) to 11.6% (GePaRD), and concurrent use of two or more antiplatelet drugs ranged from 6.3% (SIDIAP) to 13.5% (EpiChron cohort). Between 39.4% (Sweden) and 52.9% (THIN) of users discontinued cilostazol in the first 3 months. Between 41.0% (SIDIAP) and 93.4% (THIN) were considered to have received cilostazol according to the European Medicines Agency labeling. CONCLUSIONS: In this collaborative European study, most cilostazol users were elderly patients with a high prevalence of cardiovascular diseases and other comorbidity and concurrent use of interacting drugs, indicating that this is a vulnerable population at high risk of complications, especially cardiovascular events. © 2017 The Authors. Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.