Validation of algorithms in studies based on routinely collected health data: general principles.

Clinicians, researchers, regulators, and other decision-makers increasingly rely on evidence from real-world data (RWD), including data routinely accumulating in health and administrative databases. RWD studies often rely on algorithms to operationalize variable definitions. An algorithm is a combination of codes or concepts used to identify persons with a specific health condition or characteristic. Establishing the validity of algorithms is a prerequisite for generating valid study findings that can ultimately inform evidence-based health care. This paper aims to systematize terminology, methods, and practical considerations relevant to the conduct of validation studies of RWD-based algorithms. We discuss measures of algorithm accuracy; gold/reference standard; study size; prioritizing accuracy measures; algorithm portability; and implication for interpretation. Information bias is common in epidemiologic studies, underscoring the importance of transparency in decisions regarding choice and prioritizing measures of algorithm validity. The validity of an algorithm should be judged in the context of a data source, and one size does not fit all. Prioritizing validity measures within a given data source depends on the role of a given variable in the analysis (eligibility criterion, exposure, outcome or covariate). Validation work should be part of routine maintenance of RWD sources.

Association between pregnancy affected by vaginal bleeding and women's mortality: A cohort study.

OBJECTIVE: To investigate the association between vaginal bleeding (VB) in pregnancy and women's mortality, using VB-unaffected pregnancies, terminations and miscarriages as comparators. DESIGN: Observational cohort study. SETTING: Nationwide registries of Denmark linked at an individual level. POPULATION OR SAMPLE: 1 354 181 women and their 3 162 317 pregnancies (1979-2017), including 70 835 VB-affected pregnancies and comparators: 2 236 359 VB-unaffected pregnancies ending in childbirth; 589 697 terminations; and 265 426 miscarriages. METHODS: We followed pregnancies until the earliest date of woman's death, emigration or end of data. MAIN OUTCOME MEASURES: All-cause and cause-specific mortality rates per 10 000 person-years (PY) and hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted using Cox proportional hazards regression for age, calendar year, pre-existing chronic conditions and socio-economic factors. RESULTS: There were 2320 deaths from any cause among women following VB-affected pregnancy (mortality rate 15.2, 95% CI 14.6-15.9 per 10 000 PY); 55 030 deaths following VB-unaffected pregnancy (mortality rate 12.7, 95% CI 12.6-12.8); 27 500 deaths following a termination (mortality rate 21.9, 95% CI 21.6-22.1), and 10 865 deaths following a miscarriage (mortality rate 19.2, 95% CI 18.8-19.6). For comparison of VB-affected versus VB-unaffected pregnancies, associations with all-cause (HR 1.14, 95% CI 1.09-1.19), natural causes (HR 1.15, 95% CI 1.09-1.22) and non-natural causes (HR 1.27, 95% CI 1.08-1.48) mortality were attenuated in a sensitivity analysis of pregnancies recorded in 1994-2017 (HR 1.00, 95% CI 0.90-1.12, HR 0.98, 95% CI 0.85-1.14 and HR 1.04, 95% CI 0.72-1.51, respectively). Contrasts with remaining comparators did not suggest increased risks of all-cause, natural or non-natural mortality causes. CONCLUSION: We found no evidence of an increased risk of women's mortality following VB-affected versus VB-unaffected pregnancy, termination or miscarriage.

COVID-19 and pregnancy: A European study on pre- and post-infection medication use.

PURPOSE: The COVID-19 pandemic has impacted medication needs and prescribing practices, including those affecting pregnant women. Our goal was to investigate patterns of medication use among pregnant women with COVID-19, focusing on variations by trimester of infection and location. METHODS: We conducted an observational study using six electronic healthcare databases from six European regions (Aragon/Spain; France; Norway; Tuscany, Italy; Valencia/Spain; and Wales/UK). The prevalence of primary care prescribing or dispensing was compared in the 30-day periods before and after a positive COVID-19 test or diagnosis. RESULTS: The study included 294,126 pregnant women, of whom 8943 (3.0%) tested positive for, or were diagnosed with, COVID-19 during their pregnancy. A significantly higher use of antithrombotic medications was observed particularly after COVID-19 infection in the second and third trimesters. The highest increase was observed in the Valencia region where use of antithrombotic medications in the third trimester increased from 3.8% before COVID-19 to 61.9% after the infection. Increases in other countries were lower; for example, in Norway, the prevalence of antithrombotic medication use changed from around 1-2% before to around 6% after COVID-19 in the third trimester. Smaller and less consistent increases were observed in the use of other drug classes, such as antimicrobials and systemic corticosteroids. CONCLUSION: Our findings highlight the substantial impact of COVID-19 on primary care medication use among pregnant women, with a marked increase in the use of antithrombotic medications post-COVID-19. These results underscore the need for further research to understand the broader implications of these patterns on maternal and neonatal/fetal health outcomes.

Prenatal Antidepressant Exposure and the Risk of Attention-Deficit/Hyperactivity Disorder in Childhood: Accounting for Misclassification of Exposure.

BACKGROUND: Many studies of prenatal antidepressant exposure and the risk of attention-deficit/hyperactivity disorder (ADHD) have done little to reduce bias from exposure misclassification. We assessed the prenatal antidepressant-ADHD effect by incorporating information on repeatedly redeemed prescriptions and redemptions of drug classes commonly used in pregnancy in the analyses to reduce bias from exposure misclassification. METHODS: Using population-based registries, we conducted a nationwide cohort study of all children born in Denmark from 1997 to 2017. In a former-user analysis, we compared children prenatally exposed, defined by a redeemed prescription by the mother during pregnancy, to a comparison cohort consisting of prenatally unexposed children whose mothers had redeemed a prescription before pregnancy. We incorporated information on repeatedly redeemed prescriptions and redemptions of drug classes commonly used in pregnancy in the analyses to reduce bias from exposure misclassification. We used incidence rate ratios (IRRs) and incidence rate differences (IRDs) as effect measures. RESULTS: The cohort included 1,253,362 children, among whom 24,937 were prenatally exposed to antidepressants. The comparison cohort consisted of 25,698 children. During follow-up, 1,183 exposed children and 1,291 children in the comparison cohort developed ADHD yielding an IRR of 1.05 (95% confidence interval [CI] = 0.96, 1.15) and an IRD of 0.28 (95% CI = -0.20, 0.80) pr. 1,000 person-years. IRRs from analyses attempting to reduce exposure misclassification varied from 1.03 to 1.07. CONCLUSIONS: Our results were not consistent with the hypothesized effect of prenatal antidepressant exposure on the risk of ADHD. Attempts to reduce exposure misclassification did not alter this finding.

Epidemiology of male osteoporosis in Denmark (1996-2018).

Osteoporosis in men may be underdiagnosed. One in four men in Denmark will develop osteoporosis after age of 50 years, with fracture as a common presenting symptom. PURPOSE: The aim of this study was to describe epidemiology of male osteoporosis in Denmark. METHODS: In this nationwide registry-based cohort study, we identified men with osteoporosis, 50 years or older, residing in Denmark, during the years 1996-2018. Osteoporosis was defined as one of the following: a hospital diagnosis of osteoporosis; a hospital diagnosis of osteoporosis fracture; or an outpatient dispensing of an anti-osteoporosis medication. We reported annual incidence and prevalence and described the distribution of fractures, comorbidities, socioeconomic status, and initiation of anti-osteoporosis therapy among men with osteoporosis. Selected characteristics were also described among men without osteoporosis of similar age. RESULTS: There were 171,186 men fulfilling the study criteria for osteoporosis. The overall age-standardized incidence rate of osteoporosis was 8.6 per 1000 person-years (95% confidence interval (CI), 8.5-8.6), varying between 7.7 and 9.7, while the prevalence increased from 4.3% (95% CI, 4.2-4.3) to 7.1% (95% CI, 7.0-7.1) during the 22-year period. The remaining-lifetime risk of developing osteoporosis after age of 50 years was close to 30%. The proportion of men initiating anti-osteoporosis treatment within 1 year of diagnosis increased from 6.9% to 29.8%. Men with osteoporosis had more comorbidities and redeemed more medication than did men without osteoporosis of similar age. CONCLUSION: Osteoporosis among men may be undertreated despite increasing treatment initiation.

Association between vaginal bleeding in pregnancy that resulted in delivery and risk of cancer: A Danish registry-based cohort study.

BACKGROUND: Vaginal bleeding (VB) before 20 gestational weeks of a viable pregnancy is a manifestation of a threatened miscarriage. VB is associated with increased levels of pro-inflammatory cytokines such as interferon-gamma, tumour necrosis factor-alpha and interleukin-6. Increased levels of these cytokines and oxidative stress are risk factors for cancer. The risk of cancer following a VB-affected pregnancy that ended in childbirth is unknown. OBJECTIVES: To investigate the associations between VB in pregnancy that resulted in delivery and risk of incident cancer. METHODS: We conducted a cohort study (1995-2018) in Denmark using administrative and healthcare registries. We included 37,082 VB-affected deliveries, 1,363,614 VB-unaffected deliveries, 324,328 pregnancies ending in terminations, and 137,104 miscarriages. We computed the absolute risk of cancer and hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, calendar year, morbidities, and socio-economic factors using Cox proportional hazards regression. Multiple pregnancies to the same woman were accounted for in the analysis. RESULTS: The median (25th-75th percentile) follow-up in the study was 12.6 (6.9, 18.2) years. The prevalence of VB in the present study was 3%. At the end of the follow-up, there were 1320 cancer cases among the VB-affected delivery cohort, 40,420 among the VB-unaffected delivery cohort, 10,300 among the termination cohort and 4790 among the miscarriage cohort. HRs for any cancer among VB-affected deliveries were 1.03 (95% CI 0.97, 1.08) compared with VB-unaffected deliveries, 1.03 (95% CI 0.97, 1.09) compared with terminations and 0.90 (95% CI 0.84, 0.95) compared with miscarriages. There were no increased risks of premenopausal breast cancer, cervical cancer, ovary and fallopian tube cancer or uterine cancer following VB-affected deliveries vs. comparison cohorts. CONCLUSIONS: We found no evidence of an association between vaginal bleeding in pregnancy and an increased risk of cancer.

Impact of lifestyle and socioeconomic position on use of non-steroidal anti-inflammatory drugs: A population-based cohort study.

PURPOSE: Lifestyle and socioeconomic position may confound the link between non-steroidal anti-inflammatory drugs (NSAIDs) and cardiovascular events, if associated with NSAID use. We examined this association. METHODS: We conducted a cohort study of all adult first-time responders to the Danish National Health Surveys of 2010, 2013, or 2017 without an NSAID prescription within 3 months before survey completion (n = 407 395). Study exposures were weight, smoking status, alcohol consumption, binge drinking frequency, physical activity level, marital status, highest achieved level of education, income, and employment status. We used a Cox model to compute hazard ratios of time to first redemption of an NSAID prescription and a cumulative odds model to compute odds ratios (ORs) of redeeming one additional NSAID prescription in the year after survey completion. RESULTS: Total follow-up time was 1 931 902 years. The odds of redeeming one additional NSAID prescription in the year after survey completion varied within all categories of lifestyle and socioeconomic position. The largest ORs were observed within categories of weight (1.70, 95% CI: 1.65-1.74 for obesity vs. normal weight), smoking status (1.24, 95% CI: 1.21-1.27 for current vs. never use), and education (1.44, 95% CI: 1.39-1.49 for primary or other vs. university or higher education). The Cox model showed consistent results. CONCLUSIONS: Markers of unhealthy lifestyle and low socioeconomic position were associated with initiation and prolonged NSAID use. Consideration of lifestyle and socioeconomic markers as potential confounders in NSAID studies is therefore recommended.

Impact of hemoglobin A1c level on the association between non-steroidal anti-inflammatory drug use and cardiovascular events in patients with type 2 diabetes: A population-based cohort study.

OBJECTIVE: Non-steroidal anti-inflammatory drugs (NSAIDs) should be used cautiously in patients with type 2 diabetes. We examined whether the cardiovascular risks associated with NSAID use depended on HbA1c level in patients with type 2 diabetes. METHODS: We conducted a population-based cohort study of all adult Danes with a first-time HbA1c measurement ≥48 mmol/mol during 2012-2020 (n = 103 308). We used information on sex, age, comorbidity burden, and drug use to calculate time-varying inverse probability of treatment weights. After applying these weights in a pooled logistic regression, we estimated hazard ratios (HRs) of the association between use of NSAIDs (ibuprofen, naproxen, or diclofenac) and cardiovascular events (a composite of myocardial infarction, ischemic stroke, congestive heart failure, atrial fibrillation or flutter, and all-cause death). We stratified all analyses by HbA1c level (<53 or ≥53 mmol/mol). RESULTS: For ibuprofen use, the HR of a cardiovascular event was 1.53 (95% confidence interval [CI]: 1.34-1.75) in patients with HbA1c <53 and 1.24 (95% CI: 1.00-1.53) in patients with HbA1c ≥53 mmol/mol. For naproxen use, the HR was 1.14 (95% CI: 0.59-2.21) in patients with HbA1c <53 and 1.30 (95% CI: 0.49-3.49) in patients with HbA1c ≥53 mmol/mol. For diclofenac use, the HR was 2.40 (95% CI: 1.62-3.56) in patients with HbA1c <53 and 2.89 (95% CI: 1.65-5.04) in patients with HbA1c ≥53 mmol/mol. CONCLUSIONS: In patients with type 2 diabetes, glycemic dysregulation did not affect the cardiovascular risk associated with NSAID use.

Prenatal Antidepressant Exposure and the Risk of Attention-deficit/Hyperactivity Disorder in Childhood: A Cohort Study With Triangulation.

BACKGROUND: Uncontrolled confounding from maternal depression and genetic and environmental factors is expected in studies investigating the effect of prenatal antidepressant exposure on the risk of attention-deficit/hyperactivity disorder (ADHD) in childhood and may explain inconsistencies in the existing evidence. We aimed to assess this effect using triangulation. METHODS: Using population-based health registries, we conducted a nationwide cohort study of all children born in Denmark between 1997 and 2017 and followed through 2018 for ADHD. We assessed the effect of prenatal antidepressant exposure on the risk of ADHD in childhood by comparing children with and without prenatal antidepressant exposure in terms of adjusted incidence rate ratios (IRRs), adjusted incidence rate differences (IRDs), and adjusted risk differences (RDs) and the associated 95% confidence intervals (CIs). We triangulated results from four different analytic approaches: an overall analysis, a negative control analysis, a sibling analysis, and a former-user analysis. RESULTS: The overall study cohort consisted of 1,253,362 children, among whom 28,910 (2.3%) had prenatal antidepressant exposure. ADHD during follow-up was diagnosed among 1,411 (4.9%) of the exposed and in 37,196 (3.0%) of the unexposed children. Triangulation suggested an IRR of 1.09-1.15; an IRD less than 1 case/1,000 person-years, and an RD of 0.9%-2.2% over an up to 18-year period. CONCLUSIONS: Based on triangulation, we estimated a modest effect of prenatal antidepressant exposure on the risk of ADHD in childhood. However, considering the limitations of our approaches, this observed association may be partially due to residual biases. See video abstract at, http://links.lww.com/EDE/B935.

Cancer risk in patients with migraine: A population-based cohort study in Denmark.

OBJECTIVE: The purpose of this study was to examine overall and site-specific cancer risk among individuals diagnosed with migraine compared with the general population. BACKGROUND: Current evidence regarding migraine and risk of cancer is sparse and inconclusive. METHODS: We conducted a nationwide population-based cohort study with data collected routinely and prospectively from Danish population-based registries from 1995 to 2017. We computed the age- and sex-standardized incidence ratio (SIR) as the ratio of observed to expected cancers among patients diagnosed with migraine in the study population overall, and by encounter type of first diagnosis (inpatient, outpatient specialty clinic, and emergency department). Site-specific cancers were grouped according to etiology. RESULTS: We identified 72,826 patients with a first-time hospital migraine diagnosis. There were 3090 observed overall cancer cases among individuals diagnosed with migraine as compared with 3108 expected cases (SIR 0.99, 95% confidence interval [CI]: 0.96-1.03). The cumulative incidence of all cancers combined from 1995 to 2017 among those with a first-time migraine diagnosis was 9.47% (95% CI: 9.08-9.87). The SIRs for most cancers were consistent with absence of an association: 1.00 (95% CI: 0.94-1.06) for hormone-related cancers, 0.96 (95% CI: 0.88-1.03) for smoking-related cancers, 1.10 (95% CI: 0.98-1.24) for hematologic cancers, and 0.95 (95% CI: 0.85-1.06) for immune-related cancers. Exceptions were SIRs for gastrointestinal cancers (0.78, 95% CI: 0.70-0.87) and for cancers of neurological origin (1.57, 95% CI: 1.40-1.76). CONCLUSIONS: For most cancer groups, our results did not support an association with migraine. The exceptions were an increased risk for cancers of neurological origin and a decreased risk for gastrointestinal cancers. These findings may reflect a true difference in risk among individuals with migraine, or more plausibly they reflect other forces, such as differences in medication use, detection bias and reverse causation, or shared risk factors.

Cardiovascular events and all-cause mortality in patients with chronic obstructive pulmonary disease using olodaterol and other long-acting beta2-agonists.

PURPOSE: We examined the effect of olodaterol on the risk of myocardial ischaemia, cardiac arrhythmia, and all-cause mortality compared with use of other long-acting beta2-agonists (LABAs). Channelling bias was also explored. METHODS: This Danish population-based cohort study used data linked from registries of hospital diagnoses, outpatient dispensings, and deaths. It included patients (aged ≥40 years) with a diagnosis of chronic obstructive pulmonary disease (COPD) who initiated olodaterol or another LABA. Using matching and propensity score (PS) stratification, we calculated adjusted incidence rate ratios (IRRs) using Poisson regression, followed by several additional analyses to evaluate and control channelling bias. RESULTS: The IRRs of cardiac arrhythmias or myocardial ischaemia among users of olodaterol (n = 14 239) compared to users of other LABAs (n = 51 167) ranged from 0.96 to 1.65 in various analyses, although some estimates had low precision. Initial analysis suggested an increased risk for death with olodaterol compared with other LABAs (IRR, 1.63; 95% CI, 1.44-1.84). Because olodaterol prescribing was associated with COPD severity, the mortality association was attenuated by using different methods of tighter confounding control: the IRRs were 1.26 (95% CI, 0.97-1.64) among LABA-naïve LABA/LAMA users without recent COPD hospitalisation; 1.27 (95% CI, 1.03-1.57) in a population with additional trimming from the tails of the PS distribution; and 1.32 (95% CI, 1.19-1.48) after applying overlap-weights analysis. CONCLUSIONS: Olodaterol users had a similar risk for cardiac arrhythmias or myocardial ischaemia as other LABA users. The observed excess all-cause mortality associated with olodaterol use could be due to uncontrolled channelling bias.

Overview of the European post-authorisation study register post-authorization studies performed in Europe from September 2010 to December 2018.

BACKGROUND: The European post-authorisation study (EU PAS) register is a repository launched in 2010 by the European Medicines Agency (EMA). All EMA-requested PAS, commonly observational studies, must be recorded in this register. Multi-database studies (MDS) leveraging secondary data have become an important strategy to conduct PAS in recent years, as reflected by the type of studies registered in the EU PAS register. OBJECTIVES: To analyse and describe PAS in the EU PAS register, with focus on MDS. METHODS: Studies in the EU PAS register from inception to 31st December 2018 were described concerning transparency, regulatory obligations, scope, study type (e.g., observational study, clinical trial, survey, systematic review/meta-analysis), study design, type of data collection and target population. MDS were defined as studies conducted through secondary use of >1 data source not linked at patient-level. Data extraction was carried out independently by 14 centres with expertise in pharmacoepidemiology, using publicly available information in the EU PAS register including study protocol, whenever available, using a standardised data collection form. For validation purposes, a second revision of key fields for a 15% random sample of studies was carried out by a different centre. The inter-rater reliability (IRR) was then calculated. Finally, to identify predictors of primary data collection-based studies/versus those based on secondary use of healthcare databases) or MDS (vs. non-MDS), odds ratios (OR) and 95% confidence intervals (CI) were calculated fitting univariate logistic regression models. RESULTS: Overall, 1426 studies were identified. Clinical trials (N = 30; 2%), systematic reviews/meta-analyses (N = 16; 1%) and miscellaneous study designs (N = 46; 3%) were much less common than observational studies (N = 1227; 86%). The protocol was available for 63% (N = 360) of 572 observational studies requested by a competent authority. Overall, 36% (N = 446) of observational studies were based fully or partially on primary data collection. Of 757 observational studies based on secondary use of data alone, 282 (37%) were MDS. Drug utilisation was significantly more common as a study scope in MDS compared to non-MDS studies. The overall percentage agreement among collaborating centres that collected the data concerning study variables was highest for study type (93.5%) and lowest for type of secondary data (67.8%). CONCLUSIONS: Observational studies were the most common type of studies in the EU PAS register, but 30% used primary data, which is more resource-intensive. Almost half of observational studies using secondary data were MDS. Data recording in the EU PAS register may be improved further, including more widespread availability of study protocols to improve transparency.

Osteonecrosis of the jaw among patients with cancer treated with denosumab or zoledronic acid: Results of a regulator-mandated cohort postauthorization safety study in Denmark, Norway, and Sweden.

BACKGROUND: Osteonecrosis of the jaw (ONJ) is an adverse effect of antiresorptive treatment. This study estimated incidence proportions and incidence rates of ONJ in cancer patients with bone metastases from solid tumors treated for the prevention of skeletal-related events in routine clinical practice. METHODS: This cohort study in Denmark, Norway, and Sweden in 2011-2018 included 3 treatment cohorts: a denosumab inception cohort (DEIC), a zoledronic acid inception cohort (ZAIC), and a denosumab-switch cohort (DESC). The authors estimated 1- to 5-year incidence proportions and incidence rates of ONJ overall, by cancer site (breast, prostate, or other solid tumor), and by country. ONJ diagnoses were confirmed by adjudication. RESULTS: There were 1340 patients in the DEIC, 1352 in the ZAIC, and 408 in the DESC. The median ages of the 3 cohorts were 70, 69, and 70 years, respectively; the proportions of men were 72.6%, 53.8%, and 48.3%, respectively; and the median follow-up was 19.8, 12.9, and 13.3 months, respectively. The 5-year incidence proportions of ONJ were 5.7% (95% confidence interval [CI], 4.4%-7.3%) in the DEIC, 1.4% (95% CI, 0.8%-2.3%) in the ZAIC, and 6.6% (95% CI, 4.2%-10.0%) in the DESC. The corresponding ONJ incidence rates per 100 person-years were 3.0 (95% CI, 2.3-3.7), 1.0 (95% CI, 0.6-1.5), and 4.3 (95% CI, 2.8-6.3). Incidence proportions and incidence rates were highest in patients with prostate cancer and in Denmark. CONCLUSIONS: This study provides estimates of the risk of medically confirmed ONJ among patients initiating denosumab or zoledronic acid in routine clinical practice in 3 Scandinavian countries. The results varied by cancer site and by country. LAY SUMMARY: Denosumab and zoledronic acid reduce the risk of bone fractures, pain, and surgery in patients with advanced cancers involving bone. Osteonecrosis of the jaw (ONJ)-death of a jawbone-is a known side effect of treatment with denosumab or zoledronic acid. The authors examined almost 2900 denosumab- or zoledronic acid-treated patients with cancer in Denmark, Norway, and Sweden. Over the course of 5 years, ONJ developed in 5.7% of the patients whose initial treatment was denosumab, in 1.4% of the patients whose initial treatment was zoledronic acid, and in 6.6% of the patients who switched from zoledronic acid to denosumab.

Outcomes in patients with lung cancer treated with crizotinib and erlotinib in routine clinical practice: A post-authorization safety cohort study conducted in Europe and in the United States.

PURPOSE: We examined safety outcomes of interest (SOI) and overall survival (OS) among lung cancer patients initiating crizotinib and erlotinib in routine clinical practice. METHODS: This descriptive cohort study used routinely collected health data in Denmark, Finland, Sweden, the Netherlands, and the United States (US) during 2011-2017, following crizotinib commercial availability in each country. Among crizotinib or erlotinib initiators, we reported baseline characteristics and incidence rates and cumulative incidences of the SOI - hepatotoxicity, pneumonitis/interstitial lung disease, QT interval prolongation-related events, bradycardia, vision disorders, renal cysts, edema, leukopenia, neuropathy, photosensitivity, malignant melanoma, gastrointestinal perforation, cardiac failure and OS. Results from the European Union (EU) countries were combined using meta-analysis; results from the US were reported separately. RESULTS: There were 456 patients in the crizotinib cohort and 2957 patients in the erlotinib cohort. Rates of the SOI per 1000 person-years in the crizotinib cohort ranged from 0 to 65 in the EU and from 0 to 374 in the US. Rates of the SOI per 1000 person-years in the erlotinib cohort ranged from 0 to 91 in the EU and from 3 to 394 in the US. In the crizotinib cohort, 2-year OS was ~50% in both EU and US. In the erlotinib cohort, 2-year OS was 21% in the EU and 35% in the US. CONCLUSIONS: This study describes clinical outcomes among lung cancer patients initiating crizotinib or erlotinib in routine clinical practice. Differences between SOI rates in EU and US may be partially attributable to differences in the underlying databases.

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.

Use of bisphosphonates in multiple myeloma patients in Denmark, 2005-2015.

PURPOSE: To describe use of bisphosphonates in newly diagnosed multiple myeloma patients in Denmark. METHODS: Using data from the Danish National Multiple Myeloma Registry, we conducted a population-based cohort study. Among patients newly diagnosed with multiple myeloma from 2005 to 2015, we examined use of bisphosphonates at first- and at progression/second-line anti-myeloma treatment overall, by patient characteristics, and myeloma complications. RESULTS: Of 2947 patients starting first-line anti-myeloma treatment, 2207 patients (74.9%) received bisphosphonates. During a median follow-up of 27.6 (quartiles, 10.6-52.5) months, disease progression post-first-line treatment was recorded in 1546 patients, of whom 1065 (68.9%) were treated with bisphosphonates. Altogether, 80.9% of patients with and 37.6% of patients without myeloma bone disease were treated with bisphosphonates at first line and 73.0% and 42.7%, respectively, at progression/second line. Moreover, the proportion of patients treated with bisphosphonates decreased with increasing severity of renal impairment at first and at progression/second-line treatment. CONCLUSION: The proportion of patients treated with bisphosphonates as part of first- and second-line anti-myeloma treatment increased with presence of myeloma bone disease and decreased by presence and severity of renal impairment. Overall, 25% of newly diagnosed multiple myeloma patients had no record of bisphosphonate treatment, potentially indicating an unmet need.

Acute pancreatitis: 31-Year trends in incidence and mortality - A Danish population-based cohort study.

BACKGROUND: Objectives: Increasing incidence rates and declining mortality rates have made acute pancreatitis a common cause of hospitalization. We aimed to examine 31-year trends in first-time hospitalization for acute pancreatitis, the subsequent short-term and long-term mortality, and the prognostic impacts of age, sex, and comorbidity. METHODS: In this nationwide Danish population-based cohort study of 47,711 incident cases, we computed the annual sex-specific age-standardized incidence rates of acute pancreatitis for 1988-2018. Among patients with incident hospitalization for acute pancreatitis, we computed sex-specific 30-day and 31-365-day mortality rates, stratified them, and performed proportional-hazards regression to estimate mortality rate ratios adjusted for sex, age, and comorbidity, measured by Charlson Comorbidity Index categories. RESULTS: From 1988 to 2018, the standardized incidence rate of acute pancreatitis per 100,000 person-years increased by 29% for men (28.8-37.0%) and by 148% for women (15.7-38.9%). Among patients with pancreatitis, the 30-day mortality declined from 10.0% in those diagnosed in 1988-1992 to 6.3% for those diagnosed in 2013-2017. The corresponding 31-365 day mortality increased from 5.5% to 6.0%. In comparing periods 1988-1992 and 2013-17, the adjusted 30-day mortality rate ratio was 0.36 (95% confidence interval: 0.32-0.41) and the adjusted 31-365 day mortality rate ratio was 0.64 (95% confidence interval: 0.56-0.74). Comorbidity was a strong predictor of mortality among patients with pancreatitis. CONCLUSIONS: Over the 31 years of observations, annual rates of acute pancreatitis more than doubled among women, converging with those among men. The comorbidity burden was a strong prognostic factor for short and long-term mortality. Treatments for acute pancreatitis should focus on existing comorbidities.

Using negative control outcomes to assess the comparability of treatment groups among women with osteoporosis in the United States.

PURPOSE: In contrast to randomized clinical trials, comparative safety and effectiveness assessments of osteoporosis medications in clinical practice may be subject to confounding by indication. We used negative control outcomes to detect residual confounding when comparing osteoporosis medications. METHODS: Using MarketScan Commercial and Supplemental claims, we identified women aged ≥55 years who initiated an oral bisphosphonate (BP) (risedronate, alendronate, or ibandronate), denosumab (an injected biologic), or intravenous zoledronic acid (ZA) from October 1, 2010 to September 30, 2015. Women with Paget's disease or cancer were excluded. We compared individual oral BPs to each other, denosumab to ZA, denosumab to oral BPs, and ZA to oral BPs, with respect to 11 negative control outcomes identified by subject matter experts. We estimated the 12-month cumulative risk difference (RD) using inverse probability of treatment and censoring weights. RESULTS: Among 148 587 women, most initiated alendronate (57%), followed by ibandronate (12%), ZA (11%), risedronate (10%), and denosumab (10%). Compared with denosumab, patients initiating ZA had similar risks of all negative control outcomes. Compared with oral BPs, patients initiating denosumab had a higher risk of a wellness visit (RD = 1.2%, 95% CI: 0.4, 1.9) and a lower risk of receiving herpes zoster vaccine (RD = -0.6%, 95% CI: -1.1, -0.2). Comparing ZA with oral BP initiators resulted in two outcomes with positive associations. CONCLUSIONS: Caution is warranted when comparing injectable vs oral osteoporosis medications, given the potential for unmeasured confounding. Evaluating negative control outcomes could be a standard validity check prior to conducting comparative studies.

The Role of Comorbidity in Mortality After Hip Fracture: A Nationwide Norwegian Study of 38,126 Women With Hip Fracture Matched to a General-Population Comparison Cohort.

Hip fracture patients often have comorbid conditions. We investigated whether the combination of comorbidity and hip fracture could explain the previously observed excess mortality among hip fracture patients as compared with the general population. Using a population-based matched study design with 38,126 Norwegian women who suffered a hip fracture during the period 2009-2015 and the same number of women in a matched comparison cohort, we matched participants on prefracture comorbidity, age, and education. We estimated relative survival and additive and multiplicative comorbidity-hip fracture interactions. An additive comorbidity-hip fracture interaction of 4 or 9 additional deaths per 100 patients, depending on Charlson Comorbidity Index (CCI) score, was observed 1 year after hip fracture. Among women with a CCI score of ≥3, 15 additional deaths per 100 patients were observed; of these, 9 deaths could be attributed to the interaction and 6 to the hip fracture per se. On the relative scale, we observed increasing heterogeneity in survival by comorbidity over time; survival was reduced by 39% after 6 years among patients with a CCI score of ≥3, while among women with no comorbidity, survival was reduced by 17% (hip fracture vs. no hip fracture). In summary, prefracture comorbidity was associated with short-term absolute excess mortality and long-term relative excess mortality.

Stress Disorders and Dementia in the Danish Population.

There is an association between stress and dementia. However, less is known about dementia among persons with varied stress responses and sex differences in these associations. We used this population-based cohort study to examine dementia among persons with a range of clinician-diagnosed stress disorders, as well as the interaction between stress disorders and sex in predicting dementia, in Denmark from 1995 to 2011. This study included Danes aged 40 years or older with a stress disorder diagnosis (n = 47,047) and a matched comparison cohort (n = 232,141) without a stress disorder diagnosis with data from 1995 through 2011. Diagnoses were culled from national registries. We used Cox proportional hazards regression to estimate associations between stress disorders and dementia. Risk of dementia was higher for persons with stress disorders than for persons without such diagnosis; adjusted hazard ratios ranged from 1.6 to 2.8. There was evidence of an interaction between sex and stress disorders in predicting dementia, with a higher rate of dementia among men with stress disorders except posttraumatic stress disorder, for which women had a higher rate. Results support existing evidence of an association between stress and dementia. This study contributes novel information regarding dementia risk across a range of stress responses, and interactions between stress disorders and sex.