5-year adherence to adjuvant endocrine treatment in Dutch women with early stage breast cancer: A population-based database study (2006-2016).

BACKGROUND: Hormonal receptor (HR) positive breast tumors are common. Adjuvant hormonal therapy (AHT) with tamoxifen or Aromatase Inhibitors (AIs) is beneficial depending on the stage of the tumor. Despite the fact that AHT has been shown to improve survival and recurrence, Dutch adherence rates, which were mostly dependent on Tamoxifen prescriptions until 2006, plummeted from 80% after one year to 50% after five years. Nonadherence with AHT reduces its effectiveness. This research presents more recent adherence statistics (from 2006 to 2016), on a larger sample (7,996 vs 1,451), as well as factors that influence AHT adherence. In addition to tamoxifen data, AIs are now included. OBJECTIVE: As low use of adjuvant endocrine therapy is a potentially important and modifiable risk factor for poor outcome, it is important to monitor the rate as an indicator of women's burden of disease and the direction of adherence trends. METHODS: The Netherlands Cancer Registry (NCR) was used to find women with early-stage breast cancer who started AHT within a year of surgery and were linked to the PHARMO Database Network (n = 8,679). The Kaplan-Meier approach was used to measure AHT adherence five years after treatment was started, with a 60-day gap between refills as our primary outcome. Furthermore, the Medication Possession Rate (MPR) was determined using a cutoff of ≥80%. Analysis was performed on influential factors of adherence. RESULTS: The proportion of persistent women declined over time to reach 46.6% at the end of the fifth year and 53.3% of the women had a MPR ≥80% during the fifth year. Older and being diagnosed in 2006-2010 were associated with AHT adherence. CONCLUSION: Dutch 5-year AHT adherence appears to remain poor. Improving AHT adherence in HR+ breast cancer survivors is a critical medical need.

Incidence of Lyme Borreliosis in the Dutch General Practice Population: A Large-Scale Population-Based Cohort Study Across the Netherlands Between 2015 and 2019.

Background: There is a need for updated incidence rates (IRs) of Lyme borreliosis (LB) in Europe, including the Netherlands. We estimated LB IRs stratified by geographic area, year, age, sex, immunocompromised status, and socioeconomic status (SES). Methods: All subjects registered in the PHARMO General Practitioner (GP) Database without prior diagnosis of LB or disseminated LB and having ≥1 year of continuous database enrolment were included. IRs and corresponding confidence intervals (CIs) of GP-recorded LB, erythema migrans (EM), and disseminated LB were estimated during the period 2015‒2019. Results: We identified 14,794 events (suspected, probable, or confirmed) with a diagnostic code for LB that included 8219 with a recorded clinical manifestation: 7985 (97%) with EM and 234 (3%) with disseminated LB. National annual LB IRs were relatively consistent, ranging from 111 (95% CI 106‒115) in 2019 to 131 (95% CI 126‒136) in 2018 per 100,000 person-years. Incidence of LB showed a bimodal age distribution, with peak IRs observed among subjects aged 5‒14 and 60‒69 years in men and women. Higher LB incidence was found in subjects who were residents of the provinces of Drenthe and Overijssel, immunocompromised, or of lower SES. Similar patterns were observed for EM and disseminated LB. Conclusions: Our findings confirm that LB incidence remains substantial throughout the Netherlands with no indication of decline in the past 5 years. Foci in two provinces and among vulnerable populations suggest potential initial target groups for preventive strategies such as vaccination.

Treatment and low-density lipoprotein cholesterol levels in patients with hypercholesterolaemia or mixed dyslipidaemia at high or very high cardiovascular risk: a population-based cross-sectional study in the Netherlands.

OBJECTIVE: To describe treatment patterns, low-density lipoprotein cholesterol (LDL-C) levels and healthcare resource utilization (HCRU) in the Netherlands in 2018 of patients with hypercholesterolaemia or mixed dyslipidaemia at high or very high cardiovascular (CV) risk. METHODS: From the PHARMO Database Network adult patients with a diagnosis or receiving lipid lowering therapy (LLT) between 2009 and 2018 were selected. Patients at high or very high CV risk according to 2016 ESC/EAS guidelines with recorded LDL-C levels who were treated with LLT or were characterized as statin intolerant in 2018 were included. LLT treatment patterns, LDL-C levels and HCRU (General Practitioner [GP] consultations and hospitalizations) were assessed. RESULTS: The study population included 54,346 patients, of which 70% were at very high CV risk and 30% at high CV risk. The majority (93%) received statin monotherapy, mostly of moderate (73%) or high (15%) intensity. Only 3% received a combination of statin and ezetimibe. Statin intolerance, based on a treatment algorithm, was estimated at 3%. Average LDL-C decreased with LLT intensity. Overall, 74% reached LDL-C < 2.5 mmol/l and 34% <1.8 mmol/l with their current treatment, and 46% reached their LDL-C goal according to 2016 ESC/EAS guidelines. The highest rates of hospitalizations and GP consultations, including home visits, were recorded in patients with peripheral artery disease or polyvascular disease. CONCLUSION: The treatment of hypercholesterolaemia and mixed dyslipidaemia in patients at high or very high CV risk in the Netherlands was suboptimal in 2018. To further lower CV risk alternative treatment strategies using add-on therapies are needed.

Real-world data of HER2-low metastatic breast cancer: A population based cohort study.

BACKGROUND: With the introduction of investigational human epidermal growth factor receptor 2 (HER2) targeting treatments, thorough understanding of breast cancer with different HER2 expression levels is critical. The aim of this study was to compare clinicopathologic characteristics and survival of patients with metastatic breast cancer according to the level of HER2 expression. METHODS: Women with distant metastatic breast cancer during 2008-2016 were selected from PALGA, the Dutch Pathology Registry, and linked to the PHARMO Database Network. Breast cancer samples were categorised as HER2 immunohistochemistry score 0 (IHC0), HER2-low or HER2+. RESULTS: Among women with hormone receptor (HR) positive metastatic breast cancer (n = 989), 373 (38%) cancers were HER2 IHC0, 472 (48%) were HER2-low and 144 (15%) were HER2+. Among HR negative patients (n = 272), the proportion of HER2 IHC0, HER2-low and HER2+ was 110 (40%), 104 (38%) and 58 (21%) respectively. Within the HR + cohort, patients with HER2 IHC0 or HER2-low cancer were significantly older compared to HER2+ patients. This age difference was not seen in the HR-cohort. The localisation of distant metastases differed significantly between HER2 IHC0 or HER2-low versus HER2+ cases. Survival rates did not differ markedly by subtypes. CONCLUSION: Substantial proportion of patients had a HER2-low breast cancer. No clear differences in survival were found when comparing HER2 and HR status. Getting more granular insights in the level of HER2 expression and addressing HER2-low as a separate category could help to assess the impact of emerging treatment strategies. Therefore, more detailed information on HER2 expression should be routinely reported.

Incidence of malignancies in patients with multiple sclerosis versus a healthy matched cohort: A population-based cohort study in the Netherlands using the PHARMO Database Network.

This study estimated the incidence of malignancy in patients with multiple sclerosis (MS) versus a matched general population cohort in the Netherlands. Adults with a diagnosis of MS between 2006 and 2014 in the General Practitioner (GP) Database of the PHARMO Database Network with ≥ 1 year of patient history were matched to four non-MS individuals based on year of birth, sex, and GP practice. Patients were followed-up until the earliest malignancy diagnosis, death, or end of data collection. Age-adjusted incidence rates (IR) were measured overall and by cancer type. Standardized incidence ratios (SIR) were calculated as the ratio of stratification-specific IRs in the MS and non-MS cohorts. A total of 1,692 MS patients were matched to 6,768 non-MS patients. Age-adjusted IR of any malignancy, excluding non-melanoma skin cancer (n = 27), in the MS cohort was 48.3 (95%CI:30.1-66.5) per 10,000 PY. An increased incidence of any malignancy was observed in the MS cohort versus the non-MS cohort (SIR 1.8 [95%CI:1.1-2.5]). The most commonly observed malignancies in the MS cohort were breast cancer (n = 8; IR 20.4 [95%CI:6.3-34.5] per 10,000 PY) and melanoma (n = 6; IR 14.8 [95%CI:3.0-26.7] per 10,000 PY). The corresponding SIR observed between cohorts was 1.4 (95%CI:0.4-2.4) and 3.4 (95%CI:0.7-6.2), respectively. While the small increased incidence of malignancy in the MS cohort could be an artefact created by a different distribution of risk factors, an increased incidence of malignancy in MS patients in the Netherlands cannot be excluded.

Risk of heart failure among colon and rectal cancer survivors: a population-based case-control study.

AIMS: This population-based case-control study aims to investigate the occurrence of heart failure (HF) among colon and rectal cancer survivors compared with a cancer-free control population taking into account pre-existing cardiovascular risk factors and the influence of treatment. METHODS AND RESULTS: Colon and rectal cancer survivors diagnosed between 2007 and 2014 were selected from a linked cohort of cancer and primary care data in the Netherlands and matched based on gender, birth year, general practitioner (GP) practice, and follow-up period to cancer-free controls. The occurrence of HF was identified based on GP recorded diagnoses after index date (diagnosis date for cases). A Cox proportional hazards model was used to estimate hazard ratios (HRs), adjusted for age, sex, hypertension, diabetes, and hypercholesterolaemia. A total of 5333 colon cancer cases and 2468 rectal cancer cases could be matched to a total of 31 204 cancer-free controls. A statistically significant increased risk of HF was seen among all cases compared with cancer-free controls (HR 1.33; 95% confidence interval: 1.12-1.59). This was also seen when analysing colon cancer and rectal cancer separately. Being diagnosed with stage IV cancer, having hypertension, or having hypercholesterolaemia statistically significantly increased the risk of HF among colon cancer. Hypertension was a statistically significant risk factor for developing HF among rectal cancer cases. CONCLUSIONS: Colon and rectal cancer survivors are at increased risk for developing HF. More awareness should be created by treating physicians and GPs for this potential increased risk in order to further improve survival.

A population-based linked cohort of cancer and primary care data: A new source to study the management of cancer in primary care.

OBJECTIVE: Insight into the management of cancer in the primary care setting is pivotal to improve early recognition and survival of cancer patients. Therefore, the Netherlands Cancer Registry (NCR) was linked to the General Practitioner (GP) Database of the PHARMO Database Network to make this research possible. METHODS: The NCR collects tumour data on all newly diagnosed cancer patients, whereas the GP Database comprises data from electronic patient records registered by GPs. Databases were linked using a probabilistic record linkage technology. RESULTS: Through record linkage of the NCR and the GP Database, we have established a large population-based cohort (NCR-PHARMO GP cohort) of 135,868 cancer patients. Data are available on demographics, tumour characteristics, primary health care use before and after cancer diagnosis including medication use, medical conditions, laboratory tests, and referrals. Data can be used for a number of different studies, for example, to study the diagnostic pathway in the primary care setting in order to identify possibilities for early recognition. CONCLUSION: The NCR-PHARMO GP cohort provides rich data on the primary care management of cancer facilitating large-scale observational cancer research in the primary care setting. The patient-level linkage allows for long-term follow-up of cancer patients, with ongoing annual updates.

Infliximab use in the Netherlands: Uptake and characteristics of originator and biosimilars over time.

AIMS: The objective of this retrospective cohort study was to provide an overview of the utilization of originator and biosimilar infliximab in the Netherlands. METHODS: All infliximab dispensings were selected from the PHARMO In-patient Pharmacy Database from 2002-2018. Descriptive analyses were performed in order to characterise initiators and to describe switching patterns over time. RESULTS: Overall, 3840 patients with 61 274 infliximab dispensings were identified. 2496 patients initiated an originator infliximab and 777 patients initiated a biosimilar infliximab. Overall, 57% of the patients was female and mean age was 43.2 years. Both originators and biosimilars were mostly prescribed by gastroenterologists, followed by internists and rheumatologists. After market authorisation of the first biosimilar, the proportion of new patients initiating the biosimilar increased from 39% in 2015 to 91% in 2018. Out of 704 patients eligible for switching 34% switched. Among switchers, the proportion of females was 60% and mean age at index was 45.1 years. Among nonswitchers, 55% were female and mean age was 39.8 years. The median time to switch was 1.7 years and switchers were most frequently initiated on infliximab by a rheumatologist (42%), while nonswitchers were most frequently initiated by a gastroenterologist (42%). CONCLUSION: The results of this large population-based cohort show an increase in biosimilar initiation in daily clinical practice. The number of switchers remains relatively low as nonmedical switch is not encouraged in the Netherlands.

Use of potentially inappropriate medication in older patients with lung cancer at the end of life.

OBJECTIVES: Medications at the end of life should be used for symptom control. Medications which potential adverse effects outweigh their expected benefits are called 'potentially inappropriate medications' (PIMs). PIMs are related with adverse drug events and reduced quality of life. In this study, we investigated to what extent PIMs are dispensed to older patients with lung cancer in the last month of life. METHODS: We selected patients with lung cancer, aged 65+, diagnosed between 2009 and 2014, and who died before April 1st 2015 from the population-based Netherlands Cancer Registry (NCR). The NCR is linked to the PHARMO Database Network, that includes medications dispensed by community pharmacies in the Netherlands. The eight PIM groups were based on the OncPal Deprescribing Guideline: aspirin, dyslipidaemia medications, antihypertensives, osteoporosis medications, peptic ulcer prophylaxis, oral hypoglycaemics, vitamins and minerals. RESULTS: Data of 7864 patients with lung cancer were analyzed. Median age was 74 year (IQR = 70-79) and 67% was male. 45% of all patients received at least one PIM in their last month of life. Taking into account all dispensed medications, patients receiving PIMs received more different medications compared to those receiving no PIMs, respectively 10 (SD = 5) vs. 3 (SD = 4) different medications (P < 0.001). CONCLUSION: Almost half of the older patients with lung cancer in the Netherlands received PIMs in their last month of life. Since PIM use is associated with reduced quality of life, it is important that health care professionals continue to critically assess which medication can be discontinued at the end of life.

Levothyroxine use and the risk of colorectal cancer: a large population-based case-control study.

Objective: Whether an association between oral levothyroxine use, leading to supraphysiological exposure of the colon to thyroid hormones, and risk of colorectal cancer exists in humans is unclear. We therefore aimed to assess whether the use of levothyroxine is associated with a reduced risk of colorectal cancer in a linked cohort of pharmacy and cancer data. Design: Population-based matched case-control study. Methods: A total of 28,121 patients diagnosed with colorectal cancer between 1998 and 2014 were matched to 106,086 controls. Multivariable logistic regression was used to estimate the association between levothyroxine use and occurrence of colorectal cancer, adjusted for potential confounders. Results were stratified by gender, age, tumour subtype, and staging, as well as treatment duration and dosing. Results: A total of 1066 colorectal cancer patients (4%) and 4024 (4%) controls had used levothyroxine at any point before index date (adjusted odds ratio 0.95 (0.88-1.01)). Long-term use of levothyroxine was seen in 323 (30%) colorectal cancer patients and 1111 (28%) controls (adjusted odds ratio 1.00 (0.88-1.13)). Stratification by tumour subsite showed a borderline significant risk reduction of rectal cancer, while this was not seen for proximal colon cancer or distal colon cancer. There was no relationship with treatment duration or with levothyroxine dose. Conclusions: In this study, no reduced risk of colorectal cancer was seen in levothyroxine users. When stratifying by tumour subsite, a borderline significant risk reduction of rectal cancer was found and may warrant further research.

A steep increase in healthcare seeking behaviour in the last months before colorectal cancer diagnosis.

BACKGROUND: Timely recognition of colorectal cancer related symptoms is essential to reduce time to diagnosis. This study aims to investigate the primary healthcare use preceding a colorectal cancer diagnosis. METHODS: From a cohort of linked cancer and primary care data, patients diagnosed with primary colorectal cancer in the period 2007-2014 were selected and matched to cancer-free controls on gender, birth year, GP practice and follow-up period. Primary healthcare use among colorectal cancer cases before diagnosis was compared with matched cancer-free controls. Mean monthly number of GP consultations and newly prescribed medication was assessed in the year before index date (diagnosis date for cases). Results were stratified by colorectal cancer site: proximal colon cancer, distal colon cancer and rectal cancer. RESULTS: A total of 6,087 colorectal cancer cases could be matched to four cancer-free controls (N = 24,348). While mean monthly number of GP consultation were stable through the year among cancer-free controls, a statistical significant increase was seen among colorectal cancer cases in the last 4-8 months before diagnosis. Proximal colon cancer cases showed the longest time interval of increased mean monthly number of GP consultations. This increase was largely driven by a consultation for malignant neoplasm colon/rectum. The number patients receiving a newly prescribed medication was stable around 120 per 1,000 persons per month until 8 months before index date for proximal colon cancer cases, 4 months before index date for distal colon cancer cases and 3 months for rectal cancer cases. This increase was mainly driven by the prescription of laxatives drugs. CONCLUSION: An increase in the healthcare seeking behaviour of colorectal cancer patients prior to diagnosis was seen. The longest period of increased GP consultations and newly prescribed medication was seen among patients diagnosed with proximal colon cancer. This can be explained by the difficultly to diagnose proximal colon cancer given the more subtle signs compared to distal colon cancer and rectal cancer. Therefore, faster diagnosis for this specific tumour subtype may only be possible when clear clinical signs and symptoms are present.

Characteristics and Absolute Survival of Metastatic Colorectal Cancer Patients Treated With Biologics: A Real-World Data Analysis From Three European Countries.

Introduction: Biologics were approved for the treatment of advanced colorectal cancer (CRC) based on favorable benefit-risk-assessments from randomized controlled trials (RCTs), but evidence on their use in the real-world setting is scarce. Based on descriptive analyses we therefore aimed to assess characteristics and survival of CRC patients treated with biologics using large healthcare databases from three European countries (Netherlands, Italy, Germany). Methods: We included CRC patients treated with a biologic in 2010 or 2014 and characterized them regarding age, sex, comorbidities, and absolute survival. Results: Among 4,758 patients, the mean age ranged from 64.8 to 66.8 years, the majority was male, and comorbidities used as exclusion criteria in RCTs were coded in up to 30% of these patients. The proportion of bevacizumab users decreased between 2010 (72-93%) and 2014 (63-85%). In 2014, the absolute 12-month survival in new users was 64% (95% CI 51-77%), 56% (30-80%), and 61% (58-63%) in the Dutch, Italian, and German database, respectively, varying by age and comorbidity. Conclusions: Our study suggests that in the real-world setting, CRC patients treated with biologics are older and less selected regarding comorbidities compared to patients in RCTs, potentially explaining the relatively low 12-month survival we found. Treatment decisions in the real-world setting may require careful evaluation given that the risk-benefit ratio may vary depending on age and co-existing conditions.

Digoxin treatment reactivates in vivo radioactive iodide uptake and correlates with favorable clinical outcome in non-medullary thyroid cancer.

PURPOSE: Non-medullary thyroid cancer (NMTC) treatment is based on the ability of thyroid follicular cells to accumulate radioactive iodide (RAI). However, in a subset of NMTC patients tumor dedifferentiation occurs, leading to RAI resistance. Digoxin has been demonstrated to restore iodide uptake capacity in vitro in poorly differentiated and anaplastic NMTC cells, termed redifferentiation. The aim of the present study was to investigate the in vivo effects of digoxin in TPO-Cre/LSL-BrafV600E mice and digoxin-treated NMTC patients. METHODS: Mice with thyroid cancer were subjected to 3D ultrasound for monitoring tumor growth and 124I PET/CT for measurement of intratumoral iodide uptake. Post-mortem analyses on tumor tissues comprised gene expression profiling and measurement of intratumoral autophagy activity. Through PALGA (Dutch Pathology Registry), archived tumor material was obtained from 11 non-anaplastic NMTC patients who were using digoxin. Clinical characteristics and tumor material of these patients were compared to 11 matched control NMTC patients never treated with digoxin. RESULTS: We found that in mice, tumor growth was inhibited and 124I accumulation was sustainably increased after short-course digoxin treatment. Post-mortem analyses revealed that digoxin treatment increased autophagy activity and enhanced expression of thyroid-specific genes in mouse tumors compared to vehicle-treated mice. Digoxin-treated NMTC patients exhibited significantly higher autophagy activity and a higher differentiation status as compared to matched control NMTC patients, and were associated with favourable clinical outcome. CONCLUSIONS: These in vivo data support the hypothesis that digoxin may represent a repositioned adjunctive treatment modality that suppresses tumor growth and improves RAI sensitivity in patients with RAI-refractory NMTC.

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.

Long-Term Risk of Skin Cancer and Lymphoma in Users of Topical Tacrolimus and Pimecrolimus: Final Results from the Extension of the Cohort Study Protopic Joint European Longitudinal Lymphoma and Skin Cancer Evaluation (JOELLE).

PURPOSE: Evidence is insufficient to infer whether topical calcineurin inhibitors (TCIs; tacrolimus and pimecrolimus) cause malignancy. The study objective was to estimate the long-term risk of skin cancer and lymphoma associated with topical TCI use in adults and children, separately. PATIENTS AND METHODS: A cohort study in Denmark, Sweden, UK, and the Netherlands was conducted. Adjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated for nonmelanoma skin cancer (NMSC), melanoma, cutaneous T-cell lymphoma (CTCL), non-Hodgkin lymphoma (NHL) excluding CTCL, and Hodgkin lymphoma (HL) in new users of TCIs versus users of moderate/high-potency topical corticosteroids. RESULTS: The study included 126,908/61,841 adults and 32,605/27,961 children initiating treatment with tacrolimus/pimecrolimus, respectively. Follow-up was ≥10 years for 19% of adults and 32% of children. Incidence rate ratios and (95% confidence intervals) for tacrolimus versus corticosteroid users in adults were <1 for melanoma, non-Hodgkin lymphoma, and Hodgkin lymphoma; and 1.80 (1.25-2.58) for cutaneous T-cell lymphoma. For pimecrolimus, IRRs in adults were <1 for non-Hodgkin lymphoma, cutaneous T-cell lymphoma, and Hodgkin's lymphoma; and 1.21 (1.03-1.41) for melanoma; and 1.28 (1.20-1.35) for nonmelanoma skin cancer. In children, results were inconclusive due to few events. In adults, incidence rate ratios ≥5 years after first topical calcineurin inhibitor exposure were not higher than in overall analyses. CONCLUSION: Overall, we found little evidence associating use of topical calcineurin inhibitors with skin cancer and lymphoma; confounding by indication, surveillance bias, and reverse causation may have influenced these results. Even if causal, the public health impact of these excess risks would be low and confined to the first years of exposure.

Risk of cardiovascular disease following gonadotropin-releasing hormone agonists vs antagonists in prostate cancer: Real-world evidence from five databases.

Observational studies in prostate cancer (PCa) have shown an increased risk of cardiovascular disease (CVD) following gonadotropin-releasing hormone (GnRH) agonists, whereas randomised-controlled trials have shown no associations. Compared to GnRH agonists, GnRH antagonists have shown less atherosclerotic effects in preclinical models. We used real-world data from five countries to investigate CVD risk following GnRH agonists and antagonists in PCa men. Data sources included cancer registries, primary and secondary healthcare databases. CVD event was defined as an incident or fatal CVD. Multivariable Cox proportional hazard models estimated hazard ratios (HRs) and 95% confidence intervals (CIs), which were pooled using random-effects meta-analysis. Stratified analyses were conducted by history of CVD and age (75 years). A total of 48 757 men were on GnRH agonists and 2144 on GnRH antagonists. There was no difference in risk of any CVD for men on GnRH antagonists and agonists (HR: 1.25; 95% CI: 0.96-1.61; I2 : 64%). Men on GnRH antagonists showed increased risk of acute myocardial infarction (HR: 1.62; 95% CI: 1.11-2.35; I2 : 0%) and arrhythmia (HR: 1.55; 95% CI: 1.11-2.15, I2 : 17%) compared to GnRH agonists. Having a history of CVD was found to be an effect modifier for the associations with some CVD subtypes. Overall, we did not observe a difference in risk of overall CVD when comparing GnRH antagonists with agonists-though for some subtypes of CVD we noted an increased risk with antagonists. Further studies are required to address potential confounding caused by unadjusted variables such as severity of CVD history and PCa stage.

Existing Data Sources for Clinical Epidemiology: The PHARMO Database Network.

The PHARMO Database Network provides a unique opportunity to gain insight in the complete patient journey and healthcare in the Netherlands. The PHARMO Database Network is a population-based network of electronic healthcare databases and combines anonymous data from different primary and secondary healthcare settings in the Netherlands. Healthcare settings include general practitioners, out-patient and in-patient pharmacies, hospitals and clinical laboratories. Furthermore, databases are linked with external registries such as the Cancer Registry, Pathology Registry and Perinatal Registry. The different data sources are linked on a patient level through probabilistic linkage based on validated algorithms. The longitudinal and ongoing nature of the PHARMO Database Network system enables to follow up more than 10 million residents of the Netherlands for an average of 12 years. Data collection period, catchment area and overlap between data sources differ. Access to the PHARMO Database Network is, by governance regulations of the data collection, restricted to researchers of the PHARMO Institute and academic affiliates. Each data request is checked against privacy and company policies, and requires approval of the privacy and governance board. The terms and conditions and a data application form are available on the PHARMO website (www.pharmo.com).

Impact of a Forced Dose-Equivalent Levothyroxine Brand Switch on Plasma Thyrotropin: A Cohort Study.

Background: Patients with primary hypothyroidism are treated with levothyroxine (LT4) to normalize their serum thyrotropin (TSH). Finding the optimal dosage is a long-lasting process, and a small change can have major impact. Currently, limited data are available on the impact of dose-equivalent substitution between brands. This study aimed to determine the effect of the shortage of the LT4 brand Thyrax® in the Netherlands and the resulting dose-equivalent switch to another brand on plasma TSH concentrations in a large cohort of patients. Methods: Observational cohort study. Two registries representative for the Dutch population containing prescription and laboratory test data: the Nivel Primary Care Database and the PHARMO Database Network. Patients using at least 25 µg Thyrax daily for one year or longer were included. Two cohorts were formed: a switch cohort consisting of patients who switched from Thyrax to an alternative brand, and a Thyrax cohort including patients who continued to use Thyrax. Patients in the switch cohort did switch from Thyrax to a different brand of LT4 in 2016 and had two consecutive TSH measurements on the same dose of LT4, one before and one 6 weeks after the switch. Patients in the Thyrax cohort had two consecutive TSH measurements on the same dose of Thyrax that were 6 weeks apart. Results: In the Thyrax cohort, 19% of euthyroid patients using ≤100 µg had a TSH level outside the reference range at the subsequent measurement compared with 24% in the switch cohort (p < 0.0001). For patients using >100 µg Thyrax, these figures were 24% and 63%, respectively (p < 0.0001). Furthermore, patients using >50 µg Thyrax were four to five times more likely to become hyperthyroid after a dose-equivalent switch to a different brand compared with patients who stayed on Thyrax. Conclusions: In euthyroid patients continuing the LT4 product Thyrax at the same dose, TSH was out of range in 19-24% at least 6 weeks later. A dose-equivalent switch from Thyrax to other LT4 brands induced biochemical signs of overdosing in an even larger proportion (24-63%) of patients. The results indicate that a dose-equivalent LT4 brand switch may necessitate a dose adjustment in a large number of patients.

Is preoperative chemoradiation in rectal cancer patients modulated by ACE inhibitors? Results from the Dutch Cancer Registry.

BACKGROUND AND PURPOSE: The aim of this study was to assess the effect of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) on tumor response to preoperative chemoradiation for rectal cancer. MATERIALS AND METHODS: Data on patients who received chemoradiation prior to surgery for rectal cancer between 2010 and 2015 were retrieved from linkage between the PHARMO Database Network, Dutch Pathology Registry and Netherlands Cancer Registry. Pathological complete response rates (pCR) were compared between patients who did or did not use ACEIs/ARBs during treatment. Multivariable analysis was performed using logistic regression. RESULTS: Out of 345 patients, 92 patients (26.7%) used ACEIs/ARBs during treatment. Median age was 65 years (range 30-85). Older and male patients were more likely to use ACEIs/ARBs. pCR (ypT0N0) was observed in 17.4% of patients using ACEIs/ARBs compared to 14.6% of patients who did not use ACEIs/ARBs (p = 0.595). A good response (ypT0-1N0) was observed in 21.7% of ACEIs/ARBs patients vs. 19.4% of patients who did not use ACEIs/ARBs (p = 0.724). Multivariable analysis, taking into account background variables and co-medication, showed increased pCR in patients using beta-blockers (odds ratio 2.3, 95% confidence interval 1.0-5.4). CONCLUSION: In this retrospective cohort, the use of ACEIs/ARBs was not associated with tumor response to preoperative chemoradiation in rectal cancer patients. Thereby, the suggested potentiating effect of ACEIS/ARBs could not be confirmed in our study. Further research could be directed to investigate a possible benefit of beta-blockers or other anti-hypertensive drugs.

Real-world insights into risk of developing cardiovascular disease following GnRH agonists versus antagonists for prostate cancer: a methodological protocol to a study using five European databases.

One of the more recently investigated adverse long-term side effects of gonadotropin-releasing hormone (GnRH) agonists for prostate cancer (PCa) is cardiovascular disease (CVD). Studies suggest lower risk of CVD following GnRH antagonists (degarelix) than GnRH agonists. This protocol describes precise codes used to extract variables from five European databases for a study that compares risk of CVD following GnRH agonists and antagonists for PCa. PCa men on primary GnRH agonists or antagonists were identified from the UK THIN (The Health Improvement Network) database, National Health Service (NHS) Scotland, Belgian Cancer Registry (BCR), Dutch PHARMO Database Network and French National Database (SNIIRAM). Cohort entry was defined as date of treatment initiation. CVD event was defined as any first incident or fatal CVD after cohort entry. Readcodes in THIN and ICD codes in NHS Scotland, BCR, PHARMO and SNIIRAM were used to extract variables. Risk of Bias in Non-randomised studies of Interventions (ROBINS-I) tool was used to assess the potential risk of biases in this study. 51 572 men with a median follow-up time of 2 years started on GnRH agonists and 2 417 men with a median follow-up time of 1 year started on GnRH antagonists between 2010 and 2017 in the UK, Scotland, Belgium, the Netherlands and France. Data from five countries improved the study power and internal validity required to compare risk of CVD between GnRH agonists and antagonists, the latter being a fairly new drug with limited data in individual countries.