Microenvironment drives cell state, plasticity, and drug response in pancreatic cancer.

Prognostically relevant RNA expression states exist in pancreatic ductal adenocarcinoma (PDAC), but our understanding of their drivers, stability, and relationship to therapeutic response is limited. To examine these attributes systematically, we profiled metastatic biopsies and matched organoid models at single-cell resolution. In vivo, we identify a new intermediate PDAC transcriptional cell state and uncover distinct site- and state-specific tumor microenvironments (TMEs). Benchmarking models against this reference map, we reveal strong culture-specific biases in cancer cell transcriptional state representation driven by altered TME signals. We restore expression state heterogeneity by adding back in vivo-relevant factors and show plasticity in culture models. Further, we prove that non-genetic modulation of cell state can strongly influence drug responses, uncovering state-specific vulnerabilities. This work provides a broadly applicable framework for aligning cell states across in vivo and ex vivo settings, identifying drivers of transcriptional plasticity and manipulating cell state to target associated vulnerabilities.

The KDM5A/RBP2 histone demethylase represses NOTCH signaling to sustain neuroendocrine differentiation and promote small cell lung cancer tumorigenesis.

More than 90% of small cell lung cancers (SCLCs) harbor loss-of-function mutations in the tumor suppressor gene RB1 The canonical function of the RB1 gene product, pRB, is to repress the E2F transcription factor family, but pRB also functions to regulate cellular differentiation in part through its binding to the histone demethylase KDM5A (also known as RBP2 or JARID1A). We show that KDM5A promotes SCLC proliferation and SCLC's neuroendocrine differentiation phenotype in part by sustaining expression of the neuroendocrine transcription factor ASCL1. Mechanistically, we found that KDM5A sustains ASCL1 levels and neuroendocrine differentiation by repressing NOTCH2 and NOTCH target genes. To test the role of KDM5A in SCLC tumorigenesis in vivo, we developed a CRISPR/Cas9-based mouse model of SCLC by delivering an adenovirus (or an adeno-associated virus [AAV]) that expresses Cre recombinase and sgRNAs targeting Rb1, Tp53, and Rbl2 into the lungs of Lox-Stop-Lox Cas9 mice. Coinclusion of a KDM5A sgRNA decreased SCLC tumorigenesis and metastasis, and the SCLCs that formed despite the absence of KDM5A had higher NOTCH activity compared to KDM5A+/+ SCLCs. This work establishes a role for KDM5A in SCLC tumorigenesis and suggests that KDM5 inhibitors should be explored as treatments for SCLC.

Transcriptional regulation of MGE progenitor proliferation by PRDM16 controls cortical GABAergic interneuron production.

The mammalian cortex is populated by neurons derived from neural progenitors located throughout the embryonic telencephalon. Excitatory neurons are derived from the dorsal telencephalon, whereas inhibitory interneurons are generated in its ventral portion. The transcriptional regulator PRDM16 is expressed by radial glia, neural progenitors present in both regions; however, its mechanisms of action are still not fully understood. It is unclear whether PRDM16 plays a similar role in neurogenesis in both dorsal and ventral progenitor lineages and, if so, whether it regulates common or unique networks of genes. Here, we show that Prdm16 expression in mouse medial ganglionic eminence (MGE) progenitors is required for maintaining their proliferative capacity and for the production of proper numbers of forebrain GABAergic interneurons. PRDM16 binds to cis-regulatory elements and represses the expression of region-specific neuronal differentiation genes, thereby controlling the timing of neuronal maturation. PRDM16 regulates convergent developmental gene expression programs in the cortex and MGE, which utilize both common and region-specific sets of genes to control the proliferative capacity of neural progenitors, ensuring the generation of correct numbers of cortical neurons.

Prompt identification of struggling candidates in near peer-led basic life support training: piloting an online performance scoring system.

BACKGROUND: Bristol Medical School has adopted a near peer-led teaching approach to deliver Basic Life Support training to first year undergraduate medical students. Challenges arose when trying to identify early in the course which candidates were struggling with their learning, in sessions delivered to large cohorts. We developed and piloted a novel, online performance scoring system to better track and highlight candidate progress. METHODS: During this pilot, a 10-point scale was used to evaluate candidate performance at six time-points during their training. The scores were collated and entered on an anonymised secure spreadsheet, which was conditionally formatted to provide a visual representation of the score. A One-Way ANOVA was performed on the scores and trends analysed during each course to review candidate trajectory. Descriptive statistics were assessed. Values are presented as mean scores with standard deviation (x̄±SD). RESULTS: A significant linear trend was demonstrated (P < 0.001) for the progression of candidates over the course. The average session score increased from 4.61 ± 1.78 at the start to 7.92 ± 1.22 at the end of the final session. A threshold of less than 1SD below the mean was used to identify struggling candidates at any of the six given timepoints. This threshold enabled efficient highlighting of struggling candidates in real time. CONCLUSIONS: Although the system will be subject to further validation, our pilot has shown the use of a simple 10-point scoring system in combination with a visual representation of performance helps to identify struggling candidates earlier across large cohorts of students undertaking skills training such as Basic Life Support. This early identification enables effective and efficient remedial support.

Cross-cultural adaptation and its impact on research in emergency care.

The perspective of patients is increasingly recognised as important to care improvement and innovation. Patient questionnaires such as patient-reported outcome measures may often require cross-cultural adaptation (CCA) to gather their intended information most effectively when used in cultures and languages different to those in which they were developed. The use of CCA could be seen as a practical step in addressing the known problems of inclusion, diversity and access in medical research.An example of the recent adaptation of a patient-reported outcome measure for use with ED patients is used to explore some key features of CCA, introduce the importance of CCA to emergency care practitioners and highlight the limitations of CCA.

Atypical Protein Phosphatase 2A Gene Families Do Not Expand via Paleopolyploidization.

Protein phosphatase 2A (PP2A) presents unique opportunities for analyzing molecular mechanisms of functional divergence between gene family members. The canonical PP2A holoenzyme regulates multiple eukaryotic signaling pathways by dephosphorylating target proteins and contains a catalytic (C) subunit, a structural/scaffolding (A) subunit, and a regulatory (B) subunit. Genes encoding PP2A subunits have expanded into multigene families in both flowering plants and mammals, and the extent to which different isoform functions may overlap is not clearly understood. To gain insight into the diversification of PP2A subunits, we used phylogenetic analyses to reconstruct the evolutionary histories of PP2A gene families in Arabidopsis (Arabidopsis thaliana). Genes encoding PP2A subunits in mammals represent ancient lineages that expanded early in vertebrate evolution, while flowering plant PP2A subunit lineages evolved much more recently. Despite this temporal difference, our data indicate that the expansion of PP2A subunit gene families in both flowering plants and animals was driven by whole-genome duplications followed by nonrandom gene loss. Selection analysis suggests that the expansion of one B subunit gene family (B56/PPP2R5) was driven by functional diversification rather than by the maintenance of gene dosage. We also observed reduced expansion rates in three distinct B subunit subclades. One of these subclades plays a highly conserved role in cell division, while the distribution of a second subclade suggests a specialized function in supporting beneficial microbial associations. Thus, while whole-genome duplications have driven the expansion and diversification of most PP2A gene families, members of functionally specialized subclades quickly revert to singleton status after duplication events.

Producing the Ethylene Signal: Regulation and Diversification of Ethylene Biosynthetic Enzymes.

Strictly controlled production of ethylene gas lies upstream of the signaling activities of this crucial regulator throughout the plant life cycle. Although the biosynthetic pathway is enzymatically simple, the regulatory circuits that modulate signal production are fine tuned to allow integration of responses to environmental and intrinsic cues. Recently identified posttranslational mechanisms that control ethylene production converge on one family of biosynthetic enzymes and overlay several independent reversible phosphorylation events and distinct mediators of ubiquitin-dependent protein degradation. Although the core pathway is conserved throughout seed plants, these posttranslational regulatory mechanisms may represent evolutionarily recent innovations. The evolutionary origins of the pathway and its regulators are not yet clear; outside the seed plants, numerous biochemical and phylogenetic questions remain to be addressed.

Identification of Open Stomata1-Interacting Proteins Reveals Interactions with Sucrose Non-fermenting1-Related Protein Kinases2 and with Type 2A Protein Phosphatases That Function in Abscisic Acid Responses.

The plant hormone abscisic acid (ABA) controls growth and development and regulates plant water status through an established signaling pathway. In the presence of ABA, pyrabactin resistance/regulatory component of ABA receptor proteins inhibit type 2C protein phosphatases (PP2Cs). This, in turn, enables the activation of Sucrose Nonfermenting1-Related Protein Kinases2 (SnRK2). Open Stomata1 (OST1)/SnRK2.6/SRK2E is a major SnRK2-type protein kinase responsible for mediating ABA responses. Arabidopsis (Arabidopsis thaliana) expressing an epitope-tagged OST1 in the recessive ost1-3 mutant background was used for the copurification and identification of OST1-interacting proteins after osmotic stress and ABA treatments. These analyses, which were confirmed using bimolecular fluorescence complementation and coimmunoprecipitation, unexpectedly revealed homo- and heteromerization of OST1 with SnRK2.2, SnRK2.3, OST1, and SnRK2.8. Furthermore, several OST1-complexed proteins were identified as type 2A protein phosphatase (PP2A) subunits and as proteins involved in lipid and galactolipid metabolism. More detailed analyses suggested an interaction network between ABA-activated SnRK2-type protein kinases and several PP2A-type protein phosphatase regulatory subunits. pp2a double mutants exhibited a reduced sensitivity to ABA during seed germination and stomatal closure and an enhanced ABA sensitivity in root growth regulation. These analyses add PP2A-type protein phosphatases as another class of protein phosphatases to the interaction network of SnRK2-type protein kinases.

A genome-scale shRNA resource for transgenic RNAi in Drosophila.

Existing transgenic RNAi resources in Drosophila melanogaster based on long double-stranded hairpin RNAs are powerful tools for functional studies, but they are ineffective in gene knockdown during oogenesis, an important model system for the study of many biological questions. We show that shRNAs, modeled on an endogenous microRNA, are extremely effective at silencing gene expression during oogenesis. We also describe our progress toward building a genome-wide shRNA resource.

FlyRNAi.org--the database of the Drosophila RNAi screening center: 2012 update.

FlyRNAi (http://www.flyrnai.org), the database and website of the Drosophila RNAi Screening Center (DRSC) at Harvard Medical School, serves a dual role, tracking both production of reagents for RNA interference (RNAi) screening in Drosophila cells and RNAi screen results. The database and website is used as a platform for community availability of protocols, tools, and other resources useful to researchers planning, conducting, analyzing or interpreting the results of Drosophila RNAi screens. Based on our own experience and user feedback, we have made several changes. Specifically, we have restructured the database to accommodate new types of reagents; added information about new RNAi libraries and other reagents; updated the user interface and website; and added new tools of use to the Drosophila community and others. Overall, the result is a more useful, flexible and comprehensive website and database.

Patients who call emergency ambulances for primary care problems: a qualitative study of the decision-making process.

BACKGROUND: Telephone calls for emergency ambulances are rising annually, increasing the pressure on ambulance resources for clinical problems that could often be appropriately managed in primary care. OBJECTIVE: To explore and understand patient and carer decision making around calling an ambulance for primary care-appropriate health problems. METHODS: Semistructured interviews were conducted with patients and carers who had called an ambulance for a primary care-appropriate problem. Participants were identified using a purposive sampling method by a non-participating research clinician attending '999' ambulance calls. A thematic analysis of interview transcripts was undertaken. RESULTS: A superordinate theme, patient and carer anxiety in urgent-care decision making, and four subthemes were explored: perceptions of ambulance-based urgent care; contrasting perceptions of community-based urgent care; influence of previous urgent care experiences in decision making; and interpersonal factors in lay assessment and management of medical risk and subsequent decision making. CONCLUSIONS: Many calls are based on fundamental misconceptions about the types of treatment other urgent-care avenues can provide, which may be amenable to educational intervention. This is particularly relevant for patients with chronic conditions with frequent exacerbations. Callers who have care responsibilities often default to the most immediate response available, with decision making driven by a lower tolerance of perceived risk. There may be a greater role for more detailed triage in these cases, and closer working between ambulance responses and urgent primary care, as a perceived or actual distance between these two service sectors may be influencing patient decision making on urgent care.

Understanding paramedic work in general practice in the UK: a rapid realist synthesis.

BACKGROUND: General practice in the UK is under substantial pressure and practices are increasingly including paramedics as part of their workforce. Little is known about how different models of paramedic working may affect successful implementation of the role, as viewed from patient, clinician and system perspectives. This realist synthesis developed theories about 'models of paramedic working in general practice' in different UK contexts to understand their impact. METHODS: The rapid realist synthesis comprised data from: (1) empirical and grey literature searches; (2) semi-structured realist interviews with system leaders involved with the implementation of the role; and (3) a stakeholder event with healthcare professionals and the public, to develop initial programme theories that can be tested in future work. Sources were analysed using a realist approach that explored the data for novel or causal insights to generate initial programme theories. RESULTS: Empirical sources (n = 32), grey sources (n = 95), transcripts from system leader interviews (n = 7) and audio summaries from the stakeholder event (n = 22 participants) were synthesised into a single narrative document. The findings confirmed the presence of a wide variety of models of paramedic working in UK general practice. The perceived success of models was influenced by the extent to which the paramedic service was mature and embedded in practice, and according to four theory areas: (1) Primary care staff understanding and acceptance of the paramedic role; (2) Paramedic induction process, including access to training, supervision and development opportunities; (3) Patient understanding and acceptance of the role; (4) Variations in paramedic employment models. CONCLUSIONS: Variability in how the paramedic role is operating and embedding into general practice across the UK affects the success of the role. These findings provide a theoretical foundation for future research to investigate various 'models of paramedic working' in different contexts.

Lineage-specific canonical and non-canonical activity of EZH2 in advanced prostate cancer subtypes.

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and emerging therapeutic target that is overexpressed in most castration-resistant prostate cancers and implicated as a driver of disease progression and resistance to hormonal therapies. Here we define the lineage-specific action and differential activity of EZH2 in both prostate adenocarcinoma (PRAD) and neuroendocrine prostate cancer (NEPC) subtypes of advanced prostate cancer to better understand the role of EZH2 in modulating differentiation, lineage plasticity, and to identify mediators of response and resistance to EZH2 inhibitor therapy. Mechanistically, EZH2 modulates bivalent genes that results in upregulation of NEPC-associated transcriptional drivers (e.g., ASCL1) and neuronal gene programs, and leads to forward differentiation after targeting EZH2 in NEPC. Subtype-specific downstream effects of EZH2 inhibition on cell cycle genes support the potential rationale for co-targeting cyclin/CDK to overcome resistance to EZH2 inhibition.

GP roles in emergency medical services: a systematic mapping review and narrative synthesis.

BACKGROUND: A significant proportion of emergency medical services (EMS) work is for problems that may be amenable to timely primary care management and could benefit from GP input. Utilising GPs in EMS may reduce avoidable emergency department (ED) conveyance, releasing emergency ambulances for higher-acuity care, and meeting patient needs earlier in the evolution of an emergency call. AIM: To collate and summarise evidence on how GPs are utilised in EMS. DESIGN & SETTING: Systematic mapping review and narrative synthesis. METHOD: A systematic literature search was conducted using search terms for general practice and emergency care. Primary research articles investigating the utilisation of GPs in non-critical EMS were included. An inductive framework was used to structure the results alongside a narrative synthesis. RESULTS: Twenty-one articles were included. GPs were embedded in EMS for urgent management of high-acuity patients or used as an intervention to avoid unnecessary ED conveyance in selected lower-acuity patients. The importance of interprofessional relationships and training for GPs involved in EMS was highlighted. No studies explored patient-reported outcomes. Outcomes measured were predominantly ED non-conveyance and admission avoidance, with GP services as an intervention reducing the likelihood of these outcomes. CONCLUSION: Embedding GPs in EMS might service different purposes depending on context. There is some evidence that GP EMS services may reduce the likelihood of ED conveyance and hospital admission in selected cases; it is unclear whether this is owing to case selection or GP involvement. Future research should incorporate patients' views and experiences.

Parsing digital or analogue TCR performance through piconewton forces.

αß T-cell receptors (TCRs) recognize aberrant peptides bound to major histocompatibility complex molecules (pMHCs) on unhealthy cells, amplifying specificity and sensitivity through physical load placed on the TCR-pMHC bond during immunosurveillance. To understand this mechanobiology, TCRs stimulated by abundantly and sparsely arrayed epitopes (NP 366-374 /D b and PA 224-233 /D b , respectively) following in vivo influenza A virus infection were studied with optical tweezers. While certain NP repertoire CD8 T lymphocytes require many ligands for activation, others are digital, needing just few. Conversely, all PA TCRs perform digitally, exhibiting pronounced bond lifetime increases through sustained, energizing volleys of structural transitioning. Optimal digital performance is superior in vivo, correlating with ERK phosphorylation, CD3 loss, and activation marker upregulation in vitro . Given neoantigen array paucity, digital TCRs are likely critical for immunotherapies. One Sentence Summary: Quality of ligand recognition in a T-cell repertoire is revealed through application of physical load on clonal T-cell receptor (TCR)-pMHC bonds.

KDM6A epigenetically regulates subtype plasticity in small cell lung cancer.

Small cell lung cancer (SCLC) exists broadly in four molecular subtypes: ASCL1, NEUROD1, POU2F3 and Inflammatory. Initially, SCLC subtypes were thought to be mutually exclusive, but recent evidence shows intra-tumoural subtype heterogeneity and plasticity between subtypes. Here, using a CRISPR-based autochthonous SCLC genetically engineered mouse model to study the consequences of KDM6A/UTX inactivation, we show that KDM6A inactivation induced plasticity from ASCL1 to NEUROD1 resulting in SCLC tumours that express both ASCL1 and NEUROD1. Mechanistically, KDM6A normally maintains an active chromatin state that favours the ASCL1 subtype with its loss decreasing H3K4me1 and increasing H3K27me3 at enhancers of neuroendocrine genes leading to a cell state that is primed for ASCL1-to-NEUROD1 subtype switching. This work identifies KDM6A as an epigenetic regulator that controls ASCL1 to NEUROD1 subtype plasticity and provides an autochthonous SCLC genetically engineered mouse model to model ASCL1 and NEUROD1 subtype heterogeneity and plasticity, which is found in 35-40% of human SCLCs.

ALK Amplification and Rearrangements Are Recurrent Targetable Events in Congenital and Adult Glioblastoma.

PURPOSE: Anaplastic lymphoma kinase (ALK) aberrations have been identified in pediatric-type infant gliomas, but their occurrence across age groups, functional effects, and treatment response has not been broadly established. EXPERIMENTAL DESIGN: We performed a comprehensive analysis of ALK expression and genomic aberrations in both newly generated and retrospective data from 371 glioblastomas (156 adult, 205 infant/pediatric, and 10 congenital) with in vitro and in vivo validation of aberrations. RESULTS: ALK aberrations at the protein or genomic level were detected in 12% of gliomas (45/371) in a wide age range (0-80 years). Recurrent as well as novel ALK fusions (LRRFIP1-ALK, DCTN1-ALK, PRKD3-ALK) were present in 50% (5/10) of congenital/infant, 1.4% (3/205) of pediatric, and 1.9% (3/156) of adult GBMs. ALK fusions were present as the only candidate driver in congenital/infant GBMs and were sometimes focally amplified. In contrast, adult ALK fusions co-occurred with other oncogenic drivers. No activating ALK mutations were identified in any age group. Novel and recurrent ALK rearrangements promoted STAT3 and ERK1/2 pathways and transformation in vitro and in vivo. ALK-fused GBM cellular and mouse models were responsive to ALK inhibitors, including in patient cells derived from a congenital GBM. Relevant to the treatment of infant gliomas, we showed that ALK protein appears minimally expressed in the forebrain at perinatal stages, and no gross effects on perinatal brain development were seen in pregnant mice treated with the ALK inhibitor ceritinib. CONCLUSIONS: These findings support use of brain-penetrant ALK inhibitors in clinical trials across infant, pediatric, and adult GBMs. See related commentary by Mack and Bertrand, p. 2567.

Mental health and help seeking among trauma-exposed emergency service staff: a qualitative evidence synthesis.

OBJECTIVES: To identify factors and contexts that may contribute to mental health and recovery from psychological difficulties for emergency service workers (ESWs) exposed to occupational trauma, and barriers and facilitators to help-seeking behaviour among trauma-exposed ESWs. BACKGROUND: ESWs are at greater risk of stressor-related psychopathology than the general population. Exposure to occupational stressors and trauma contribute to the observed rates of post-trauma psychopathology in this occupational group with implications for workforce sustainability. Types of organisational interventions offered to trauma-exposed ESWs are inconsistent across the UK, with uncertainty around how to engage staff. DESIGN: Four databases (OVID MEDLINE, EMBASE, PsycINFO and SCOPUS) were systematically searched from 1 January 1980 to March 2020, with citation tracking and reference chaining. A modified Critical Appraisal Skills Programme tool and quality appraisal prompts were used to identify fatally flawed studies. Qualitative studies of trauma-exposure in front-line ESWs were included, and data were extracted using a customised extraction table. Included studies were analysed using thematic synthesis. RESULTS: A qualitative evidence synthesis was conducted with 24 qualitative studies meeting inclusion criteria, as defined by the PerSPEcTiF framework. Fourteen descriptive themes emerged from this review, categorised into two overarching constructs: (1) factors contributing to mental health (such as the need for downtime, peer support and reassurance) and (2) factors influencing help-seeking behaviour (such as stigma, the content/form/mandatory nature of interventions, and mental health literacy issues including emotional awareness and education). CONCLUSION: ESWs reported disconnect between the organisations' cultural positioning on trauma-related mental health, the reality of undertaking the role and the perceived applicability and usefulness of trauma interventions. Following traumatic exposure, ESWs identify benefitting from recovery time and informal support from trusted colleagues. A culture which encourages help seeking and open dialogue around mental health may reduce stigma and improve recovery from mental ill health associated with trauma exposure.

Potential for Paramedic roles in Irish General Practice: A qualitative study of stakeholder's perspectives.

Background: Irish health policy emphasises the role of Primary Care and General Practice however, there is a growing shortage of General Practitioners (GPs) in Ireland. Paramedics have traditionally focused on emergency care in the community. More recently Paramedics have taken on roles in General Practice in international jurisdictions, but not yet in Ireland. This study aimed to explore key stakeholder perceptions of 'the potential for Paramedic roles in Irish General Practice'. Methods: We conducted an exploratory, qualitative stakeholder consultation study incorporating in-depth semi structured telephone interviews followed by thematic analysis. Interviews were conducted with a total of eighteen participants that included six senior Paramedics (Advanced Paramedics), seven General Practitioners (GPs), three Practice Nurses and two Practice Managers. Results: Participants in this study expressed polarised views on the potential for Paramedic roles in Irish General Practice. Paramedics were enthusiastic, highlighting opportunity for professional development and favourable working conditions. GPs, Practice Nurses and Managers were more circumspect and had concerns that Paramedic scope and skillset was not currently aligned to General Practice care. GPs, Practice Nurses and Managers emphasised a greater role for expanded General Practice Nursing. There were varied perceptions on what the potential role of a Paramedic in General Practice might entail, but consensus that Government support would be required to facilitate any potential developments. Conclusions: The findings of this research can inform future development of novel roles in Irish General Practice and suggests that there is appetite from within the Paramedic profession to pursue such roles. A pilot demonstration project, grounded in an action research framework could address data gaps and potential concerns. Any future developments should occur in tandem with and with due consideration for the expansion of General Practice Nursing in Ireland.

Regression discontinuity analysis for pharmacovigilance: statin example reflected trial findings showing little evidence of harm.

OBJECTIVES: The study aims to explore the use of regression discontinuity analysis (RDA) to examine effects of prescription of statins on total cholesterol and adverse outcomes (type 2 diabetes, rhabdomyolysis and myopathy, myalgia and myositis, liver disease, CVD, and mortality). STUDY DESIGN AND SETTING: We conducted a prospective cohort study using the Clinical Practice Research Datalink including patients with QRISK scores of 10 to 30 in 2010 to 2013 who were last followed-up in October 2016. Comparing patients with QRISK≥20 and QRISK<20, we explored RDA assumptions, provided proof of concept analyses (total cholesterol as outcome), and investigated the effect of statins prescription on adverse outcomes. RESULT: RDA confirmed statin prescription reduced total cholesterol (Mean difference (MD) -1.33 mmol/L, 95%Confidence Interval (CI) -1.93 to -0.73). RDA provided little evidence for adverse effects on diabetes, myalgia and myositis, liver disease, CVD, or mortality. The RDA analysis findings are similar to RCT results. Findings from non-RDA analysis agree with published observational studies. CONCLUSION: RDA can be used with large routine clinical datasets to provide evidence on effects of medications which are prescribed according to a threshold. Testable RDA assumptions were satisfied, but confidence intervals were wide, partly due to the low compliance with the prescribing threshold.