Don't be misled: Three misconceptions about external validation of clinical prediction models.

Clinical prediction models provide risks of health outcomes that can inform patients and support medical decisions. However, most models never make it to actual implementation in practice. A commonly heard reason for this lack of implementation is that prediction models are often not externally validated. While we generally encourage external validation, we argue that an external validation is often neither sufficient nor required as an essential step before implementation. As such, any available external validation should not be perceived as a license for model implementation. We clarify this argument by discussing three common misconceptions about external validation. We argue that there is not one type of recommended validation design, not always a necessity for external validation, and sometimes a need for multiple external validations. The insights from this paper can help readers to consider, design, interpret, and appreciate external validation studies.

Predictive factors of clot propagation in patients with superficial venous thrombosis towards deep venous thrombosis and pulmonary embolism: a systematic review and meta-analysis.

OBJECTIVE: A subset of patients with superficial venous thrombosis (SVT) experiences clot propagation towards deep venous thrombosis (DVT) and/or pulmonary embolism (PE). The aim of this systematic review is to identify all clinically relevant cross-sectional and prognostic factors for predicting thrombotic complications in patients with SVT. DESIGN: Systematic review. DATA SOURCES: PubMed/MEDLINE and Embase were systematically searched until 3 March 2023. ELIGIBILITY CRITERIA: Original research studies with patients with SVT, DVT and/or PE as the outcome and presenting cross-sectional or prognostic predictive factors. DATA EXTRACTION AND SYNTHESIS OF RESULTS: The CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling (CHARMS) checklist for prognostic factor studies was used for systematic extraction of study characteristics. Per identified predictive factor, relevant estimates of univariable and multivariable predictor-outcome associations were extracted, such as ORs and HRs. Estimates of association for the most frequently reported predictors were summarised in forest plots, and meta-analyses with heterogeneity were presented. The Quality in Prognosis Studies (QUIPS) tool was used for risk of bias assessment and Grading of Recommendations, Assessment, Development and Evaluations (GRADE) for assessing the certainty of evidence. RESULTS: Twenty-two studies were included (n=10 111 patients). The most reported predictive factors were high age, male sex, history of venous thromboembolism (VTE), absence of varicose veins and cancer. Pooled effect estimates were heterogenous and ranged from OR 3.12 (95% CI 1.75 to 5.59) for the cross-sectional predictor cancer to OR 0.92 (95% CI 0.56 to 1.53) for the prognostic predictor high age. The level of evidence was rated very low to low. Most studies were scored high or moderate risk of bias. CONCLUSIONS: Although the pooled estimates of the predictors high age, male sex, history of VTE, cancer and absence of varicose veins showed predictive potential in isolation, variability in study designs, lack of multivariable adjustment and high risk of bias prevent firm conclusions. High-quality, multivariable studies are necessary to be able to identify individual SVT risk profiles. PROSPERO REGISTRATION NUMBER: CRD42021262819.

[Coumarin or DOAC in frail elderly patients with atrial fibrillation?] / Cumarine of DOAC bij kwetsbare ouderen met atriumfibrilleren?

OBJECTIVE: To investigate whether frail elderly people with atrial fibrillation (AF) who are currently using a vitamin K antagonist (VKA) should be switched to a direct-acting oral anticoagulant (DOAC). DESIGN: Randomized clinical trial. METHODS: 662 frail elderly AF patients were switched to a DOAC, and 661 patients continued their VKA. The primary endpoint was a major or clinically relevant non-major bleeding during 1 year of follow-up. Secondary endpoints included thrombo-embolic events. RESULTS: The mean age of the included patients was 83 years. In the 'switch to DOAC arm', 101 bleeding events (15.3%) occurred and in the 'continue with VKA arm', 62 bleeding events (9.4%); an increase of 69% more bleeding events (P-value 0.001). The number of thrombo-embolic events was not significantly different between both groups. CONCLUSION: Switching from a VKA to a DOAC in frail elderly people with AF leads to 69% more bleeding, without a difference in thrombo-embolic events.

Practice visitations in primary care to improve performance of cardiovascular risk management.

BACKGROUND: Despite programmatic protocolized care and structured support, considerable variation is observed in completeness of registration and achieving targets of cardiovascular risk management between individual general practitioners in the Netherlands. AIM: To determine whether completeness of registration and achieved targets of cardiovascular risk factors improves with practice visitation. DESIGN & SETTING: Observational study utilizing the care groups' database (2016-2019) comparing changes in registration and achieved targets in non-visited practices and visited practices. METHOD: We compared completeness scores of registration and scores of targets achieved before visitation and 1 year after visitation. Data were analyzed on patient level and on general practitioners level. Separate analyses were performed among general practitioners who were ranked in the lower 25% of score distributions. RESULTS: We observed no clinically relevant improvements in completeness of registration and targets achieved in 2017, 2018 and 2019 that could be attributed to visitations in the previous year, both on individual patient level as on aggregated level per general practice.In practices ranked in the lower 25% of the distribution, improvements over time were clinically relevant and larger than the overall changes. Yet, these findings were irrespective of the number of practice visitations. CONCLUSION: Practice visitations in our setting did not seem to lead to improvements in practice performance, nor in completeness of registration of risk factors or in reaching predefined target goals for cardiovascular risk factors.

Patient characteristics and reasons for discontinuation in a cardiovascular risk management programme in The Netherlands.

BACKGROUND: Since 2010, an increasing number of patients have participated in a nurse-led integrated cardiovascular risk management programme in the Netherlands. Because it is important to understand which patients discontinue and why, when evaluating the effectiveness of the care programme, the aim was to identify the reasons for discontinuation. METHODS: Electronic health records of 3997 patients enrolled in a nurse-led integrated cardiovascular risk management programme that started on April 1st, 2010, were manually scrutinized for reasons for discontinuation between April 1st, 2010, and April 1st, 2018. In addition to death and moving to a diabetes care programme, we describe 7 different reasons why patients discontinued the programme and compared the patient characteristics of those who discontinued the programme without specific reasons with those who remained in the care programme for 8 years. RESULTS: Between April 1st, 2010, and April 1st, 2018, 1,190 participants (29.8%) discontinued the CVRM care programme, of whom 271 participants died (6.8%) and 195 were transferred to a diabetes care programme (4.9%). The remaining 724 patients (18.1%) participated 5 years before discontinuation. Of these, 67 (9.3%) had a previous cardiovascular event at the start of the programme. In 355 patients, a specific reason for discontinuation was not found. At baseline, these patients less frequently had a history of CVD than those who continued the programme for 8 years (1.7 vs. 22.6%), were younger (62 vs. 67 years), had less registered cardiovascular comorbidity (atrial fibrillation: 1.1 vs. 7.2%; congestive heart failure 0.3 vs. 1.2%; chronic kidney disease 0.0 vs. 4.5%), were more often smokers (13.0% vs. 4.3%) and took blood pressure- and lipid-lowering drugs twice as often. CONCLUSIONS: In our study we observed that participants who discontinued the nurse-led integrated CVRM care programme between 2010 and 2018 without specific reason or on request were younger, without previous CVD, had less cardiovascular comorbidity and were better adjusted to medication. Exploring the patients' reasons for discontinuation can contribute to an individualized approach to prevent or reduce discontinuation.

Safety of Switching From a Vitamin K Antagonist to a Non-Vitamin K Antagonist Oral Anticoagulant in Frail Older Patients With Atrial Fibrillation: Results of the FRAIL-AF Randomized Controlled Trial.

BACKGROUND: There is ambiguity whether frail patients with atrial fibrillation managed with vitamin K antagonists (VKAs) should be switched to a non-vitamin K oral anticoagulant (NOAC). METHODS: We conducted a pragmatic, multicenter, open-label, randomized controlled superiority trial. Older patients with atrial fibrillation living with frailty (≥75 years of age plus a Groningen Frailty Indicator score ≥3) were randomly assigned to switch from international normalized ratio-guided VKA treatment to an NOAC or to continued VKA treatment. Patients with a glomerular filtration rate <30 mL·min-1·1.73 m-2 or with valvular atrial fibrillation were excluded. Follow-up was 12 months. The cause-specific hazard ratio was calculated for occurrence of the primary outcome that was a major or clinically relevant nonmajor bleeding complication, whichever came first, accounting for death as a competing risk. Analyses followed the intention-to-treat principle. Secondary outcomes included thromboembolic events. RESULTS: Between January 2018 and June 2022, a total of 2621 patients were screened for eligibility and 1330 patients were randomly assigned (mean age 83 years, median Groningen Frailty Indicator score 4). After randomization, 6 patients in the switch-to-NOAC arm and 1 patient in the continue-with-VKA arm were excluded due to the presence of exclusion criteria, leaving 662 patients switched from a VKA to an NOAC and 661 patients continued VKAs in the intention-to-treat population. After 163 primary outcome events (101 in the switch arm, 62 in the continue arm), the trial was stopped for futility according to a prespecified futility analysis. The hazard ratio for our primary outcome was 1.69 (95% CI, 1.23-2.32). The hazard ratio for thromboembolic events was 1.26 (95% CI, 0.60-2.61). CONCLUSIONS: Switching international normalized ratio-guided VKA treatment to an NOAC in frail older patients with atrial fibrillation was associated with more bleeding complications compared with continuing VKA treatment, without an associated reduction in thromboembolic complications. REGISTRATION: URL: https://eudract.ema.europa.eu; Unique identifier: 2017-000393-11. URL: https://eudract.ema.europa.eu; Unique identifier: 6721 (FRAIL-AF study).

Incidence and individual risk prediction of post-COVID-19 cardiovascular disease in the general population: a multivariable prediction model development and validation study.

Aims: Previous studies suggest relatively increased cardiovascular risk after COVID-19 infection. This study assessed incidence and explored individual risk and timing of cardiovascular disease occurring post-COVID-19 in a large primary care database. Methods and results: Data were extracted from the UK's Clinical Practice Research Datalink. Incidence rates within 180 days post-infection were estimated for arterial or venous events, inflammatory heart disease, and new-onset atrial fibrillation or heart failure. Next, multivariable logistic regression models were developed on 220 751 adults with COVID-19 infection before 1 December 2020 using age, sex and traditional cardiovascular risk factors. All models were externally validated in (i) 138 034 vaccinated and (ii) 503 404 unvaccinated adults with a first COVID-19 infection after 1 December 2020. Discriminative performance and calibration were evaluated with internal and external validation. Increased incidence rates were observed up to 60 days after COVID-19 infection for venous and arterial cardiovascular events and new-onset atrial fibrillation, but not for inflammatory heart disease or heart failure, with the highest rate for venous events (13 per 1000 person-years). The best prediction models had c-statistics of 0.90 or higher. However, <5% of adults had a predicted 180-day outcome-specific risk larger than 1%. These rare outcomes complicated calibration. Conclusion: Risks of arterial and venous cardiovascular events and new-onset atrial fibrillation are increased within the first 60 days after COVID-19 infection in the general population. Models' c-statistics suggest high discrimination, but because of the very low absolute risks, they are insufficient to inform individual risk management.

Integrated care in patients with atrial fibrillation- a predictive heterogeneous treatment effect analysis of the ALL-IN trial.

INTRODUCTION: Integrated care is effective in reducing all-cause mortality in patients with atrial fibrillation (AF) in primary care, though time and resource intensive. The aim of the current study was to assess whether integrated care should be directed at all AF patients equally. METHODS: The ALL-IN trial (n = 1,240 patients, median age 77 years) was a cluster-randomized trial in which primary care practices were randomized to provide integrated care or usual care to AF patients aged 65 years and older. Integrated care comprised of (i) anticoagulation monitoring, (ii) quarterly checkups and (iii) easy-access consultation with cardiologists. For the current analysis, cox proportional hazard analysis with all clinical variables from the CHA2DS2-VASc score was used to predict all-cause mortality in the ALL-IN trial. Subsequently, the hazard ratio and absolute risk reduction were plotted as a function of this predicted mortality risk to explore treatment heterogeneity. RESULTS: Under usual care, after a median of 2 years follow-up the absolute risk of all-cause mortality in the highest-risk quarter was 31.0%, compared to 4.6% in the lowest-risk quarter. On the relative scale, there was no evidence of treatment heterogeneity (p for interaction = 0.90). However, there was substantial treatment heterogeneity on the absolute scale: risk reduction in the lowest risk- quarter of risk 3.3% (95% CI -0.4% - 7.0) compared to 12.0% (95% CI 2.7% - 22.0) in the highest risk quarter. CONCLUSION: While the relative degree of benefit from integrated AF care is similar in all patients, patients with a high all-cause mortality risk have a greater benefit on an absolute scale and should therefore be prioritized when implementing integrated care.

Screening over 100 000 patients in 39 general practices in the Netherlands for anticoagulation underprescription in atrial fibrillation: a descriptive, cross-sectional study.

OBJECTIVES: To investigate the underprescription of oral anticoagulation (OAC) in individual atrial fibrillation (AF) patients in primary care. SETTING: Screening of patient records in 39 participating general practitioners (GPs) across the Netherlands. PARTICIPANTS: We screened 101 207 patient records identifying 2375 non-valvular AF patients. METHODS: Using electronic patient files, we were able to screen the entire GP population for AF, CHA2DS2-VASc stroke risk scores, and the use of guidelines recommended OAC prescription. In case of a deviation from guidelines recommended OAC prescription, we checked the electronic patient file for any documented reason. Additionally, 6 weeks following the screening, we asked all GPs to provide information on any actions taken for the underprescribed patients. RESULTS: We found a mean CHA2DS2-VASc score of 3.2. OAC prescription consisted of direct OAC in 1342/1984 (68%) and vitamin K-antagonists in the remainder of patients. OAC underprescription was present in 93/944 (9.9%) females and 101/1374 (9.7%) in males, respectively. In 111/146 (76.0%) of the underprescribed AF patients, no reason to withhold OAC was reported. Reported reasons to withhold OAC were patient refusal (n=10), cardiologist advice (n=7) and high risk of bleeding (n=7). Data regarding actions following the identification of OAC underprescription were available for 92/194 (47%) of the OAC underprescribed cases. After consultation OAC was initiated in 9/92 (10%) only. CONCLUSIONS: In this large Dutch study among GPs, we observed 9.8% underprescription of OAC in AF patients. In 76% of the AF patients lacking a prescription for OAC, no documentation for deviating from the guidelines was found. Only in a minority of cases detection of OAC underprescription lead to OAC initiation.

Clinical consequences of off-label reduced dosing of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation: a systematic review and meta-analysis.

OBJECTIVE: Postmarketing observational studies report that a substantial percentage of patients with atrial fibrillation (AF) receive a reduced non-vitamin K antagonist oral anticoagulant (NOAC) dose without a clear indication. Recently, increasing evidence has become available to explore the clinical consequences of such off-label reduced dosing (OLRD). This study aims to systematically review and meta-analyse observational studies that report clinical outcomes associated with OLRD of NOACs compared with on-label non-reduced dosing (OLNRD) of NOACs in patients with AF. METHODS AND ANALYSIS: We performed a systematic literature review and meta-analysis of observational studies reporting clinical outcomes in AF patients with OLRD of an NOAC compared with AF patients with OLNRD of an NOAC. Using random effects meta-analyses, we estimated the risk of stroke/thromboembolism, bleeding and all-cause mortality. RESULTS: We included 19 studies with a total of 170 394 NOAC users. In these studies, the percentage of OLRD among patients with an indication for an on-label non-reduced NOAC dose ranged between 9% and 53%. 7 of these 19 studies met the predefined criteria for meta-analysis (n=80 725 patients). The pooled HR associated with OLRD of NOACs was 1.04 (95% CI 0.83 to 1.29; 95% prediction interval (PI) 0.60 to 1.79) for stroke/thromboembolism, 1.10 (95% CI 0.95 to 1.29; 95% PI 0.81 to 1.50) for bleeding and 1.22 (95% CI 0.81 to 1.84; 95% PI 0.55 to 2.70) for all-cause mortality. CONCLUSION: This meta-analysis shows no statistically significant increased risk of stroke/thromboembolism, nor a decreased bleeding risk, nor a difference in risk of all-cause mortality in patients with OLRD of NOACs. Future research may focus on differences between NOACs.

Prescribing of low-dose rivaroxaban in patients with atherosclerotic cardiovascular disease in the United Kingdom and the Netherlands.

AIMS: Low-dose rivaroxaban has been indicated for the management of atherosclerotic cardiovascular disease (ASCVD) after recent (2019-2020) updates to European guidelines. We aimed to describe prescription trends of low-dose rivaroxaban in ASCVD patients over the period 2015-2022 in two European countries, to compare the trends before and after guideline changes, and to determine the characteristics of users. METHODS: In a cross-sectional interrupted time series analysis, utilization of low-dose rivaroxaban (2.5 mg, twice daily) was measured in Clinical Practice Research Datalink Aurum (United Kingdom [UK]) and the PHARMO Database Network (the Netherlands) from 1 January 2015 to 28 February 2022 in patients with an ASCVD diagnosis. Incidence rates (IRs) and incidence rate ratios (IRRs) of new use (within 182 days) compared to the reference period, 2015-2018, were calculated. Age, sex and comorbidities of users were compared to those of nonusers. RESULTS: In the UK, from 721 271 eligible subjects the IR of new use of low-dose rivaroxaban in the period 2015-2018, before guideline changes, was 12.4 per 100 000 person-years and after guideline changes in 2020-2022 was 124.0 (IRR 10.0, 95% confidence interval [CI] 8.5, 11.8). In the Netherlands from 394 851 subjects, the IR in 2015-2018 was 2.4 per 100 000 person-years and in 2020 was 16.3 (IRR 6.7, 95% CI 4.0, 11.4). Users were younger (UK mean difference [MD] -6.1 years, Netherlands -2.4 years; P < .05) and more likely to be male (UK difference 11.5%, Netherlands 13.4%; P < .001) than nonusers. CONCLUSIONS: There was a statistically significant increase in the use of low-dose rivaroxaban for the management of ASCVD after guideline changes in the UK and the Netherlands. There were international differences, but low-dose rivaroxaban has not been put into widespread practice.

Cardiovascular risk reduction with integrated care: results of 8 years follow up.

BACKGROUND: Care groups organize integrated cardiovascular risk management programs in primary care for high risk patients. Results of long term cardiovascular risk management are scarce. The aim was to describe changes in low density lipoprotein cholesterol, systolic blood pressure and smoking between 2011 and 2018 in patients participating in an integrated program for cardiovascular risk management organized by a care group in the Netherlands. AIM: To explore whether long-term participation in an integrated cardiovascular risk management program could lead to the improvement of 3 important risk factors for cardiovascular disease. METHODS: A protocol was developed for delegated practice nurse activities. A multidisciplinary data registry was used for uniform registration. The care group organized annual education for general practitioners and practice nurses on cardiovascular topics and regular meetings for practice nurses only to discuss complex patient cases and implementation issues. From 2015 onwards, the care group started with practice visitations to discuss performance and support practices with organizing integrated care. RESULTS: In patients eligible for primary prevention as well as for secondary prevention similar trends were observed: lipid modifying and blood pressure lowering medication increased, mean low density lipoprotein cholesterol and mean systolic blood pressure decreased, patients on target for low density lipoprotein cholesterol and systolic blood pressure increased and the proportion of non-smokers with both low density lipoprotein cholesterol and systolic blood pressure on target increased. Improved registration between 2011 and 2013 was partly responsible for the sharp increase of patients on target for low density lipoprotein cholesterol and systolic blood pressure. CONCLUSION: In patients participating in an integrated cardiovascular risk management program, we saw annual improvements in 3 important cardiovascular risk factors between 2011 and 2018.

Safety of off-label dose reduction of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation.

AIM: To investigate the effects of off-label non-vitamin K oral anticoagulant (NOAC) dose reduction compared with on-label standard dosing in atrial fibrillation (AF) patients in routine care. METHODS: Population-based cohort study using data from the United Kingdom Clinical Practice Research Datalink, comparing adults with non-valvular AF receiving an off-label reduced NOAC dose to patients receiving an on-label standard dose. Outcomes were ischaemic stroke, major/non-major bleeding and mortality. Inverse probability of treatment weighting and inverse probability of censoring weighting on the propensity score were applied to adjust for confounding and informative censoring. RESULTS: Off-label dose reduction occurred in 2466 patients (8.0%), compared with 18 108 (58.5%) on-label standard-dose users. Median age was 80 years (interquartile range [IQR] 73.0-86.0) versus 72 years (IQR 66-78), respectively. Incidence rates were higher in the off-label dose reduction group compared to the on-label standard dose group, for ischaemic stroke (0.94 vs 0.70 per 100 person years), major bleeding (1.48 vs 0.83), non-major bleeding (6.78 vs 6.16) and mortality (10.12 vs 3.72). Adjusted analyses resulted in a hazard ratio of 0.95 (95% confidence interval [CI] 0.57-1.60) for ischaemic stroke, 0.88 (95% CI 0.57-1.35) for major bleeding, 0.81 (95% CI 0.67-0.98) for non-major bleeding and 1.34 (95% CI 1.12-1.61) for mortality. CONCLUSION: In this large population-based study, the hazards for ischaemic stroke and major bleeding were low, and similar in AF patients receiving an off-label reduced NOAC dose compared with on-label standard dose users, while non-major bleeding risk appeared to be lower and mortality risk higher. Caution towards prescribing an off-label reduced NOAC dose is therefore required.

The Frequency of Primary Healthcare Contacts Preceding the Diagnosis of Lower-Extremity Arterial Disease: Do Women Consult General Practice Differently?

Background. Women with lower-extremity arterial disease (LEAD) are often underdiagnosed, present themselves with more advanced disease at diagnosis, and fare worse than men. Objective. To investigate to what extent potential gender differences exist in the frequency and reasons for general practitioner (GP) consultation six months prior to the diagnosis of LEAD, as potential indicators of diagnostic delay. Methods. Individuals older than 18 years diagnosed with LEAD, sampled from the Julius General Practitioner's Network (JGPN), were included and compared with a reference population, matched (1:2.6 ratio) in terms of age, sex, and general practice. We applied a zero-inflated negative binomial (ZINB) regression model. Results. The study population comprised 4044 patients with LEAD (43.5% women) and 10,486 subjects in the reference population (46.3% women). In the LEAD cohort, the number of GP contacts was 2.70 (95% CI: 2.42, 3.02) in women and 2.54 (2.29, 2.82) in men. In the reference cohort, 1.77 (95% CI: 1.62, 1.94) in women and 1.63 (95% CI: 1.50, 1.78) in men. In the LEAD cohort, 21.9% of GP contacts occurred one month prior to diagnosis. In both cohorts and both sexes, the most common cause of consultation during the last month before the index date was cardiovascular problems. Conclusions. Six months preceding the initial diagnosis of LEAD, patients visit the GP more often than a similar population without LEAD, regardless of gender. Reported gender differences in the severity of LEAD at diagnosis do not seem to be explained by a delay in presentation to the GP.

Cardiovascular vulnerability predicts hospitalisation in primary care clinically suspected and confirmed COVID-19 patients: A model development and validation study.

OBJECTIVES: Cardiovascular conditions were shown to be predictive of clinical deterioration in hospitalised patients with coronavirus disease 2019 (COVID-19). Whether this also holds for outpatients managed in primary care is yet unknown. The aim of this study was to determine the incremental value of cardiovascular vulnerability in predicting the risk of hospital referral in primary care COVID-19 outpatients. DESIGN: Analysis of anonymised routine care data extracted from electronic medical records from three large Dutch primary care registries. SETTING: Primary care. PARTICIPANTS: Consecutive adult patients seen in primary care for COVID-19 symptoms in the 'first wave' of COVID-19 infections (March 1 2020 to June 1 2020) and in the 'second wave' (June 1 2020 to April 15 2021) in the Netherlands. OUTCOME MEASURES: A multivariable logistic regression model was fitted to predict hospital referral within 90 days after first COVID-19 consultation in primary care. Data from the 'first wave' was used for derivation (n = 5,475 patients). Age, sex, the interaction between age and sex, and the number of cardiovascular conditions and/or diabetes (0, 1, or ≥2) were pre-specified as candidate predictors. This full model was (i) compared to a simple model including only age and sex and its interaction, and (ii) externally validated in COVID-19 patients during the 'second wave' (n = 16,693). RESULTS: The full model performed better than the simple model (likelihood ratio test p<0.001). Older male patients with multiple cardiovascular conditions and/or diabetes had the highest predicted risk of hospital referral, reaching risks above 15-20%, whereas on average this risk was 5.1%. The temporally validated c-statistic was 0.747 (95%CI 0.729-0.764) and the model showed good calibration upon validation. CONCLUSIONS: For patients with COVID-19 symptoms managed in primary care, the risk of hospital referral was on average 5.1%. Older, male and cardiovascular vulnerable COVID-19 patients are more at risk for hospital referral.

Differences in Symptom Presentation in Women and Men with Confirmed Lower Limb Peripheral Artery Disease: A Systematic Review and Meta-Analysis.

OBJECTIVE: To evaluate the differences in symptoms between men and women that present with lower limb peripheral artery disease (PAD). DATA SOURCES: Systematic review and meta-analysis using PubMed, EMBASE, and the Cochrane Library. REVIEW METHODS: A systematic search of the literature to identify studies that examined PAD and its symptoms using PubMed, EMBASE, and the Cochrane Library, which were screened in duplicate by two reviewers. Information on study design, source of data, population characteristics, and outcomes of interest was extracted and used the Newcastle-Ottawa Scale and Cochrane risk of bias tool. Quality of evidence was rated using the GRADE methodology. Estimates of relative effects were pooled to generate pooled odds ratios (OR) and their 95% confidence interval (CI) using a random effects model. RESULTS: Thirteen cross sectional studies, six cohorts, one case control, and one randomised clinical trial, reporting on 1 929 966 patients with confirmed PAD (established by clinical history, clinical examination, and/or ankle brachial index, or further tests) were included. Women presented less often with intermittent claudication than men (25.9% vs. 30.2%) OR 0.78 (95% CI 0.72 - 0.84, very low quality of evidence), while rest pain and atypical leg symptoms were more prevalent in women (12.8% vs. 9.2%) OR 1.40 (95% CI 1.22 - 1.60, very low quality of evidence) and (22.8% vs. 19.8%) OR 1.18 (95% CI 0.96 - 1.45, very low quality of evidence), respectively. CONCLUSION: Women with PAD more often present with rest pain, while their prevalence of intermittent claudication is lower. They also tend to present more often with atypical leg symptoms. This study underlines that PAD symptom presentation differs between the sexes. Therefore, clinicians and researchers should not consider men and women as a single population and report their data separately.

Data mining to retrieve smoking status from electronic health records in general practice.

Aims: Optimize and assess the performance of an existing data mining algorithm for smoking status from hospital electronic health records (EHRs) in general practice EHRs. Methods and results: We optimized an existing algorithm in a training set containing all clinical notes from 498 individuals (75 712 contact moments) from the Julius General Practitioners' Network (JGPN). Each moment was classified as either 'current smoker', 'former smoker', 'never smoker', or 'no information'. As a reference, we manually reviewed EHRs. Algorithm performance was assessed in an independent test set (n = 494, 78 129 moments) using precision, recall, and F1-score. Test set algorithm performance for 'current smoker' was precision 79.7%, recall 78.3%, and F1-score 0.79. For former smoker, it was precision 73.8%, recall 64.0%, and F1-score 0.69. For never smoker, it was precision 92.0%, recall 74.9%, and F1-score 0.83. On a patient level, performance for ever smoker (current and former smoker combined) was precision 87.9%, recall 94.7%, and F1-score 0.91. For never smoker, it was 98.0, 82.0, and 0.89%, respectively. We found a more narrative writing style in general practice than in hospital EHRs. Conclusion: Data mining can successfully retrieve smoking status information from general practice clinical notes with a good performance for classifying ever and never smokers. Differences between general practice and hospital EHRs call for optimization of data mining algorithms when applied beyond a primary development setting.

Call Characteristics of Patients Suspected of Transient Ischemic Attack (TIA) or Stroke During Out-of-Hours Service: A Comparison Between Men and Women.

Background: In the Netherlands, a digital decision support system for telephone triage at out-of-hours services in primary care (OHS-PC) is used. Differences in help-seeking behavior between men and women when transient ischemic attack (TIA) or stroke is suspected could potentially affect telephone triage and allocation of urgency. Aim: To assess patient and call characteristics and allocated urgencies between women and men who contacted OHS-PC with suspected TIA/stroke. Methods: A cross-sectional study of 1,266 telephone triage recordings of subjects with suspected neurological symptoms calling the OHS-PC between 2014 and 2016. The allocated urgencies were derived from the electronic medical records of the OHS-PC and the final diagnosis from the patient's own general practitioner, including diagnoses based on hospital specialist letters. Results: Five hundred forty-six men (mean age = 67.3 ± 17.1) and 720 women (mean age = 69.6 ± 19.5) were included. TIA/stroke was diagnosed in 294 men (54%) (mean age = 72.3 ± 13.6) and 366 women (51%) (mean age = 78.0 ± 13.8). In both genders, FAST (face-arm-speech test) symptoms were common in TIA/stroke (men 78%, women 82%) but also in no TIA/stroke (men 63%, women 62%). Men with TIA/stroke had shorter call durations than men without TIA/stroke (7.10 vs. 8.20 min, p = 0.001), whereas in women this difference was smaller and not significant (7.41 vs. 7.56 min, p = 0.41). Both genders were allocated high urgency in 75% of the final TIA/stroke cases. Conclusion: Overall, patient and call characteristics are mostly comparable between men and women, and these only modestly assist in identifying TIA/stroke. There were no gender differences in allocated urgencies after telephone triage in patients with TIA/stroke.

Inferring the Effect of Species Interactions on Trait Evolution.

Models of trait evolution form an important part of macroevolutionary biology. The Brownian motion model and Ornstein-Uhlenbeck models have become classic (null) models of character evolution, in which species evolve independently. Recently, models incorporating species interactions have been developed, particularly involving competition where abiotic factors pull species toward an optimal trait value and competitive interactions drive the trait values apart. However, these models assume a fitness function rather than derive it from population dynamics and they do not consider dynamics of the trait variance. Here, we develop a general coherent trait evolution framework where the fitness function is based on a model of population dynamics, and therefore it can, in principle, accommodate any type of species interaction. We illustrate our framework with a model of abundance-dependent competitive interactions against a macroevolutionary background encoded in a phylogenetic tree. We develop an inference tool based on Approximate Bayesian Computation and test it on simulated data (of traits at the tips). We find that inference performs well when the diversity predicted by the parameters equals the number of species in the phylogeny. We then fit the model to empirical data of baleen whale body lengths, using three different summary statistics, and compare it to a model without population dynamics and a model where competition depends on the total metabolic rate of the competitors. We show that the unweighted model performs best for the least informative summary statistic, while the model with competition weighted by the total metabolic rate fits the data slightly better than the other two models for the two more informative summary statistics. Regardless of the summary statistic used, the three models substantially differ in their predictions of the abundance distribution. Therefore, data on abundance distributions will allow us to better distinguish the models from one another, and infer the nature of species interactions. Thus, our framework provides a conceptual approach to reveal species interactions underlying trait evolution and identifies the data needed to do so in practice. [Approximate Bayesian computation; competition; phylogeny; population dynamics; simulations; species interaction; trait evolution.].