| 1. |
- Sultan, Alyshah Abdul, et al.
(författare)
-
Defining venous thromboembolism and measuring its incidence using Swedish health registries : a nationwide pregnancy cohort study
- 2015
-
Ingår i: BMJ Open. - London, United Kingdom : BMJ Publishing Group Ltd. - 2044-6055. ; 5:11
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To accurately define venous thromboembolism (VTE) in the routinely collected Swedish health registers and quantify its incidence in and around pregnancy. Study design: Cohort study using data from the Swedish Medical Birth Registry (MBR) linked to the National Patient Registry (NPR) and the Swedish Prescribed Drug Register (PDR). Setting: Secondary care centres, Sweden. Participant: 509 198 women aged 15-44 years who had one or more pregnancies resulting in a live birth or stillbirth between 2005 and 2011. Main outcome measure: To estimate the incidence rate (IR) of VTE in and around pregnancy using various VTE definitions allowing direct comparison with other countries. Results: The rate of VTE varied based on the VTE definition. We found that 43% of cases first recorded as outpatient were not accompanied by anticoagulant prescriptions, whereas this proportion was much lower than those cases first recorded in the inpatient register (9%). Using our most inclusive VTE definition, we observed higher rates of VTE compared with previously published data using similar methodology. These reduced by 31% (IR=142/100 000 person-years; 95% CI 132 to 153) and 22% (IR=331/100 000 person-years; 95% CI 304 to 361) during the antepartum and postpartum periods, respectively, using a restrictive VTE definition that required anticoagulant prescriptions associated with diagnosis, which were more in line with the existing literature. Conclusions: We found that including VTE codes without treatment confirmation risks the inclusion of false-positive cases. When defining VTE using the NPR, anticoagulant prescription information should therefore be considered particularly for cases recorded in an outpatient setting.
|
|
| 2. |
- Sultan, Alyshah Abdul, et al.
(författare)
-
Development and validation of risk prediction model for venous thromboembolism in postpartum women : multinational cohort study
- 2016
-
Ingår i: BMJ-BRITISH MEDICAL JOURNAL. - London, United Kingdom : B M J Group. - 1756-1833. ; 355
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To develop and validate a risk prediction model for venous thromboembolism in the first six weeks after delivery (early postpartum).DESIGN: Cohort study.SETTING: Records from England based Clinical Practice Research Datalink (CPRD) linked to Hospital Episode Statistics (HES) and data from Sweden based registry.PARTICIPANTS: All pregnant women registered with CPRD-HES linked data between 1997 and 2014 and Swedish medical birth registry between 2005 and 2011 with postpartum follow-up.MAIN OUTCOME MEASURE: Multivariable logistic regression analysis was used to develop a risk prediction model for postpartum venous thromboembolism based on the English data, which was externally validated in the Swedish data.RESULTS: 433 353 deliveries were identified in the English cohort and 662 387 in the Swedish cohort. The absolute rate of venous thromboembolism was 7.2 per 10 000 deliveries in the English cohort and 7.9 per 10 000 in the Swedish cohort. Emergency caesarean delivery, stillbirth, varicose veins, pre-eclampsia/eclampsia, postpartum infection, and comorbidities were the strongest predictors of venous thromboembolism in the final multivariable model. Discrimination of the model was similar in both cohorts, with a C statistic above 0.70, with excellent calibration of observed and predicted risks. The model identified more venous thromboembolism events than the existing national English (sensitivity 68% v 63%) and Swedish guidelines (30% v 21%) at similar thresholds.CONCLUSION: A new prediction model that quantifies absolute risk of postpartum venous thromboembolism has been developed and externally validated. It is based on clinical variables that are available in many developed countries at the point of delivery and could serve as the basis for real time decisions on obstetric thromboprophylaxis.
|
|
| 3. |
- Walker, Alex J., et al.
(författare)
-
Venous thromboembolism in children with cancer : A population-based cohort study
- 2014
-
Ingår i: Thrombosis Research. - : Elsevier. - 0049-3848 .- 1879-2472. ; 133:3, s. 340-344
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Cancer is a known risk factor for venous thromboembolism (VTE) in adults, but population-based data in children are scarce.Materials and methods: We conducted a cohort study utilising linkage of the Clinical Practice Research Database (primary care), Hospital Episodes Statistics (secondary care), UK Cancer Registry data and Office for National Statistics cause of death data. From these databases, we selected 498 children with cancer diagnosed between 1997 and 2006 and 20,810 controls without cancer. We calculated VTE incidence rates in children with cancer vs. controls, and hazard ratios (HRs) using Cox regression.Results: We identified four VTE events in children with cancer compared with four events in the larger control population corresponding to absolute risks of 1.52 and 0.06 per 1000 person-years respectively. The four children with VTE and cancer were diagnosed with hematological, bone or non-specified cancer. Childhood cancer was hence associated with a highly increased risk of VTE (HR adjusted for age and sex: 28.3; 95% CI = 7.0-114.5).Conclusions: Children with cancer are at increased relative risk of VTE compared to those without cancer. Physicians could consider thromboprophylaxis in children with cancer to reduce their excess risk of VTE however the absolute risk is extremely small and the benefit gained therefore would need to be balanced against the risk invoked of implementing such a strategy.Novelty & Impact Statements: While there is a reasonable level of knowledge about the risk of VTE in adult populations, it is not well known whether this risk is reflected in paediatric patients. We found a substantial increase in risk of VTE in children with cancer compared to a child population without cancer. While this finding is important, the absolute risk of VTE is still low and must be balanced with the risks of anticoagulation. (C) 2014 The Authors. Published by Elsevier Ltd. All rights reserved.
|
|
| 4. |
- Middleton, Matthew J., et al.
(författare)
-
Bright radio emission from an ultraluminous stellar-mass microquasar in M 31
- 2013
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 493:7431, s. 187-190
-
Tidskriftsartikel (refereegranskat)abstract
- A subset of ultraluminous X-ray sources (those with luminosities of less than 10(40) erg s(-1); ref. 1) are thought to be powered by the accretion of gas onto black holes with masses of similar to 5-20M(circle dot), probably by means of an accretion disk(2,3). The X-ray and radio emission are coupled in such Galactic sources; the radio emission originates in a relativistic jet thought to be launched from the innermost regions near the black hole(4,5), with the most powerful emission occurring when the rate of infalling matter approaches a theoretical maximum (the Eddington limit). Only four such maximal sources are known in the Milky Way(6), and the absorption of soft X-rays in the interstellar medium hinders the determination of the causal sequence of events that leads to the ejection of the jet. Here we report radio and X-ray observations of a bright new X-ray source in the nearby galaxy M 31, whose peak luminosity exceeded 10(39) erg s(-1). The radio luminosity is extremely high and shows variability on a timescale of tens of minutes, arguing that the source is highly compact and powered by accretion close to the Eddington limit onto a black hole of stellar mass. Continued radio and X-ray monitoring of such sources should reveal the causal relationship between the accretion flow and the powerful jet emission.
|
|
