1 / 69

1 st October 2010

Hormonal contraception and risk of venous thromboembolism: national follow-up study BMJ Sept 2009;339:b2890. 1 st October 2010. A critical appraisal by Mark Chadwick. Hormonal contraception and risk of VTE. Presentation of paper Critical appraisal Questions Thoughts for the weekend.

patch
Download Presentation

1 st October 2010

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Hormonal contraception and risk of venous thromboembolism:national follow-up studyBMJ Sept 2009;339:b2890 1st October 2010 • A critical appraisal by Mark Chadwick

  2. Hormonal contraception and risk of VTE • Presentation of paper • Critical appraisal • Questions • Thoughts for the weekend

  3. Introduction • Studies show increased risk in VTE on OCP • Higher in first yr • Higher with desogestrel / gestodene • Lower with levonorgestrel • Shift from 50mcg to 40-20mcg ethinylestradiol • Theoretical lower risk • Equivocal evidence

  4. Objective • To assess risk of VTE in current users of different types of hormonal contraception

  5. Methods • Stated Cohort study • Linkage of 4 National registries • Central personal registry • Prescriptions • Education • Health

  6. Methods • Study Population • 01 Jan 1995 – 31 Dec 2005 • All Danish women, 15-49 yrs • Prior Malignancy & CVD excluded • New diagnoses censored • Emigrants censored • Pregnancy excluded +12/+4wks

  7. Methods • End points • First time VTE diagnosis

  8. Methods • Groupings • Length = Sum of valid Rx – periods of no valid Rx

  9. Methods • Contraception Categories • Time of usage • Regime (OCP / POP / IUD) • Oestrogen dose • Progestogen • Current usage (<1yr, 1-4yrs, >4yrs) • POP type

  10. Methods • Statistics • Poisson regression • Time at risk (women yrs) • Number of VTEs • Group

  11. Methods • Confounders • drugs for DM, HT, Diuretics, β/Ca blockers, ACE-I, Statins • Schooling / Education

  12. Results

  13. Results

  14. Results

  15. Results

  16. Results • Age Related use • Young use newer OCPs , short intervals

  17. Results • VTE risk increased with • Age • Study period 1.05 (95%CI 1.04 – 1.06)/yr • Decreasing education • First year use • Some longer term use • POP No increased VTE risk cf non-users • Levonorgestrel /noresthisterone 0.59 (CI 0.33 – 1.04) • Desogestrel 1.1 (CI 0.35 – 3.41) • IUD • 0.89 (95CI 0.64 – 1.26)

  18. Discussion • Aims achieved • Factors causing VTE • Excluding cancer /CHD => increased risk estimate • Pregnancy / POP => decrease risk • Change over time • Better detection

  19. Discussion • Risk of sub-types OCP discussed • Oestrogen dose • Type of progestogen • Concern re desogestrel / gestodene • Length of use • 20mcg significant only when accounted • Strengths and limitations • Omission of BMI • Family Predisposition

  20. Take home Points • The risk of VTE • Decreases with dose of oestrogen • desogestrel / gestodene > levonorgestrel • Unchanged by POP & IUDs • Absolute risk of VTE in any COP in young women is <1:1000 user yrs

  21. Hormonal contraception and risk of VTE • Presentation of paper • Critical appraisal • Questions • Thoughts for the weekend

  22. AUTHOR

  23. Critical appraisal • Is the paper interesting and relevant? YES • Who wrote the paper? • Do they or the institution have a proven academic record? • Appropriate Experience • Area of Expertise • Previous publications

  24. Prof. Øjvind Lidegaard, Copenhagen, Denmark • 81 graduated Copenhagen University • 81-87 Clinical residences in neurology, internal medicine, gastro­enterology, psychiatry, pediatrics • 92 Specialist in O&G • 93-97 senior resident O&G at Herlev Uni Hospital • 97-06 Appointed consultant & associate Professor • 06- Professor of the Gynecological Clinic at Copenhagen Uni

  25. Prof. Øjvind Lidegaard, Copenhagen, Denmark • published 135 scientific publications • first author on 102 • Majority epidemiological studies on risk factors • female cancers • cardiovascular diseases • ‘96 dissertation on oral contraceptives and thrombotic strokes

  26. Prof. Øjvind Lidegaard, Copenhagen, Denmark • Member of Board of Directors, Danish Society of Medical Informatics, 1988–1993. • Head of “Working group on gynecological technology assessment and quality assurance”, Danish Society of Obstetrics and Gynecology (DSOG) 1990–1997. • Head of “Committee on postgraduate education”, DSOG, April 1992 to April 1996. • Head of “Scandinavian Committee on postgraduate education”, Scandinavian Society of Obstetrics and Gynecology (NFOG) August 1994 to August 1996. • Consultant in “Committee on postgraduate education”, Danish Medical Association, 1991–1996. • Consultant in WHO on the project “Obstetrical quality indicators”, 1991–1995. • Head of guideline group in gynaecological reproduction, DSOG, 2000–2008. • Member of guideline group in hormone replacement therapy, DSOG 2000–2003 • Member of guideline group in contraception, • DSOG 2000–2008. • Member of Climate and health working group, Danish Medical Association since 2008.

  27. INTRODUCTION

  28. Introduction • Title • Clear / Concise / Appropriate • YES • Was the study original? • No, but follow-up to original

  29. Introduction • Literature Review • Did the study introduction address the relevant points? • Yes • Method / Extent / Up to date • Yes

  30. Introduction • Hypothesis • Were the hypotheses/aims clearly stated? • YES • Purpose • Who sponsored - Uni , pharm companies ? who • Who benefits - • Need for answer - YES

  31. METHOD / DATA

  32. Methods 1 • Type of research? • Objective / Subjective / Questionnaire / Interview

  33. Methods 1 Type of research? Objective / Subjective / Questionnaire / Interview Was there Ethics approval? DATA PROTECTION ONLY AS NOT REQUIRED

  34. Methods 1 • Was there Validation? • YES … but .. • 10% VTE uncertain • Therefore of remainder • 97% imaged, 2% treated • 94% imaged & treated • Uncertainty <1% • NO 11%

  35. Methods 2 • Level of Evidence? • Ia Meta-analysis of RCCT • Ib RCCT • IIa controlled trial NOT randomised • IIb quasi-experimental study • III descriptive study • IV expert opinion

  36. Methods 2 Level of Evidence? Ia Meta-analysis of RCCT Ib RCCT IIa controlled trial NOT randomised IIb quasi-experimental study III descriptive study IV expert opinion

  37. Methods 3 • Was the study design appropriate? • Review - systematic or meta-analysis • Drug treatment - randomised controlled trail • Causation - case - control study • Prognosis - cohort study

  38. Methods 3 • Was the study design appropriate? • Review - systematic or meta-analysis • Drug treatment - randomised controlled trail • Causation - case - control study • Prognosis - cohort study • Unclear if historic • Previously was case-control !

  39. ….!!! Time Out !!!…..

  40. Cohort Study • an observational study that takes a group (cohort) of patients and follows their progress in order to measure outcomes such as disease or mortality rates, and make comparisons according to the treatments that patients received. A Daly, 2008

  41. Cohort Study

  42. Disease + Exposed Disease - Study population Disease + Non-exposed Disease - Cohort Study

  43. Case-Control Study • a study that starts with the identification of a group of individuals sharing the same characteristics (disease) and a suitable comparison group (no disease). All subjects are then assessed with respect to things that happened in the past that might be related to contracting the disease. A Daly, 2008

  44. Case-Control Study Exposed Cases Non-exposed Study Population Exposed Controls Non-exposed

  45. Disease + Exposed Disease - Study population Disease + Non-exposed Disease - Retrospective Cohort Study

  46. Cohort Analysis • Analysis of results is a matter of calculating and comparing rates, which are commonly expressed in terms of person-years of observation. • 1 person is observed for 10 years, = 10 person-years. • 2 years observation of 5 persons, = 10-person years. • The use of person-years is a convenient way to generate larger numbers for calculation of rates that are more stable than with smaller numbers over numerous timelines. J Last, enotes.com

More Related