Studiedesigns og evidensniveau

Transcription

1 Studiedesigns og evidensniveau Benny Dahl, professor Overlæge, ph.d.,dr.med. Rygsektionen Ortopædkirurgisk afdeling Rigshospitalet Hoveduddannelseskursus i Forskning og Forsikringsmedicin august 2015

2 Studiedesigns, evidensniveau og litteratursøgning Benny Dahl, professor Overlæge, ph.d.,dr.med. Rygsektionen Ortopædkirurgisk afdeling Rigshospitalet Hoveduddannelseskursus i Forskning og Forsikringsmedicin august 2015

3 Hvorfor forske?

4 Hvorfor forske? Karriere Interesse Tradition Faglig indsigt Ph.d. Disputats Pres fra ældre kolleger

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6 Descriptive vs. Hypothesis test

7 Study designs Retrospective vs. Prospective

8 Abstract/synopsis Title Authors Introduction/background Purpose/hypothesis Material and methods Results Discussion Conclusion

9 Idea Mortality in complex spine surgery

10 Definitions Mortality? Complex spine surgery?

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13 Manual search

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21 Inspiration/copying/plagiarism

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25 Hypothesis Centralization of complex spine surgery increases 30-day mortality

26 Hypothesis Centralization of complex spine surgery increases 30-day mortality Centralization of complex spine surgery significantly increases 30-day mortality

27 Abstract/synopsis Title Authors Introduction/background Purpose/hypothesis Material and methods Results Discussion Conclusion

28 Title 30-day mortality after centralization of complex spine surgery - a retrospective, cohort study

29 Authors Vancouver criteria: Idea/hypothesis Collection of data Analysis of data Inclusion of patients Preparation of manuscript

30 xx yy zz Contributions Idea, primary draft of protocol and manuscript Statistical analysis, material and methods Data extraction from database

31 Introduction Increasing spinal surgical activity Increasing use of implants Few prospective cohort studies on morbidity and mortality

32 End-point? 30 day mortality One-year mortality Survival days

33 Missing data Not significantly different regarding: Age Gender Indication

34 Material and methods Spine surgery January 2008 December 2011

35 Discussion Age Gender Indication Acute vs. elective Co-morbidity ASA

36 Conclusions 1. In spite of increased activity and complexity a statistical significant decrease in 30-day mortality was observed comparing 2008 with The centralized organization of complex spine surgery resulted in a significant increase in 30-days mortality compared to the period prior to centralization.

37 Godkendelser?

38 Godkendelser? Videnskabsetisk komite Datatilsynet Sundhedsstyrelsen Clincialtrials.gov

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44 JBJS publications One year

45 David L. Sackett

46 Sackett et al. BMJ 1996;312: Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.

47 Evidence-based medicine Conscientious Current Decisions on individual patients Best available external clinical evidence Individual clinical expertice

48 Hierarchy of evidence Randomized controlled trial Prospective cohort study Retrospective cohort study Case-control study Case series Case report Expert opinion Personal opinion

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50 The randomized controlled clinical trial (RCT) Minimize the effect of: Post-hoc variables Lost data Subtle exclusion

51 RCT drawbacks?

52 RCT drawbacks? External validity Ethics Sample size Long-term outcome

53 Observational studies Cohort studies Case-control studies Case series and/or case reports

54 Cohort study

55 Case-control study

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57 SORT The Standard of Reporting Trials Group. JAMA 1994;272: SORT Working Group on Recommendations for Reporting of Clinical Trials in the Biomedical Literature

58 CONSORT Consolidated Standards of Reporting Trials

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60 Strengthening the Reporting of Observational Studies in Epidemiology

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63 Take home message Hypothesis Protocol End-point Minimal important/relevant difference Approval Product abstract national/international publication

64 Thank you for your attention