The GRADE approach to assessing individual studies Peter Morley and - - PowerPoint PPT Presentation

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The GRADE approach to assessing individual studies Peter Morley and - - PowerPoint PPT Presentation

Aug 24, 2022 105 likes •368 views

1 1 Vienna 2012 The GRADE approach to assessing individual studies Peter Morley and Eddy Lang 2 Vienna 2012 GRADE expands quality of evidence determinants Individual study Inconsistency Risk of bias of results Failure of blinding

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1 Vienna 2012

The GRADE approach to assessing individual studies

Peter Morley and Eddy Lang

1

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2 Vienna 2012

GRADE expands quality of evidence determinants

Methodological limitations Inconsistency

  • f results

2

Risk of bias Allocation concealment Failure of blinding Losses to follow-up Incomplete reporting Indirectness

  • f evidence

Imprecision

  • f results

Publication bias

Individual study Across studies for an outcome

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3 Vienna 2012

Risk of Bias (RCTs)

  • Consider studies that provided data for the outcome
  • Consider overall risk of bias of these studies:

– Allocation concealment – Adequate sequence generation – Blinding – Selective outcome reporting – Complete outcome data assessed – other

  • Is Risk of Bias likely to reduce our confidence in the

effect we found?

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4 Vienna 2012

Risk of Bias (observational studies)

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5 Vienna 2012

Adequate sequence generation

  • use of a mechanism that ensures that the

same sorts of participants receive each intervention – that participants are randomly assigned

  • results in a balance of baseline characteristics

between groups

  • “randomisation computer generated list”
  • “randomised by data of birth, when signed up

for study”

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6 Vienna 2012

Lack of allocation concealment

  • Those enrolling patients are aware of the

group to which the next enrolled patient will be allocated

  • “sealed opaque envelopes”
  • ‘transparent envelopes”
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7 Vienna 2012

Blinding

  • Patient, caregivers, those recording outcomes,

those adjudicating outcomes, or data analysts are aware of the arm to which patients are allocated

  • ? “double blinded”
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8 Vienna 2012

Selective outcome reporting

  • Reporting of some outcomes and not others
  • n the basis of the results
  • With protocol
  • Without protocol

– Heparin (blood thinner) did not measure bleeding as an adverse event – Weight loss diet but did not measure weight!

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9 Vienna 2012

Incomplete outcome assessment

  • Loss to follow-up and failure to adhere to the

intention to treat principle when indicated

  • Reasons for loss to follow up would not affect
  • utcome

– moved away – But left trial due to adverse events

  • Uneven loss to follow up between groups
  • Rule of thumb: >20% concern
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10 Vienna 2012

Other limitations:

  • stopping early for benefit observed in

randomized trials, in particular in the absence

  • f adequate stopping rules
  • use of un-validated patient-reported outcomes
  • cross over studies
  • cluster randomised studies
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11 Vienna 2012

C2015 PICO

  • Population: adult cardiac arrest (prehospital

[OHCA], in-hospital [IHCA])

  • I ntervention: the use of an ITD
  • Comparison: compared with no ITD
  • Outcomes

– Neurologically intact survival (critical 9) – Discharge from hospital alive (critical 8) – Return of spontaneous circulation (important 6)

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12 Vienna 2012

Inclusion/Exclusion/Articles Found

  • I ncluded all studies with concurrent

controls.

  • Excluded review articles, studies with historical

controls, animal studies, and studies that did not specifically answer the question. Excluded unpublished studies, studies only published in abstract form, unless accepted for publication.

  • 8 Articles Finally Evaluated
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13 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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14 Vienna 2012

Risk of Bias in stu tudies ta table: IT ITD+ACDCPR vs vs Sta tandard rd CPR

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15 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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16 Vienna 2012

Risk of Bias in stu tudies ta table: IT ITD+ACDCPR vs vs Sta tandard rd CPR

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17 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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18 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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19 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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20 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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21 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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22 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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23 Vienna 2012

Overall risk of bias for study: Low, Moderate or High

  • “Low” risk of bias = most or all key criteria listed

are met, and any violations are not crucial.

  • “Moderate” risk of bias if have a crucial limitation

in one criterion or some limitations in multiple criteria, sufficient to lower the confidence in the estimate of effect.

  • “High” risk of bias if have a crucial limitation in
  • ne or more criteria, sufficient to substantially

lower the confidence in the estimate of effect.

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24 Vienna 2012

Risk of Bias in stu tudies table le: ITD+ D+ACDC DCPR vs vs Sta tandard rd CPR

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25 Vienna 2012