Skills for Evidence-Based Health Care

Suzana Alves da Silva, MD, MSc, PhDSenior Researcher at the Health Technology Assessment Unit of Amil Assistência Médica Internacional S/A, Rio de Janeiro, Brazil

Conflict of interest

None to declare

Suzana Silva, JECP 2010

“Knowledge does not extend from

those who consider they know to those who consider they

do not know. Knowledge is built in the relationship between human

beings and perfects it self in the critical problematization of

these relations.”Paulo Freire

Scientifically Informed Medical Practice and Learning - SIMPLE Model

Scientifically Informed Medical Practice and Learning - SIMPLE Model

Circumstances

Expertise

Patients Evidence

Suzana Silva, JECP 2010

Problem Delineation

Problem Delineation

“Knowledge does not extend from

those who consider they know to those who consider they

do not know. Knowledge is built in the relationship between human

beings and perfects it self in the critical problematization of

these relations.”Paulo Freire

Scientifically Informed Medical Practice and Learning - SIMPLE Model

PROBLEM

Categories of problem

Categories of problems

Categories Targets Description

Probability Frequency of outcomes over time of a condition

Performance

Effect

of a characterisc on the risk of an outcomeof a test on the presence of a condition

Utility Magnitude of the benefit offeredof the harm caused

Actions and Choices will varie according to the domains of Therapy, Diagnosis, Prognosis and Harm

Prognosis

Probability

Performance

Utility

What is the risk of AMI in 1 year in a asymptomatic pt with dislipidemia and calcium score of 100?

For how many times this risk will be increased if this pt has diabetes and smokes?

For how much the use of calcium score as a prognostic test decrease the risk of cardiovascular events in asymptomatic pt with dislipidemia?

Diagnosis

Probability

Performance

Utility

What is the pretest probability of coronary artery disease in a 40 y/o women with atypical chest pain?

What is the test with best performance to investigate this patient?

For how much the use of angiotomography to investigate CAD in patients like mine decrease the risk of cardiovascular events compared to other strategies?

Actions and Choices will varie according to the domains of Therapy, Diagnosis, Prognosis and Harm

Analytical Framework

DIAGNOSIS HARM

Probability Performance Utility Probability

PP40 y/o female with atypical chest pain, with fears and priorities

Patient wonders about AngioCT scan

Health ManagersPatient and physician wonders about safety

AATo assess the predictors: type of chest pain, age and sex

AngioCT scan, TTest, Cintigraphy, Stress echo

AngioCT scan AngioCT scan

CC No alternative is available

Coronariography

TTest, Cintigraphy, Stress echo

TTest, Cintigraphy, Stress echo

TTPre-test probability of coronary artery disease

Accuracy of the tests

Impact on cardiovascular events rate and costs

Risk of cancer due to radiation exposureRisk of renal failure dure to contrast exposure

Analytical Framework

DIAGNOSIS HARM

Probability Performance Utility Probability

PP 40 y/o female with atypical chest pain

40 y/o female with low to intermediate pre-test prob

40 y/o female with low to intermediate pre-test prob

40 y/o female with low to intermediate pre-test prob

II Type of chest pain, age and sex

AngioCT scan, TTest, Cintigraphy, Stress echo

AngioCT scan AngioCT scan

CC Coronariography

TTest, Cintigraphy, Stress echo

TTest, Cintigraphy, Stress echo

OOProbability of coronary artery disease

Accuracy of the tests

Cardiovascular events rate and costs

CancerRenal failure

Types of information, study designs and sources

Suzana Silva and Peter Wyer. The Roadmap: a blueprint for evidence literacy within a Scientifically Informed Medical Practice and Learning model. The International Journal of Person Centered Medicine. In press.

The TDS Evidence Pyramids

• Types of informationSummariesSynthesesSingle Studies

• DesignsGuidelinesSystematic ReviewsRandomized and non randomized studies

• SourcesSynopsesFiltered DatabasesLarge Biomedical Databases

DIAGNOSIS PROBABILITYDIAGNOSIS PROBABILITYSummary

Synthesis

Single Study

CAD indicates coronary artery disease; and CASS, Coronary Artery Surgery Study. *Each value represents the percent with significant CAD on catheterization. Adapted from Forrester and Diamond

Pretest Likelihood of CAD in Symptomatic Patients According to Age and Sex* (Combined Diamond/Forrester and CASS Data)

Finh et al. ACCF/AHA/ACP Guideline on Stable Ischemic Heart Disease. JACC 2012.

22222222

TestTest Author, Author, yearyear SexSex SensitivitySensitivity SpecificitySpecificity + LR+ LR - LR- LR

Treadmill Test

Morise and

Diamond,

1995

M 0,96 (0,94-0,98)

0,40 (0,34-0,46)

10,00 (5,67-23)0,63 (0,55-

0,70)

F 0,89 (0,85-0,93)

0,33 (0,25-0,41)

3,00 (1,67-5,86)

0,75 (0,63-0,88)

SPECTSantana

Boado, 1998

M 0,89 (0,67-0,99)

0,93 (0,87-0,98)

8,45 (2,64-98)0,08 (0,02-

0,19)

F 0,91 (0,78-0,97)

0,85 (0,62-0,97)

9,44 (2,82-32,33)

0,16 (0,03-0,49)

Multislice CT Mowat, 2008 T 0,87 (0,85-0,91)

0,96 (0,95-0,99)

7,38 (5,28-11)0,05 (0,01-

0,06)

DIAGNOSIS PERFORMANCEDIAGNOSIS PERFORMANCESummary

Synthesis

Single Study

xAngio CTx

Angio CTx

AngioCTMowat 2008

+LR 9.5

-LR 0.05

xSPECT

Angio CTx

CintigraphyBoado 1998

+LR 7.5

-LR 0.16

x

Treadmill TestMorise and Diamond 1995

+LR 3.0

-LR 0.75

x

if Test Result is +

if Test Result is -

Can we trust these results?

Does the use of angiotomography

compared to myocardium perfusion decreases the

risk of cardiovascular outcomes?

Sheribati el al. Association of Coronary CT Angiography or Stress Testing with Subsequent Utilization and Spending Among Medicare Beneficiares. JAMA 2011

DIAGNOSIS UTILITYDIAGNOSIS UTILITYSummary

Synthesis

Single Study

What is the risk of cancer if this

patient is submitted to

radiation exposure?

HARM PROBABILITYHARM PROBABILITYSummary

Synthesis

Single StudyEstimated Number of Patients Undergoing Computed Tomography (CT) That Would Lead to the Development of 1 Radiation-Induced Cancer, by Type of CT Examination and Age at the Time of Exposure, Based on the Median and Interquartile Radiation Dose Observed

Directness of evidence

Obrigada!

Thank You!

suzana.silva@amil.com.br