Evidence-based practice -

Obstetrics and

Gynaecology

Evidence-based Practice



What is EBM?



What EBM is not.



Do we need EBM?



Is Obstetrics and Gynaecology a
special case?

Evidence-based practice:

the reactions



Incensed - practice is evidence-based



Indifferent - there is no evidence to use



Enthusiastic but disillusioned - great
idea but where is the ‘wherewithal’ to
do it

What evidence-based

practice is:

Evidence-based medicine is the
conscientious, explicit and judicious
use of current best evidence in
making decisions about the care of
individual patients. Its
philosophical base dates back to
the sceptics of post-revolutionary
Paris (Bichat, Louis, Magendie).

What evidence-based

practice is:

The practice of EBM requires the

integration of



individual clinical expertise

with the



best available external clinical
evidence from systematic research.

What evidence-based

medicine is:



Good doctors use both individual clinical
expertise and the best available external
evidence, and neither alone is enough.

»

Without the former, practice risks becoming
evidence-tyrannised, for even excellent
external evidence may be inapplicable or
inappropriate for an individual patient.

»

Without the latter, practice risks becoming
rapidly out of date, to the detriment of
patients and patient-care.

What is Evidence-based

Practice

Clinical Skills

Keeping
up to date

Clinical question

Audit

Find the Evidence

Apply to Practice

Critical Appraisal

What is evidence-based

practice?

Clinical Skills

Keeping
up to date

Clinical question

THE

PATIENT

Audit

Find the Evidence

Apply to Practice

Critical Appraisal

What evidence-based

medicine is:



this definition also helps us identify
and understand what evidence-
based medicine is not.

Evidence-based medicine

is not “cook-book”

medicine:



Patients cannot go through a ‘treatment
tunnel’ assuming the same management is
appropriate and the same outcomes
important to each



External clinical evidence can inform, but can
never replace, individual clinical expertise



Your clinical accumen decides whether the
external evidence applies to the individual
patient at all and, if so, how it should be
integrated into a clinical decision.

Evidence-based medicine

is not “cost-cutting”

medicine:



The aim is to give most benefit to
each individual patient



To apply the most efficacious
interventions which will maximise
their function, quality, and quantity
of life



may raise rather than lower the
cost of their care.

EBM is neither old-hat nor

impossible to practice:



The former argument falls before the evidence:

»

of striking variations in the integration of
patient values into our clinical behaviour

»

of striking variations in the rates with which
clinicians provide interventions of established
benefit and uselessness to their patients.

»

in the inability of clinicians to keep abreast of
important medical advances reported in
primary journals

EBM is not restricted to

randomised trials:



Practising EBM requires the best clinical
evidence with which to answer our clinical
questions.

»

On diagnostic tests: a proper cross-
sectional study of patients clinically
suspected of harbouring the target
disorder, not a randomised trial.

»

On prognosis, a proper follow-up study of
patients assembled at a uniform, early
point in the clinical course of their disease.

Levels of Evidence

I. Systematic Review of RCTs
II.

RCT of appropriate size and power

III. well-designed cohort or case-

controlled studies

IV. non-experimental studies from

more than one centre

V.

respected authorities,descriptive

studies

Do we Need EBM?

Do we need EBM?



What do you need to do to keep
abreast?

»

20,000 medical journals

»

General physician - 19 articles per day
every day of the year

Clinicians need Information

If asked:



we need it twice a week,



we get it from our text books &
journals.

Clinicians really need

information!

If shadowed:



we need it up to 60 times per week
(twice per every three patients), and
it could affect eight decisions per day.



but we get only 30% of it,



and that comes from passers-by

»

textbooks are out of date/journals too
disorganised/library closed/ too far

Textbooks?



Antenatal Steroids?

»

clear beneift since the first trial

»

since 1972 just improved the precision
of the confidence intervals?

»

textbooks 1990, 1991, 1992 - “ there
is no role for antenatal steroids”

Luteal Progestagens - HMB



1960 first subjective study



1987 first RCT no benefit



1995 first review no benefit



1995 38% of prescriptions for
HMB by

GPs



1998 RCT of 21 day progestagens

»

87% reduction

Textbooks?



Tranexamic acid

»

first RCT 1967

»

first RCT comparing it against another
Rx 1988

»

first systematic review 1995

»

first meta-analysis 1998

»

Textbooks

Our textbooks are out-of-

date



Fail to recommend Rx up to ten
years after it’s been shown to be
efficacious.



Continue to recommend therapy up
to ten years after it’s been shown
to be useless.

Time spent reading around

one’s patients is slim:

Self-reports from Oxford (medians):



Medical Students: 60 minutes per week



House Officers:

none



S.H.O.’s:

10 minutes



Registrars:

90 minutes



Senior Registrars: 45 minutes



Consultants:

»

Post 1975: 60 minutes

»

Pre 1975: 30 minutes

Time spent reading around

one’s patients is slim:

Self-reports (median minutes last week):



Medical Students: 60-120



House Officers:

0-20 (up to 75%=none)



S.H.O.’s:

10-30 (up to 15%=none)



Registrars:

10-90 (up to 40%=none)



Senior Registrars: 10-45 (up to 15%=none)



Consultants:

»

Post 1975: 15-60 (up to 30%=none)

»

Pre 1975: 10-45 (up to 40%=none)

Time spent reading vs.

time spent driving:

Self-reports - Leicester GPs (medians):



Travelling to and from the library = 60
minutes



Reading re patients in the library = 10
minutes



Median ratio of travelling to reading = 1.8

The Slippery Slope

The Slippery Slope

years

since

graduatio

n

r = -0.54

p<0.001

...
...

. ..

. . ....

.

....
....

...

..

...

knowled

ge

of

current

best

care

Performance deteriorates,

too



Screened 6,000 steelworkers and
found 300 untreated, uncontrolled
hypertensives.



Evaluated and confirmed their
hypertension over the next 3
months.



Then got them into the offices of 85
local GPs.

6 months later, only 2/3

had been started on Rx

Determinants of the clinical decision

to treat some, but not others:

1

The level of diastolic blood pressure.

2

The patient’s age.

4

The amount of target-organ damage.

Performance deteriorates,

too

Determinants of the clinical decision

to treat some, but not other,
hypertensives:

3

The doctor’s year of graduation
from medical school.

Do we Need EBM?



Vulnerable Health Carers



‘Questioning’ patients

Running Summary



Clinicians need information, but most
of our needs are never met:

»

Our textbooks are out of date.

»

Important and relevant information lost in
the deluge of information irrelevant to us



Consequently, our knowledge and
performance deteriorate.

The onus on us?

•

The patient population

•

Archie Cochrane - GO for go ahead
without evaluation

•

Pregnancy and Childbirth Cochrane
Review Group

Incensed?

Our practice is already

evidence-based

Is EBM already in practice?

•

Variation in practice?

– Post-menopausal Bleeding?
– Endometrial sampling?
– Stress incontinence?
– Hysterectomy rates?
– Management of spontaneous abortions?

Is EBM already in Practice?



Information applied? - The Past

»

Antenatal steroids

– First meta-analysis 1990 ( Crowley,1990)
– <25% of those who would have benefited

received antenatal steroids in the UK
(Osiris 1992)

– 18% of those who would have benefited

received antenatal steroids in the USA
(NIH,1994)

Is EBM already in Practice?



Information applied? - The present.

»

Electronic Fetal heart rate monitoring in
the low risk group

– increases the operative delivery rate

(Neilson, 1993, 1995)

»

Eclampsia - 1995 only 60% of UK units
used MgSO

4

»

Heavy menstrual Bleeding - Tranexamic
acid (5%) norethisterone (38%)

The indifferents

There is no evidence for

anything we do so what’s

the use?

Is the evidence there?



‘only about 15% of medical
interventions are supported by solid
scientific evidence’ ( BMJ
Editorial,1995)



only 21% of 126 diagnostic and
therapeutic technologies assessed by
the US NIH were firmly based in
research-generated scientific evidence

Is the Evidence there?



Acute General Medicine - 82%



General Practice - 81%



Acute General Psychiatry - 65%

Is the Evidence there?

•

When the patients, not clinical
manoeuvres, are used as the
denominator

•

When the evidence is either
systematic reviews of RCTs or RCTs

or

Convincing non-experimental
evidence

Gynaecology OPD



4 weeks of new patients (84 patients)



70 patients (14 DNAs)



5 awaiting urodynamics



Divided into

»

SR and RCT evidence

»

Convincing non-experimental evidence

»

lesser evidence

Gynae OPD - SR and RCT-

34%



PMB - D&C, Hysteroscopy

8



Heavy menstrual bleeding
13



Fibroid Uterus 26/40-Zoladex 1



Infertil. Male factor - IVF

1

»

Unexplained (age) - IVF

1

Non-exp evidence-44%



Uterine prolapse-surgery/pessary 1/3



Cyclical pain-laparoscopy

1



Simple cyst -review 2



Dermoid 6 cm - remove 1



Cystocele/rectocele -surgery 2



Oligomenorrhoea COCP 1



Sterilization

21

? Level of Evidence- 20%



Backache, pain not gynae

5



3 yr old labial adhesions

1



cyclical umbilical bleed

1



Infertility unexplained - wait

2



Stress incontinence - Physio

5

Enthusiastic but

Disillusioned

There is no time to find

and implement the

evidence?

What is Evidence-based

Practice

Clinical Skills

Keeping
up to date

Clinical question

Audit

Find the Evidence

Apply to Practice

Critical Appraisal

Clinical, focused question

1.

The patient/population

2.

The intervention

3.

The comparision intervention

4.

The outcome of clinical importance

What is Evidence-based

Practice

Clinical Skills

Keeping
up to date

Clinical question

Audit

Find the Evidence

Apply to Practice

Critical Appraisal

Searching Filters

Clinical Topic

Medline

(WINSPIRS)

Treatment

clinical-trial in pt

Prognosis

exp cohort-studies

Aetiology/cause

risk in ti,ab,MeSH

Diagnosis

sensitivity in ti, ab,
MeSH

The Cochrane Library



Pregnancy and Childbirth



Subfertility / Menstrual Disorders



Gynaecological Malignancies



Incontinence



Osteoporosis



Fertility Control



Sexually Transmitted Diseases

‘Highlighting journals’



ACP journal Club



Evidence-based Medicine

»

Search journals

»

select methodologically sound articles

»

select clinically relevant/important
articles

»

produce summary and comment

What is Evidence-based

Practice

Clinical Skills

Keeping
up to date

Clinical question

Audit

Find the Evidence

Apply to Practice

Critical Appraisal

Mastering some simple

rules of evidence



for determining validity:

»

of diagnostic/screening tests: was there
an independent, blind comparison with a
“gold standard” of diagnosis?

»

of prognostic markers: was there an
inception cohort?

»

of therapy: was assignment to
treatments randomised and concealed?

Mastering some simple

rules of evidence



For determining clinical usefulness:

»

of diagnostic/screening tests: do these
results move my patient across a
treatment/ no treatment threshold ?

»

of therapy: how many patients like
mine need to be treated with this
therapy in order to prevent one
clinical event (NNT)?

NNT - Third stage



How many women need active
management of the third stage of
labour to save one woman from a
PPH
(> 500mls blood loss)?

NNT = 16

Number Needed to Harm



How many women need active
management of the third stage of
labour to cause one extra woman
to be sick compared to the
expectantly managed group?

NNH = 15

NNT - Heavy mens.

Bleeding



How many women will be treated
with mefenamic acid to prevent
one woman from heavy menstrual
bleeding
(> 80mls/cycle blood loss)?

NNT = 4

NNT - Heavy mens.

bleeding



How many women will be treated
with tranexamic acid to prevent
one woman from heavy menstrual
bleeding
(> 80mls/cycle blood loss)?

NNT = 2

NNT - Heavy mens.

bleeding



How many women will be treated with
tranexamic acid compared to
mefenamic acid to prevent one extra
woman from heavy menstrual
bleeding
(> 80mls/cycle blood loss)?

NNT = 8

The results

Endometr.

Thickness

Endometr.

Cancer

Other

diagnosis

Endometr.

Thickness

Endometr.

Cancer

Other

Diagnosis

≤ 4mm

0 (0%)

518(51%) 16-20mm 27 (24%) 38 (4%)

5mm

2 (2%%)

86 (8%)

21-25mm 17 (14.9%) 17 (2%)

6-10mm 13 (11.%) 232(23%)

>25mm

27 (24%)

16 (2%)

11-15mm 28 (25%) 117 (11%)

Total

114

1024

Likelihood Ratios

LR =

% of patients with disease

% of patients without the disease

LR < 0.1

strong negative evidence

LR > 10 strong positive evidence

Likelihood ratios

Endometrial

Thickness

LR

Endometrial

Thickness

LR

≤4mm

0

16-20

6.4

5mm

0.2

21-25

8.8

6 - 10mm

0.5

>25

14.8

11-15mm

2.2

What is Evidence-based

Practice

Clinical Skills

Keeping
up to date

Clinical question

Audit

Find the Evidence

Apply to Practice

Critical Appraisal

Evidence-Based Medicine:

Does it work?

No wonder, then, that

CME is mushrooming



Big, and getting huge.



Usually instructionally (fact)
oriented.

An RCT of CME

Clinicians with similar preferences were

randomised into:



an Experimental Group (who would
receive CME now for “high preference”
conditions if they agreed to study “low
preference” conditions, too).



a Control Group (who would receive
CME later).

An RCT of CME

Then measured the quality-of-care

provided high-preference, low-
preference, and “hidden” indicator
conditions:



in both experimental and control
practices



both before and after the former
group received their CME

An RCT of CME:

High Preference Conditions



Quality of care rose slightly
(statistically, but not clinically
significant) in the Experimental
Practices



An identical rise was observed in
Control Practices !

An RCT of CME:

High Preference Conditions

(“If you want CME, you don’t need

it!”)

An RCT of CME:

Low Preference Conditions



Quality of care rose substantially in
Experimental Practices.



Quality of care declined slightly in
Control Practices.

An RCT of CME:

Low Preference Conditions

(“CME only works if you don’t want

it!”)

An RCT of CME:

Hidden Conditions



Quality of care deteriorated slightly
in both Experimental and Control
practices.

An RCT of CME:

Hidden Conditions

(“CME does not cause general

improvements in the quality of
care.”)

Running Summary



Clinicians need information, but
most of our needs are never met:

»

Our textbooks are out of date.

»

Our journals are disorganised.



Consequently, our knowledge and
performance deteriorate.



And traditional instructional CME
doesn’t improve our performance.

Where’s the evidence

about evidence-based

medicine?



Short term evidence from a trial
among clinical clerks nearing
graduation.



Long term evidence from a natural
experiment among clinicians up to
15 years following graduation.

Short term Evidence

among Clinical Clerks: A

Trial



Experimental clerks: worked with
Clinical Tutors who’d taken a crash
course in critical appraisal and had
worked up diagnostic tests and
treatments bound to arise in their
clerkship.



Control clerks: worked with usual
Clinical Tutors.

Short term Evidence

among Clinical Clerks: A

Trial

Before and after the clerkship, both sets

of clerks were given patient scenarios:

1

describing the patient’s clinical problem;

2

calling for diagnostic and treatment
decisions;

3

accompanied by a clinical article
advocating a specific diagnostic test or
treatment for such patients.

Short term Evidence

among Clinical Clerks: A

Trial



After an evidence-based clerkship,
Experimental Clerks made more
correct decisions, and were better
able to justify them.

Short term Evidence

among Clinical Clerks: A

Trial



Control Clerks deteriorated, and
were more likely to be wrong after
their clerkship than before it!

»

they had become more accepting of
recommendations from authority
figures.

Long term evidence up to

15 years following

graduation

Compared the up-to-date knowledge

of graduates of a self-directed EBM
medical school vs. a traditional
medical school.

Three solutions

Clinical performance can keep up to date:

1

by learning how to practice evidence-
based medicine ourselves.

2

by seeking and applying evidence-based
medical summaries generated by others.

3

by accepting evidence-based practice
protocols developed by our colleagues.

Getting research into

practice



What might work

»

Audit and feedback

»

Local consensus

»

Local opinion leaders

»

Patient mediated interventions

Getting Research into

practice



What may work

»

Interactive educational meetings

»

Multifaceted

»

Educational outreach visits

»

Reminders (manual, computerized)

Number needed to treat



Relative risk reduction

= CER-EER / CER



Absolute risk reduction = CER - EER



NNT = 1 / ARR

NNT - FHM



How many low risk pregnancies will
be monitored by Electronic fetal
heart rate monitoring compared to
intermittent ausculatation to save
one neonate from a seizure?

NNT = 409

NNT- Eclampsia



How many women with eclampsia
will need to get magnesium
sulphate instead of phenytoin to
stop one of those women from
recurrent convulsions?

NNT = 9

NNT - Eclampsia



How many women with eclampsia will
need to get magnesium sulphate
instead of diazepam to stop one of
those women from recurrent
convulsions?

NNT = 7

EBM is neither old-hat nor

impossible to practice:



The latter argument, that it can be
conducted only from ivory towers and
armchairs, is refuted by audits in the front
lines of clinical care where at least some
inpatient clinical teams in general
medicine, psychiatry, and surgery have
provided evidence-based care to the vast
majority of their patients.