Thực Hành Y Học Chứng Cứ
trong Y Tế Công Cộng
Gs Ts Bs Lê Hoàng Ninh
Thực hành y tế công
cộng dựa trên chứng
cứ
Kiến thức/
nghiên cứu
Kinh nghiêm
lâm sàng/ sự
cân nhắc
Thực trạng
bệnh nhân/ các
tham khảo
Câu Hỏi
PICO
Tìm kiếm
trên y văn
Đánh Giá
chứng cứ
• “Một trong những khám phá quan
trọng nhất, đáng kính ngạc nhất là
biết cái mà Ta có thể làm và biết sợ
cái mà Ta không thể làm.”
Henry Ford
Mục tiêu
Cây hỏi
PICO
Tìm y
văn
Đánh giá
chứng cứ
1)Hiểu ý nghĩa về đánh giá các chứng cứ
2) Mô tả mức độ chứng cứ được dùng trong
đánh giá các chứng cứ
3) Thăm dò các phương pháp khác như (
thống kê…) có thể dùng trong đánh giá
chứng cứ.
4)ứng dụng qui trình nầy trong y tế công cộng.
Thực Hành Y Học Chứng Cứ
• Dùng những hiểu biết có chất lượng cao
nhất trong chăm sóc sức khỏe cho cá nhân
và cả cộng đồng
Đánh Giá Chứng Cứ
• Là chìa khóa quan trong trong thực hành
chứng cứ
• Là kỹ năng cần, cốt lõi trong thực hành y
học
Đánh Giá Chứng Cứ
• Phải đảm bảo rằng chứng cứ tìm thấy trên
dân số nghiên cứu có thể được thực hiện
trên dân số mà các bạn muốn áp dụng
Nội Dung Đánh Giá Chứng Cứ
• 1) Định lượng sức / độ mạnh của chứng cứ
khoa học
• 2) Đánh giá chất lượng và khả năng áp
dụng khi ra quyết định chăm sóc sức khỏe
1)Độ Mạnh của Bằng Chứng
• Xếp hạng độ mạnh của chứng cứ cần xem xét kết
hợp :
• Chất lượng (Quality)
▫ Sai lệch hệ thống được giảm thiểu không?, Như
Thế nào?
• Số Lượng (Quantity)
▫ Độ lớn của ảnh hưởng, tác động, Số nghiên cứu,
cỡ mẫu và lực của mẫu.
• Tính hằng định / Ổ định
Những nghiên cứu khác, tương tự cho kết
quả
giống nhau
1) Độ mạnh của chứng cứ
• Evidence exists on a continuum of rigor
• Amount of research attention or maturity of
science varies, therefore evidence varies
• Type of research design reflects the strength of
the evidence – known as levels of evidence
Stevens & Ledbetter, 2000
Các Mức Độ của Chứng Cứ
• Xếp hạng cao là các chứng cứ từ những
nghiên cứu can thiệp lâm sàng
• Độ mạnh của chứng cứ: tin cậy càng lớn
khi xác suất áp dụng chứng cứ vào thực
hành sẽ mang lại hiệu quả
• Các mức độ chứng cứ : được dựa vào
loại thiết kế nghiên cứu
Các Mức Độ Chứng Cứ
• Experts have developed
a number of
taxonomies to rate
strength of evidence
• Most are organized
around research
designs
Các Mức Độ Chứng Cứ
• Theo National Guidelines Clearinghouse
• Ia Evidence obtained from meta-analysis or systematic review of
randomized controlled trials
• Ib Evidence obtained from at least one randomized controlled trial
• IIa Evidence obtained from at least one well-designed controlled study
without randomization
• IIb Evidence obtained from at least one other type of well-designed quasiexperimental study, without randomization
• III Evidence obtained from well-designed non-experimental descriptive
studies, such as comparative studies, correlation studies, and case studies
• IV Evidence obtained from expert committee reports or opinions and/or
clinical experiences of respected authorities
Mức Độ Chứng Cứ
• “Rating System for the Hierarchy of Evidence”
• Level I: Evidence from a systematic review or meta-analysis
of all relevant randomized controlled trials (RCTs), or
evidence based clinical practice guidelines based on
systematic reviews of RCTs
• Level II: Evidence obtained from at least one well-designed
RCT
• Level III: Evidence obtained from well-designed controlled
trials without randomization (quasi-experimental)
• Level IV: Evidence from well-designed case-control and
cohort studies (studies of prognosis)
• Level V: Evidence from systematic reviews of descriptive and
qualitative studies
• Level VI: Evidence form a single descriptive or qualitative
study
• Level VII: Evidence from the opinion of authorities and/or
reports of expert committees
(Melnyk & Fineout-Overholt, 2005)
Mức Độ Chứng Cứ
• Hê thống xếp hạng mức độ chứng cứ
• Type of evidence
• I. Meta analysis or comprehensive systematic review of multiple
experimental research studies (Cochrane , National Guidelines Clearinghouse
(AHRQ), The Joanna Briggs Institute, Other groups)
• II. Well designed experimental study
• III. Well designed quasi-experimental study (Non-randomized controlled,
Single group pre-post design, Cohort, Time series (one group of subjects over time),
Matched case-controlled studies (two or more groups are matched on certain
variables)
• IV. Well designed non-experimental study (Correlational or comparative
descriptive studies, Case study design, Qualitative studies)
• V. Clinical examples and expert opinion (Text books, Non-research journal
articles, Verbal report, Non-research based professional standards/guidelines/
• group article)
• Strength of evidence
• A. Type I evidence or consistent findings from multiple studies from levels II, III, or
IV.
• B. Multiple studies with evidence types II, III, or IV that are generally consistent.
• C. Multiple studies with evidence types II, III, or IV that are inconsistent.
• D. Limited research evidence or one type II study only.
• E. Type IV or V evidence only
•
•
•
•
Adapted from Joanna Briggs Institute and AHCPR
Eilers & Heerman, 2005
The U.S. Preventive Services Task Force (2008)
Level of Certainty
Description
High
The available evidence usually includes consistent results from well-designed, well
conducted studies in representative primary care populations. Thee studies assess the
effects of the preventive service on health outcomes. This conclusion is therefore unlikely
to be strongly affected by the results of future studies.
Moderate
The available evidence is sufficient to determine the effects of the preventive service on
health outcomes, but confidence in the estimate is constrained by such factors as:
• The number, size, or quality of individual studies
• Inconsistency of findings across individual studies
• Limited generalizability of findings to routine primary care practice
• Lack of coherence in the chain of evidence
As more information becomes available, the magnitude or direction of the observed effect
could change, and this change may be large enough to alter the conclusion.
Low
The available evidence is insufficient to assess effects on health outcomes. Evidence is
insufficient because:
• The limited number or size of studies
• Important flaws in study design or methods
• Inconsistency of findings across individual studies
• Gaps in the chain of evidence
• Findings not generalizable to routine primary care practices
• Lack of information on important health outcomes
More information may allow estimation of effects on health outcomes
Đánh giá/ xem xét hệ thống
(Systematic Reviews)
▫ Provides state of the science conclusions about
evidence supporting benefits and risks of a given
healthcare practice (Stevens, 2001)
▫ Most powerful and useful evidence available
▫ Tổng hợp các kết quả có giá trị , được sử dụng từ
các nghiên cứu nguyên phát vào trong thực hành
lâm sàng
Systematic Reviews &
Meta Analysis
Phân Tích Meta (Meta-Analysis)
• Cách tiếp cận thống kê để tổng hợp các kết quả
từ các nghiên cứu – tóm tắt kết qủa từ các
nghiên cứu đưa vào review
• Produces a larger sample size and thus greater
power to determine the true magnitude of an
effect, yields a summary statistic
Systematic Reviews &
Meta Analysis
Thử Nghiêm có nhóm chứng và phân phối ngẫu nhiên
(Randomized Controlled Trial )
▫ Experimental studies are the gold standard of
research design (randomization of participants to
treatment and control, rigorous methods used to
minimize bias)
▫ Provides most valid, dependable research
conclusion about clinical effectiveness of an
intervention and establishing cause and effect
▫ Allows us to say with a high degree of certainty
that the intervention we used was the cause of the
outcome
Randomized
Controlled Trials
Systematic
Reviews & Meta
Analysis
Giả Thực Nghiệm
(Quasi-Experimental )
▫ Differs from RCT’s only in
that participants are NOT
randomized to treatment
and control groups
QuasiExperimental
Randomized
Controlled Trials
Systematic
Reviews & Meta
Analysis
Phi Thực Nghiệm
Non-Experimental
▫ Cohort – participants are studied over time, study
population shares common characteristics
▫ Case-Control – studies that address questions about
harm or causation, investigates why some people develop
a disease or behave the way they do vs others who do not
▫ Descriptive – main objective is to describe some
phenomena
▫ Qualitative - "any kind of research that produces
findings not arrived at by means of statistical procedures
or other means of quantification" (Strauss and Corbin, 1990, p. 17).
Non-Experimental
Randomized
Quasi-Experimental Controlled Trials
Systematic
Reviews & Meta
Analysis
. Ý Kiến chuyên gia và Thí dụ về lâm sàng
(Clinical Examples & Expert Opinion).
▫ Expert Opinion – arriving
at a value judgement which
incorporates the main
information available on the
subject as well as previous
experiences
▫ Clinical examples –
▫ The “5 rights”
Clinical Examples &
Expert Opinion
NonExperimental
QuasiExperimental
Randomized
Controlled Trials
Systematic
Reviews & Meta
Analysis
2) Đánh giá chất lượng và tính ứng
dụng (Evaluating Quality & Applicability)
• What are the results?
• Are the results valid?
• Can the results be applied to the targeted
population and/or public health practice and
intervention?
What are the results?
• Kết quả có tương tự với kết
quả từ các n.cứu khác
không ( nếu có systematic
review hay meta-analysis)?
• Kết quả đó là gì?
• Kết quả có chính xác
không?
• Có thể có sự liên hệ bên
trong từ bộ dữ liệu không?
Kết quả có giá trị không?
• Does this article explicitly address our public
health question?
• Was the search for our article detailed and
exhaustive? Is it likely that important, relevant
studies were missed?
• Does the study selected appear to be of high
methodological quality?
• Do you feel the study selected is reproducible?
Kết quả có ứng dụng được không?
• How can the results be interpreted
and applied to public health practice
and intervention?
• Are study subjects similar to clients
to whom care is to be delivered?
• Were all important outcomes
considered?
• Are the benefits worth the costs and
potential risks?
Search evidence rich resources first
EBP Rich Resources
• Cochrane review
http://www.cochrane.org/reviews/
• DARE – Database of Abstracts of Reviews of
• Effectiveness
http://www.mrw.interscience.wiley.com/
cochrane/cochrane_cldare_articles_fs.ht
ml
Agency for Healthcare Research and
Quality (AHRQ)
• National Guidelines Clearinghouse
www.guidelines.gov
• Guide to Clinical Preventive Services
(2008)
http://www.ahrq.gov/clinic/pocketg
d.htm
• Evidence reports ahrq
www.ahrq.gov/clinic/epcix.htm
EBP Rich Resources for P/CHN
• Guide to Community Preventive Services
• http://www.thecommunityguide.org/inde
x.html
Centers for Disease Control &
Prevention
• CDC for Public Health Professionals
http://www.cdc.gov/CDCForYou/public_h
ealth_professionals.html
Association of State and Territorial
Health Officials
• Evidence Based Practice
• http://www.astho.org/?template=evidenc
e_based_ph_practice.html
National Association of City and County
Public Health Officials
• The Model Practices Database
• http://www.naccho.org/topics/modelpractices/
• http://archive.naccho.org/modelPractices/
▫ Online searchable collection of practices across public
health areas.
▫ Allows you to benefit from colleagues' experiences, to learn
what works, and to ensure that resources are used wisely on
effective programs that have been implemented with good
results.
• The database features practices in the following areas:
▫
▫
▫
▫
Community Health
Environmental Health
Public Health Infrastructure
Emergency Preparedness
EBP Rich Resources
• Health Services/Technology Assessment Text
(HSTAT)
• http://hstat.nlm.nih.gov
• Searchable collection of large, fulltext practice
guidelines, technology assessments and health
information
EBP Rich Resources
• Health Policy Guide
• http://www.healthpolicyguide.org/
▫ evidence-based policies to improve the public’s
health
▫ 150 policy topics to support advocacy and
decision making at the state and local levels
EBP Rich Resources
• http://guides.nursinglibrary.yale.edu/content.p
hp?pid=14371&sid=96991
• National Institute for Health & clin
NICE is an independent organisation
responsible for providing national guidance on
promoting good health and preventing and
treating ill health.
Application Exercise
• PICO QUESTION:
• For the 4 year old pre-K
age group, are there
fewer injection site
complications with
giving the
immunizations in the
thigh as compared to
giving the
immunizations in the
arm?
Cochrane Review
• Tinnion O, Hanlon M. Acellular vaccines for
preventing whooping cough in children. Cochrane
Database of Systematic Reviews 1999, Issue 2. Art.
No.: CD001478. DOI:
10.1002/14651858.CD001478.pub2
• “…Differences in trial design precluded pooling of
the efficacy data and results should be interpreted
with caution. Most systemic and local adverse
events were significantly less common with
acellular than with whole cell pertussis vaccines….”
• Emailed page to print off
National Guidelines Clearinghouse
• 1) General recommendations on
immunization: recommendations of the
Advisory Committee on Immunization
Practices (ACIP). 2) Update:
recommendations from the Advisory
Committee on Immunization Practices
(ACIP) regarding administration of
combination MMRV vaccine.
http://www.guidelines.gov/summary/summary.aspx?doc_id=12325&nbr=
006390&string=vaccine+AND+administration+AND+site+AND+route
National Guidelines Clearinghouse
• Injection Route and Injection Site
• With the exception of Bacillus Calmette-Guerin
(BCG) vaccine, injectable vaccines are administered
by the intramuscular and subcutaneous route. The
method of administration of injectable vaccines is
determined, in part, by the presence of adjuvants in
some vaccines. The term adjuvant refers to a vaccine
component distinct from the antigen that enhances
the immune response to the antigen. The majority of
vaccines containing an adjuvant (e.g., DTaP, DT, Td,
Tdap, PCV, Hib, HepA , HepB, and HPV) should be
injected into a muscle because administration
subcutaneously or intradermally can cause local
irritation, induration, skin discoloration,
inflammation, and granuloma formation.
National Guidelines Clearinghouse
• Routes of administration are recommended
by the manufacturer for each immunobiologic.
Deviation from the recommended route of
administration might reduce vaccine efficacy or
increase local adverse reactions.
CDC: Advisory Committee on Immunization
Practices
• Route
• Administering a vaccine by the recommended
route is imperative. Deviation from the
recommended route of administration might
reduce vaccine efficacy or increase the risk of
local reactions. (p. D5)
CDC: Advisory Committee on Immunization
Practices
• Site
• Although there are several IM injection sites on the
body, the recommended IM sites for vaccine
administration are the vastus lateralis muscle
(anterolateral thigh) and the deltoid muscle (upper
arm). The site depends on the age of the individual
and the degree of muscle development.
• The usual sites for vaccine administration
subcutaneously are the thigh (for infants <12
months of age) and the upper outer triceps of the
arm (for persons >12 months of age). If necessary,
the upper outer triceps area can be used to
administer subcutaneous injections to infants.
CDC: Advisory Committee on Immunization
Practices
• Injectable Vaccine Administration for Children
Birth to 6 years
• IM
▫ anterolateral thigh or deltoid – Use of deltoid
muscle in children 18 monts and older (if
adequate muscle mass) is an option for IM
injections (p. D22)
• SC
▫ anterolateral thigh or lateral upper arm (p. D22)
• Schecter, Zempsky, Cohen, McGrath, McMurtry, &
Bright (2007). Pain reduction during pediatric
immunizations: evidence-based review and
recommendations. Pediatrics, 119(5), e1184-98.
• Evidence is limited and somewhat controversial…..
▫ The limited data available suggests that
intramuscular administration of immunizations
should occur in the anterolateral thigh or vastus
lateralis for children < 18 months of age and in the
upper arm or deltoid for those > 36 months of age.
▫ Controversy exists in site selection for 18 to 36 month
old children.
Schecter, Zempsky, Cohen, McGrath, McMurtry, &
Bright (2007). Pain reduction during pediatric
immunizations: evidence-based review and
recommendations. Pediatrics, 119(5), e1184-98.
• The shift from thigh to arm should occur when
the upper arm has adequate muscle mass to
allow injection. This shift is driven by research
with 18month old infants that suggests that
injection in the thigh is more painful and causes
more incapacitation (decreased movement of
the extremity, limping) than injection in the
arm. However, redness and swelling was found
to occur more frequently when given in the
arm.
Application Exercise
• PICO QUESTION:
• For the 4 year old pre-K age group, are there
fewer injection site complications with giving the
immunizations in the thigh as compared to
giving the immunizations in the arm?
Source
Level of Evidence
Cochrane Review
?
National Guidelines
Clearinghouse
?
CDC: Advisory Committee on
Immunization Practices
?
Evidence Based Review
?
Cochrane
Review
Did the Evidence Answer
our PICO Question?
National Guidelines
Clearinghouse
CDC: ACIP
Evidence
Based Review