Using the Medical Literature
to Make Decisions About
Preventive Health Services
Kenny Lin, MD
Associate Editor, Essential Evidence Plus
Associate Editor, American Family Physician
May 17, 2011
Disclosures


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Associate Editor, Essential Evidence Plus (Wiley)
Associate Editor, American Family Physician
(AAFP)
Adjunct Faculty Positions
Georgetown University School of Medicine
 Johns Hopkins Univ. School of Public Health
 Uniformed Services Univ. of the Health Sciences

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Former Medical Officer, Agency for Healthcare
Research and Quality (DHHS)
Learning Objectives
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Review the burden of chronic preventable diseases in
the United States.
Estimate the potential for improving health through
effective clinical prevention.
Understand the importance of using an evidencebased process to develop preventive health guidelines
based on searches of the medical literature.
Introduce multiple tools for accessing preventive
health information at the point of care.
“An ounce of prevention is worth a
pound of cure”
Burden of Chronic Illness in
the United States
Causes of Death - Diagnoses,
2000
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Cause
No of deaths
death rate*
Heart disease
Cancer
Cerebrovascular disease 167 661
COPD
Unintentional injuries
Diabetes mellitus
Influenza and pneumonia
Alzheimer disease
Nephritis/nephrosis
Septicemia
Other
Total
710 760
553 091
258.2
200.9
60.9
122 009
97 900
69 301
65 313
49 558
37 251
31 224
499 283
2 403 351
* Per 100,000
Ref: Mokdad AH, Marks JS, Stroup DF, Gergerding JL. JAMA. 2004;291:1238-1245
44.3
35.6
25.2
23.7
18
13.5
11.3
181.4
873.1
Actual Causes of Death - 2000
Actual Cause
Tobacco
Diet/phys. inactivity
ETOH
Microbial agents
Toxic agents
Motor vehicle
Firearms
Sexual behavior
Illicit drug use
Total
No. (%) in 1990*
400 000 (19)
300 000 (14)
100 000 (5)
90 000 (4)
60 000 (3)
25 000 (1)
35 000 (2)
30 000 (1)
20 000 (1)
1 060 000 (50)
No. (%) in 2000
435 000 (18.1)
365 000 (15.2)
85 000 (3.5)
75 000 (3.1)
55 000 (2.3)
43 000 (1.8)
29 000 (1.2)
20 000 (0.8)
17 000 (0.7)
1 124 000 (46.7)
Ref: Mokdad AH, Marks JS, Stroup DF, Gergerding JL. JAMA. 2004;291:1238-1245
Preventable Deaths in the U.S.
U.S. ranks last among industrialized nations in
preventable deaths
Could prevent 100,000 deaths annually if rates
were similar to high-performing nations
Health Affairs, Sept. 2006
Mortality Amenable to Health Care
U.S. Rank Fell from 15th to Last out of 19 Countries
Deaths per 100,000 population*
150
1997/98
2002/03
116
109
99
100
88
84
81
76
89
97
89
65
74
71
77
74
115
134
128
115
113
106
97
88
50
71
130
80
82
84
82
84
90
93
96
101
103
103
104
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* Countries’ age-standardized death rates, ages 0–74; includes ischemic heart disease.
Source: Commonwealth Fund; E. Nolte and C. M. McKee, Measuring the Health of Nations: Updating an
Earlier Analysis, Health Affairs, January/February 2008, 27(1):58–71
110
Costs of Preventable Diseases
We cannot effectively address escalating health care costs
without addressing the problem of chronic diseases and
finding ways to delay or prevent their onset.
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More than 90 million Americans live with chronic illness
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Chronic diseases account for 70% of all deaths in the U.S.
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The medical costs of people with chronic diseases account for
more than 75% of the nation’s approximately $1.5 trillion in
annual medical care costs.
Challenges in Prevention
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Most important messages about prevention may not be
getting through to clinicians and patients
Not everything that might work does work
Services should be supported by good evidence (but
often aren’t) before they are widely recommended
Necessity of providing individual preventive services
often skewed by:
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Beliefs, anecdotal experiences of clinicians and patients
Inaccurate media messages
Advocacy groups
Political considerations
Primary care: is there time enough
for prevention?
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Yarnall KS et al., Am J Public Health, 2003
Used published and estimated times to
determine the total physician time required to
provide all recommended preventive services to
a patient panel of 2500 with an age and sex
distribution similar to that of the US population
1773 hours annually, or 7.4 hours per working
day
How much time do primary care clinicians
actually spend on preventive care?
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Pollak KI et al., BMJ Health Serv Res, 2008
Data on family and internal medicine visits from 200104 National Ambulatory Medical Care Survey
Most time spent on: PSA (4.9 minutes), cholesterol, Pap
smear, mammograms, exercise counseling, and blood
pressure
Spent less time than recommended on tobacco
cessation (0.11 vs. 3 minutes) and nutrition counseling
(1.34 vs. 8.2 minutes)
Rethinking Current Health Approaches
Problem of Underuse of Clinical
Preventive Services
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Insurance coverage makes a difference in whether
people receive preventive services
Approximately half (52%) of adults receive preventive
care according to guidelines for their age and sex.1
In 2004, NCQA identified 48,600 cases of late-stage
breast cancer and colorectal cancer and osteoporosisrelated fractures that could have been averted if
individuals received appropriate and timely preventive
care.2
Sources: 1. The Commonwealth Fund Commission on a High Performance Healthcare System, Sept 2006; 2.
National Committee for Quality Assurance. The State of Healthcare Quality 2005. Washington, DC; NCQA: 2006.
Preventive Services in Health
Reform
Why Evidence-Based?
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Need transparent, systematic process to
obtain and distill best available evidence to
support clinical decision making
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Identifying, evaluating and summarizing scientific
evidence about outcomes or interventions or
policies
Translating research evidence into clinical practice
recommendations
General Attributes of Good Clinical
Practice Guidelines
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Comprehensive, systematic evidence search
Evidence linked directly to recommendations via
strength of recommendation grading system
Recommendations based on patient-oriented rather
than disease-oriented outcomes
Development process is transparent
Potential conflicts of interest identified and addressed
Prospective validation
Clinical flexibility
U.S. Preventive Services Task Force:
Prevention in the Clinical Setting
What is the US Preventive
Services Task Force?
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Congressionally mandated, independent panel of nonFederal experts in prevention and evidence-based
medicine, established in 1984
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16 primary care clinicians (internists, pediatricians, family
physicians, ob/gyns, nurses and health behavior
specialists) appointed to rotating 4-year terms
http://www.uspreventiveservicestaskforce.org/about.htm
What is the USPSTF Mission?
“to evaluate the benefits of individual [preventive]
services based on age, gender, and risk factors for
disease;
make recommendations about which preventive
services should be incorporated routinely into primary
medical care and for which populations;
and identify a research agenda for clinical preventive
care.”
www.uspreventiveservicestaskforce.org/about.htm
Who Supports the USPSTF?
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Administrative, research, technical and dissemination support
provided by the Agency for Healthcare Research and Quality
(AHRQ), a division of the Department of Health and
Human Services (DHHS)
Scientific support from AHRQ-funded Evidence-Based
Practice Centers (EPCs)

EPCs conduct systematic evidence reviews on topics in
clinical prevention that serve as the scientific basis for
USPSTF recommendations
www.uspreventiveservicestaskforce.org/about.htm
What are US Preventive Services
Task Force Activities?
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Guidelines published in the form of “recommendation
statements”
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2010 Affordable Care Act singles out positive
recommendations by the USPSTF ( “A” or “B”) for
coverage without cost-sharing
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Recommendations are graded to convey two major
elements: certainty and magnitude of net benefit of the
preventive service
http://www.uspreventiveservicestaskforce.org/about.htm
The USPSTF Steps:
Brief and Generic
Step 1: Define key questions and outcomes, including an
analytic framework
(Note: CEA = carotid endarterectomy)
www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm
The USPSTF Steps:
Brief and Generic
Step 2: Define, retrieve and summarize relevant
evidence from the medical literature
Step 3: Judge quality of individual studies:
good, fair, poor
Step 4: Synthesize and judge the adequacy of the
evidence about benefits and harms:
convincing, adequate, inadequate
www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm
Systematic Reviews
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A planned, comprehensive, reproducible,
exhaustive review of the world’s literature on a
given topic
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Includes electronic resources (e.g., MEDLINE,
EMBASE), experts and review of reference lists
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May include unpublished studies (but often does
not, so ‘publication bias’ is always a concern)
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Always valuable
The USPSTF Steps (continued):
Step 5: Determine and judge the magnitude of both
benefits and harms: substantial, moderate, small, zero
Step 6: Determine and judge the balance of benefits
and harms (net benefit)
Step 7: Judge the certainty of net benefit: low,
moderate, high
Step 8: Judge the magnitude of net benefit:
substantial, moderate, small, zero/negative
Step 9: Assign a letter grade: A, B, C, D, I
www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm
Concept of “Net Benefit”
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Net Benefit = Benefits minus Harms of preventive
service
USPSTF recommends that clinicians routinely provide
services that have strong evidence of large (“A”) or
moderate (“B”) net benefit
USPSTF does not routinely recommend services that
provide small (“C”) or zero (“D”) net benefit
If unable to determine net benefit, TF issues “I”
(insufficient evidence) statement
USPSTF Grades of
Recommendations
Certainty of Net
Benefit
Magnitude of Net Benefit
Substantial
Moderate
Small
Zero/negative
High
A
B
C
D
Moderate
B
B
C
D
Low
Insufficient
Accessing Prevention Guidelines at the
Point of Care
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Annual pocket-sized Guide to Clinical Preventive Services
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www.uspreventiveservicestaskforce.org
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Web-based and PDA Electronic Preventive Services Selector
(ePSS)
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www.healthfinder.gov (for patients)
Essential Evidence Plus online and mobile resource
American Family Physician journal
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ePSS app for smartphones
ePSS app for smartphones
Contending with
“prevention for profit”
Not everything that might work does
work – that’s why guidelines require
evidence!
An advertisement in my church’s
bulletin earlier this year
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Life Line Screening, the nation's leading provider of preventive
health screenings, will offer their affordable, non-invasive,
painless health screenings.
Five screenings will be offered that scan for potential health
problems related to: blocked arteries, which is a leading cause
of stroke; abdominal aortic aneurysms, which can lead to a
ruptured aorta; hardening of the arteries in the legs, which is
a strong predictor of heart disease; atrial fibrillation or irregular
heart beat, which is closely tied to stroke risk; and a bone
density screening, for men and women, used to assess the risk
of osteoporosis.
Register for a Wellness Package with Heart Rhythm for $149.
Add Disease Risk Assessment with blood testing & biometrics
for $79 more.
Sounds good … but what
does the evidence say?
USPSTF Systematic Reviews,
2005 through 2010
Stroke screenings? Just say no
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"Blocked arteries" / stroke screening is most likely a
carotid ultrasound scan, which doesn't help because
most patients with asymptomatic carotid artery
blockages will not suffer strokes. Although the
screening test is "non-invasive and painless," the
confirmatory test, angiography, is not (it actually causes
a stroke in a small number of patients) and unnecessary
carotid endarterectomy can lead to death.
AAA screening? Not for most people
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Abdominal aortic aneurysm screening is only
recommended in men ages 65 to 75 who have
ever smoked, because aneurysms are much less
common in younger, female, and non-smoking
populations. Even in men who are eligible for
the test, it's important to weigh the potential
benefits against the potential harms of
corrective surgery, which has a not insignificant
mortality rate itself.
Pass on screening for PVD
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"Hardening of the arteries in the legs," or
screening for peripheral vascular disease with an
arterial-brachial index, hasn't been proven to
prevent heart attacks but will certainly lead to
many false positive results.
Screening for atrial fibrillation? Are
you kidding me?
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I've never even heard of atrial fibrillation
(irregular heart beat) screening, which I presume
is doing a screening EKG, which is also totally
unproven. Absolutely no organizations
recommend this.
Even “good” screening tests should
be cleared by clinicians
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Screening for osteoporosis with bone density testing is
the only test on the list that's actually worthwhile for a
large number of adults, especially women over 65. But
it's not appropriate to do this test without a prior
consultation with a clinician who can discuss the risks
and benefits of undergoing this type of screening. And
there are still questions about whether men benefit to
the same degree as women, or at all.
The Bottom Line
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Preventive services have great potential to
improve national health outcomes
An evidence-based process is critical to select
services of value and discourage ineffective
and/or harmful tests
That process is based upon a careful, systematic
search of the medical literature on a topic
Clinicians have many options for accessing
prevention guidelines at the point of care
Thank you!
Questions?