Problems with Prevention: A Clinical Perspective

Problems with Prevention:A Clinical Perspective

Michel Accad, MDOctober 17, 2011

GABA Panel Discussion

Cardiovascular Disease• Long latency period• No easily identifiable external signs• Natural history difficult to predict• First manifestation may be benign,

serious or fatal• Tightly connected to aging

Prevention is bound to be difficult

Ann Intern Med 1961

Blood Pressure

LDL Cholesterol

HDL Cholesterol (negative)

Impaired Glucose

Tolerance

Cigarette Smoking Triglycerides

Body Mass Index

C-Reactive Protein Others

Commonly Identified RFs

Disease• Symptoms• Sharp demarcation from

normal• Disease is target for therapy• Deterministic (present or

not)

Risk Factor• Compatible with well-being

over a wide range of values• Continuum of risk • Risk is target for therapy

(risk reduction)• Statistical

Risk Factor≠

Disease

T H ED I S T I N C T I O N

B E T W E E NR I S K F A C T O R

A ND D I S E A S E

H A SB E E N

B L U R R E D

Risk Assessment:A Fluid Concept

• Imperfect Quantitative Models• Doctor’s perspective• Patient’s perspective• Patient’s means

Treating Populations:The Paradox of Prevention

Risk Factors:Disease by fiat

• Cut-off numbers “define” disease

• Numbers selected by super-committees

• Changing cut-off numbers creates millions of patients overnight

Risk factors as disease…

…doctors as weathermen?

118 CVD Risk Factors

And counting…

Risk factor as disease

• The problem of the J-curve

Risk factor

Bad

outc

ome

Public Awareness Campaigns…

(the answer is most certainly yes…)

“It is not the healthy who need a doctor, but the sick.”

Matthew 9:12

Dr. is everything OK?

DO I HAVE

LATENT CVD?

A better approach?

Focus on the early detection

• Atherosclerosis• Hypertensive

Cardiovascular Disease

• Vascular elasticity• Endothelial function• Digital retinal scan• CIMT• Microalbumin• Cardiac stress markers

(eg. BNP)• Vascular calcium• Others

Early detection approach

PROS• Focused on the individual• Not a statistical assessment• Can be monitored in

response to intervention• May identify patients

without risk factors who have CVD

• Facilitates dialogue regarding future risk

CONS• Does not avoid problem of

prediction• Must distinguish disease

patterns from age-related changes in the vasculature

• More expensive• Not “validated”

No longitudinal data

No super committee

endorsement

No reimbursement

by insurance

Limited experience

The conundrum for early detection technologies

A role for the private sector?

The good news for the people

Thank you