The Public Health Problem of Pain: Epidemiology and Phenomenology
Rollin M. Gallagher, MD, MPH


University of Pennsylvania School of Medicine

Philadelphia Veterans Medical Center



 	Email: rgallagh@mail.med.upenn.edu


“Pain is a more terrible lord of   mankind than even death itself.”
Albert S. Schweitzer, 1931

On the Edge of the Primeval Forest. 
New York: Macmillan, 1931:652
Most common reasons for under-treated PAIN ??? 
Attitude: Pain isn’t important

Lack of Awareness and Knowledge: 
* Pain’s prevalence 
* Pain’s impact 
- On people and their families
- On healthcare costs and on society
* The pathophysiology of the disease of pain

Lack of Good Training
* The assessment of pain and pain co-morbidities
* The use of evidence-based treatment algorithms
Pain’s prevalence and impact

- 75 million Americans with chronic or recurring pain
- 40% with moderate to severe impact on their lives
- pain levels affect outcome of disease
- National economy
- $150 billion yearly: medical care, wage replacement, disability, etc
- Businesses:
- $61 billion yearly in lost productivity in working adults

Not all pain is the same: 
The pathophysiology of painful diseases


Pain’s Impact: Issues and challenges
      Established effects (by research) of chronic pain
Pain’s Impact: Issues and challenges
      Established effects (by research) of chronic pain
If chronic pain is a biopsychosocial  catastrophe and a huge public cost,

how do you deliver clinical care that is driven by performance based, biopsychosocial outcomes?
Back Pain      



• Low back pain accounts for 75% of all chronic pain conditions (> OA, HA, migraine, FM, cancer pain)

• 50% of working-age report “back pain” symptoms each year

• Most common cause of disability in persons < 45 yo

• At any given time, 1% of US population is chronically disabled because of back problems and another 1% is temporarily disabled

Back Pain      


• Most common reason for office visits to orthopedic surgeons, neurosurgeons, pain medicine physicians

• Estimated total annual societal cost of back pain in the US is greater than $50 billion	

• 22% of chronic back pain patients have changed doctors “at least 3 times” in search of pain relief

• The primary reasons why chronic pain patients change physicians is due to their doctor’s:
» Attitude toward pain
» Knowledge about pain
» Ability to treat pain					                   

Problems in classifying pain
Problems in classifying pain
By region:	
	low back pain
By anatomy
	- spine
	- muscles
	- kidneys
Problems in classifying pain
By Mechanism	
- Neuropathic

- Nociceptive

- Myofascial
Radiculopathy

• Definition:
  “Disturbance in the function of one or more nerve roots”

• Hallmark characteristic:
  “Pain in the presence of segmental nerve dysfunction”

• Described as shooting or electric shock-like

• Symptoms result from inflammation or compression of the nerve root

• May include both sensory and motor loss



Radiculopathy - Etiology
• Mechanical Stimulation:
   Common  
–  disc bulge, herniation, fragmentation
–  contact with a facet  joint osteophyte
–  ligamentum flavum thickening

Less Common (serious)
–  infection, hematoma formation, tumor



Radiculopathy - Diagnosis
• 80% of adults over  55 years of age have degenerative disk changes by MRI and are often asymptomatic

     Jensen MC et al.  Magnetic resonance imaging of the lumbar spine in people without back pain. N Engl J Med 1994, 331:69-73.


Nature or Nurture? 
MacGregor et al, Arthritis Rheum 2004
• 1064 twins from UK registry
• Genetic overlap between:
• Conclusions: The following must be considered in developing a genetic model of LBP:
– Psychological variables (e.g., depression)
– Past pain experience
– Patterns of learning
– Cultural factors


Course of LBP 


Course of LBP 


Course of LBP 


Risk factors for 
Chronic LBP in VA populations
• Traumatic spine injury, e.g.,
– Jumping from moving vehicles
– Parachuting
– Heavy lifting in hurried conditions
• Repetitive strain:
– Industrial level manual labor in high stress conditions
• Wartime environment leading to denial of injury, redeployment and repetitive injury
• High stress and life disruption leading to psychiatric comorbidities



Summary
• Chronic pain is common
• Chronic pain has consequences for the individual and society
• There are many pain diseases 
• Each pain diseases has its own phenomenology
• Treatment addresses pain generators, mechanisms and biopsychosocial phenomenology