The Public Health Problem of Pain: Epidemiology and Phenomenology

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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_at_mail.med.upenn.edu

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Pain is a more terrible lord of mankind than
even death itself.
What is pain?

• Albert S. Schweitzer, 1931
• On the Edge of the Primeval Forest.
• New York Macmillan, 1931652

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Most common reasons for under-treated PAIN ???

• Attitude Pain isnt important
• Lack of Awareness and Knowledge
• Pains prevalence
• Pains 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

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Pains 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

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Not all pain is the same The pathophysiology of
painful diseases
Nociceptive pain Caused by activity in neural
pathways in response to potentially
tissue-damaging stimuli
Neuropathic pain Initiated or caused by a
primary lesion or dysfunction in the nervous
system
Neuropathic low-back pain
Peripheralneuropathy
Postoperativepain
Arthritis
CRPS
Diabeticneuropathy
Sickle cellcrisis
Mechanicallow-back pain
Trigeminalneuralgia
Central post-stroke pain
Postherpeticneuralgia
Sports/exerciseinjuries
CRPS complex regional pain syndrome.
R Gallagher, adapted from Portenoy RK et al. Pain
Management Theory and Practice. 1996
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Defining Pain
Arthritis Spinal Stenosis Failed
Back Neuropathy DM,PHN,HIV,post CVA Cancer
Acute Chronic lt episodic lt persistent End
of life
Pain Mechanisms
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Nociceptive pain Caused by activity in neural
pathways in response to potentially
tissue-damaging stimuli
Neuropathic pain Initiated or caused by a
primary lesion or dysfunction in the nervous
system

• EXAMPLES OF MIXED PAIN STATES
• Postoperative pain
• Mastectomy
• Low back and neck surgery
• Pelvic surgery
• Spine disease
• Cancer (cured, in remission, metastatic)
• Amputation pain
• Pelvic pain and interstitial cystitis

Inflammatory/Immunological /Neurophysiologic
Mediation
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Pains Impact Issues and challenges
Established effects (by research) of chronic pain

• Psychological morbidity
• Fear, anger, suffering
• Sleep disturbances
• Loss of self-esteem

• Quality of life
• Physical functioning
• Ability to perform ADLs
• Work

• Medical morbidity consequences
• Accidents
• Medication effects
• Immune function
• Clinical depression

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Pains Impact Issues and challenges
Established effects (by research) of chronic pain

• Social consequences
• Marital/family relations
• Intimacy/sexual activity
• Social role and friendships

• Societal consequences
• Health care costs
• Disability
• Lost workdays
• Business failures
• Higher taxes

Mismanaged chronic pain is often a personal,
biopsychosocial catastrophe!
.and is a huge public health problem.
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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?

• You start by understanding
• the causal models of disease
• the mechanisms underlying these
• models
• the biopsychosocial phenomenology of each unique
  disease population
• - the biopsychosocial formulation for each
  individual

You then assess the characteristics of the care
delivery system. Finally, you formulate and
implement a goal-oriented management plan.
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Back Pain
Facts

• Low back pain accounts for 75 of all chronic
  pain conditions (gt OA, HA, migraine, FM, cancer
  pain)
• 50 of working-age report back pain symptoms
  each year
• Most common cause of disability in persons lt 45
  yo
• At any given time, 1 of US population is
  chronically disabled because of back problems and
  another 1 is temporarily disabled

Courtesy of B. Todd Sitzman, MD, MPH
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Back Pain
Facts

• 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 doctors
• Attitude toward pain
• Knowledge about pain
• Ability to treat pain

Courtesy of B. Todd Sitzman, MD, MPH
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Problems in classifying pain

• By Intensity
• No pain
• Mild
• Moderate
• Severe
• Excruciating
• Unbearable
• Is person Xs 10 the same as person Ys 10
  (or person Ys 8, 5 , or 3)?

0 2 4 6 8 10

• By Duration
• Acute
• Recurrent
• Persistent
• When does acute pain become chronic?
• - laboratory changes indicating chronicity
  changes begin within minutes.
• - clinically, changes start happening soon after
  onset, often within 1-2 weeks.

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Problems in classifying pain

• By region
• low back pain
• By anatomy
• - spine
• - muscles
• - kidneys

BY PATHOLOGY
Osteoporosis Fracture Tumor Spondylolisthesis Scol
iosis Degenerated Annulus tear Herniation with
or without fragment Arthritis Instability Infl
ammation Compression Avulsion
Vertebral body Disk Facet joint Nerve Root
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Problems in classifying pain
Sensitization - peripheral - central Sympathetic
ally mediated Nerve injury/damage (surgery,
radiation, chemotherapy) Neuroma Neuralgias,
Neuropathies Radiculopathies Deafferentation /
Excitotoxicity Rebound headache Migraine headache

• By Mechanism
• Neuropathic
• Nociceptive
• Myofascial

Tissue injury Auto-immune disease
Inflammation Infection Arthritis Cancer
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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

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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

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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, 33169-73.

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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

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Course of LBP

• Gallagher RM et al Pain 1989, 1995
• 150 workers disabled by LBP
• Medical, radiographic, psychological,
  motivational and functional testing (5 hour
  battery)
• Independent predictors of poor return to work at
  6 months?
• Older Age
• Less Education
• Longer time out of work
• External locus of control
• unless received workers compensation benefits!
• NOT physical examination findings

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Course of LBP

• Hestbaek L et al. Eur Spine J 2003
• Review of studies of course of LBP
• After 12 months, the proportion of patients
  still with LBP averaged 62 across studies
  (range 42-75)
• LBP more chronic / recurrent than we thought

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Course of LBP

• Burton AK et al Man Ther 2004. (UK Study)
• Predictors of outcome at 4 years
• Depressive symptoms
• Fear-avoidance
• Weiner D et al, Pain Med 2003
• Adults gt 70 y/o with LBP (Medicare data)
• Predictors of functional disability
• Pain severity
• Duration of pain

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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

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The derivation of a disabled LBP population
(Adapted from Gallagher et al, Geriatrics 1999
D. Pre morbid risk factors Scoliosis Combat
exposure Prolonged deployment Airborne troop
Stiff upper lip Older Less education Psychiatri
c disorder Personality Disorder External locus
of control
1. Factors increasing risk for disability at
injury onset? TBI Poor injury mgt Pain
impairments Anxiety, depression, addiction
disorder Inappropriate back surgery
3. Factors reducing risks for chronicity Compete
ncy/ coping skills Access to pain
medicine/rehab RTW or vocation Re-entry crisis
Rx Early depression Rx Occupational mobility
Education level Social support Internal locus
of control
D
C
A. DISABLED PAIN POPULATION
2. Factors perpetuating pain disability
Uncontrolled pain Stoicism Redeployment
Psychosocial morbidities Fear-avoidance
Untreated depression / PTSD / SA Obesity Poor
coping No rehab Inflexible workplace.
B
B. Soldiers with onset of injury causing LBP
C. Injured at increased risk for pain
disability
-1
1
2
0
6 months
TIME
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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