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

What is pain?

Most common reasons for under-treated PAIN ???

Attitude: Pain isn’t importantAttitude: Pain isn’t important

Lack of Awareness and Knowledge: Lack of Awareness and Knowledge: 1)1) Pain’s prevalence Pain’s prevalence 2)2) Pain’s impact Pain’s impact

- On people and their familiesOn people and their families- On healthcare costs and on societyOn healthcare costs and on society

3)3) The pathophysiology of the disease of painThe pathophysiology of the disease of pain

Lack of Good TrainingLack of Good Training1)1) The assessment of pain and pain co-morbiditiesThe assessment of pain and pain co-morbidities2)2) The use of evidence-based treatment algorithmsThe use of evidence-based treatment algorithms

Pain’s prevalence and impactPain’s prevalence and impact

- 75 million Americans with chronic or recurring pain75 million Americans with chronic or recurring pain- 40% with moderate to severe impact on their lives40% with moderate to severe impact on their lives- pain levels affect outcome of diseasepain levels affect outcome of disease- National economyNational economy

- $150 billion yearly: medical care, wage replacement, $150 billion yearly: medical care, wage replacement, disability, etcdisability, etc

- Businesses:Businesses:- $61 billion yearly in lost productivity in working adults$61 billion yearly in lost productivity in working adults

Defining Pain

Arthritis

Spinal Stenosis

Failed Back

Neuropathy DM,PHN,HIV,post CVA Cancer

Pain Mechanisms

Acute

Chronic < episodic < persistent

End of life

Pain’s Impact: Issues and challenges Established effects (by research) of chronic pain

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

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

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

Pain’s Impact: Issues and challenges Established effects (by research) of chronic pain

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

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

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

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.

Back Pain 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

Courtesy of B. Todd Sitzman, MD, MPHCourtesy of B. Todd Sitzman, MD, MPH

Back Pain 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

Courtesy of B. Todd Sitzman, MD, MPHCourtesy of B. Todd Sitzman, MD, MPH

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.

Problems in classifying painBy Intensity

No pain

-Mild

-Moderate

-Severe

-Excruciating

-Unbearable

Is person X’s “10” the same as person Y’s “10” (or person Y’s “8”, “5” , or “3”)?

0

2

4

6

8

10

Problems in classifying pain

By region:

low back pain

By anatomy

- spine

- muscles

- kidneys

Vertebral body

Disk

Facet joint

Nerve Root

OsteoporosisFractureTumorSpondylolisthesisScoliosis

DegeneratedAnnulus tearHerniation with or without fragment

ArthritisInstability

InflammationCompressionAvulsion

BY PATHOLOGY

By Mechanism

- Neuropathic

- Nociceptive

- Myofascial

Problems in classifying pain Sensitization

- peripheral- central

Sympathetically mediatedNerve injury/damage

(surgery, radiation, chemotherapy)NeuromaNeuralgias, NeuropathiesRadiculopathiesDeafferentation / ExcitotoxicityRebound headacheMigraine headache

Tissue injuryAuto-immune disease InflammationInfectionArthritisCancer

RadiculopathyRadiculopathy

• 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 - EtiologyRadiculopathy - 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 - DiagnosisRadiculopathy - 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

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

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

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 > 70 y/o with LBP (Medicare data) Predictors of functional disability

Pain severityDuration of pain

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

D

The derivation of a disabled LBP population

D. Pre morbid risk factors:

Scoliosis; Combat exposure;

Prolonged deployment;Airborne troop; Stiff

upper lip;Older; Less education;Psychiatric disorder;Personality Disorder;

Externallocus of control

B. Soldierswith onset of injury causing LBP

A. DISABLED PAIN POPULATION

C. Injured at increased risk for pain disability:

1. Factors increasing risk for disability at injury onset?: TBI; Poor injury mgt; Pain impairments; Anxiety, depression, addiction disorder; Inappropriate back surgery

2. Factors perpetuating pain & disability: Uncontrolled pain;

Stoicism; Redeployment; Psychosocial morbidities; Fear-avoidance; Untreated depression / PTSD / SA; Obesity; Poor coping; No rehab; Inflexible workplace.

TIME

3. Factors reducing risks for chronicity:Competency/ 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 controlB

C

(Adapted from Gallagher et al, Geriatrics 1999;

-1 + 6 months0 +1 +2

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