The Public Health Problem of Pain: Epidemiology and Phenomenology

1. 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

2. What is pain? “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

3. 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

4. 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

5. Defining Pain Arthritis Spinal Stenosis Failed Back Neuropathy DM,PHN,HIV,post CVA Cancer Acute Chronic < episodic < persistent End of life Pain Mechanisms

6. Pain’s 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

7. Pain’s 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.

8. 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.

9. Back Pain Facts • 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, MPH

10. Facts 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, MPH

11. Problems in classifying pain • By 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 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.

12. Problems in classifying pain BY PATHOLOGY By region: low back pain By anatomy - spine - muscles - kidneys Osteoporosis Fracture Tumor Spondylolisthesis Scoliosis Degenerated Annulus tear Herniation with or without fragment Arthritis Instability Inflammation Compression Avulsion Vertebral body Disk Facet joint Nerve Root

13. Problems in classifying pain Sensitization - peripheral - central Sympathetically 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

14. 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

15. 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

17. 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.

19. 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

20. 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

21. 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

22. 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 severity • Duration of pain

23. 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

24. 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; Psychiatric 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: 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 control D C A. DISABLED PAIN POPULATION B 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. Soldiers with onset of injury causing LBP C. Injured at increased risk for pain disability: -1 +1 +2 0 + 6 months TIME

25. 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