Neuropathic pain

Peter KamermanXXII World Congress of Neurology, Santiago, Chile, 2015

EPIDEMIOLOGY, RISKS, AND PREVENTION

Disclosures

I have no actual or potential conflicts of interest related to the material being presented.

Nor do I discuss off-label indications for any medications.

Learning objectives

By the end of this presentation, delegates will be able to:

● Describe the burden of chronic pain in the general population;

● Report the proportion of chronic pain that is neuropathic in origin;

● Describe the prevalence of neuropathic pain in special populations;

● Appraise the socio-economic consequences of having neuropathic pain.

Key message

Neuropathic pain:

● Is common, especially in special populations (e.g., diabetes, HIV, spinal cord injury);

● Has a significant negative impact on the affected individual, and society

What is epidemiology?

“The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to control health problems.”

Last, 1995

Epidemiology and neuropathic pain

Adapted from: Smith and Torrance, 2012

To inform understanding, at a population level, of:

Prevalence and incidence

Risk factors and aetiology

Impact on quality of life and prognosis

Prevention

Design, targeting, and evaluation of treatment strategies

Allocation of health resources

Allocation of educational resources

Epidemiology and neuropathic pain

To inform understanding, at a population level, of:

Prevalence and incidence

Risk factors and aetiology

Impact on quality of life and prognosis

Prevention

Design, targeting, and evaluation of treatment strategies

Allocation of health resources

Allocation of educational resources

Predictions on the future

Adapted from: Smith and Torrance, 2012

Prevalence of neuropathic pain

How common is chronic pain?

Breivik et al., 2004Bootstrap mean and 95% CI (data available at https://github.com/kamermanpr)

Chronic pain prevalence in 46,394 adults from 15 European countries and IsraelPain on most days within the last 6 months

How common is chronic pain?

Breivik et al., 2004; Nahin, 2015Bootstrap mean and 95% CI (data available at https://github.com/kamermanpr)

Pain on most days within the last 6 months Chronic pain prevalence in 8,466 adults from the US

Pain on most days within the last 3 months

How much of chronic pain is neuropathic?

Breivik et al., 2004

Source of chronic pain in a subset of 4,389 / 46,394 Europeans with chronic pain

Neuropathic pain in the general population

Torrance et al., 2007; Bouhassira et al.,2008; Toth et al., 2009; Yawn et al., 2009; de Moraes Vieira et al., 2012; Harifi et al., 2013

Median (9%)

How good are the data?

Imperfect tools provide poor estimates of true prevalence

Imperfect tools provide poor estimates of true prevalence

Bouhassira et al.,2008; Stevenson et al., 2015

Imperfect screening toolsModelling based on: ● DN4 Interview

○ sensitivity = 82% ○ specificity = 86%

● n = 3000

Imperfect tools provide poor estimates of true prevalence

Imperfect screening toolsDN4-interview: ● Sensitivity = 82%● Specificity = 86%

S-LANSS: ● Sensitivity = 75%● Specificity = 80%

Torrance et al., 2007; Bouhassira et al.,2008; Toth et al., 2009; Yawn et al., 2009; de Moraes Vieira et al., 2012; Harifi et al., 2013; Stevenson et al., 2015

The burden of neuropathic pain

The burden of neuropathic pain

“17% of people with neuropathic pain rated their quality of life as being, worse than death.”

Torrance et al., 2013

The burden of pain varies according to cause

Not everyone with damage to the nervous system has pain

Veves et al., 2007; Sadosky et al., 2008; Haanpaa et al., 2009; van Hecke et al., 2014

The burden of neuropathic pain

Schaefer et al., 2014a

Dysfunction is similar across aetiologies

The burden of neuropathic pain

Doth et al., 2010; Attal et al., 2011; Torrance et al., 2013; Schaefer et al., 2014a

Chronic pain

● Reduced mobility

● Reduced quality of life

● Reduced sleep / sleep quality

● Increased unemployment

● Increased work impairment

● Increased depression / anxiety

● Increased use of healthcare

NEUROPATHIC PAIN● Reduced mobility

● Reduced quality of life

● Reduced sleep / sleep quality

● Increased unemployment

● Increased work impairment

● Increased depression / anxiety

● Increased use of healthcare

The burden of neuropathic pain

Lalli et al., 2013

Attribute Diabetes(%; n = 20)

Diabetes + Neuropathy(%; n = 20)

Diabetes + Neuropathic pain(%; n = 20)

Fell in the last year 15 20 45

Fear of falling 5 20 64

Presence of pain increases gait variance, number of fall, and fear of falling:

The burden of neuropathic pain

Schaefer et al., 2014b

The effect on work productivity is related to pain intensity (n = 624 people clinically diagnosed with neuropathic pain, 33 study sites, 45% recruitment rate)

Burden of neuropathic pain

van Hecke et al., 2014

Risk factors for neuropathic pain:

○ Diseases/exposures that increased risk of nervous system injury○ Female sex○ Older age○ Lower socio-economic status○ Employment status and occupational factors○ History of abuse/interpersonal violence○ Genetic vulnerability○ Acute pain burden○ Psychological factors

The future

The future

Oxman et al., 2008; Ellis et al., 2010; Kamerman, 2015

Decreasing HIV-SN? Decreasing Zoster?

The future

Veves et al., 2007; Gauriguata et al 2013

But….increasing diabetes mellitus

Summary

Neuropathic pain:

● Affects 1-8% of the adult population;

● Is more common in specific patient populations (e.g., diabetes, HIV, spinal cord injury);

● Has a significant, negative impact on the affected individual, and society;

● Resulting from diabetes mellitus could reach epidemic levels.

Selected reading

Bibliography

Breivik H, Collett B, Ventafridda V, et al. Survey of chronic pain in Europe: Prevalence, impact on daily life, and treatment. European Journal of Pain 10: 287-287, 2005. doi: 10.1016/j.ejpain.2005.06.009.

van Hecke O, Austin SK, Khan RA, et al. Neuropathic pain in the general population: A systematic review of epidemiological studies. PAIN 155: 654-662, 2013. doi: 10.1016/j.pain.2013.11.013.

Smith BH, Torrance N. Epidemiology of Neuropathic Pain and Its Impact on Quality of Life. Current Pain and Headache Reports 16: 191-198, 2012. doi: 10.1007/s11916-012-0256-0.