Handbook of Pain Syndromes

Biopsychosocial Perspectives

Andrew R. Block, Ephrem Fernandez, Edwin Kremer

• Publisher: Psychology Press
• Year: 2013
• eBook ISBN:
  9781134806614
• Topic: Psychologie
• Subtopic: Histoire et théorie en psychologie

Pain syndromes involve a complex interaction of medical and psychological factors. In each syndrome unique physiological mechanisms are mediated by emotional states, personality traits, and environmental pressures to determine the nature and extent of pain complaints and pain-related disability. The Handbook addresses the complexities of chronic pain in three ways.

Section I describes general concerns that cross-cut the different syndromes, such as the use of narcotic pain medications, the detection of deception and malingering, and the epidemiology of pain. Section II presents comprehensive reviews of a wide range of pain syndromes. Each covers basic pathophysiology, psychological factors found to influence the course of the syndrome, and syndrome-specific multidisciplinary treatment approaches. Most of the Section II chapters are coauthored by psychologists and physicians. Section III discusses pain in special populations, including the elderly and children.

The Handbook is the most up-to-date, comprehensive, and integrated single-volume resource for all those professionally concerned with pain.

Part I

GENERAL CONSIDERATIONS

Chapter 1

Epidemiology of Chronic Pain

Linda LeResche

University of Washington

Michael Von Korff

Center for Health Studies—
Group Health Cooperative of Puget Sound

EPIDEMIOLOGIC PERSPECTIVES

Epidemiology is defined as the study of distribution, determinants, and natural history of disease in populations (Lillienfeld & Lillienfeld, 1980). This definition embodies the three important perspectives of epidemiology: the population perspective, the environmental perspective, and the developmental perspective. We have elaborated the implications of these perspectives for research and treatment of chronic pain elsewhere (Dworkin, Von Korff, & LeResche, 1992). Here we provide a brief review.

Population Perspective

Much of this book is written from the perspective of clinicians who treat patients with chronic pain. Such pain patients, often seen in tertiary care centers, certainly experience a great deal of suffering and interference with social roles associated with their pain; they also account for significant health care costs and disability. However, as a group these patients represent only a small fraction of persons in the population who experience pain, or even persistent pain. Thus, inferences about pain generated from the study of this highly selected group of patients may not be useful, and may even be misleading, in terms of developing an understanding of the etiology and natural history of acute, recurrent, and chronic pain conditions (Fields, 1987).

In contrast, study of pain in populations allows for the documentation of the full spectrum of pain severity. For example, we can determine the extent to which pain of a particular type, persistence, or intensity is associated with interference with work, social, or family activities. In addition, the population perspective provides data for defining or delineating disease and illness from the range of normal variation. Because pain is such a prevalent human experience, in order to develop an understanding of when “pain” becomes a “pain problem” either for the individual or society, it is essential to study the full range of persons with pain—both in and outside treatment settings. Examination of pain in the population (as opposed to exclusively in treatment settings) also allows for investigation of etiologic and risk factors for pain, as distinct from factors that may be associated with seeking treatment. Finally, only studies in the population can provide data on the full burden of pain in society.

Ecological Perspective

The ecological perspective of epidemiology implies that diseases are a product of the dynamic interaction of disease agents, host factors that increase disease susceptibility, and environmental factors that influence exposure to the agent or increase its virulence. Environmental factors are viewed broadly, and include both physical and social factors. Although this perspective was initially developed in the investigation of acute, infectious disease, it holds equally well for chronic diseases and conditions. In fact, the ecological perspective of epidemiology is quite similar to the biopsychosocial model of illness first elaborated by Engel(1960) and now espoused by most clinicians and researchers as the most useful model for the investigation of chronic pain conditions.

Developmental/Temporal Perspective

The developmental perspective suggests that diseases have specific temporal characteristics within an individual, and have a natural history within the population as a whole that is a product of the individual patterns. Within the individual, important temporal characteristics include age of onset, duration of the condition, temporal patterning (e.g., episodic vs. constant), and staging or course of the illness. Within the population, important elements of natural history include the predictability of temporal patterning, as well as the typical course of the condition. In the area of chronic pain, important issues of natural history include the rates with which people make transitions between acute, recurrent and chronic pain states, what the typical course or prognosis of a pain condition is, and how the course is affected by host and environmental factors.

A Dynamic Population Model of Pain

Incorporating the perspectives of epidemiology outlined previously, epidemiologic research on chronic pain aims to investigate pain in populations as a dynamic process characterized by the interactions of agent, host, and environmental factors. One possible approach to characterizing change in pain status over time is the dynamic population model we have presented elsewhere (Von Korff, 1992). This model suggests that at any given point in time, persons may be pain free or may be experiencing acute, recurrent, or persistent pain with or without dysfunction. In terms of this dynamic model, some of the aims of epidemiologic research involve characterizing and defining pain states across this spectrum of severity. Because pain is dynamic, transitions among these states over time are to be expected. Thus, additional aims of epidemiology are to estimate the probability of being in a particular state during a given time period, to estimate the probability of transition among states over time, and to identify factors predicting or controlling the probabilities of transition.

Epidemiologic Measures

The basic measures employed by epidemiologists to describe the distribution, determinants and natural history of disease in populations include prevalence, incidence, duration, and risk. These measures are defined as follows.

Prevalence. This is defined as the proportion of persons in the population with a disease or condition at a particular time. Thus, both the number of persons with the condition and the total population at risk of having the condition (i.e., the numerator and denominator, respectively) have to be known in order to calculate a prevalence rate. If the enumeration is done at a single point in time (or approximates this kind of measure), the prevalence rate is called a point prevalence rate. Other commonly reported kinds of prevalence rates include period prevalence (e.g., number of cases in the population over a 3- or 6-month time period) or lifetime prevalence (number of persons who experience the condition over the course of their lifetime). Period prevalence is probably the most appropriate type of prevalence measure for chronic pain conditions, since it better captures significant pain problems that may be frequent or persistent, but may not be present at the exact time of the survey.

Incidence is defined as the rate of onset of the condition over a defined time period (usually 1 year). Calculation of incidence requires knowledge of the number of new cases appearing in a population over the time period (numerator of the incidence rate) as well as the number of persons at risk of developing the condition (the denominator). Note that persons at risk include all those capable of developing the condition (e.g., men in the case of prostate cancer) who do not already have the condition, or who have no history of the condition.

Duration is simply the length of time the condition lasts. For conditions that are episodic or recurrent, the total duration would be equivalent to the sum of the durations of each episode.

Prevalence, incidence, and duration are related, by a steady-state equation, such that (under steady-state conditions):

For recurrent conditions, in a steady-state population,

Risk is defined as the likelihood that persons who do not have a specific condition (but who have particular attributes or are exposed to certain “risk factors”) will develop the condition.

Most of the epidemiologic literature in the field of pain involves reporting of prevalence rates. There are some studies aimed at identifying risk factors, a few that specifically examine the temporal course of pain, and only a handful of studies of the incidence, or rates of onset of specific pain conditions.

PREVALENCE DATA

An exhaustive review of the literature on the prevalence of particular pain conditions is beyond the scope of this chapter. However, the following sections present age- and gender-specific prevalence rates for those pain conditions that are most common in the adult population. In addition, data are presented on a few less common conditions (e.g., fibromyalgia) that may be of particular interest to researchers and pain clinicians. Only studies investigating entire populations are reviewed (e.g., studies of a particular occupational group are excluded). Although absolute prevalence rates of specific pain conditions may vary from study to study depending on the definitions used and the population studied, the age- and gender-specific patterns of prevalence for particular pain conditions are of interest because they can potentially shed light on biologic, psychologic, and social factors that might influence rates of onset or duration of these pain conditions in a given age-gender group. Thus we selectively review those studies that have examined age by gender-specific prevalence. This chapter focuses on pain in adults; for a review of the epidemiology of pain in children and adolescents, see Goodman and McGrath (1991).

Back Pain

Given the public health importance of back pain, there are numerous epidemiologic studies of the condition; however, data are not always presented in such a way that it is possible to calculate age by gender-specific prevalence rates. Figure 1.1 shows prevalence rates for back pain in several studies of the adult population, where age- by gender-specific prevalence rates could be determined. The studies employed a range of definitions of back pain, and a variety of study methods and populations.

FIG. 1.1 Patterns of age- and gender-specific prevalence rates of back pain from four population-based studies. Solid lines indicate rates for men, dotted lines for women. Study sites were: Seattle (Von Korff et al., 1988); rural Great Britain (Walsh et al., 1992); Northwest England (Wright et al., 1995); and a national sample of the population of Great Britain (Croft et al., 1994). Data for each age group are plot ed at the approximate midpoint of the age interval. Detailed age- and gender-specific prevalence rates (e.g., for 32-year-old men) cannot be inferred, due to the form of the original data. See text for specific age groupings and definitions of prevalence used in these studies.

Von Korff, Dworkin, LeResche, and Kruger (1988) conducted an epidemiologic study of five common pain conditions in a stratified random sample of 1,016 enrollees of a large HMO in Seattle. Respondents were asked to report pains occurring in the last six months that had lasted at least a day and were not fleeting or minor. Prevalence rates for back pain among men increased with age, with the 6-month prevalence being 33% among 18–24 year-olds, 37% in those 25–44, 41% in the 45–64 year-olds and 46% among men 65 and older. In contrast, the prevalence of back pain declined with age in women, at least up to the age of 65. (Rates were 47%) in women 18–24, 43% in 25–44 year-olds, 34% in 45–64 year-olds, and 51% in women over 65.)

In contrast to the findings of the Seattle study, data from a study of back pain in a sample of 2,667 persons from small towns and rural areas in Great Britain (Walsh, Cruddas, & Coggon, 1992) indicate 1-year prevalence rates that are higher in young men than in young women (i.e., 35% in men vs. 27% in women 20–29 years of age) and increase only slightly for men with increasing age (rates of 37% among men in their 30s, 38% of those in their 40s and 40% of those in their 50s). For women, rates increased to 34% in those 30–39, 44% in those 40–49 and then dropped to 36% among women 50–59 years old, so that in the oldest group, back pain prevalence was again higher for men than for women.

Two other population-based studies in Great Britain have found back pain to be somewhat more prevalent in women than in men at all ages. Croft and Rigby (1994) used data from the Health and Lifestyle Survey of 9,003 adults from a representative sample of households in Great Britain to assess the 1-month prevalence of “trouble with a bad back.” Given the shorter time frame and the wording of the question used to identify back pain in this study, it is perhaps not surprising that the rates of pain observed were lower than in the studies described previously. Rates for men ranged from 11.8% in those 18–25 to 17.4% in those 65–74, with a rather gradual rise with age. For women, rates ranged from 15.7% in those 18–25 to 27.9% in those 65–74, however rates did not rise continuously wit...

Table of contents

• Cover
• Half Title
• Full Title
• Copyright
• Dedication
• Contents
• Preface
• Part I: General Considerations
• Part II: Specific Pain Syndromes
• Part III: Special Populations
• Author Index
• Subject Index