Epidemiology is defined by MacMahon and Pugh (1970) as ‘the study of the distribution and determinants of disease frequency in man’. It has its origins in the early days of modern medicine and continues to develop its science and expand its roles. In recognition of this, Porta et al.'s Dictionary of Epidemiology (2008) extends the definition to imply greater clinical relevance, and describes ‘the study of the occurrence and distribution of health-related states or events in specific populations, including the study of the determinants influencing such states, and the application of this...
Epidemiology is defined by MacMahon and Pugh (1970) as ‘the study of the distribution and determinants of disease frequency in man’. It has its origins in the early days of modern medicine and continues to develop its science and expand its roles. In recognition of this, Porta et al.'s Dictionary of Epidemiology (2008) extends the definition to imply greater clinical relevance, and describes ‘the study of the occurrence and distribution of health-related states or events in specific populations, including the study of the determinants influencing such states, and the application of this knowledge to control health problems’ (Porta et al. 2008). It is the latter part of this definition that makes epidemiology an important clinical discipline, particularly for chronic low back pain (CLBP), an important purpose being to inform the provision of health services. Rothman and Greenland (1998) suggest that the ultimate goal of epidemiology is to identify the causes of disease, but good epidemiological data on chronic pain will also provide valuable information on a wide range of important areas (Box 1.1).
Epidemiological research should, therefore, have as one of its ultimate goals the development of effective healthcare interventions, through an understanding of the distribution and determinants of illnesses (Porta et al. 2008). The last 20 years has seen a large number of population-based epidemiological studies of chronic pain, including back pain, and these have provided important information for educational and clinical service resource requirements, and for prevention and management strategies (Verhaak et al. 1998; Manchikanti 2000; Harstall and Ospina 2003). These studies have consistently demonstrated that chronic back pain is a highly prevalent condition, with an important detrimental impact on individuals’ health, the healthcare services and society, and for which successful treatment outcomes are difficult to achieve.
CLBP is a heterogeneous group of clinical conditions, a minority of which are associated with a specific, demonstrable structural disorder (such as lumbar disc degeneration or ankylosing spondylitis), and many of which coexist with chronic pain at other anatomical sites. (Smith et al. 2004a) The International Association for the Study of Pain classifies well over 100 different diagnostic categories of (low) back pain, though good evidence for the epidemiology of most of these remains elusive, and the great majority (90%) of back pain cases have no identifiable cause in any case (Manek and MacGregor 2005). Given that the majority of CLBP is managed in primary care, if anywhere (Croft et al. 1998), where neither the facilities nor expertise generally exist to render such specific diagnosis feasible or appropriate, it is often practically necessary to consider low back pain (LBP) as a single global entity (after excluding ‘red flag’ diagnoses such as fracture and malignancy (Royal College of General Practitioners 1999)). This is also true of population-based epidemiological research, which generally relies on questionnaires or interviews administered by non-specialists. A site-specific case definition, perhaps enhanced by a criterion referring to back pain-related disability (Dionne et al. 2008) is therefore the most frequently encountered classification of back pain, both clinically and epidemiologically. Despite this lack of specificity in case definition, there is remarkable consistency in studies across the world and in different population groups, on the risk factors (particularly mechanical, psychological, and social) and therefore prospective intervention targets for CLBP.
We therefore need generic treatment strategies, including pharmacological and non-pharmacological approaches that can address CLBP as a global entity. This should be reflected in the epidemiological approach to seeking aetiological and risk factors, while also seeking a deeper understanding of sub-groups of CLBP that might benefit from more specific, targeted therapeutic approaches. This chapter will review the outcomes of this approach to the chronic pain continuum, and consider the potential rewards of adding measurement of biological factors to the knowledge and methods developed to date.
Chapter. 10498 words.
Subjects: Neuroscience ; Pain Medicine
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