Epidemiology and burden of chronic pain within the Eastern Cape Province, South Africa
Pain is a complex biopsychosocial phenomenon that can have a profound impact on people's lives (Access Economics [AE], 2007). lts clinical relevance is well known - pain is suggestive of "actual or potential tissue damage" and plays a role in the diagnosis and clinical management of diseases and/or injury (International Association for the Study of Pain [IASP], 1986). It has both sensory and emotional aspects and is behaviourally expressed by how it is communicated by the sufferer and by its effect on the sufferer's behaviour (IASP, 1986; Linton, 2005; AE, 2007). Even though the experience of pain is associated with tissue damage or is described in terms of such damage, this association is variable so that "the size of an injury can be a poor guide as to how much an individual experiences pain" (AE, 2007). In fact, pain can exist without an objective evidence of tissue damage making pain the "ultimate subjective experience" (Odendaal, 2006). This phenomenon may relate to the fact that the interpretation of nociceptive signals as pain is influenced by a number of personal and environmental factors including past experience, integrity of the nervous system, beliefs and the situation in which tissue damage occurs (Eccleston, 2001; Turk, 2002a; Flor and Hermann, 2004; AE, 2007). As such, decisive and objective measurements are difficult to arrive at and pain is not always easily assessed by the healthcare provider. The translation of pain from acute to chronic however, means that pain and discomfort remains beyond the normal time of healing and by definition, persists either continuously or intermittently for 3 months or longer (Elliot et al., 1999). This changes the physiognomy of pain and the condition of chronic pain ensues. Chronic pain is an important but often neglected public health problem. It is disabling and associated with interference in normal activities of daily living (ADLs) such as work, home chores, family and sporting activities. Research shows that chronic pain is a key complaint that motivates many to seek health care (Crook et al., 1984, 1989; Sullivan et al., 1990; Smith et al., 1996; Mantyselka et al., 2001, 2002; Eriksen et al., 2004; AE, 2007) leading to high and ongoing consumption of treatments (AE, 2007). In fact, studies have shown that persons with chronic pain use health services up to five times more frequently than the rest of the population (Von Korff et al., 1990, 1991; Elliot et al., 1999; Eriksen et al., 2004). Side-effects of treatment are common with medication use including gastric problems such as ulcerations, nausea, constipation and mental slowing or confusion which can affect functioning. Chronic pam is also associated with mood and sleep disturbances such as depression or adjustment problems and trouble getting to sleep and/or frequent wakening during the night. For the sufferer, the effect of disuse of the aspect of the body in which pain is experienced is another manifestation of chronic pain. Muscles and joints become de-conditioned and pain sufferers may lose general body fitness (AE, 2007). Within the community, pain is a common cause of considerable suffering and disability affecting the general health and quality of life of individuals (Von Korff et al., 1990, 1992; Magni et al., 1990,1993; Walsh et al., 1992; Smith et al., 1996,2001; Verhaak et al., 1998; Elliot et al., 1999, 2002; Blyth et al., 2001; Reyes-Gibby et al., 2002; Lanteri-Minet et al., 2003). Significant amounts of working days are lost among the labour force impacting a profound economic and social toll on society (Bowsher et al., 1991; Elliot et al., 1999; Blyth et al., 2003; Igumbor et al.,2003). Simply put, "chronic pain is a human tragedy" (Odendaal, 2006). It is a serious and common problem that causes distress to patients and their caregivers, is a burden on health care professionals and health care resources and results in significant lost productivity. Chronic pain is therefore a problem of public health importance.