Pain does not appear as a cause of global mortality or disease burden in World Health Organization (WHO) statistics on leading causes of death and disease burden worldwide.¹ However, pain causes immense suffering, especially in those with two of the world’s major causes of morbidity and death, which are most prevalent in developing countries: cancer and HIV/AIDS. Apart from the suffering of individuals, these conditions give rise to significant burdens for their families and carers and diminish their quality of life. In order to tackle these problems with cancer, HIV/AIDS and the many other causes of acute and chronic pain as a focus, the International Association for the Study of Pain (IASP), the European Federation of IASP Chapters (EFIC) and WHO marked the European Week Against Pain in 2004, and launched the first IASP Global Year Against Pain, with the declaration that “pain treatment is a human right”.

In economically developed countries, chronic pain affects about 20% of the adult population, of which those with cancer account for 1–2%. Comparable figures are not available for developing countries, but will be greater, especially because of the high and rising prevalence of cancer.² Of the 6.6 million individuals in the world who die from cancer each year, 70% die in low- and middle-income countries and 70–80% of these people will have suffered severe pain.³ Over 42 million people are living with HIV/AIDS worldwide and over 70% of these individuals live in sub-Saharan Africa. The number living in eastern Europe and central Asia was estimated at 1.7 million in 2006, and the numbers have been rising steadily for several years. In 1999,⁴ the majority of those affected lived in the Russian Federation and the Ukraine, and in 2006 these populations accounted for 90% of all people living with HIV/AIDS in eastern Europe and central Asia.

Estimates of the prevalence of cancer pain have varied widely, but published figures indicate that in general about 75% of individuals with advanced stages of the disease have pain. Figures for HIV/AIDS are similar, with pain intensity appearing to be of the same severity as or even greater than in cancer. Opioids, and especially morphine, are vital for the treatment of the severe pain experienced in these conditions because the drugs are both effective and relatively affordable. Cancer pain arises from a variety of causes, including pain due to the disease process and pain caused by cancer treatment, and patients may also suffer from painful conditions unrelated to cancerand its treatment. Most have two or more sites of pain and more than 40% have four or more sites. A study at the Sloane Kettering Cancer Center in New York revealed a rising incidence of pain with advancing HIV/AIDS. Sixty per cent of patients had pain presumed to be due to the viral burden or immunosuppression, 30% due to treatment and 10% due to non-AIDS disorders.⁵ Neuropathic syndromes are common in AIDS, being present in 30–40% of patients, in addition to which pain due to myelopathy is present in 10%. These and other neurologically based pain conditions include immune-mediated neuropathy, toxic neuropathies and nutritional deficiencies, and antiretroviral therapies, surgery and treatment with phenytoin make up a significant proportion of the morbidity of HIV/AIDS. Other common pains include abdominal pain, headache, oral pain and skin and joint pains.



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