Gout. Epidemiology of gout

Gout is the most prevalent form of inflammatory arthritis and is associated with impaired quality of life [1-3]. Elevation of serum uric acid (SUA) levels, or hyperuricaemia, is an essential prerequisite for the development of gout. As SUA levels rise and the physiological saturation threshold for uric acid is exceeded in body fluids, the formation and deposition of monosodium urate (MSU) crystals occurs in and around joints. Clinical manifestations of MSU crystal deposition include acute attacks of severe pain and inflammation affecting peripheral joints, most commonly the first metatarsophalangeal (MTP) joint, chronic joint damage, and tophaceous deposits of MSU crystals in the joints and skin. Recent epidemiological studies have described trends in the prevalence and incidence of gout, and have increased our understanding of risk factors for its development and the implications of co-morbid disease on mortality and cardiovascular morbidity.Epidemiological evidence from New Zealand, the USA, the UK and China suggests that gout is becoming more prevalent (Table 1) [4-20]. The findings of three similarly-conducted successive surveys from New Zealand show an increase in the prevalence of gout, diagnosed by interview and physical examination, in both European US and Maori subjects [4-6].In the USA, the prevalence of gout in a managed-care administrative claims database increased from 2.9/1,000 in 1990 to 5.2/1,000 in 1999 [7], most notably in men aged over 75 years. Successive National Health Interview Surveys in the USA show an increasing prevalence of self-reported gout, starting from a low of 4.8/1,000 in 1969, increasing steadily to peak at 9.9/1,000 in 1983 to 1985, and then decreasing slightly to 8.4/1,000 in 1992 [8,9].Epidemiological surveys from the UK also suggest that gout is becoming more prevalent. Surveys undertaken in general practice diagnostic indices reported gout prevalence per 1,000 of 2.6 in 1975 [10], 3.4 in 1987 [11], and 9.5 in 1993 [12]. Subse