Overview of gout

Robinson, 2015Robinson, 2012Roughley, 2015Smith, 2014Ting, 2016

Gout is a chronic disease that involves the deposition of monosodium urate crystals in the body, primarily in joints, soft tissues and kidneys. The main symptoms of gout are joint pain and swelling, which may represent an initial or recurrent acute attack, chronic gouty arthritis, or an acute attack in a patient with underlying chronic gouty arthritis (see Clinical features of acute gout). The major manifestations of gout in the kidney are nephrolithiasis and chronic urate nephropathy; both of which can progress to chronic kidney disease.

Gout occurs when the serum uric acid concentration is elevated (usually greater than 0.42 mmol/L [7 mg/dL]), and the solubility coefficient of monosodium urate is exceeded long enough for crystals to form in tissues in susceptible individuals and cause an inflammatory response. While the presence of hyperuricaemia is important in the diagnosis of gout, patients with acute gout may have a normal serum uric acid concentration (see Diagnosis of gout). Conversely, patients can have asymptomatic hyperuricaemia, which is a risk factor for developing gout (see Pathogenesis of and risk factors for gout).

The incidence of gout increases with age, and in females gout rarely occurs before menopause. Gout is rare in children; a diagnosis of gout in a child cannot be supported unless the child has a genetic defect in urate metabolism.

The prevalence of gout is increasing worldwide, particularly in affluent countries such as Australia and New Zealand. In these countries, increasing prevalence relates to the ageing population, higher consumption of alcohol and fructose-sweetened drinks, other changes in dietary habits, and increasing rates of obesity. Certain ethnic groups have a higher prevalence of gout; in particular indigenous populations, including Aboriginal, Torres Strait Islander, Māori and Pacific peoples.

Gout can be effectively treated and its complications prevented with adherence to lifelong urate-lowering therapy using a treat-to-target approach (see Principles of managing chronic gout); however, gout is often poorly managed in Australian primary care, with low rates of allopurinol prescribing, serum uric acid monitoring and achievement of serum uric acid targets. Patient adherence to urate-lowering therapy is also often suboptimal.