Dual-energy computed tomography: a valid tool in the assessment of gout?

Gout is the most common inf lammatory arthropathy worldwide and arises from the crystallization of monosodium uric acid (MSU) within the joints. Currently in the USA alone, more than 8 million individuals over the age of 20 years are suffering from this disease [1]. Burden of disease for individuals suffering from gout continues to expand with the prevalence in the USA increasing by nearly 150% in the last decade [1]. Lifestyle factors, dietary choices and socioeconomic parameters have been proposed to explain these epidemiological observations [2]. Arguably, unhealthy dietary habits and sedentary lifestyle appear to be a major factor for the rise of gout in western countries. Choi et al. reported a 1.85 relative risk factor for incidence of gout in males consuming two or more sugar-sweetened soft drinks per day [3]. This is attributed to an increased production of uric acid in the liver as well as an attenuated renal uric acid clearance, both secondary to excessive fructose consumption. Sugar-sweetened soft drinks represent the single largest food source of calories in the US population [4,5], and their consumption have consistently increased over the last decades [4]. Moreover, obesity, hypertension and insulin resistance, which are all associated with the metabolic syndrome, are well-established independent risk factors for the incidence of gout. Hence, the increased prevalence of gout is partially a consequence of the rapidly increasing incidence of these comorbid conditions [2]. Moreover, hyperuricemia, often present in gout, is an alternate independent risk factor for stroke [6]. Lastly, gout itself has been recognized as an independent risk factor for cardiovascular morbidity and mortality [7]. Therefore, along with pharmacological and lifestyle changes, new techniques for early detection and treatment of gout will be necessary in managing this rising epidemic. Many physicians rely on clinical presentation and elevated serum urate levels for the diagnosis of gout; this dependence may lead to misdiagnosis or a late diagnosis associated with irreversible anatomical damage. Elevated serum uric acid levels are present in 5–8% of the population but only 5–20% of individuals with hyperuricemia develop gout. Patients with hyperuricemia may not necessarily develop gout, and those with gout may have normal serum uric acid levels, particularly during acute gout attacks [8–10]. Higher degrees and longer durations of elevated urate levels can lead to greater severity of disease which is the impetus behind lowering urate levels in the treatment of gout.