[Nonalcoholic fatty liver disease and psoriasis].

Psoriasis is an inflammatory immune-mediated disease that mainly affects the skin and is often associated with obesity, type 2 diabetes, dyslipidemia, and insulin resistance, all of which are components of the so-called metabolic syndrome.1,2 Nonalcoholic fatty liver disease is an anatomical-clinical spectrum that encompasses the mildest form of simple steatosis, nonalcoholic steatohepatitis, and fatty cirrhosis, the most severe form. It is considered as the manifestation of metabolic syndrome in the liver, is the most common cause of elevated transaminase levels, and the most prevalent form of liver disease in developed countries, affecting around a third of the population overall.3,4 Although we have known of this entity for over 25 years, little importance has been placed on its relation to patient health. Only recently has the significance of nonalcoholic fatty liver been recognized and studied: while individuals with simple steatosis have a life expectancy similar to that of the general population and a low risk of developing terminal liver disease, those with steatohepatitis have a 37% risk of progressing to fibrosis in 3.2 years, in the presence of a high body mass index (BMI) and diabetes. Moreover, mortality attributable to both liver and cardiovascular causes is also higher in patients with nonalcoholic steatohepatitis. Although liver biopsy is the gold standard for diagnosis, other noninvasive methods include ultrasound of the liver and FibroScan (Echosens SA, Paris, France). For a diagnosis of nonalcoholic fatty liver disease significant use of ethanol (>20 g/d), hepatotoxic drugs in the last 5 years, autoimmune liver disease, and hepatitis B or C virus infection must first be ruled out. Nonalcoholic fatty liver disease is treated by reducing the BMI and recovering insulin sensitivity because there is no approved drug for treatment as yet. It is therefore very important that dermatologists become directly involved in ensuring that patients with psoriasis and obesity reach an appropriate BMI. Given that psoriasis is often associated with metabolic syndrome and nonalcoholic fatty liver disease is yet another manifestation of that syndrome, it is unsurprising that fatty liver disease is more common in patients with psoriasis. References to nonalcoholic fatty liver disease in the context of psoriasis were few before 2009 and no epidemiologic studies had ever been done until 2 Italian papers were published that year.8,9 In Verona, Girolomoni et al compared 130 patients with plaque psoriasis with 260 controls matched for age, sex, BMI, and alcohol consumption. They found nonalcoholic fatty liver disease to be more common in patients with psoriasis than in controls (47% vs 28% P<.0001). Analysis of the subgroup of patients with both psoriasis and nonalcoholic fatty liver disease (n=61) revealed a higher frequency of metabolic syndrome, higher serum levels of C-reactive protein, and greater severity of psoriasis according to the Psoriasis Area and Severity Index (PASI) than in patients with psoriasis alone. A multivariate regression analysis showed that nonalcoholic fatty liver disease in patients with psoriasis was associated with a OPINION ARTICLE