Hyperuricemia and metabolic syndrome: associations with chronic kidney disease

The effects of serum uric acid (SUA) and metabolic syndrome on chronic kidney disease (CKD) remain controversial. This study grouped subjects according to a combination of their uric acid and metabolic syndrome status and investigated the association between these groups and CKD to clarify the relationships of SUA and metabolic syndrome to CKD. This survey analyzed data from 81,799 adults (45,148 men and 36,651 women) who underwent health examinations at Chang Gung Memorial Hospital, in northern Taiwan, from 2000 through 2007. Hyperuricemia was defined as an SUA greater than 7.7 mg/dL in men or greater than 6.6 mg/dL in women. Patients were classified by uric acid-metabolic syndrome status as follows: A = no hyperuricemia and no metabolic syndrome, B = presence of metabolic syndrome but not hyperuricemia, C = presence of hyperuricemia but no metabolic syndrome, and D = presence of both hyperuricemia and metabolic syndrome. Kidney function was assessed in terms of the estimated glomerular filtration rate (eGFR) by using the Modification of Diet in Renal Disease Study equation modified for Chinese. CKD was defined as an eGFR < 60 mL/min/1.73 m(2). The prevalences of hyperuricemia, metabolic syndrome, and CKD were 22.8% (26.3% in men and 18.6% in women), 13.5% (15.0% in men and 11.6% in women), and 2.2% (2.1% in men and 2.2% in women), respectively. In men, the age-adjusted odds ratios for CKD, with group A as reference, were 1.95 for group B, 4.86 for group C, and 5.85 for group D. In women, the age-adjusted odds ratios were 1.96 for group B, 6.66 for group C, and 9.01 for group D. Hyperuricemia is strongly associated with CKD, independent of the presence of metabolic syndrome.