Decline in kidney function is a major concern for patients with type 2 diabetes. The importance of serum uric acid level as the risk factor for chronic kidney disease (CKD) remains unconfirmed. We therefore evaluated the relationship between baseline serum uric acid level and the risk of incident CKD among men with untreated type 2 diabetes at baseline examination in a 10-11 years prospective cohort study. We included 717 middle-aged Japanese subjects with fasting plasma glucose level ≥126 mg/dL or HbA1c ≥6.5% at baseline who were not taking hypoglycemic medications nor insulin, who had an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2, who did not have proteinuria nor malignant tumors, and who were not taking anti-hypertensive medications nor urate-lowering medications at baseline. CKD was defined as eGFR <60 ml/min/1.73 m2. Cox proportional hazards models were used in the multivariate analysis.
During the 5961 person-years follow-up period, 87 subjects developed CKD. Higher serum uric acid level was associated with an increased risk of CKD after adjustment for age, body mass index, systolic blood pressure, diastolic blood pressure, HbA1c, smoking habits (nonsmokers, past smokers, and current smokers), regular leisure-time physical activity (yes/no), daily alcohol consumption (g ethanol/day), and eGFR at baseline. Multiple-adjusted hazard ratios of CKD for quintile 4 (6.2-6.9 mg/dL) and quintile 5 (≥7.0 mg/dL) of serum uric acid levels were 1.30 (95% CI, 0.73-2.30) and 1.80 (95% CI, 1.04-3.11), respectively, compared with quintile 1 to 3 (0.7-6.1 mg/dL). Moreover, when we modeled serum uric acid level as a continuous variable, serum uric acid level per 1.0 mg/dL increase was significantly associated with a 25% increased risk of incident CKD.
In conclusion, higher serum uric acid level is independently and significantly associated with an increased risk of CKD in patients with untreated type 2 diabetes.
Y. Okada: None. K.K. Sato: None. M. Shibata: None. S. Uehara: None. H. Koh: None. K. Oue: None. H. Kambe: None. M. Morimoto: None. T. Hayashi: None.