The role of uric acid for predicting future metabolic syndrome and type 2 diabetes in older people

Objective: Although it is known that high uric acid (UA) level is associated with type 2 diabetes (T2DM) and metabolic syndrome (MetS), most of the previous studies were focused on adults. Since aging becomes a major problem for many societies, in this longitudinal study, we investigated the role of UA in future T2DM and MetS in a large cohort of people who were older than 65 years. Design: A cross-sectional and longitudinal study. Setting/Participants: 18,907 elderly (9,732 men, 9,175 women) aged above 65 years, enrolled from health check-up centers, were classified into three subgroups by 10-year intervals (young old 65-74 years, YO; old old 75-84 years, OO; and oldest old 85-94 years, ODO), with the average follow-up period of 4.3 years. Measurements: The optimal cut-off values (CoVs) of baseline UA to predict future MetS and T2DM were determined by receiving operating characteristic (ROC) curve analysis. Using these CoVs of UA, the participants were divided into normal- and high-level groups of UA. Cox proportional hazard analysis was used to calculate hazard ratios (HRs) for the subjects with a high level of UA for the risk of future MetS and T2DM. In addition, Kaplan-Meier plots and log rank test were used to evaluate the time effect on the incidence of developing MetS and T2DM between the two groups. Results: In ROC curve analysis, the optimal CoVs of baseline UA were 6.0, 6.3 and 6.7 mg/dl in YO, OO, and ODO men, respectively; 5.5 and 4.9 mg/dl in YO and OO women, respectively (all p < 0.05). However, the CoVs of UA in ODO women (6.1 mg/dl) failed to show its discriminant power (p = 0.13). The Cox regression analysis showed the YO subjects with a higher baseline level of UA had a higher risk of developing MetS (HRs 1.56 and 1.58 for men and women, respectively, both p < 0.001); as for T2DM the HRs were 1.39 and 1.57. In OO men, the HRs was 1.89 for developing future MetS. However, no significant findings could be noted in the ODO group. Kaplan-Meier plots and log rank test also showed the same findings. Conclusion: Our study showed that old subjects with high levels of UA will have a higher chance to have MetS and T2DM, particularly in the YO group (6.0 mg/dl for men and 5.5 mg/dl for women, respectively). Using UA as one of the metabolic biomarkers may help clinicians to early detect and prevent MetS and diabetes.