Microalbuminuria mediates the association between serum uric acid and elevation of blood pressure: a longitudinal analysis in the Gusu cohort.

OBJECTIVES: Although hyperuricemia, microalbuminuria, and hypertension are highly correlated, their temporal relationship is largely unknown. We aimed to examine whether microalbuminuria mediated the association between hyperuricemia and hypertension. METHODS: Leveraging a longitudinal cohort including 1981 Chinese adults who had blood pressures, urinary albumin to creatinine ratio (UACR), and uric acid measured twice 4 years apart, we examined the temporal relationships among hyperuricemia, microalbuminuria, and hypertension by cross-lagged panel analysis followed by a causal mediation analysis to confirm the temporal consequence. Age, sex, education level, cigarette smoking, alcohol consumption, obesity, blood glucose, and lipids were adjusted. RESULTS: The cross-lagged panel analysis demonstrated that the relationship from baseline UACR to follow-up uric acid was significantly smaller than that from baseline uric acid to follow-up UACR (beta: 0.010 vs. 0.054, P < 0.001). The relationships from baseline blood pressures to follow-up UACR were also significantly smaller than that from baseline UACR to follow-up blood pressures (beta: 0.031 vs. 0.092, P < 0.001 for systolic and beta: 0.015 vs. 0.096, P < 0.001 for diastolic). The causal mediation analysis found that UACR partially mediated the association of baseline uric acid with follow-up SBP (mediate proportion: 9.14%, 95% CI: 1.58-23.00%) and DBP (mediate proportion: 7.38%, 95% CI: 1.05-19.00%). CONCLUSION: Microalbuminuria may follow elevated uric acid and partially mediate its effect on future risk of hypertension in Chinese adults.