J-shaped association of serum uric acid with all-cause and cardiovascular mortality in patients with diabetic kidney disease.

Aims: The association of serum uric acid (SUA) with mortality remains unclear in patients with diabetic kidney disease (DKD). Thus, this prospective cohort study aimed to explore the association of SUA with all-cause and cardiovascular disease (CVD) mortality among patients with DKD in a large, nationally representative sample.

Methods: This cohort study included data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 and the National Death Index mortality data until 31 December 2019. The restricted cubic spline and the Cox proportional hazards regression were conducted to describe the association of SUA with all-cause and CVD mortality and evaluate potential nonlinear associations.

Results: The analysis included 3470 patients with DKD from NHANES 1999-2018. During the follow-up time of 24,633 person-years, we recorded 1489 all-cause deaths, including 542 CVD deaths. We identified a J-shaped association of SUA with all-cause and CVD mortality. The corresponding inflection points were observed at 5.1 and 5.7 mg/dL. When SUA were higher than inflection points, each 1 mg/dL increase in SUA was linked to a 13% and 22% higher risk of all-cause (HR: 1.13; 95% CI: 1.07-1.20;P < 0.001) and CVD (HR: 1.22; 95% CI: 1.06-1.41;P = 0.006) mortality, respectively.

Conclusions: This study indicated the J-shaped association of SUA with all-cause and CVD mortality in patients with DKD. The corresponding inflection points were 5.1 mg/dL for all causes and 5.7 mg/dL for CVD, respectively. More clinical randomized trials are needed to confirm the optimal uric acid-lowering target.