Longitudinal serum uric acid trajectories and chronic kidney disease progression.

BACKGROUND: For patients with chronic kidney disease (CKD), the causal relationship between serum uric acid (SUA) levels and clinical outcomes remains controversial. This study aimed to investigate the association between longitudinal trends in SUA levels and CKD progression, taking related clinical parameters into account for patients with CKD. METHODS: Adult patients with CKD who were followed for at least 12 months and were not receiving renal replacement therapy (RRT) at the start of follow-up were eligible to be involved in the study. SUA levels of the patients were recorded at three time points (baseline, median, and final). A priori threshold of 20% change was used to categorize SUA levels changes. Patients with a ≥ 20% increase in both intervals were classified as "increasing," those with a ≥ 20% decrease as "decreasing," those with < 20% change as "stable," and those with an increase in one interval and a decrease in the other as "non-monotonic". Univariate and multivariable binary logistic regression analyses were performed to assess the association of SUA levels with CKD progression. RESULT: 478 patients met the inclusion criteria. They were 67.3 ± 12.3 years old and 53.3% of them were males. The mean clinical follow-up duration was 60.6 ± 28.1 months. At the end of follow-up, 6.7% of patients initiated dialysis (n = 32), 37.4% experienced rapid progression (n = 179), and 2.3% died (n = 11). SUA trajectory patterns were as follows: 11.5% increasing, 5.0% decreasing, 3.6% stable and 79.9% non-monotonic. Trajectory with an increasing pattern were more frequent in rapid progressors than non-rapid progressors (15.6% vs 9.0%, p = 0.002). Having a stable SUA was also protective from rapid progression (p = 0,043). SUA measured at individual time points and use of urate-lowering therapy were not independently associated with rapid CKD progression or dialysis initiation. CONCLUSIONS: Dynamic changes in SUA levels over time, rather than isolated measurements, may be associated with CKD progression, suggesting that longitudinal SUA trajectories may provide more meaningful prognostic information in patients with CKD.