Hyperuricemia is associated with progression of chronic kidney disease in patients with reduced functioning kidney mass

Background and objectives: Hyperuricemia plays a major role in the development and progression of chronic kidney disease (CKD). Many large observational studies have indicated that increased serum uric acid level predicts the development and progression of CKD in some population, however this hypothesis has not been yet studied in patients with reduced renal mass. Design, setting, participants, & measurements: Retrospective study with a cohort of 324 patients with reduced renal mass from an outpatient basis, followed during 60 (36–98) months. Demographics variables, cardiovascular factors, concomitant medications, albuminuria and uric acid levels were recorded yearly. The primary endpoint was the annual fall of estimated glomerular filtration rate (eGFR) by MDRD-4. The sample was divided into three successive groups (A1: patients with fall of eGFR lower than median, A2: greater than median, B: without fall of eGFR). Factors associated and predictors of kidney function decline were analyzed. Results: One hundred and seventy out of 324 patients suffered a fall of eGFR (group A), (median of fall −1.6 ml/min/1.73 m2/year (−3.0, −0.7)). Male gender, albuminuria > 100 mg/day and higher pulse pressure were associated to progression in our cohort (group A). Hyperuricemia was more frequent among patients with higher kidney disease progression (group A2) (33% vs 49%, p = 0.04) when comparing to lower progression (group A1). Adjusted Cox regression models showed that hyperuricemia, pulse pressure and albuminuria were independent predictors of kidney disease progression (HR 1.67 (1.06–2.63), p = 0.023; 1.02 (1.01–1.03), p = 0.001 and HR: 2.14 (1.26–3.64), p = 0.005, respectively). Kidney disease progression was higher in patients with unilateral renal atrophy or agenesis than nephrectomy (log rank: 7.433, p = 0.006). Conclusions: Hyperuricemia is independently associated with kidney disease progression in patients with reduce functioning renal mass