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 -1.6ml/min/1.73m2/year (-3.0, -0.7)). Male gender, albuminuria>100mg/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.

Current evidence on the use of anti-RAAS agents in congenital or acquired solitary kidney.

RATIONAL: The inhibition of renin-angiotensin-aldosterone system (RAAS) is a major strategy for slowing the progression of chronic kidney disease (CKD). The utility of anti-RAAS agents in patients with congenital or acquired solitary kidney is still controversial. OBJECTIVE: A systematic literature review was conducted. MAIN FINDINGS: The conclusions of the few available studies on the topic are homogeneously in agreement with a long-term reno-protective activity of anti-RAAS drugs in patients with solitary kidney, especially if patients are hypertensive or proteinuric. However, angiotensin 2 (ANG2) levels permit a functional adaptation to a reduced renal mass in adults and is crucial for sustaining complete kidney development and maturation in children. A hormonal interference on ANG2 levels has been supposed in women. Consequently, at least in children and women, the use of ARBs appears more appropriate. Principle conclusions: Available data on this topic are limited; however, by their overall assessment, it would appear that anti-RAAS drugs might also be reno-protective in patients with solitary kidney. The use of ARBs, especially in children and in women, seems to be more appropriate. However, more experimental data would be strictly necessary to confirm this hypothesis.