BackgroundHyperuricemia (HUA) is very common in chronic kidney disease (CKD). HUA is associated with an increased risk of cardiovascular events and accelerates the progression of CKD. Our study aimed to explore the relationship between baseline serum uric acid levels and renal histopathological features.MethodsOne thousand seventy patients receiving renal biopsy in our center were involved in our study. The baseline characteristics at the time of the kidney biopsy were collected from Renal Treatment System (RTS) database, including age, gender, serum uric acid (UA), glomerular filtration rate (eGFR), serum creatinine (Cr), urea, albumin (Alb), 24 h urine protein quantitation (24 h-u-pro) and blood pressure (BP). Pathological morphological changes were evaluated by two pathologists independently. Statistical analysis was done using SPSS 21.0.ResultsAmong 1070 patients, 429 had IgA nephropathy (IgAN), 641 had non-IgAN. The incidence of HUA was 38.8% (n = 415), 43.8% (n = 188), and 43.2% (n = 277) in all patients, patients with IgAN and non-IgAN patients, respectively. Serum uric acid was correlated with eGFR (r = − 0.418, p < 0.001), Cr (r = 0.391, p < 0.001), urea (r = 0.410, p < 0.001), 24-u-pro (r = 0.077, p = 0.022), systolic blood pressure (SBP) (r = 0.175, p < 0.001) and diastolic blood pressure (DBP) (r = 0.109, p = 0.001). Multivariate logistic regression analysis showed that after adjustment for Cr, age and blood pressure, HUA was a risk factor for segmental glomerulosclerosis (OR = 1.800, 95% CI:1.309–2.477) and tubular atrophy/interstitial fibrosis (OR = 1.802, 95% CI:1.005–3.232). HUA increased the area under curve (AUC) in diagnosis of segmental glomerulosclerosis.ConclusionsHyperuricemia is prevalent in CKD. The serum uric acid level correlates not only with clinical renal injury indexes, but also with renal pathology. Hyperuricemia is an independent risk factor for segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis.

Purpose of review Severe acute kidney injury in the ICU setting often requires renal replacement therapy (RRT). Intermittent hemodialysis (IHD), hybrid forms of RRT such as sustained low-efficiency dialysis (SLED), as well as continuous renal replacement therapy (CRRT) are the three common modalities of extracorporeal RRT used in the adult ICU setting in developed countries. This review summarizes recently published data regarding comparisons of these three RRT modalities on clinical outcomes (e.g., mortality and recovery of renal function) in severe acute kidney injury (AKI) patients. Recent findings There is still controversy on the superiority of one RRT modality over another in terms of clinical outcomes in patients with AKI in ICU. Although there is increasing acceptance that CRRT should be used in hemodynamic unstable patients, its survival advantages over IHD remains unproven because of inadequate evidence from suitably powered randomized controlled trials (RCTs). Moreover, CRRT does not show superiority to intermittent renal replacement therapy (IRRT) in hemodynamic stable patients. Although patients receiving sustained low-efficiency dialysis appear to have lower mortality than CRRT, its survival benefit is largely derived from observational studies and is confounded by selection bias. Current literature supports no differences in mortality among the three RRT modalities. However, the effect of choice of RRT modality on short-term and long-term renal outcomes need further studies, especially larger RCTs and longer duration of follow-up. Summary There is lack of solid evidence showing superiority of any mode of RRT in patients with severe AKI in terms of patient survival. However, based on observational data, IHD treatment of AKI may delay renal recovery. Patients’ hemodynamic status, coexisting medical conditions, local expertise, and availability of staff and resources as well as potential effect on long-term renal outcomes should be taken into consideration when selecting modalities of RRT for adult ICU patients.

In the RENAL study, thrombocytopenia is a common phenomenon in patients with severe AKI receiving CRRT. An abnormal baseline SOFA-CS and reductions in platelet counts were associated with increased mortality at 90 days.