BACKGROUND Among patients in the United States with chronic kidney disease, black patients are at increased risk for end-stage renal disease, as compared with white patients. METHODS In two studies, we examined the effects of variants in the gene encoding apolipoprotein L1 (APOL1) on the progression of chronic kidney disease. In the African American Study of Kidney Disease and Hypertension (AASK), we evaluated 693 black patients with chronic kidney disease attributed to hypertension. In the Chronic Renal Insufficiency Cohort (CRIC) study, we evaluated 2955 white patients and black patients with chronic kidney disease (46% of whom had diabetes) according to whether they had 2 copies of high-risk APOL1 variants (APOL1 high-risk group) or 0 or 1 copy (APOL1 low-risk group). In the AASK study, the primary outcome was a composite of end-stage renal disease or a doubling of the serum creatinine level. In the CRIC study, the primary outcomes were the slope in the estimated glomerular filtration rate (eGFR) and the composite of end-stage renal disease or a reduction of 50% in the eGFR from baseline. RESULTS In the AASK study, the primary outcome occurred in 58.1% of the patients in the APOL1 high-risk group and in 36.6% of those in the APOL1 low-risk group (hazard ratio in the high-risk group, 1.88; P<0.001). There was no interaction between APOL1 status and trial interventions or the presence of baseline proteinuria. In the CRIC study, black patients in the APOL1 high-risk group had a more rapid decline in the eGFR and a higher risk of the composite renal outcome than did white patients, among those with diabetes and those without diabetes (P<0.001 for all comparisons). CONCLUSIONS Renal risk variants in APOL1 were associated with the higher rates of end-stage renal disease and progression of chronic kidney disease that were observed in black patients as compared with white patients, regardless of diabetes status. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.)

Background Hyperkalemia is a potential threat to patient safety in chronic kidney disease (CKD). This study determined the incidence of hyperkalemia in CKD and whether it is associated with excess mortality. Methods This retrospective analysis of a national cohort comprised of 2,103,422 records from 245,808 veterans with at least one hospitalization and at least one inpatient or outpatient serum potassium record during fiscal year 2005. CKD and treatment with ACE-I and/or ARBs (RAAS blockers) were the key predictors of hyperkalemia. Death within one day of a hyperkalemic event was the principal outcome. Results Of the 66,529 hyperkalemic events (3.2% of records), more occurred inpatient (34937 (52.7%)) versus outpatient (31322 (47.3%)). The adjusted rate of hyperkalemia was higher in patients with CKD than without CKD among individuals treated with RAAS blockers (7.67 vs. 2.30 per 100 patient months, p<0.0001) and those without RAAS blocker treatment (8.22 vs. 1.77 per 100 patient months, p<0.0001). The adjusted odds (OR) of death with a moderate (K+≥ 5.5 and < 6.0mg/dl) and severe (K+≥ 6.0 mg/dl) hyperkalemic event was highest with no CKD (OR: 10.32, 31.64, respectively), versus Stage 3 (5.35, 19.52), Stage 4 (OR: 5.73, 11.56), or Stage 5 CKD (OR: 2.31, 8.02) with all p<0.0001 versus normokalemia and no CKD. Conclusion The risk of hyperkalemia is increased with CKD, and its occurrence increases the odds of mortality within one day of the event. These findings underscore the importance of this metabolic disturbance as a threat to patient safety in CKD.

Background and objectives: The Chronic Renal Insufficiency Cohort (CRIC) Study was established to examine risk factorsfor the progression of chronic kidney disease (CKD) and cardiovascular disease (CVD) in patients with CKD. We examined baseline demographic and clinical characteristics.Design, setting, participants, & measurements: Seven clinical centers recruited adults who were aged 21 to 74 yr and had CKD using age-based estimated GFR (eGFR) inclusion criteria. At baseline, blood and urine specimens were collected and information regarding health behaviors, diet, quality of life, and functional status was obtained. GFR was measured using radiolabeled iothalamate in one third of participants.Results: A total of 3612 participants were enrolled with mean age ؎ SD of 58.2 ؎ 11.0 yr; 46% were women, and 47% had diabetes. Overall, 45% were non-Hispanic white, 46% were non-Hispanic black, and 5% were Hispanic. Eighty-six percent reported hypertension, 22% coronary disease, and 10% heart failure. Mean body mass index was 32.1 ؎ 7.9 kg/m 2 , and 47% had a BP >130/80 mmHg. Mean eGFR was 43.4 ؎ 13.5 ml/min per 1.73 m 2 , and median (interquartile range) protein excretion was 0.17 g/24 h (0.07 to 0.81 g/24 h). Lower eGFR was associated with older age, lower socioeconomic and educational level, cigarette smoking, self-reported CVD, peripheral arterial disease, and elevated BP.Conclusions: Lower level of eGFR was associated with a greater burden of CVD as well as lower socioeconomic and educational status. Long-term follow-up of participants will provide critical insights into the epidemiology of CKD and its relationship to adverse outcomes.

Abstract. Insights into end-stage renal disease have emerged from many investigations but less is known about the epidemiology of chronic renal insufficiency (CRI) and its relationship to cardiovascular disease (CVD). The Chronic Renal Insufficiency Cohort (CRIC) Study was established to examine risk factors for progression of CRI and CVD among CRI patients and develop models to identify high-risk subgroups, informing future treatment trials, and increasing application of preventive therapies. CRIC will enroll approximately 3000 individuals at seven sites and follow participants for up to 5 yr. CRIC will include a racially and ethnically diverse group of adults aged 21 to 74 yr with a broad spectrum of renal disease severity, half of whom have diagnosed diabetes mellitus. CRIC will exclude subjects with polycystic kidney disease and those on active immunosuppression for glomerulonephritis. Subjects will undergo extensive clinical evaluation at baseline and at annual clinic visits and via telephone at 6 mo intervals. Data on quality of life, dietary assessment, physical activity, health behaviors, depression, cognitive function, health care resource utilization, as well as blood and urine specimens will be collected annually.125 I-iothalamate clearances and CVD evaluations including a 12-lead surface electrocardiogram, an echocardiogram, and coronary electron beam or spiral CT will be performed serially. Analyses planned in CRIC will provide important information on potential risk factors for progressive CRI and CVD. Insights from CRIC should lead to the formulation of hypotheses regarding therapy that will serve as the basis for targeted interventional trials focused on reducing the burden of CRI and CVD.The rate of ESRD has increased steadily in the United States over the past three decades. Insights into the epidemiology and treatment of ESRD have emerged from many investigations including those conducted by the United States Renal Disease System. Much less is known about the epidemiology of pre-ESRD chronic renal insufficiency (CRI), especially the relationship between CRI and cardiovascular disease (CVD).CRI has been recognized as a silent epidemic (1) affecting more than ten million Americans. The burden of morbidity and mortality from CRI derives from the progression of CRI to ESRD and the disproportionate risk of CVD in the setting of CRI. CRI is strongly and independently associated with CVD, even after adjustment for traditional CVD risk factors. These findings led to the hypothesis that specific "uremia-related risk factors" augment the rate of CVD (2) and cause many patients with CRI to succumb to fatal cardiovascular events before needing renal replacement therapy.The National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK) established the Chronic Renal Insufficiency Cohort (CRIC) Study in 2001 to improve understanding of the relationship between CRI and CVD. The CRIC Study goals are to examine risk factors for progression of CRI and CVD among patients with CRI and develop predictive mo...

Abstract. Polyoma virus (PV) can cause interstitial nephritis and lead to graft failure in renal transplant recipients. The clinical course of patients with polyoma virus nephritis (PVN) is not well understood, partially due to its relatively low incidence. This study is a retrospective analysis of our experience over 4 yr. The specific purpose is to outline the clinical course and outcome of patients with PVN and to study the relationship between immunosuppression and the disease process. Between