Background: There is strong biologic plausibility to support change in albuminuria as a surrogate endpoint for progression of chronic kidney disease (CKD), but empirical evidence to supports its validity in epidemiologic studies is lacking. Methods: We analyzed 28 cohorts including 693,816 individuals (80% with diabetes) and 7,461 end-stage kidney disease (ESKD) events, defined as initiation of kidney replacement therapy. Percent change in albuminuria was quantified during a baseline period of 1, 2 and 3 years using linear regression. Associations with subsequent ESKD were quantified using Cox regression in Coresh et al.

SummaryBackground and objectives The incidence and prevalence of metabolic acidosis increase with declining kidney function. We studied the associations of both low and high serum bicarbonate levels with all-cause mortality among stage 3 and 4 chronic kidney disease (CKD) patients.Design, setting, participants, & measurements We examined factors associated with low (Ͻ23 mmol/L) and high (Ͼ32 mmol/L) serum bicarbonate levels using logistic regression models and associations between bicarbonate and all-cause mortality using Cox-proportional hazard models, Kaplan-Meier survival curves, and time-dependent analysis.Results Out of 41,749 patients, 13.9% (n ϭ 5796) had low and 1.6% (n ϭ 652) had high serum bicarbonate levels. After adjusting for relevant covariates, there was a significant association between low serum bicarbonate and all-cause mortality (hazard ratio [HR] 1.23, 95% CI 1.16, 1.31). This association was not statistically significant among patients with stage 4 CKD and diabetes. The time-dependent analysis demonstrated a significant mortality risk associated with a decline from normal to low bicarbonate level (HR 1.59, 95% CI 1.49, 1.69). High serum bicarbonate levels were associated with death irrespective of the level of kidney function (HR 1.74, 95% CI 1.52, 2.00). When serum bicarbonate was examined as a continuous variable, a J-shaped relationship was noted between serum bicarbonate and mortality.Conclusions Low serum bicarbonate levels are associated with increased mortality among stage 3 CKD patients and patients without diabetes. High serum bicarbonate levels are associated with mortality in both stage 3 and stage 4 CKD patients.

Background/Aims: Hypokalemia and hyperkalemia are often noted in chronic kidney disease (CKD) patients, but their impact on mortality and end-stage renal disease (ESRD) is less well understood. We aimed at studying the associations between potassium disorders, and mortality and progression to ESRD in a CKD population. Methods: Using our electronic health record-based CKD registry, 36,359 patients with eGFR <60 ml/min/1.73 m² and potassium levels measured from January 1, 2005 to September 15, 2009 were identified. We examined factors associated with hypokalemia (<3.5 mmol/l) and hyperkalemia (>5.0 mmol/l) using logistic regression models and associations between serum potassium levels (both as continuous and categorical variables) and all-cause mortality or ESRD using Cox-proportional hazards models. Results: Serum potassium <3.5 mmol/l was noted among 3% and >5.0 mmol/l among 11% of the study population. In the multivariable logistic regression analysis, lower eGFR, diabetes and use of ACE inhibitors or Angiotensin-Receptor Blockers were associated with higher odds of having hyperkalemia. Heart failure and African American race were factors associated with higher odds of hypokalemia. After adjustment for covariates including kidney function, serum potassium <4.0 and >5.0 mmol/l were significantly associated with increased mortality risk, but there was no increased risk for progression to ESRD. Time-dependent repeated measures analysis confirmed these findings. When potassium was examined as a continuous variable, there was a U-shaped association between serum potassium levels and mortality. Conclusion: In patients with stage 3-4 CKD, serum potassium levels <4.0 and >5.0 mmol/l are associated with higher mortality but not with ESRD.

Aneurysm repair with fenestrated endovascular grafts is associated with a significant risk for adverse renal events (16% in those without renal dysfunction, although none developed a creatinine >2 mg/dL, and 39% for patients with preoperative renal dysfunction). These patients must be meticulously followed, particularly within the first month after such a procedure. When renal artery restenosis is suspected or diagnosed, aggressive approach might be warranted to limit the extent of late renal dysfunction.

Despite the high costs of treatment of people with kidney disease and associated comorbid conditions, the amount of reliable information available to guide the care of such patients is very limited. Some treatments have been assessed in randomized trials, but most such trials have been too small to detect treatment effects of a magnitude that would be realistic to achieve with a single intervention. Therefore, KDIGO convened an international, multidisciplinary controversies conference titled "Challenges in the Conduct of Clinical Trials in Nephrology" to identify the key barriers to conducting trials in patients with kidney disease. The conference began with plenary talks focusing on the key areas of discussion that included appropriate trial design (covering identification and evaluation of kidney and nonkidney disease outcomes) and sensible trial execution (with particular emphasis on streamlining both design and conduct). Break out group discussions followed in which the key areas of agreement and remaining controversy were identified. Here we summarize the main findings from the conference and set out a range of potential solutions. If followed, these solutions could ensure future trials among people with kidney disease are sufficiently robust to provide reliable answers and are not constrained by inappropriate complexities in design or conduct.