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Background: Low and high blood potassium levels are common and were both associated with poor outcomes in patients with chronic kidney disease (CKD). Whether such relationships may be altered in CKD patients receiving optimized nephrologist care is unknown.Methods: NephroTest is a hospital-based prospective cohort study that enrolled 2078 nondialysis patients (mean age: 59 ± 15 years, 66% men) in CKD stages 1 to 5 who underwent repeated extensive renal tests including plasma potassium (PK) and glomerular filtration rate (GFR) measured (mGFR) by 51Cr-EDTA renal clearance. Test reports included a reminder of recommended targets for each abnormal value to guide treatment adjustment. Main outcomes were cardiovascular (CV) and all-cause mortality before end-stage kidney disease (ESKD), and ESKD.Results: At baseline, median mGFR was 38.4 mL/min/1.73m2; prevalence of low PK (<4 mmol/L) was 26.5%, and of high PK (>5 mmol/L) 6.4%; 74.4% of patients used angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). After excluding 137 patients with baseline GFR < 10 mL/min/1.73m2 or lost to follow-up, 459 ESKD events and 236 deaths before ESKD (83 CV deaths) occurred during a median follow-up of 5 years. Compared to patients with PK within [4, 5] mmol/L at baseline, those with low PK had hazard ratios (HRs) [95% CI] for all-cause and CV mortality before ESKD, and for ESKD of 0.82 [0.58-1.16], 1.01 [0.52-1.95], and 1.14 [0.89-1.47], respectively, with corresponding figures for those with high PK of 0.79 [0.48-1.32], 1.5 [0.69-3.3], and 0.92 [0.70-1.21]. Considering time-varying PK did not materially change these findings, except for the HR of ESKD associated with high PK, 1.39 [1.09-1.78]. Among 1190 patients with at least two visits, PK had normalized at the second visit in 39.9 and 54.1% respectively of those with baseline low and high PK. Among those with low PK that normalized, ARB or ACEi use increased between the visits (68.3% vs 81.8%, P < .0001), and among those with high PK that normalized, potassium-binding resin and bicarbonate use increased (13.0% vs 37.0%, P < .001, and 4.4% vs 17.4%, P = 0.01, respectively) without decreased ACEi or ARB use.Conclusion: In these patients under nephrology care, neither low nor high PK was associated with excess mortality. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD) is a global health burden, yet it is still underrepresented within public health agendas in many countries. Studies focusing on the natural history of CKD are challenging to design and conduct, because of the long time-course of disease progression, a wide variation in etiologies, and a large amount of clinical variability among individuals with CKD. With the difference in health-related behaviors, healthcare delivery, genetics, and environmental exposures, this variability is greater across countries than within one locale and may not be captured effectively in a single study.Methods: Studies were invited to join the network. Prerequisites for membership included: 1) observational designs with a priori hypotheses and defined study objectives, patient-level information, prospective data acquisition and collection of bio-samples, all focused on predialysis CKD patients; 2) target sample sizes of 1,000 patients for adult cohorts and 300 for pediatric cohorts; and 3) minimum follow-up of three years. Participating studies were surveyed regarding design, data, and biosample resources.Results: Twelve prospective cohort studies and two registries covering 21 countries were included. Participants age ranges from >2 to >70 years at inclusion, CKD severity ranges from stage 2 to stage 5. Patient data and biosamples (not available in the registry studies) are measured yearly or biennially. Many studies included multiple ethnicities; cohort size ranges from 400 to more than 13,000 participants. Studies' areas of emphasis all include but are not limited to renal outcomes, such as progression to ESRD and death.Conclusions: iNET-CKD (International Network of CKD cohort studies) was established, to promote collaborative research, foster exchange of expertise, and create opportunities for research training. Participating studies have many commonalities that will facilitate comparative research; however, we also observed substantial differences. The diversity we observed across studies within this network will be able to be leveraged to identify genetic, behavioral, and health services factors associated with the course of CKD. With an emerging infrastructure to facilitate interactions among the investigators of iNET-CKD and a broadly defined research agenda, we are confident that there will be great opportunity for productive collaborative investigations involving cohorts of individuals with CKD. [ABSTRACT FROM AUTHOR]