Significance Statement: Although CKD incidence is increasing, no evidence-based lifestyle recommendations for CKD primary prevention apparently exist. To evaluate evidence associating modifiable lifestyle factors and incidence of CKD, the authors undertook a systematic review and meta-analysis. Their analysis, which included 104 observational studies of 2,755,719 participants, demonstrated consistency of evidence for a number of measures associated with preventing CKD onset, including increasing dietary intake of vegetables and potassium (21% reduced odds and 22% reduced odds, respectively), increasing physical activity levels (18% reduced odds), moderating alcohol consumption (15% reduced risk), lowering sodium intake (21% increased odds), and stopping tobacco smoking (18% increased risk). In the absence of clinical trial evidence, these findings can help inform public health recommendations and patient-centered discussions in clinical practice about lifestyle measures to prevent CKD. Background: Despite increasing incidence of CKD, no evidence-based lifestyle recommendations for CKD primary prevention apparently exist. Methods: To evaluate the consistency of evidence associating modifiable lifestyle factors and CKD incidence, we searched MEDLINE, Embase, CINAHL, and references from eligible studies from database inception through June 2019. We included cohort studies of adults without CKD at baseline that reported lifestyle exposures (diet, physical activity, alcohol consumption, and tobacco smoking). The primary outcome was incident CKD (eGFR<60 ml/min per 1.73 m²). Secondary outcomes included other CKD surrogate measures (RRT, GFR decline, and albuminuria). Results: We identified 104 studies of 2,755,719 participants with generally a low risk of bias. Higher dietary potassium intake associated with significantly decreased odds of CKD (odds ratio [OR], 0.78; 95% confidence interval [95% CI], 0.65 to 0.94), as did higher vegetable intake (OR, 0.79; 95% CI, 0.70 to 0.90); higher salt intake associated with significantly increased odds of CKD (OR, 1.21; 95% CI, 1.06 to 1.38). Being physically active versus sedentary associated with lower odds of CKD (OR, 0.82; 95% CI, 0.69 to 0.98). Current and former smokers had significantly increased odds of CKD compared with never smokers (OR, 1.18; 95% CI, 1.10 to 1.27). Compared with no consumption, moderate consumption of alcohol associated with reduced risk of CKD (relative risk, 0.86; 95% CI, 0.79 to 0.93). These associations were consistent, but evidence was predominantly of low to very low certainty. Results for secondary outcomes were consistent with the primary finding. Conclusions: These findings identify modifiable lifestyle factors that consistently predict the incidence of CKD in the community and may inform both public health recommendations and clinical practice.

Emerging evidence suggests that diet, particularly one that is rich in dietary fiber, may prevent the progression of chronic kidney disease (CKD) and its associated complications in people with established CKD. This narrative review summarizes the current evidence and discusses the opportunities for increasing fiber intake in people with CKD to improve health and reduce disease complications. A higher consumption of fiber exerts multiple health benefits, such as increasing stool output, promoting the growth of beneficial microbiota, improving the gut barrier and decreasing inflammation, as well decreasing uremic toxin production. Despite this, the majority of people with CKD consume less than the recommended dietary fiber intake, which may be due in part to the competing dietary potassium concern. Based on existing evidence, we see benefits from adopting a higher intake of fiber-rich food, and recommend cooperation with the dietitian to ensure an adequate diet plan. We also identify knowledge gaps for future research and suggest means to improve patient adherence to a high-fiber diet.

Background and objectives: Community-acquired infections are common, contributing to adverse outcomes and increased health care costs. We hypothesized that, with lower eGFR, the incidence of community-acquired infections increases, whereas the pattern of site-specific infections varies. Design, setting, participants, & measurements: Among 1,139,470 health care users (mean age =52±18 years old, 53% women) from the Stockholm CREAtinine Measurements Project, we quantified the associations of eGFR with the risk of infections, overall and major types, over 12 months. Results: A total of 106,807 counts of infections were recorded throughout 1,128,313 person-years. The incidence rate of all infections increased with lower eGFR from 74/1000 person-years for individuals with eGFR=90–104 ml/min per 1.73 m² to 419/1000 person-years for individuals with eGFR<30 ml/min per 1.73 m². Compared with eGFR of 90–104 ml/min per 1.73 m², the adjusted incidence rate ratios of community-acquired infections were 1.08 (95% confidence interval, 1.01 to 1.14) for eGFR of 30–59 ml/min per 1.73 m² and 1.53 (95% confidence interval, 1.39 to 1.69) for eGFR<30 ml/min per 1.73 m². The relative proportions of lower respiratory tract infection, urinary tract infection, and sepsis became increasingly higher along with lower eGFR strata (e.g., low respiratory tract infection accounting for 25% versus 15% of community-acquired infections in eGFR<30 versus 90–104 ml/min per 1.73 m², respectively). Differences in incidence associated with eGFR were in general consistent for most infection types, except for nervous system and upper respiratory tract infections, for which no association was observed. Conclusions: This region-representative health care study finds an excess community-acquired infections incidence in individuals with mild to severe CKD. Lower respiratory tract infection, urinary tract infection, and sepsis are major infections in CKD.

Background and objectives Community-based reports regarding eGFR and the risk of cancer are conflicting. We here explore plausible links between kidney function and cancer incidence in a large Scandinavian population–based cohort. Design, setting, participants, & measurements In the Stockholm Creatinine Measurements project, we quantified the associations of baseline eGFR with the incidence of cancer among 719,033 Swedes ages ≥40 years old with no prior history of cancer. Study outcomes were any type and site-specific cancer incidence rates on the basis of International Classification of Diseases-10 codes over a median follow-up of 5 years. To explore the possibility of detection bias and reverse causation, we divided the follow-up time into different time periods (≤12 and >12 months) and estimated risks for each of these intervals. Results In total, 64,319 cases of cancer (affecting 9% of participants) were detected throughout 3,338,226 person-years. The relationship between eGFR and cancer incidence was U shaped. Compared with eGFR of 90–104 ml/min, lower eGFR strata associated with higher cancer risk (adjusted hazard ratio, 1.08; 95% confidence interval, 1.05 to 1.11 for eGFR=30–59 ml/min and adjusted hazard ratio, 1.24; 95% confidence interval, 1.15 to 1.35 for eGFR<30 ml/min). Lower eGFR strata were significantly associated with higher risk of skin, urogenital, prostate, and hematologic cancers. Any cancer risk as well as skin (nonmelanoma) and urogenital cancer risks were significantly elevated throughout follow-up time, but they were higher in the first 12 months postregistration. Associations with hematologic and prostate cancers abrogated after the first 12 months of observation, suggesting the presence of detection bias and/or reverse causation. Conclusions There is a modestly higher cancer risk in individuals with mild to severe CKD driven primarily by skin and urogenital cancers, and this is only partially explained by bias. Visual Abstract

Significance Statement: Serum creatinine is not a sensitive biomarker for neonatal AKI because it is confounded by maternal creatinine level, gestational age, and neonatal muscle mass. In this multicenter cohort study of 52,333 hospitalized Chinese neonates, the authors proposed serum cystatin C–related criteria (CyNA) for neonatal AKI. They found that cystatin C (Cys-C) is a robust and sensitive biomarker for identifying AKI in neonates who are at an elevated risk of in-hospital mortality and that CyNA detects 6.5 times as many cases as the modified Kidney Disease Improving Global Outcomes creatinine criteria. They also show that AKI can be detected using a single test of Cys-C. These findings suggest that CyNA shows promise as a powerful and easily applicable tool for detecting AKI in neonates. Background: Serum creatinine is not a sensitive biomarker for AKI in neonates. A better biomarker-based criterion for neonatal AKI is needed. Methods: In this large multicenter cohort study, we estimated the upper normal limit (UNL) and reference change value (RCV) of serum cystatin C (Cys-C) in neonates and proposed cystatin C–based criteria (CyNA) for detecting neonatal AKI using these values as the cutoffs. We assessed the association of CyNA-detected AKI with the risk of in-hospital death and compared CyNA performance versus performance of modified Kidney Disease Improving Global Outcomes (KDIGO) creatinine criteria. Results: In this study of 52,333 hospitalized neonates in China, Cys-C level did not vary with gestational age and birth weight and remained relatively stable during the neonatal period. CyNA criteria define AKI by a serum Cys-C of ≥2.2 mg/L (UNL) or an increase in Cys-C of ≥25% (RCV) during the neonatal period. Among 45,839 neonates with measurements of both Cys-C and creatinine, 4513 (9.8%) had AKI detected by CyNA only, 373 (0.8%) by KDIGO only, and 381 (0.8%) by both criteria. Compared with neonates without AKI by both criteria, neonates with AKI detected by CyNA alone had an increased risk of in-hospital mortality (hazard ratio [HR], 2.86; 95% confidence interval [95% CI], 2.02 to 4.04). Neonates with AKI detected by both criteria had an even higher risk of in-hospital mortality (HR, 4.86; 95% CI, 2.84 to 8.29). Conclusions: Serum Cys-C is a robust and sensitive biomarker for detecting neonatal AKI. Compared with modified KDIGO creatinine criteria, CyNA is 6.5 times more sensitive in identifying neonates at elevated risk of in-hospital mortality.