Nomenclature for Kidney Function and Disease: Executive Summary and Glossary From a Kidney Disease: Improving Global Outcomes (KDIGO) Consensus Conference

Prevalence of unrecognized or "silent" myocardial ischemia in chronic kidney disease patients: Protocol for a systematic review and meta-analysis

INTRODUCTION

Chronic kidney disease (CKD) patients are at an extremely high risk of silent myocardial ischemia (SMI). However, there is a dearth of evidence on the worldwide prevalence of this very lethal and yet unrecognizable complication of CKD. The proposed systematic review and meta-analysis aims to estimate the global prevalence of SMI among CKD patients.

METHODS AND ANALYSES

This protocol was conceived according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) statement. The systematic review will involve all observational studies and clinical trials published until April 30, 2021, and reporting on the prevalence of SMI in CKD patients. Electronic sources including MEDLINE, Embase, Web of Science, and Cochrane database of systematic reviews will be perused for potentially eligible studies, restricted to only studies published in English or French. Two investigators will independently select studies and use a pre-pilot tested form to extract data. Further, they will independently perform a qualitative assessment of the risk of bias and overall quality of the selected studies, followed by a quantitative assessment using funnel plots and Egger's tests. The heterogeneity between studies will be assessed with the Cochrane's Q statistic, and the I2 statistic will measure the percentage of variation across studies that is due to their heterogeneity rather than chance; the I2 will decide if a meta-analysis can be conducted. In case it cannot be conducted, a descriptive analysis will be performed. Otherwise, study-specific estimates will be pooled using either a fixed-effects or a random-effects model, depending on the value of the I2 statistic. Subgroup and random effects meta-regression analyses will further investigate the potential sources of heterogeneity. Finally, sensitivity analyses will be performed to measure the impact of low-quality studies on the results of the meta-analysis, and power calculations will determine the probability that we will detect a true effect if it does exist.

PROSPERO REGISTRATION NUMBER

CRD42020211929.

STRENGTHS AND LIMITATIONS OF THIS STUDY

The intended systematic review and meta-analysis will fill the knowledge gap on the global prevalence of silent myocardial ischemia (SMI) in CKD patients. The eligible studies will be identified through a methodic literature search followed by a rigorous screening process; we will then use robust meta-analysis tools to pool the data and provide reliable estimates of the global prevalence of SMI in CKD patients. Two major limitations could be: the predominance of clinical trials that might limit the generalizability of the findings, given that some informative patients might have been sidelined by the strict inclusion criteria of these studies; the high probability of type 1 error originating from the important number of subgroup and sensitivity analyses.

Nomenclature in nephrology: preserving 'renal' and 'nephro' in the glossary of kidney health and disease

A recently published nomenclature by a "Kidney Disease Improving Global Outcomes" (KDIGO) Consensus Conference suggested that the word "kidney" should be used in medical writings instead of "renal" or "nephro" when referring to kidney disease and kidney health. Whereas the decade-old move to use "kidney" more frequently should be supported when communicating with the public-at-large, such as the World Kidney Day, or in English speaking countries in communications with patients, care-partners, and non-medical persons, our point of view is that "renal" or "nephro" should not be removed from scientific and technical writings. Instead, the terms can coexist and be used in their relevant contexts. Cardiologists use "heart" and "cardio" as appropriate such as "heart failure" and "cardiac care units" and have not replaced "cardiovascular" with "heartvessel", for instance. Likewise, in nephrology, we consider that "chronic kidney disease" and "continuous renal replacement therapy" should coexist. We suggest that in scientific writings and technical communications, the words "renal" and "nephro" and their derivatives are more appropriate and should be freely used without any pressure by medical journals to compel patients, care-partners, healthcare providers, researchers and other stakeholders to change their selected words and terminologies. We call to embrace the terms "kidney", "renal" and "nephro" as they are used in different contexts and ask that scientific and medical journals not impose terminology restrictions for kidney disease and kidney health. The choice should be at the discretion of the authors, in the different contexts including in scientific journals.

Clinical significance of glomerular C3 deposition in primary membranous nephropathy

BACKGROUND

We aimed to investigate the effects of glomerular C3 deposition on clinical, histopathological features, and outcomes of patients with primary membranous nephropathy (MN).

METHODS

A total of 261 patients with biopsy-proven primary MN, who were on follow up for at least 6 months, were included in the study. The patients were grouped according to their C3 immunostaining in kidney biopsy samples at the time of diagnosis: Low intensity [LI; (C3 1 +)] and high intensity [HI; (C3 2 + or C3 3 +)]. The primary outcome was the development of kidney failure. Complete (CR) or partial remission (PR) was defined as secondary outcome.

RESULTS

Sixteen patients reached the primary outcome after a median follow-up of 33.8 months. Patients in the high intensity group (119 cases) had lower eGFR and higher proteinuria at admission and last follow-up compared to patients in the low intensity group (142 cases). Also, more patients in the high intensity group reached the primary outcome compared to patients in the low intensity group: twelve patients (10.1%) in the high intensity group and four patients (2.8%) in the low intensity group reached the primary outcome (p = 0.015). Kaplan-Meier analysis demonstrated that patients in the high intensity group had a higher risk for kidney failure (p = 0.02). In multivariate logistic regression analysis, high intensity C3 deposition and initial estimated glomerular filtration rate (eGFR) indepenently predicted primary outcome.

CONCLUSION

Extensive glomerular C3 deposition is a predictor of kidney failure in patients with MN.