The process of aging population will inevitably increase age-related comorbidities including chronic kidney disease (CKD). In light of this demographic transition, the lack of an age-adjusted CKD classification may enormously increase the number of new diagnoses of CKD in old subjects with an indolent decline in kidney function. Overdiagnosis of CKD will inevitably lead to important clinical consequences and pronounced negative effects on the health-related quality of life of these patients. Based on these data, an appropriate workup for the diagnosis of CKD is critical in reducing the burden of CKD worldwide. Optimal management of CKD should be based on prevention and reduction of risk factors associated with kidney injury. Once the diagnosis of CKD has been made, an appropriate staging of kidney disease and timely prescriptions of promising nephroprotective drugs (e.g., RAAS, SGLT-2 inhibitors, finerenone) appear crucial to slow down the progression toward end-stage kidney disease (ESKD). The management of elderly, comorbid and frail patients also opens new questions on the appropriate renal replacement therapy for this subset of the population. The non-dialytic management of CKD in old subjects with short life expectancy features as a valid option in patient-centered care programs. Considering the multiple implications of CKD for global public health, this review examines the prevalence, diagnosis and principles of treatment of kidney disease in the aging population.

The prognostic value of within-day sCr variation serum creatinine variation is unknown in the setting of the novel coronavirus disease 2019 (COVID-19). We evaluated the prognostic significance of 24-hour serum creatinine variation in COVID-19 patients. A monocentric retrospective analysis was conducted in COVID-19 patients not admitted to the intensive care unit. Three groups were subdivided based on 24 hours serum creatinine variation from admission. In the stable kidney function group, 24-hour serum creatinine variation ranged from +0.05 to -0.05 mg/dL; in the decreased kidney function group, 24-hour serum creatinine variation was >0.05 mg/dL; in the improved kidney function group, 24-hour serum creatinine variation was <-0.05 mg/dL. The study population included 224 patients with a median age of 66.5 years and a predominance of males (72.3%). Within 24 hours of admission, renal function remained stable in 37.1% of the subjects, whereas it displayed improved and deteriorated patterns in 45.5% and 17.4%, respectively. Patients with decreased kidney function were older and had more severe COVID-19 symptoms than patients with stable or improved kidney function. About half of patients with decreased kidney function developed an episode of acute kidney injury (AKI) during hospitalization. Decreased kidney function was significantly associated with AKI during hospitalization (hazard ratio [HR], 4.6; 95% confidence interval [CI], 1.9-10.8; p < 0.001) and was an independent risk factor for 30-day in-hospital mortality (HR, 5.5; 95% CI, 1.1-28; p = 0.037). COVID-19 patients with decreased kidney function within 24 hours of admission were at high risk of AKI and 30-day in-hospital mortality.

Background. Although diabetic kidney disease (DKD) could affect up to one-third of patients with diabetes mellitus (DM), these patients can develop kidney diseases different from DKD, or these conditions can superimpose on DKD. Several potential predictors of nondiabetic kidney disease (NDKD) have been proposed, but there are no definitive indications available for kidney biopsy in diabetic patients. Methods. We designed a single-center, cross-sectional, and retrospective cohort study to identify clinical and laboratory factors associated with a diagnosis of NDKD after native kidney biopsy in diabetic patients and to investigate differences in time to end-stage kidney disease (ESKD) in patients with a diagnosis of DKD and NDKD. Results. Of 142 patients included in our analysis, 89 (62.68) had a histopathological diagnosis of NDKD or mixed NDKD+DKD. Patients in the NDKD group had significantly lower HbA1C, lower prevalence of diabetic retinopathy (DR), and less severe proteinuria, and there was a lower proportion of patients with nephrotic syndrome; the DKD group had significantly lower proportion of patients with hematological conditions. In the multivariate binary logistic regression, only absence of DR and presence of a hematological condition significantly predicted NDKD after adjustment for age and sex. Time to ESKD was significantly higher in patients with NDKD or mixed forms than in those with DKD. Conclusions. After a careful selection, more than half of kidney biopsies performed in diabetic patients can identify NDKD (alone or with concomitant DKD). Absence of DR and coexistence of a hematological condition (especially MGUS) were strong predictors of NDKD in our cohort.

Chronic kidney disease is a long-term condition with significant implications for quality of life and health care costs. To uncover the etiology in selected cases suspected of monogenicity, a genomic approach can be employed. There are multiple technologies available, but there is currently no consensus on the most effective diagnostic approach. This review provides a comparison of currently available diagnostic methods in terms of diagnostic yield. However, the heterogeneity of patient cohort inclusion criteria limits direct comparisons. Our review identified three studies which compared a targeted gene panel and whole-exome sequencing for the same patient population. However, the results are inconclusive due to the different sizes and specificity of the targeted panels employed. The contribution of a whole-genome sequencing approach is highly debated. It is noteworthy that a large number of data are generated by these sequencing technologies. This allows for rapid analysis of coding and non-coding regions. However, the interpretation of variants is a significant burden, and the reporting of incidental findings is still challenging. Therefore, the identification of the most efficient technology is pivotal but still controversial. To conclude, an objective comparison of the three methods for the same population could overcome the limits of these studies’ heterogeneity and highlight the weaknesses and the strengths of individual approaches.

Key Points: This retrospective study analyzed clinical, histological, and biochemical data from a large cohort of participants with biopsy-proven primary C3 glomerulopathy/immune complex-mediated membranoproliferative GN. C3 glomerulopathy and immune complex-mediated membranoproliferative GN subjects shared most baseline and longitudinal features; 10-year kidney survival did not differ across histological subtypes. Older age at onset and higher proteinuria levels at 1 year from biopsy were the strongest predictors of kidney failure. Background: Membranoproliferative glomerulonephritides (MPGNs) are defined by a typical glomerular histopathological pattern including C3 glomerulopathy (C3G) and immune complex-mediated MPGN (IC-MPGN). The overall prognosis is poor and the treatment options remain limited. Outcome predictors and reliable surrogate endpoints are critically needed for interventional trials. Herein, we described the natural history and analyzed clinical, histological and biochemical data from a large cohort of patients with primary C3G/IC-MPGN. Methods: This is a retrospective analysis of patients with biopsy-proven primary C3G or IC-MPGN from the Italian Registry of MPGN. Demographic, clinical and histopathological data, molecular complement profiles, treatment patterns, and outcomes were collected. We performed univariable and multivariable Cox regressions and Kaplan–Meier survival analyses to assess risk associations with kidney disease progression. The composite endpoint included ESKD (defined by either eGFR <15 ml/min per 1.73 m ² , initiation of chronic dialysis or kidney transplantation), doubling of serum creatinine at the last available follow-up, or death by kidney-related causes. Results: Of the 349 patients identified, 208 had C3G and 141 IC-MPGN. Females were 41%, and over half were younger than 18 years old at time of biopsy. C3G and IC-MPGN patients shared most baseline and longitudinal features, with IC-MPGN patients presenting with higher baseline proteinuria (median 4.0 versus 2.3 g/24 hours, P < 0.001). Median eGFR at presentation was 83 ml/min per 1.73 m ² . Twenty-six percent of patients progressed to ESKD over a median follow-up of 5 years from diagnosis. Higher proteinuria levels at 1 year from biopsy, particularly ≥1 g/24 hours, were significantly associated with a higher risk of adverse kidney outcomes. Pediatric onset was associated with better kidney survival, whereas kidney survival at 10 years did not statistically differ across histological subtypes. Complement dysregulation and rare functional variants in complement genes were not associated with outcomes. Conclusions: Our findings from a large and well-characterized cohort of individuals with primary C3G/IC-MPGN identify age at onset and proteinuria levels as associations with kidney survival, a finding that should inform future interventional trials.

COVID-19 Rapid Antigen Test Screening in Patients on Hemodialysis: Introduction. Patients receiving in-center hemodialysis are extremely vulnerable to COVID-19. It is unclear if routine screening of asymptomatic hemodialysis patients is an effective strategy to prevent COVID-19 outbreaks within the dialysis unit. Methods. We conducted a retrospective analysis of in-center hemodialysis patients who underwent bimonthly COVID-19 rapid antigen test screening from February 15^th to December 26^th, 2021. Nasal rapid antigen testing was performed in all asymptomatic patients. All rapid antigen-positive tests were confirmed by RT-PCR nasopharyngeal swab. Besides universal rapid antigen screening, RT-PCR testing was conducted in all symptomatic patients and contacts of COVID-19 subjects. Results. Overall, 4079 rapid antigen tests were performed in 277 hemodialysis patients on chronic hemodialysis with a mean age of 68.414.6 years. Thirty-eight (0.9) rapid antigen tests resulted positive. Only five (13.8) positive-rapid antigen tests were also positive by RT-PCR testing. During the same period, 219 patients regularly screened by rapid antigen tests bimonthly underwent 442 RT-PCR nasopharyngeal swabs for clinical reasons. RT-PCR testing yielded a positive result in 13 (5.9) patients. The time elapsed between PCR and the negative-rapid antigen test was 7.74.6 days (range 1.813.9 days). At the end of the follow-up, 6.4 of the population on in-center hemodialysis contracted COVID-19, and routine rapid antigen tests detected only 5 out of 18 (27.7) COVID-19 cases. No outbreaks of COVID-19 were identified within the dialysis unit. Conclusion. Bimonthly rapid antigen screening led to the early diagnosis of COVID-19 in less than one-third of cases. The short incubation period of the new SARS-CoV-2 variants makes bimonthly test screening inadequate for an early diagnosis of COVID-19. More frequent tests are probably necessary to improve the utility of COVID-19 nasal rapid antigen test in patients on hemodialysis.