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BackgroundRenal replacement therapy (RRT) is usually indicated for patients with chronic kidney disease (CKD) with glomerular filtration rate below 10 ml/ml/min/1.73m2. However, the need for RRT and timing of dialysis initiation are debatable for patients aged 70 years or older. We here describe the study design and methodology of the Aging Nephropathy Study (AGNES) protocol that aims at evaluating to what extent geriatric-related conditions such as frailty, cognitive dysfunction, and presence of comorbidities have an impact on survival and RRT initiation in this group of patients. In this manuscript we provide detailed information about the AGNES study design and methodology.MethodsAGNES is a prospective observational cohort that aim to investigate clinical, biochemical and demographic factors associated with RRT initiation and mortality of patients with CKD stage 4 or 5 who are aged 70 years and older. We plan to include 200 patients over 5 years. Clinically stable outpatients on conservative management for at least 6 months will be recruited from the Nephrogeriatric Clinic at theHospital das Clinicas da Universidade de Sao Paulo, Brazil. Eligible patients are submitted to a full clinical examination, geriatric assessment, and blood test at baseline. Following the baseline visit the patients are being monitored during an observational follow up period of at least 12 months during which patients will be contacted in the clinic at their regular follow up or by phone until either RRT initiation or death occurs. This cohort includes evaluation of cognition by the education-adjusted 10-point Cognitive Screener (10-CS), frailty by Fried index score, a complete nutritional assessment (by body composition assessment, global subjective assessment and dietary intake), comorbidities by Charlson comorbidity index and biochemical markers including FGF-23 and Klotho.DiscussionThe AGNES cohort, a real-world study of current clinical practice in elderly patients with advanced CKD prior to dialysis initiation, will shed light into progression of CKD and its complications, indications of RRT and factors determining survival. This investigation will elucidate to what extent geriatric conditions, nutritional status and clinical factors are associated with survival, quality of life and RRT initiation in elderly CKD patients not yet on dialysis.Trial registrationRegistered onClinicalTrials.govon 18 October 2019 (NCT04132492).

article i nfo Article history: Three smectiteswith distinct chemical compositionsweretreated with potassium fluoride and the catalysts thus obtained were used in the transesterification of soybean oil with methanol. The smectites and catalysts were ex- amined by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Fourier transform infrared spectros- copy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), and the BET gas adsorption method to verify if their chemical composition influences the properties of the resulting catalysts. Anexperimentaldesignwasappliedtoevaluatetheeffectofthevariablesofthetransesterificationreaction:tem- perature, mass ratio of the catalyst, and the molar ratio of oil to methanol. The results indicate that increasing the SiO2/Al2O3 ratio of the smectites causes an increase in the basicity of the catalysts, and hence, in the conversion rate into methyl esters.