Analysis of the Clinical and Epidemiological Meaning of Screening Test for SARS-CoV-2: Considerations in the Chronic Kidney Disease Patients during the COVID-19 Pandemic.

The COronaVIrus Disease 19 (COVID-19) pandemic is an emerging reality in nephrology. In a continuously changing scenario, we need to assess our patients' additional risk in terms of attending hemodialysis treatments, follow-up peritoneal dialysis, and kidney transplant visits. The prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-20 infection in the general population plays a pivotal role in estimating the additional COVID-19 risk in chronic kidney disease (CKD) patients. Unfortunately, local prevalence is often obscure, and when we have an estimation, we neglect the number of asymptomatic subjects in the same area and, consequently, the risk of infection in CKD patients. Furthermore, we still have the problem of managing COVID-19 diagnosis and the test's accuracy. Currently, the gold standard for SARS-CoV-2 detection is a real-time reverse transcription-polymerase chain reaction (rRT-PCR) on respiratory tract samples. rRT-PCR presents some vulnerability related to pre-analytic and analytic problems and could impact strongly on its diagnostic accuracy. Specifically, the operative proceedings to obtain the samples and the different types of diagnostic assay could affect the results of the test. In this scenario, knowing the local prevalence and the local screening test accuracy helps the clinician to perform preventive measures to limit the diffusion of COVID-19 in the CKD population.

Renal plasma flow, filtration fraction and microalbuminuria in hypertensive patients: effects of chronic smoking.

INTRODUCTION: Albumin excretion rate is usually increased in people who smoke, but the physiological basis of this phenomenon is not fully understood. METHODS: The effect of chronic smoking on renal haemodynamics was studied in a cohort of 66 men. Twenty-seven were smokers and 36 were hypertensive. In all subjects, the albumin excretion rate was evaluated; in hypertensive patients, a renoscintigraphic evaluation of renal plasma flow and glomerular filtration were carried out and the filtration fraction was calculated. RESULTS: The hypertensive smoking population presented an increased urinary albumin excretion rate in comparison with hypertensive non-smoking patients. No significant differences were found for the mean values of renal plasma flow, the glomerular filtration rate and the filtration fraction between hypertensive smokers and hypertensive non-smoking patients. CONCLUSIONS: In hypertensive patients, smoking does not modify typical renal haemodynamic changes of arterial hypertension; however, it significantly increases the albumin excretion rate.

Insulin resistance and glomerular hemodynamics in essential hypertension.

BACKGROUND: Arterial hypertension is an important cause of end-stage renal failure. Insulin has been shown to modify glomerular hemodynamics in hypertensive subjects. The aim of this work, therefore, was to observe the relationships between renal hemodynamics and insulin resistance in arterial hypertension. METHODS: Sixty-two non-diabetic hypertensive patients and 25 healthy normal subjects were studied. Renal plasma flow and the glomerular filtration fraction were determined by renoscintigraphy and the insulin sensitivity by an oral glucose test. RESULTS: Renal plasma flow in hypertensive subjects was lower than expected and was related to pressure values, whereas the mean glomerular filtration rates were not different in the two groups. In most patients the filtration fraction was higher than expected. A lower glomerular filtration rate and lower filtration fraction were found in patients with higher insulin resistance. CONCLUSIONS: The progressive decrease of glomerular function in subjects with hypertension is linked with insulin-resistance.