Estimated glomerular filtration rate in clinical practice: Consensus positioning of the Brazilian Society of Nephrology (SBN) and Brazilian Society of Clinical Pathology and Laboratory Medicine (SBPC/ML) / Estimativa da taxa de filtração glomerular na prática clínica: posicionamento consensual da Sociedade Brasileira de Nefrologia (SBN) e Sociedade Brasileira de Patologia Clínica e Medicina Laboratorial (SBPC/ML)

ABSTRACT Chronic kidney disease (CKD) represents one of today's main public health problems. Serum creatinine measurement and estimation of the glomerular filtration rate (GFR) are the main tools for evaluating renal function. There are several equations to estimate GFR, and CKD-EPI equation (Chronic Kidney Disease - Epidemiology) is the most recommended one. There are still some controversies regarding serum creatinine measurement and GFR estimation, since several factors can interfere in this process. An important recent change was the removal of the correction for race from the equations for estimating GFR, which overestimated kidney function, and consequently delayed the implementation of treatments such as dialysis and kidney transplantation. In this consensus document from the Brazilian Societies of Nephrology and Clinical Pathology and Laboratory Medicine, the main concepts related to the assessment of renal function are reviewed, as well as possible existing controversies and recommendations for estimating GFR in clinical practice.

RESUMO A doença renal crônica (DRC) representa um dos principais problemas de saúde pública da atualidade. A dosagem da creatinina sérica e a estimativa da taxa de filtração glomerular (TFG) são as principais ferramentas para avaliação da função renal. Para a estimativa da TFG, existem diversas equações, sendo a mais recomendada a CKD-EPI (Chronic Kidney Disease - Epidemiology). Existem ainda algumas controvérsias com relação à dosagem da creatinina sérica e da estimativa da TFG, uma vez que vários fatores podem interferir nesse processo. Uma importante mudança recente foi a retirada da correção por raça das equações para estimativa da TFG, que superestimavam a função renal, e consequentemente retardavam a implementação de tratamentos como diálise e transplante renal. Neste documento de consenso da Sociedade Brasileira de Nefrologia e Sociedade Brasileira de Patologia Clínica e Medicina Laboratorial são revisados os principais conceitos relacionados à avaliação da função renal, possíveis controvérsias existentes e recomendações para a estimativa da TFG na prática clínica.

The role of podocyte injury in the pathogenesis of Fabry disease nephropathy.

Renal involvement is one of the most severe morbidities of Fabry disease (FD), a multisystemic lysosomal storage disease with an X-linked inheritance pattern. It results from pathogenic variants in the GLA gene (Xq22.2), which encodes the production of alpha-galactosidase A (α-Gal), responsible for glycosphingolipid metabolism. Insufficient activity of this lysosomal enzyme generates deposits of unprocessed intermediate substrates, especially globotriaosylceramide (Gb3) and derivatives, triggering cellular injury and subsequently, multiple organ dysfunction, including chronic nephropathy. Kidney injury in FD is classically attributed to Gb3 deposits in renal cells, with podocytes being the main target of the pathological process, in which structural and functional alterations are established early and severely. This configures a typical hereditary metabolic podocytopathy, whose clinical manifestations are proteinuria and progressive renal failure. Although late clinical outcomes and morphological changes are well established in this nephropathy, the molecular mechanisms that trigger and accelerate podocyte injury have not yet been fully elucidated. Podocytes are highly specialized and differentiated cells that cover the outer surface of glomerular capillaries, playing a crucial role in preserving the structure and function of the glomerular filtration barrier. They are frequent targets of injury in many nephropathies. Furthermore, dysfunction and depletion of glomerular podocytes are essential events implicated in the pathogenesis of chronic kidney disease progression. We will review the biology of podocytes and their crucial role in regulating the glomerular filtration barrier, analyzing the main pathogenic pathways involved in podocyte injury, especially related to FD nephropathy.

Safety and feasibility of transcranial direct current stimulation in end-stage renal disease patients undergoing hemodialysis: an exploratory study.

INTRODUCTION: Patients with end-stage renal disease often face a challenging routine of hemodialysis, dietary restrictions, and multiple medications, which can affect their hemodynamic function. Home-based, safe, and nonpharmacological approaches such as transcranial direct current stimulation (tDCS) should be combined with conventional treatment. OBJECTIVE: To assess the safety and feasibility of tDCS on blood pressure and heart rate in patients with end-stage renal disease undergoing hemodialysis. METHOD: This is a parallel, randomized, sham-controlled trial. Patients undergoing hemodialysis for more than three months were included. The patients received ten non-consecutive 2mA tDCS sessions on the primary motor cortex . Each session lasted 20 minutes. At baseline and after each of the ten sessions, blood pressure and heart rate of the patients were measured hourly for four hours. RESULTS: Thirty patients were randomized to the active or sham group. The mean difference between the groups was calculated as the mean value of the sham group minus the mean value of the active group. Despite there were no statistical changes for all outcomes considering all 10 sessions, we found differences between groups for systolic -10.93 (-29.1;7.2), diastolic -3.63 (-12.4; 5.1), and mean blood pressure -6.0 (-16.3; 4.2) and hear rate 2.26 (-2.5; 7.1). No serious adverse events were found. The active group showed higher blood pressure values at all points, while heart rate was lower in the active group. CONCLUSION: tDCS is safe and feasible for patients with end-stage renal disease undergoing hemodialysis. Future studies should investigate whether tDCS could potentially induce a hypotensive protective effect during hemodialysis.

Understanding of the role of serum creatinine in a subset of the Brazilian population / Conhecimento de uma amostragem da população brasileira sobre a função da creatinina sérica

Abstract Introduction: Chronic kidney disease is usually asymptomatic, and its diagnosis depends on laboratory tests, with emphasis on serum creatinine and proteinuria. Objective: To assess knowledge on the role of serum creatinine as a biomarker of kidney function in a sample of the Brazilian population. Method: Cross-sectional observational study conducted in São Paulo (SP, Brazil), in which a random adult population was interviewed. Results: A total of 1138 subjects were interviewed, with a median age of 36 years old (27-52); 55.1% were female. Regarding the "creatinine" biomarker, 40.6% stated they had never performed such a test. When asked about their knowledge on the usefulness of this exam, only 19.6% knew its function. The other responses were "I don't know" (71.6%), evaluating heart function (0.9%) and liver function (7.8%). Of those who reported they had already taken a creatinine test, only 29.4% correctly identified the role of creatinine. When dividing the groups into "knows" and "does not know" the function of creatinine, a statistically significant difference (p < 0.05) was observed regarding level of education, female sex, being a healthcare student/worker, having ever measured creatinine, knowing someone with kidney disease and older age. In the multivariate analysis, the main variable related to knowing the creatinine role was having previously taken the test (OR 5.16; 95% CI 3.16-8.43, p < 0.001). Conclusion: There is a significant lack of knowledge about creatinine and its use in checkups. The results indicate that greater efforts are needed from healthcare professionals to raise awareness on the role of serum creatinine.

Resumo Introdução: A doença renal crônica costuma ser assintomática e seu diagnóstico depende da realização de exames laboratoriais, com destaque para a creatinina sérica e pesquisa de proteinúria. Objetivo: Avaliar em uma amostra da população brasileira o conhecimento sobre o papel da creatinina sérica como marcador de função renal. Método: Estudo observacional transversal realizado na cidade de São Paulo (SP, Brasil), em que foi entrevistada uma população adulta aleatória. Resultados: Foram entrevistados 1138 indivíduos, com idade mediana de 36 anos (27-52); 55,1% do sexo feminino. Com relação ao marcador "creatinina", 40,6% afirmaram que nunca realizaram tal dosagem. Quando questionados quanto ao conhecimento sobre a utilidade desse exame, somente 19,6% sabiam a sua função. As outras respostas foram "não sei" (71,6%), avaliar o funcionamento do coração (0,9%) e fígado (7,8%). Dos que afirmaram já terem realizado o exame de creatinina, somente 29,4% acertaram a função da creatinina. Ao dividir os grupos em "sabe" e "não sabe" a função da creatinina, percebeu-se diferença estatisticamente significante (p < 0,05) em relação ao grau de escolaridade, sexo feminino, ser aluno/trabalhador da saúde, ter dosado creatinina alguma vez, conhecer alguém com doença renal e maior idade. Na análise multivariada, a principal variável relacionada com conhecer a função da creatinina foi ter realizado o exame anteriormente (OR 5,16; IC 95% 3,16-8,43, p < 0,001). Conclusão: Há grande desconhecimento sobre a creatinina e seu uso em check-ups. Os resultados indicam que é necessário maior esforço por parte dos profissionais de saúde para divulgar o papel da creatinina sérica.

Laboratory-based surveillance of chronic kidney disease in people with private health coverage in Brazil

BACKGROUND Although approximately 25% of Brazilians have private health coverage (PHC), studies on the surveillance of chronic kidney disease (CKD) in this population are scarce. The objective of this study was to estimate the prevalence of CKD in individuals under two PHC regimes in Brazil, who total 8,335,724 beneficiaries. METHODS Outpatient serum creatinine and proteinuria results of individuals from all five regions of Brazil, ≥18 years of age, and performed between 10/01/2021 and 10/31/2022, were analyzed through the own laboratory network database. People with serum creatinine measurements were evaluated for the prevalence and staging of CKD, and those with simultaneous measurements of serum creatinine and proteinuria were evaluated for the risk category of the disease. CKD was classified according to current guidelines and was defined as a glomerular filtration rate (GFR)<60 ml/min/1.73 m² estimated by the 2021 CKD-EPI equation. RESULTS The number of adults with serum creatinine results was 1,508,766 (age 44.0 [IQR, 33.9­56.8] years, 62.3% female). The estimated prevalence of CKD was 3.8% (2.6%, 0.8%, 0.2% and 0.2% in CKD stages 3a, 3b, 4 and 5, respectively), and it was higher in males than females (4.0% vs. 3.7%, p<0.001, respectively) and in older age groups (0.2% among 18-29-year-olds, 0.5% among 30-44-year-olds, 2.0% among 45-59-year-olds, 9.4% among 60-74-yearolds, and 32.4% among ≥75-year-olds, p<0.001) Adults with simultaneous results of creatinine and proteinuria were 64,178 (age 57.0 [IQR, 44.8­67.3] years, 58.1% female). After adjusting for age and gender, 70.1% were in the low-risk category of CKD, 20.0% were in the moderate-risk category, 5.8% were in the high-risk category, and 4.1% were in the very high-risk category. CONCLUSION The estimated prevalence of CKD was 3.8%, and approximately 10% of the participants were in the categories of high or very high-risk of the disease. While almost 20% of beneficiaries with PHC had serum creatinine data, fewer than 1% underwent tests for proteinuria. This study was one of the largest ever conducted in Brazil and the first one to use the 2021 CKD-EPI equation to estimate the prevalence of CKD.

Laboratory-based surveillance of chronic kidney disease in people with private health coverage in Brazil.

BACKGROUND: Although approximately 25% of Brazilians have private health coverage (PHC), studies on the surveillance of chronic kidney disease (CKD) in this population are scarce. The objective of this study was to estimate the prevalence of CKD in individuals under two PHC regimes in Brazil, who total 8,335,724 beneficiaries. METHODS: Outpatient serum creatinine and proteinuria results of individuals from all five regions of Brazil, ≥ 18 years of age, and performed between 10/01/2021 and 10/31/2022, were analyzed through the own laboratory network database. People with serum creatinine measurements were evaluated for the prevalence and staging of CKD, and those with simultaneous measurements of serum creatinine and proteinuria were evaluated for the risk category of the disease. CKD was classified according to current guidelines and was defined as a glomerular filtration rate (GFR) < 60 ml/min/1.73 m² estimated by the 2021 CKD-EPI equation. RESULTS: The number of adults with serum creatinine results was 1,508,766 (age 44.0 [IQR, 33.9-56.8] years, 62.3% female). The estimated prevalence of CKD was 3.8% (2.6%, 0.8%, 0.2% and 0.2% in CKD stages 3a, 3b, 4 and 5, respectively), and it was higher in males than females (4.0% vs. 3.7%, p < 0.001, respectively) and in older age groups (0.2% among 18-29-year-olds, 0.5% among 30-44-year-olds, 2.0% among 45-59-year-olds, 9.4% among 60-74-year-olds, and 32.4% among ≥ 75-year-olds, p < 0.001) Adults with simultaneous results of creatinine and proteinuria were 64,178 (age 57.0 [IQR, 44.8-67.3] years, 58.1% female). After adjusting for age and gender, 70.1% were in the low-risk category of CKD, 20.0% were in the moderate-risk category, 5.8% were in the high-risk category, and 4.1% were in the very high-risk category. CONCLUSION: The estimated prevalence of CKD was 3.8%, and approximately 10% of the participants were in the categories of high or very high-risk of the disease. While almost 20% of beneficiaries with PHC had serum creatinine data, fewer than 1% underwent tests for proteinuria. This study was one of the largest ever conducted in Brazil and the first one to use the 2021 CKD-EPI equation to estimate the prevalence of CKD.

Estimated glomerular filtration rate in clinical practice: Consensus positioning of the Brazilian Society of Nephrology (SBN) and Brazilian Society of Clinical Pathology and Laboratory Medicine (SBPC/ML).

Chronic kidney disease (CKD) represents one of today's main public health problems. Serum creatinine measurement and estimation of the glomerular filtration rate (GFR) are the main tools for evaluating renal function. There are several equations to estimate GFR, and CKD-EPI equation (Chronic Kidney Disease - Epidemiology) is the most recommended one. There are still some controversies regarding serum creatinine measurement and GFR estimation, since several factors can interfere in this process. An important recent change was the removal of the correction for race from the equations for estimating GFR, which overestimated kidney function, and consequently delayed the implementation of treatments such as dialysis and kidney transplantation. In this consensus document from the Brazilian Societies of Nephrology and Clinical Pathology and Laboratory Medicine, the main concepts related to the assessment of renal function are reviewed, as well as possible existing controversies and recommendations for estimating GFR in clinical practice.

Understanding of the role of serum creatinine in a subset of the Brazilian population.

INTRODUCTION: Chronic kidney disease is usually asymptomatic, and its diagnosis depends on laboratory tests, with emphasis on serum creatinine and proteinuria. OBJECTIVE: To assess knowledge on the role of serum creatinine as a biomarker of kidney function in a sample of the Brazilian population. METHOD: Cross-sectional observational study conducted in São Paulo (SP, Brazil), in which a random adult population was interviewed. RESULTS: A total of 1138 subjects were interviewed, with a median age of 36 years old (27-52); 55.1% were female. Regarding the "creatinine" biomarker, 40.6% stated they had never performed such a test. When asked about their knowledge on the usefulness of this exam, only 19.6% knew its function. The other responses were "I don't know" (71.6%), evaluating heart function (0.9%) and liver function (7.8%). Of those who reported they had already taken a creatinine test, only 29.4% correctly identified the role of creatinine. When dividing the groups into "knows" and "does not know" the function of creatinine, a statistically significant difference (p < 0.05) was observed regarding level of education, female sex, being a healthcare student/worker, having ever measured creatinine, knowing someone with kidney disease and older age. In the multivariate analysis, the main variable related to knowing the creatinine role was having previously taken the test (OR 5.16; 95% CI 3.16-8.43, p < 0.001). CONCLUSION: There is a significant lack of knowledge about creatinine and its use in checkups. The results indicate that greater efforts are needed from healthcare professionals to raise awareness on the role of serum creatinine.

ACE2, ACE, DPPIV, PREP and CAT L enzymatic activities in COVID-19: imbalance of ACE2/ACE ratio and potential RAAS dysregulation in severe cases.

OBJECTIVE AND DESIGN: Circulating enzymatic activity and RAAS regulation in severe cases of COVID-19 remains unclear, therefore we measured the serum activity of several proteases as potential targets to control the SARS-CoV-2 infection. MATERIAL OR SUBJECTS: 152 patients with COVID-19-like symptoms were grouped according to the severity of symptoms (COVID-19 negative, mild, moderate and severe). METHODS: Serum samples of COVID-19 patients and controls were subjected to biochemical analysis and enzymatic assays of ACE2, ACE, DPPIV, PREP and CAT L. One-way ANOVA and multivariate logistic regression analysis were used. Statistical significance was accepted at p < 0.05. RESULTS: We detected a positive correlation among comorbidities, higher C-reactive protein (CRP) and D-dimer levels with disease severity. Enzymatic assays revealed an increase in serum ACE2 and CAT L activities in severe COVID-19 patients, while ACE, DPPIV and PREP activities were significantly reduced. Notably, analysis of ACE2/ACE activity ratio suggests a possible imbalance of ANG II/ANG(1-7) ratio, in a positive association with the disease severity. CONCLUSION: Our findings reveal a correlation between proteases activity and the severity of COVID-19. These enzymes together contribute to the activation of pro-inflammatory pathways, trigger a systemic activation of inflammatory mediators, leading to a RAAS dysregulation and generating a significant damage in several organs, contributing to poor outcomes of severe cases.

Onychomycosis in immunocompromised population: Phenotypic and molecular identification.

Onychomycosis is common among immunosuppressed individuals. Renal transplant recipients (RTR) and lupus nephritis (LN) patients are submitted to corticosteroid and other immunosuppressive therapy; and diabetes mellitus (DM) patients are intrinsically immunocompromised. OBJECTIVES: The aim of this study was to characterise and identify fungal infections on the nails (feet and hands) in immunocompromised patients. METHODS: The clinical material, nail scales (foot and/or hand), was collected from 47 RTR, 66 LN, 67 DM, and 78 immunocompetent individuals (control group). Phenotypic and molecular analyses were performed. RESULTS: A total of 258 patients were examined. There was a female predominance, except in the RTR. The average age was 52 years old. Lateral distal subungual onychomycosis (OSDL) (75.2%), mainly affecting the hallux nail, was frequent. The predominance of dermatophyte on toenails and Candida species on fingernails was statistically significant. A higher frequency of fingernail involvement in LN and DM, and for LN, the difference was significant (p = .0456). Infections by Candida spp. were more frequent in DM. Using molecular methods, 87.2% of diagnoses were confirmed, identifying fungal agents at the species level. Dermatophytes, Trichophyton rubrum and Trichophyton interdigitale and the species of Candida, C. parapsilosis and C. albicans, were the most frequent fungal agents. CONCLUSIONS: Molecular techniques (sequencing of ITS regions of rDNA) offer greater accuracy, although there is no difference, regarding the detection. Clinical presentation and fungal species may differ somewhat from the general population. Immunosuppression did not increase fungal detection positivity.

A Cross-Sectional Study on the Prevalence and Risk Stratification of Chronic Kidney Disease in Cardiological Patients in São Paulo, Brazil.

Chronic kidney disease (CKD) provides a worse prognosis for patients with heart disease. In Latin America, studies that analyzed the prevalence and risk stratification of CKD in this population are scarce. We aimed to evaluate CKD prevalence and risk categories in patients of a public referral cardiology hospital in São Paulo, Brazil. This was a cross-sectional study based on a laboratory database. Outpatient serum creatinine and proteinuria results performed between 1 January 2021 and 31 December 2021 were analyzed. CKD was defined by estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and proteinuria, by the albumin/creatinine ratio in a spot urine sample (UACR) >30 mg/g. A total of 36,651 adults were identified with serum creatinine levels (median age 72.4 [IQR, 51.0-73.6] years, 51% male). Among them, 51.9% had UACR dosage (71.5% with UACR < 30 mg/g, 22.6%, between 30-300 mg/g, and 5.9% with UACR > 300 mg/g). The prevalence of CKD was 30.9% (15.3% stage 3a, 10.2% stage 3b, 3.6% stage 4, and 1.7% stage 5), and the distribution of patients in the risk categories of the disease was: 52.0% with low-risk, 23.5%, moderate risk, 13.0%, high risk, and 11.2%, very high. In an outpatient setting, the prevalence of CKD in cardiological patients was almost three times (31%) that of the general population; about half of the individuals evaluated (48%) were not screened for an important risk marker (proteinuria), and approximately a quarter of these patients (24%) were in the high or very high CKD risk categories.

A Cross-sectional study on the prevalence and risk stratification of chronic kidney disease in cardiological patients in São Paulo, Brazil

ABSTRACT: Chronic kidney disease (CKD) provides a worse prognosis for patients with heart disease. In Latin America, studies that analyzed the prevalence and risk stratification of CKD in this population are scarce. We aimed to evaluate CKD prevalence and risk categories in patients of a public referral cardiology hospital in São Paulo, Brazil. This was a cross-sectional study based on a laboratory database. Outpatient serum creatinine and proteinuria results performed between 1 January 2021 and 31 December 2021 were analyzed. CKD was defined by estimated glomerular filtration rate (eGFR) 30 mg/g. A total of 36,651 adults were identified with serum creatinine levels (median age 72.4 [IQR, 51.0­73.6] years, 51% male). Among them, 51.9% had UACR dosage (71.5% with UACR < 30 mg/g, 22.6%, between 30­300 mg/g, and 5.9% with UACR > 300 mg/g). The prevalence of CKD was 30.9% (15.3% stage 3a, 10.2% stage 3b, 3.6% stage 4, and 1.7% stage 5), and the distribution of patients in the risk categories of the disease was: 52.0% with low-risk, 23.5%, moderate risk, 13.0%, high risk, and 11.2%, very high. In an outpatient setting, the prevalence of CKD in cardiological patients was almost three times (31%) that of the general population; about half of the individuals evaluated (48%) were not screened for an important risk marker (proteinuria), and approximately a quarter of these patients (24%) were in the high or very high CKD risk categories.

Prevalence and risk stratification of chronic kidney disease in a tertiary cardiology hospital: a cross-sectional study

INTRODUCTION: Chronic kidney disease (CKD) is common, preventable and silent in its early stages. Therefore, early detection of this condition in the population at risk, through laboratory tests, is essential. OBJECTIVES: To estimate the CKD prevalence and perform its risk stratification in a tertiary health service specialized in cardiology. METHODS: The study was cross-sectional and based on laboratory records of patients from a public hospital specialized in cardiology. The evaluated tests were serum creatinine and urinary albumin/creatinine ratio (ACR, random sample) performed on an outpatient basis between 01/01/2021 and 12/31/2021. Duplicate exams and patients under 18 years of age were excluded. The estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI creatinine equation. CKD was defined by eGFR 300mg/g). According to the CKD risk map, individuals with simultaneous creatinine and ACR measurements were stratified into low, moderate, high or very high risk. RESULTS: The sample consisted of 36,651 patients in whom the same number of serum creatinine results and 19,031 ACR results were evaluated (median patients'age 72.5 [51.0-73.6] years, 51.3% male). The prevalence of CKD was 30.9% and patients with stages 3a, 3b, 4 and 5 corresponded to 15.3%, 10.2%, 3.6% and 1.7%, respectively. CKD was more frequent in older age groups: 18- 29 years (2.5%), 30-44 years (8.4%), 45-59 years (25.5%), 60-74 years (30 .7%) and ≥75 years (56.8%) (p<0.001). Patients with albuminuria categories A1, A2 and A3 were 71.5%, 22.6% and 5.9%, respectively. ACR ≥30mg/g was not associated with age: 18-29 years (23.3%), 30-44 years (23.4%), 45-69 years (26.0%), 60-74 years (28 .5%) and ≥75 years (36.9%) (p=0.671). Patients with simultaneous measurements of serum creatinine and ACR were 19,031 and their distribution in the CKD risk categories was: low (52.0%), moderate (23.8%), high (13.1%) and very high risk (11.2%). CONCLUSIONS: The results showed that CKD is present in about 30% of the patients assisted in the cardiology institute evaluated. In up to half of the patients, the risk of major outcomes such as hospitalization, need for renal replacement therapy, and death was moderate, high, or very high.

Supply/demand ratio for medical consultations, diagnostic tests and chronic kidney disease monitoring in the Brazilian National Health System: a descriptive study, state of São Paulo, Brazil, 2019. / Razão oferta/necessidade de consultas médicas, exames de diagnóstico e acompanhamento da doença renal crônica no Sistema Único de Saúde: estudo descritivo, estado de São Paulo, 2019.

OBJECTIVE: To determine the supply/demand ratio for procedures related to diagnosis and treatment for chronic kidney disease in the Brazilian National Health System (SUS), in the state of São Paulo, Brazil, 2019. METHODS: This was a descriptive study, using data from the SUS outpatient and hospital information systems. The numbers of medical consultations, diagnostic and chronic kidney disease monitoring tests, performed in the period, were compared with the demand estimation, obtained through ministerial guidelines. RESULTS: Exclusive SUS users were 28,791,244, and individuals with arterial hypertension and/or diabetes mellitus, 5,176,188. The number of procedures performed and the ratio between this number and the needs of the population were 389,414 consultations with nephrologists (85%); 11,540,371 serum creatinine tests (223%); 705,709 proteinuria tests (14%); 438,123 kidney ultrasounds (190%); and 1,045 kidney biopsies (36%). CONCLUSION: In the chronic kidney disease care in the SUS it could be seen simultaneous existence of lack of supply, waste and inadequate screening of important procedures.

The first appointment with a nephrologist: Brazilian patients' demographic and kidney function characteristics. A retrospective study

ABSTRACT BACKGROUND: The number of nephrologists has risen slowly, compared with the prevalence of chronic kidney disease (CKD) in Brazil. Data on patients referred to nephrology outpatient clinics remains scarce. OBJECTIVE: To determine the demographic and kidney function characteristics of patients at their first appointment with a nephrologist. DESIGN AND SETTING: Retrospective study conducted at three nephrology outpatient clinics (public and private services), in São Paulo, Brazil. METHODS: From December 2019 to February 2020, we collected patient data regarding demographics, kidney function parameters and comorbidities. We then analyzed data on 394 patients who met a nephrologist for their first appointment. RESULTS: The main comorbidities were hypertension (63.7%), diabetes (33.5%) and nephrolithiasis (22.3%). Regarding CKD stages, 24.1%, 9.1%, 13.7%, 15.2%, 15.2% and 2.3% of the patients were in stages 1, 2, 3a, 3b, 4 and 5, respectively. Proteinuria was absent or mild, moderate and high in 17.3%, 15.2% and 11.7%, respectively; and 16.2% had not undergone previous investigation of serum creatinine or proteinuria (55.8%). For 17.5%, referral to a nephrologist occurred late. Patients in public services were older than those in private services (59 years versus 51 years, respectively; P = 0.001), more frequently hypertensive (69.7% versus 57.5%; P = 0.01) and reached a nephrologist later (22.4% versus 12.4%; P = 0.009). CONCLUSION: Referrals to a nephrologist were not being made using any guidelines for CKD risk and many cases could have been managed within primary care. Late referral to a nephrologist happened in one-fifth of the cases and more frequently in the public service.