José Vinhas

Prevalence of Chronic Kidney Disease and Associated Risk Factors, and Risk of End-Stage Renal Disease: Data from the PREVADIAB Study

Background/Aims: Chronic kidney disease (CKD) is a growing public health problem. However, data on risk factors and prevalence of CKD exist only in a small number of countries. Portugal has the highest incidence of end-stage renal disease (ESRD) among European countries, but there are huge disparities among countries. Whether these disparities reflect differences in risk factors, prevalence of CKD or other factors is currently unknown. Methods: We analyzed data from a nationally representative sample of 5,167 subjects, and estimated the prevalence of CKD and associated risk factors, and combined these prevalence estimates with available data on ESRD. Results: The prevalence of risk factors such as diabetes (11.7%), obesity (33.7%), and metabolic syndrome (41.5%) was similar to that in the US, but greater than in most European countries. The prevalence of CKD stages 3–5 was 6.1%, which is similar to that in other Western countries. The risk of ESRD was greater than in other European countries, but lower than in the US. Conclusion: The high incidence of ESRD among the Portuguese population is not due to a greater prevalence of CKD. A higher rate of progression associated with the high prevalence of risk factors may account for the high incidence of ESRD. The role of unmeasured factors needs to be evaluated in further studies.

A Prospective Study on Incidence of Bacterial Infections in Portuguese Dialysis Units

Background: Viral infection has been the main epidemiologic concern in the hemodialysis unit; however, bacterial infection is responsible for more than 30% of all causes of morbidity and mortality in our patients, vascular access infection being the culprit in 73% of all bacteremias. Methods: A prospective multicenter cohort study of bacterial infections incidence, conducted from January to July 2004 in five hemodialysis units, to record and track bacterial infections, using a validated database from CDC’s Dialysis Surveillance Network Program. Results: 4,501 patient-months (P-M) were surveilled, being dialyzed through a native fistula (AVF) in 60.6%, a graft (PTFE) in 31.3%, a tunneled catheter (TC) in 7.6%, and a transient catheter (C) in 0.5%. As target events, we registered 166 hospitalizations – 3.7/100 P-M (2.2/100 P-M in patients with AVF, 4 in PTFE, 9.9 in TC, and 19 in C), and 182 intravenous antibiotic courses. Of these 182 antibiotic treatments, 47.8% included vancomycin, only 30% had blood cultures drawn pretreatment, and only 36% were positive. We recorded 98 infections at the vascular access site 2.18/100 P-M (0.95 in AVF, 1.6 in PTFE, 12.6 in TC, and 42.85 in C) and 2.13 infections/100 P-M at other sites. The isolated microorganisms were Staphylococcus epidermidis in 40.1%, Staphylococcus aureus in 30.1%, Pseudomonas in 13.3%, and Escherichia coli in 3.3%. Although we found a diversity of practice patterns, the number of target events (8.4/100 P-M) and the bacterial infections incidence (4.31/100 P-M) were remarkably homogeneous in the five centers. Conclusion: (1) High incidence of bacterial infections, causing major morbidity; (2) infectious risk is vascular access type-dependent, with dramatic rise in catheters; (3) underutilization of blood cultures to orient diagnosis and therapy, and (4) high rates of vancomycin prescription.

Treatment of Anaemia with Erythropoiesis-Stimulating Agents in Patients with Chronic Kidney Disease Does Not Lower Mortality and May Increase Cardiovascular Risk: A Meta-Analysis

Background/Aims: Interpretation of the results of earlier meta-analyses in chronic kidney disease (CKD) patients on the impact of anaemia treatment with erythropoiesis-stimulating agents (ESAs) on clinical outcomes has been hampered by the inclusion of small trials and trials of short duration. We re-evaluated the benefits and harms of treating anaemia, including only relevant clinical trials. Methods: We conducted a systematic review and meta-analysis of randomised controlled trials performed in adults with CKD which allocated patients to different doses of ESAs, and we compared the effect of these interventions on vascular access thrombosis, stroke, risk of end-stage renal disease (ESRD) and all-cause mortality. Additional inclusion criteria were studies with a duration of at least 1 year and enrolling more than 500 participants. Results: Five trials (7,902 participants) met the inclusion criteria and were included in the meta-analysis. The number of patients enrolled in each trial ranged from 596 to 4,038. The mean/median duration of follow-up ranged from 14 to 36 months. A higher haemoglobin target was associated with increased risk of vascular access thrombosis (RR 1.343; 95% CI 1.162–1.554; p = 0.0005) and stroke (RR 1.735; 95% CI 1.323–2.275; p = 0.0005), and no effect on risk of ESRD (RR 1.089; 95% CI 0.986–1.203; p = 0.094) or all-cause mortality (RR 1.148; 95% CI 0.977–1.350; p = 0.093). Conclusion: In CKD patients, treatment of anaemia with ESAs targeting a higher haemoglobin value does not lower mortality or reduce the risk of ESRD, and may increase cardiovascular risk.

Inferring Disease Mechanisms from Epidemiological Data in Chronic Kidney Disease: Calcium and Phosphorus Metabolism

Background/Aims: By applying numerical filtering to epidemiological data of 2,512 chronic kidney disease patients, we aimed to identify some of the underlying mechanisms of the calcium/phosphorus metabolism perturbations. Methods: The measured variables, serum calcitriol, calcidiol, total calcium ([Ca]s) and phosphorus ([P]s) and the urinary excretions of calcium and phosphorus, were paired in the same patients with the glomerular filtration rate (GFR) or the serum concentrations of parathormone (i[PTH]s) (used as independent variables) numerically filtered with a moving average and partitioned into 15–25 frequency classes. All variables exhibited unimodal frequency distributions. Results: There was a steep fall of i[PTH]s, [P]s, and urinary excretion fractions of Ca and P up to a value of GFR in the range of 25–45 ml/min/1.73 m2. The increase in the phosphorus urinary excretion preceded the steep increase in i[PTH]s. Except [Ca]s, all factors exhibited their physiological correlation with i[PTH]s when GFR was above 90 ml/min/1.73 m2 and reverted to a feedback correlation below 80 ml/min/1.73 m2. Conclusion: The perturbation of mineral metabolism in chronic kidney disease results in the maintenance of a normal range of [Ca]s and [P]s acting as the controlled factors at the cost of large variations of i[PTH]s, and calcium and phosphate urinary excretions behaving as controlling factors.

Antibody-mediated pure red cell aplasia (PRCA) on switching from darbepoetin alfa to epoetin beta: what are the implications?

We report the development of antibody-mediated pure red cell aplasia (PRCA) in a 63-year-old man with end-stage renal disease following a switch from darbepoetin alfa to epoetin beta. Haemoglobin levels began to decrease 6 months after the switch. Increasing the epoetin beta dose produced no response and regular blood transfusions were required; PRCA was confirmed and epoetin beta was discontinued. The patient responded positively to immunosuppression; after 2 months on prednisone and cyclophosphamide, haemoglobin levels stabilized and no further transfusions were required. This case highlights the difficulty in establishing a cause-effect relationship where more than one erythropoiesis-stimulating agent is involved.

Haemolytic uraemic syndrome associated with H1N1 influenza

Haemolytic uraemic syndrome (HUS) is one of the two forms of thrombotic microangiopathies and is characterized by the triad of microangiopathic haemolytic anaemia, thrombocytopaenia, and acute renal failure. It has been associated with bacterial and viral infections as well as non-infective causes. We report a subject who presented with HUS associated with an influenza-like syndrome which was confirmed as an influenza A (H1N1) infection. There are reports of HUS associated with seasonal influenza, but there have been no reported cases of HUS after novel influenza A (H1N1) in the literature so far.

Self limited membranous glomerulonephritis due to syphilis

Syphilis is known as “the great mimic” owing to the wide range of clinical presentations. Primary syphilis usually presents as a highly contagious ulcerated lesion that appears 9-90 days after infection (1). Secondary syphilis manifests after hematogenous and lymphatic dissemination. This article is protected by copyright. All rights reserved.