The risks associated with percutaneous native kidney biopsies: a prospective study.

BACKGROUND: The known risks and benefits of native kidney biopsies are mainly based on the findings of retrospective studies. The aim of this multicentre prospective study was to evaluate the safety of percutaneous renal biopsies and quantify biopsy-related complication rates in Italy. METHODS: The study examined the results of native kidney biopsies performed in 54 Italian nephrology centres between 2012 and 2020. The primary outcome was the rate of major complications 1 day after the procedure, or for longer if it was necessary to evaluate the evolution of a complication. Centre and patient risk predictors were analysed using multivariate logistic regression. RESULTS: Analysis of 5304 biopsies of patients with a median age of 53.2 years revealed 400 major complication events in 273 patients (5.1%): the most frequent was a ≥2 g/dL decrease in haemoglobin levels (2.2%), followed by macrohaematuria (1.2%), blood transfusion (1.1%), gross haematoma (0.9%), artero-venous fistula (0.7%), invasive intervention (0.5%), pain (0.5%), symptomatic hypotension (0.3%), a rapid increase in serum creatinine levels (0.1%) and death (0.02%). The risk factors for major complications were higher plasma creatinine levels [odds ratio (OR) 1.12 for each mg/dL increase, 95% confidence interval (95% CI) 1.08-1.17], liver disease (OR 2.27, 95% CI 1.21-4.25) and a higher number of needle passes (OR for each pass 1.22, 95% CI 1.07-1.39), whereas higher proteinuria levels (OR for each g/day increase 0.95, 95% CI 0.92-0.99) were protective. CONCLUSIONS: This is the first multicentre prospective study showing that percutaneous native kidney biopsies are associated with a 5% risk of a major post-biopsy complication. Predictors of increased risk include higher plasma creatinine levels, liver disease and a higher number of needle passes.

[Hyperphosphatemic pseudotumoral calcinosis due to FGF23 mutation with secondary amyloidosis].

A 44 years old man was admitted for nephrotic syndrome and rapidly progressive renal failure. Two firm, tumour-like masses were localized around the left shoulder and the right hip joint. Since the age of 8 years old, the patient had a history of metastatic calcification of the soft tissues suggesting hyperphosphatemic pseudotumoral calcinosis. Despite treatment for a long time with phosphate binders the metastatic calcinosis had to be removed with several surgeries. The patient had also a history of recurrent fever associated with pain localized toward the two masses and underwent multiple antibiotic courses. Laboratory findings at admission confirmed nephrotic syndrome. S-creatinine was 2.8 mg/dl. Calcium was 8.4 mg/dl, Phosphorus 8.2 mg/dl, PTH 80 pg/ml, 25 (OH)VitD 8 ng/ml. Serum amyloid A was slightly increased. We performed renal biopsy and we found AA amyloid deposits involving the mesangium and the tubules. The bone marrow biopsy revealed the presence of AA amyloid in the vascular walls. During the next two months renal failure rapidly progressed and the patient started hemodialysis treatment. We performed genetic analysis that confirmed homozygous mutation of the FGF23 gene. After 14 months on hemodialysis, the patient's lesions are remarkably and significantly reduced in dimension. The current phosphate binder therapy is based on sevelamer and lanthanum carbonate. Serum amyloid A is persistently slightly increased as well as C reactive protein. Proteinuria is in the nephrotic range without nephrotic syndrome.

Survival and time-to-transplantation of peritoneal dialysis versus hemodialysis for end-stage renal disease patients: competing-risks regression model in a single Italian center experience.

AIMS: Despite several studies reporting similar outcomes for peritoneal dialysis (PD) and hemodialysis (HD), the former is underused worldwide, with a PD prevalence of 15% in Italy. In 2008, the Unit of Nephrology and Dialysis of the Healthcare Trust of the Autonomous Province of Trento implemented a successful PD program which has increased the proportion of PD incident patients from 7 to 47%. We aimed to assess the effect of this extensive use of PD by comparing HD and PD in terms of survival and time-to-transplantation. METHODS: A total of 334 HD and 153 PD incident patients were enrolled between January 2008 and December 2014. After screening for exclusion criteria and propensity score matching, 279 HD and 132 PD patients were analyzed. Survival and time-to-transplantation were assessed by competing-risks regression models, using death and transplantation as primary and competing events. RESULTS: Crude and adjusted regression models for survival revealed the absence of significant differences between HD and PD cumulative incidence functions (subhazard ratio: 1.09, p = 0.62 and 1.34, p = 0.10, respectively). Differently, crude and adjusted regression models for transplantation revealed a lower time-to-transplantation for PD versus HD patients (subhazard ratio: 2.34, p < 0.01, and 2.57, p < 0.01, respectively). The waiting time for placement in the transplant waiting list was longer in HD than PD patients (330 vs. 224 days, p < 0.01). CONCLUSIONS: The extensive use of PD did not lead to any statistically significant difference in mortality. Furthermore, PD was associated with lower time to transplantation. PD may be a viable option for large-scale dialytic treatment in the advanced chronic kidney disease population.

[Genetics and nosological classification of renal cystic diseases]. / Genetica e nosografia delle malattie renali cistiche.

Renal cystic diseases are the major group of inherited renal disorders in humans and a leading cause of end-stage renal disease. Dominant and recessive polycystic kidney disease (ADPKD and ARPKD, respectively) account for most of the clinical conditions. However, nephronophthisis (NPHP), medullary cystic kidney disease (MCKD), and dominant glomerulocystic kidney disease (GCKD) still have a relevant clinical impact, particularly in children. The discovery that the proteins that are defective in ADPKD and ARPKD localize to the primary cilium and the recognition of the role of this organelle in cystogenesis have led to the term ''ciliopathies''. In the last decade, the list of ciliopathies has continued to grow. Analysis of the protein products of the nine NPHP genes (NPHP 1-9) evinced a strong relation between ciliary function and pathogenesis of NPHP. The oral-facial-digital syndrome (OFD) type I, characterized by congenital malformations and cystic kidney disease, was found to result from mutations in the OFD1 gene, which encodes a protein located to the primary cilium. Parallel to these advances, mutations in UMOD, the gene encoding uromodulin, were identified in pedigrees with MCKD2, familial juvenile hyperuricemic nephropathy, and autosomal dominant GCKD. In all these disorders, uromodulin was found to be accumulating in intracellular aggregates, suggesting a common pathogenesis. Taken together, these findings suggest the need for the separation of renal cystic diseases due to UMOD mutations (uromodulin-associated diseases) from renal cystic diseases related to mutation of genes encoding for proteins expressed in the primary cilium (ciliopathies).

Cost-benefit analysis of supplemented very low-protein diet versus dialysis in elderly CKD5 patients.

BACKGROUND: Dialysis increases patient life expectancy but is associated with clinically severe and costly complications. Health and economic benefits could derive from postponing dialysis with a supplemented very low-protein diet (sVLPD). METHODS: An economic evaluation was conducted to compare benefits and costs of sVLPD versus dialysis in elderly CKD5 patients. Data from 57 patients aged >or=70 years, with glomerular filtration rate (GFR) 5-7 mL/min, previously participating in a clinical trial demonstrating non-inferior mortality and morbidity of starting sVLPD compared to dialysis treatment, were analysed: 30 patients were randomized to dialysis and 27 to sVLPD. A cost-benefit analysis was conducted, in the perspective of the National Health Service (NHS). Direct medical and non-medical benefits and costs occurring in 3.2 mean years of follow-up were quantified: time free from dialysis, cost of dialysis treatment, hospitalization, drugs, laboratory/instrumental tests, medical visits and travel and energy consumption to receive dialysis. Prices/tariffs valid in 2007 were used, with an annual discount rate of 5% applied to benefits and costs occurring after the first year. Sensitivity analyses were conducted to identify how estimates could vary in different contexts of applications. Results are reported as net benefit, expressed as mean euro/patient (patient-year). RESULTS: The opportunity to safely postpone initiation of dialysis of 1 year/patient on average translated into an economic benefit to the NHS, corresponding to 21 180 euro/patient in the first, 6500 euro/patient in the second and 682 euro/patient in the third year of treatment, with a significant net benefit in favour of sVLPD even in a worst-case hypothesis. CONCLUSION: The initiation of sVLPD in elderly CKD5 subjects is a safe and beneficial strategy for these patients and allows them to gain economic resources that can be allocated to further health care investments.

[Atheroembolic renal disease: a diagnostic challenge]. / La malattia renale ateroembolica: una sfida diagnostica.

Atheroembolic renal disease is a part of a multisystem disease and can be defined as renal failure secondary to the occlusion of renal arterioles and glomerular capillaries with cholesterol crystal emboli deriving from the aorta and other major arteries. The kidney is usually involved because of the proximity of the renal arteries to abdominal aorta (where the erosion of atheromatous plaque is most likely to occur), and the high renal blood flow. Cholesterol crystal embolism can also occur in other visceral organs, as well as in the upper and lower extremities. Embolization may occur spontaneously or after angiographic and surgical procedures, and anticoagulation. Atheroembolic renal disease is an important yet underdiagnosed component of the spectrum of kidney diseases associated with atherosclerosis and remains an unexplored field of nephrology research.

Cholesterol crystal embolism (atheroembolism).

Cholesterol crystal embolism, known as atheroembolic disease, is caused by showers of cholesterol crystals from an atherosclerotic plaque that occludes small arteries. Embolization can occur spontaneously or as an iatrogenic complication from an invasive vascular procedure (angiography or vascular surgery) and after anticoagulant therapy. The atheroembolism can give rise to different degrees of renal impairment. Some patients show a moderate loss of renal function, others severe renal failure requiring dialysis. Renal outcome can be variable: some patients deteriorate or remain on dialysis, some improve and some remain with chronic renal impairment. Clinically, three types of atheroembolic renal disease have been described: acute, subacute or chronic. More frequently a progressive loss of renal function occurs over weeks. Atheroembolization can involve the skin, gastrointestinal system and central nervous system. The diagnosis is difficult and controversial for the protean extrarenal manifestations. In the past, the diagnosis was often made post-mortem. In the last 10 yrs, awareness of atheroembolic renal disease has improved. The correct diagnosis requires the clinician to be alert. The typical patient is a white male aged >60 yrs with a history of hypertension, smoking and arterial disease. The presence of a classic triad (precipitating event, renal failure and peripheral cholesterol crystal embolization) suggests the diagnosis. This can be confirmed by a biopsy of the target organs. A specific treatment is lacking; however, it is an important diagnosis to make because an aggressive therapeutic approach can be associated with a more favorable clinical outcome.

Access site-related infection in dialysis: the AStRID project: a multicenter prospective Italian study.

A multicenter prospective study has been planned, in a large sample of Italian end-stage renal disease (ESRD) patients, aiming to assess the vascular access (VA) site-related infection rates and to identify variables associated with them. All ESRD patients undergoing chronic hemodialysis (HD) in the participating centers will be enrolled in the study. Participating centers were selected on a voluntary basis. Patients will be enrolled within an 18-month recruitment period. Primary study end points are the overall incidence rate of VA-related infections in ESRD patients on chronic HD (defined as infection episodes/100 patient-months), and the incidence rate of different types of VA-related infections (exit site, tunnel and bacteraemia/sepsis). All VA types in use will be evaluated: fistula, graft, tunneled (permanent) central venous catheter (CVC) and temporary CVC.