Humoral and cellular response after BNT162b2 vaccine booster in hemodialysis patients and kidney transplant recipients.

BACKGROUND: Vulnerable populations, such as hemodialysis (HD) patients and kidney transplant (RTx) recipients, have priority for anti-COVID-19 vaccination, because of their impaired immune status. Here, we investigated the immune response after vaccination with BNT162b2 (two doses plus booster) in HD and RTx patients. METHODS: A prospective, observational study was started in two homogeneous groups of 55 HD and 51 RTx patients previously matched from a cohort of 336 patients. Anti-RBD IgG levels, assayed after the second dose with BNT162b2 mRNA, were used to stratify subjects into quintiles. After the second dose and after booster, anti-RBD and IGRA test were evaluated in RTx and HD, belonging to the first and fifth quintiles. RESULTS: After the second dose of vaccine, the median circulating levels of anti-RBD IgG were significantly higher in HD (1456 AU/mL) compared to RTx (27.30 AU/mL). IGRA test showed significantly higher values in the HD (382 mIU/mL) compared with the RTx (73 mIU/mL). After the booster, humoral response increased significantly in both HD (p = 0.0002) and RTx groups (p = 0.009), whereas the T-cellular immunity remained essentially stable in most patients. In RTx patients with a low humoral response after the second dose, the third dose did not significantly strengthen either humoral or cellular immunity. CONCLUSIONS: For HD and RTx, there is great variability in the humoral response to anti-COVID-19 vaccination, with a stronger response in the HD group. The booster dose was ineffective at reinforcing the humoral and cellular immune response in most RTx patients hyporesponsive to the second dose.

Vitamin D in patients with chronic kidney disease: a position statement of the Working Group "Trace Elements and Mineral Metabolism" of the Italian Society of Nephrology.

In the late 1970s, calcitriol was introduced into clinical practice for the management of secondary renal hyperparathyroidism in chronic kidney disease (CKD). Since then, the use of calcifediol or other native forms of vitamin D was largely ignored until the publication of the 2009 Kidney Disease Improving Global Outcomes (KDIGO) recommendations. The guidelines suggested that measurement of circulating levels of 25(OH)D (calcifediol) and its supplementation were to be performed on the same basis as for the general population. This indication was based on the fact that the precursors of active vitamin D had provided to CKD patients considerable benefits in survival, mainly due to their pleiotropic effects on the cardiovascular system. However, despite the long-term use of various classes of vitamin D in CKD, a clear definition is still lacking concerning the most appropriate time for initiation of therapy, the best compound to prescribe (active metabolites or analogs), the proper dosage, and the most suitable duration of therapy. The aim of this position statement is to provide and critically appraise the current plentiful evidence on vitamin D in different clinical settings related to CKD, particularly focusing on outcomes, monitoring and treatment-associated risks. However, it should be taken in account that position statements are meant to provide guidance; therefore, they are not to be considered prescriptive for all patients and, importantly, they cannot replace the judgment of clinicians.

Impact of BMI on cardiovascular events, renal function, and coronary artery calcification.

BACKGROUND/AIMS: High BMI increases the risk of cardiovascular events (CVEs) in the general population. Conflicting results have been reported on the role of BMI on CVEs and on decline of renal function in patients with chronic kidney disease not on dialysis (CKD). This study evaluates the impact of BMI on CVEs, dialysis initiation, and coronary artery calcification (CAC) in CKD patients. METHODS: CKD patients were divided in normal-BMI and high-BMI patients. CVEs, initiation of dialysis, and extent and progression of CAC were assessed. Univariate and multivariable analysis were performed (adjustment variables: age, diabetes, hypertension, gender, CKD stage, serum concentration of hemoglobin, parathyroid hormone, calcium, phosphorus, albumin, C-reactive protein, LDL-cholesterol, total calcium score, 24-hour proteinuria). Patients were followed to the first event (CVE, dialysis) or for 2 years. RESULTS: 471 patients were evaluated. A CVE occurred in 13.5 and 21.3% (p < 0.05) of normal-BMI and high-BMI patients, respectively. High BMI did not increase the risk for CVEs in univariate (HR: 1.86; 95% CI: 0.97-3.54; p = 0.06) or multivariable analysis (HR: 1.36; 95% CI: 0.57-3.14; p = 0.50). High BMI did not increase the risk for initiation of dialysis in univariate (HR: 0.96; 95% CI: 0.58-1.60; p = 0.9) or multivariable analysis (HR: 1.77; 95% CI: 0.82-3.81; p = 0.14). Adding the interaction term (between BMI and glomerular filtration rate) to other variables, the risk of dialysis initiation significantly increased (HR: 3.06; 95% CI: 1.31-7.18; p = 0.01) in high-BMI patients. High BMI was not a predictor of CAC extent or progression. CONCLUSIONS: High BMI was not a predictor of CVEs. High BMI increased the risk for dialysis initiation, but high BMI was not associated to CAC extent and progression. The presence of confounders may underestimate the impact of high BMI on dialysis initiation.

What can we learn from a statistically inconclusive trial? Consensus conference on the EVOLVE study results.

The link between serum parathyroid hormone (iPTH) and cardiovascular (CVS) mortality has not been fully elucidated. The EVOLVE Study was designed to test whether a drug such as cinacalcet, aimed at lowering iPTH, could reduce the astonishingly high cardiovascular risk in patients on maintenance dialysis (CKD-5D). Accordingly, the primary outcome of the study was the combined endpoint of time to death or hospitalization due to CVS factors or from any cause. Time to bone fracture and parathyroidectomy were regarded as secondary endpoints. At study completion, the Intention-To-Treat analysis documented a non- significant 7% (Hazard Ratio: 0.93; 95% Confidence interval: 0.85-1.02; P = 0.11) reduction of the primary composite endpoint. However, the intention to treat analysis does not take into account adherence to drug regimens or control for factors that may potentially jeopardize the conduction of the study. In particular, in spite of a careful pre-planned study sample calculation, the final power of the EVOLVE study was 54% instead of the assumed 90%, greatly reducing the reliability of study results. Furthermore, the pre-planned multivariable adjustment of the primary endpoint suggests a nominally significant reduction of the risk of the primary composite endpoint when age is entered into the statistical model. The sensitivity analysis further corroborates this result. The Lag Time Censoring Analysis (LTCA) evidenced a nominally significant 15% risk reduction of the composite endpoint among patients allocated to cinacalcet if the patients follow-up was terminated 6 months after the study drug discontinuation, as pre-planned in the protocol. It is interesting that the LTCA suggests that the effect of cinacalcet weakened over time and became insignificant after about 1 year from drug discontinuation. Although authors could not detect any effect of cinacalcet on bone fracture associated with cinacalcet use, the secondary analyses of the EVOLVE trial suggest a nominally significant 60-70% risk reduction of parathyroidectomy and a reassuring safety profile of prolonged exposure to cinacalcet. In summary, the EVOLVE study adds to the list of inconclusive randomized clinical trials in Nephrology. However, the preplanned exploratory and sensitivity analyses suggest that when imbalances of patients characteristics at study entry (i.e. age) or study drug discontinuation are considered, a 'nominally' significant risk reduction in CVS and parathyroidectomy associated with cinacalcet treatment is noted.

Uric acid: a starring role in the intricate scenario of metabolic syndrome with cardio-renal damage?

Elevated uric acid levels are a common finding in patients with metabolic syndrome and in those with cardiovascular and renal disease, but the meaning of this elevation is still unclear. In patients with chronic kidney diseases, it could merely reflect the reduction in glomerular filtration rate: but uric acid levels are known to be elevated in people, also in younger ones, prior to the development of hypertension or renal disease, independently of several risk factors. Multiple potential mechanisms suggest a causative role for uric acid in vascular disease. Uric acid has been shown to be involved in metabolic pathways that lead to oxidative stress, endothelial disfunction, and to a vascular and systemic inflammatory response. Moreover, the elevation in uric acid levels observed after fructose ingestion, with a consequent reduction in nitric oxide, may lead to a reduced glucose uptake in the skeletal muscle, hyperinsulinemia, and insulin resistance. Besides these bench research data, also clinical studies showed the beneficial effects of lowering uric acid therapies on several markers of cardiovascular and renal disease. To date, however, there is no evidence indicating that such therapies, that are not free of risk, may reduce cardiovascular events; so that to manage our prescriptions, we need larger, prospective, interventional data.

Diagnostic Workup for Disorders of Bone and Mineral Metabolism in Patients with Chronic Kidney Disease in the Era of KDIGO Guidelines.

KDIGO (KIDNEY DISEASE: Improving Global Outcomes) is an international nonprofit organization devoted to "improve the care and outcomes of kidney disease patients worldwide through promoting coordination, collaboration, and integration of initiatives to develop and implement clinical practice guidelines." The mineral and bone disorder (MBD) in patients with chronic kidney disease (CKD) has been the first area of interest of KDIGO international initiative. KDIGO guidelines on CKD-MBD were published in 2009 with the intent to modify the previous KDOQI guidelines that had failed to consistently change the global outcome of CKD patients. After the publication of KDOQI guidelines for bone metabolism and disease in 2003, a large number of observational data emerged in literature linking disordered mineral metabolism with adverse clinical outcomes. Notwithstanding this large body of observational data, a paucity of evidence from high-quality clinical trials was available for the development of KDIGO guidelines. Herein, a summary will be provided of the most important findings of KDIGO guidelines regarding the diagnostic workup and clinical monitoring of CKD-MBD patients.

Variability of pulse wave velocity and mortality in chronic hemodialysis patients.

We have already demonstrated that in chronic hemodialysis (HD) patients, the cyclic variations in both hydration status and blood pressure are responsible for changes in pulse wave velocity (PWV). The aim of this study is to verify whether the cyclic variation of PWV influences mortality in dialysis patients. We studied 167 oligoanuric (urinary output <500 mL/day) patients on chronic standard bicarbonate HD for at least 6 months. They performed 3 HD sessions of 4 hours per week. Patients were classified into 3 groups: normal PWV before and after dialysis (LL); high PWV before and normal PWV after dialysis (HL); and high PWV before and after dialysis (HH). The carotid-femoral PWV was measured with an automated system using the foot-to-foot method. Analysis of variance was used to compare the different groups. The outcome event studied was all-cause mortality and cardiovascular mortality. The PWV values observed were LL in 44 patients (26.3%); HL in 53 patients (31.8%); and HH in 70 patients (41.9%). The 3 groups of patients are homogenous for sex, age, and blood pressure. The HH group had a higher prevalence of (P<0.001) ASCVD. It is interesting that the distribution of patients in the 3 groups is correlated with the basal value of PWV. In fact, when the basal measure of PWV is elevated, there is a higher probability that an HD session cannot reduce PWV (<12 ms). A total of 53 patients (31.7%) died during the follow-up of 2 years: 5 patients in the LL group (11.4%); 16 in the HL group (30.2%); and 32 in the HH group (50.7%) (LL vs. HL, P=0.047; LL vs. HH, P<0.00001; HL vs. HH, P=0.034). We evidence for the first time that different behaviors of PWV in dialysis subjects determine differences in mortality.

Interaction between parathyroid hormone and the Charlson comorbidity index on survival of incident haemodialysis patients.

BACKGROUND: Haemodialysis patients are ageing and have with a high rate of comorbidities. The impact of this novel clinical setting on intact parathyroid hormone (iPTH) is not well established. METHODS: For this observational, prospective multicentre cohort study, incident haemodialysis patients were recruited in 40 Italian centres and followed up for a mean period of 18 +/- 6.7 months. Clinical characteristics and biochemistry were recorded at baseline. Comorbid conditions were scored by the Charlson comorbidity index (CCI). RESULTS: Data of 411 patients (mean age: 66.5 +/- 14.8 years; 17.3% >80 years old) were recorded. The mean CCI was 4.17 +/- 2.8. In patients with CCI >0, an inverse correlation was observed between CCI (excluding age) and iPTH (P = 0.00002). Independently of CCI, patients with iPTH <150 pg/ml had 76% as high as the risk of all-cause mortality. After multivariable adjustment, the combination of the first tertile of iPTH with second and third tertiles of CCI was significantly associated with all-cause mortality (RR = 3.83, P = 0.02; RR = 3.79, P = 0.01, respectively). CONCLUSIONS: Incident haemodialysis patients suffer from a high rate of clinical complications. In these patients, low iPTH and high CCI are often associated and very likely responsible for an adverse outcome.

Application of a combined protocol for rational request and utilization of antibody assays improves clinical diagnostic efficacy in autoimmune rheumatic disease.

CONTEXT: Because of a marked increase in the number of requests for antinuclear antibodies, anti-extractable nuclear antigen antibodies, and anti-double-stranded DNA antibodies for the diagnosis of autoimmune rheumatic disease, guidelines have been proposed for their appropriate use. OBJECTIVE: To evaluate in terms of clinical efficacy and cost-benefit ratio the outcome of applying a protocol for the diagnosis of autoimmune rheumatic disease. DESIGN: A diagnostic protocol for the rational utilization of second-level tests (anti-extractable nuclear antigen antibodies and anti-double-stranded DNA antibodies) was applied at Hospital Polyclinic beginning January 2004. The appropriateness of 685 consecutive requests received at the clinical pathology laboratory from January to June 2004 was assessed. Patients who underwent these laboratory tests were followed up for 12 months after blood sample drawing. RESULTS: Introduction of the protocol led to a significant reduction in the number of second-level tests prescribed (27.9% vs 49.5% for anti-extractable nuclear antigen antibodies; 27.5% vs 56.6% for anti-double-stranded DNA antibodies). After the period of observation, none of the 163 patients who had negative results on the first-level test and were asymptomatic, for whom second-level tests had not therefore been performed, were found to have autoimmune rheumatic disease. In 90.5% (77/85) of patients positive for the second-level tests, clinical confirmation of autoimmune rheumatic disease was obtained. CONCLUSIONS: Not only did application of the diagnostic protocol reduce the number of second-level tests performed but it also increased their specificity. Our data thus indicate that the use of shared guidelines by clinical and laboratory specialists yields satisfactory results.

Kinetics of the circulating levels of bone alkaline phosphatase in a case of hungry bone disease following total parathyroidectomy.

We present the case of a 55-year-old patient who underwent total parathyroidectomy for severe hyperparathyroidism unresponsive to medical therapy, 4 years after having started hemodialysis treatment. It was decided to perform total parathyroidectomy because at macroscopic evaluation the parathyroid glands appeared completely compromised. After surgery, the patient developed hungry bone disease, characterized by severe hypocalcemia and hypophosphatemia. After parathyroidectomy, serial measurements were made for the long-term monitoring of the calcemia, phosphatemia and the serum levels of intact parathormone and bone alkaline phosphatase, a marker of bone turnover that mainly expresses bone formation. There was initially a slight decrease in the circulating levels of bone alkaline phosphatase as the calcemia dropped dramatically, then a new increase that anticipated the subsequent calcemia increase and finally, 6 months later, a decrease to very low values. We believe that the calcemia and blood bone alkaline phosphatase could be useful for the laboratory monitoring of the hungry bone state, providing information which may be useful to avoid excessive calcium administration and the dangerous consequences such as soft-tissue calcification.

The Italian experience of the national registry of renal biopsies.

BACKGROUND: Although several registries collecting data of patients with kidney diseases exist, there are only a few registries which specifically collect data relating to renal biopsy; one such registry is the Italian Registry of Renal Biopsies (IRRB). The aim of this study was to report on the relative frequency of nephropathies according to gender, age at time of biopsy, clinical presentation and renal function, based on the histologic diagnosis during the years 1996 to 2000. METHODS: We evaluated data relating to 14607 renal biopsies, provided by 128 renal units in Italy. Data entry was performed by using the Internet-based database directly (URL http://www.irrb.net). Clinical presentation was defined as urinary abnormalities (UA), nephrotic syndrome (NS), acute nephritic syndrome (ANS). Renal diseases were divided in four major categories: (1) primary glomerulonephritides (GN); (2) secondary GN; (3) tubulointerstitial nephropathies (TIN); and (4) vascular nephropathies (VN). RESULTS: Primary GN, TIN, and VN were more frequent in males compared to females while secondary GN was more frequent in females. Diseases whose frequency was higher in males were IgA nephropathy (IgAN), benign nephroangiosclerosis (BNA), and acute tubular necrosis (ATN). A significantly higher frequency of immune-mediated secondary GN, as well as primary GN, including minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), and mesangiocapillary GN (MCGN), was shown in females. Primary and secondary GN, TIN, and VN were more frequent in the range 15 to 65 years of age. At the time of biopsy 77% of primary GN and 61% of secondary GN presented with normal renal function. Acute renal failure (ACR) was more present in TIN (52%), while chronic renal failure (CRF) was more frequent in VN (47%). CONCLUSION: We believe collection of data relating to renal biopsies in a national registry is a useful tool for nephrologists in that it meets one of the current challenges facing the clinical research enterprise. The availability of these data will allow epidemiologic studies in health care to answer the several open questions in both prevention and treatment of renal diseases.