New-Onset Anemia and Associated Risk of ESKD and Death in Non-Dialysis CKD Patients: A Multi-Cohort Observational Study

Background

Anemia is a common complication of chronic kidney disease (CKD), but its incidence in nephrology settings is poorly investigated. Similarly, the risks of adverse outcomes associated with new-onset anemia are not known.

Methods

We performed a pooled analysis of three observational cohort studies including 1031 non-anemic CKD patients with eGFR <60 mL/min/1.73 m² regularly followed in renal clinics. We estimated the incidence of mild anemia (hemoglobin 11–12 g/dL in women and 11–13 g/dL in men) and severe anemia (hemoglobin <11 g/dL or use of erythropoiesis-stimulating agents) during a 3-year follow-up period. Thereafter we estimated the risk of end-stage kidney disease (ESKD) and all-cause death associated with new-onset mild and severe anemia.

Results

The mean age was 63 ± 14 years, 60% were men and 20% had diabetes. The mean estimated glomerular filtration rate (eGFR) was 37 ± 13 mL/min/1.73 m² and the median proteinuria was 0.4 g/day [interquartile range (IQR) 0.1–1.1]. The incidence of mild and severe anemia was 13.7/100 patients-year and 6.2/100 patients-year, respectively. Basal predictors of either mild or severe anemia were diabetes, lower hemoglobin, higher serum phosphate, eGFR <30 mL/min/1.73 m² and proteinuria >0.50 g/day. Male sex, moderate CKD (eGFR 30–44 mL/min/1.73 m²) and moderate proteinuria (0.15–0.50 g/day) predicted only mild anemia. The incidence of anemia increased progressively with CKD stages (from 8.77 to 76.59/100 patients-year) and the proteinuria category (from 13.99 to 25.02/100 patients-year). During a median follow-up of 3.1 years, 232 patients reached ESKD and 135 died. Compared with non-anemic patients, mild anemia was associated with a higher adjusted risk of ESKD {hazard ratio [HR] 1.42 [95% confidence interval (CI) 1.02–1.98]} and all-cause death [HR 1.55 (95% CI 1.04–2.32)]. Severe anemia was associated with an even higher risk of ESKD [HR 1.73 (95% CI 1.20–2.51)] and death [HR 1.83 (95% CI 1.05–3.19)].

Conclusions

New-onset anemia is frequent, particularly in patients with more severe renal damage and in those with diabetes mellitus. The occurrence of anemia, even of a mild degree, is associated with mortality risk and faster progression towards ESKD.

A Modified Two-Bun Method for Routine Urea Modeling: Clinical Validation in 120 Patients on a Free Diet

Recently, a modified algorithm of the Two-BUN method (MA2p), avoiding dialyzer clearance measurement, was presented for routine assessment of Kt/V and NPCR. To validate MA2p in patients on a free diet (FDP), we studied 120 stable dialysis FDP by measuring Kt/V and NPCR with both MA2p and a modified version of the standard Three-BUN method (MA3p), for the 3 weekly sessions. The NPCR values (g/kg/day), calculated by MA3p for the 3 interdialyses were: 1.286∓0.274, 1.256∓0.276, and 1.116∓0.230, respectively. The correlation coefficient (r) for averaged Kt/V values obtained by the two methods was 0.999 and the percent error (Error%) for MA2p vs. MA3p results ranged from -1.5 to +0.78%. The respective results for NPCR were: r=0.967, Error% range from -11.7 to +13.9%. In conclusion, MA2p can be safely used in patients on a free diet. The lowest NPCR values were observed during the long interdialysis.

Global approach to cardiovascular risk in chronic kidney disease: reality and opportunities for intervention

The current implementation into nephrology clinical practice of guidelines on treatment of cardiovascular (CV) risk factors in chronic kidney disease (CKD) is unknown. We designed a cross-sectional analysis to evaluate the prevalence and treatment of eight modifiable CV risk factors in 1058 predialysis CKD patients (stage 3: n=486; stage 4: n=430, stage 5: n=142) followed for at least 1 year in 26 Italian renal clinics. The median nephrology follow-up was 37 months (range: 12-391 months). From stages 3 to 5, hypertension was the main complication (89, 87, and 87%), whereas smoking, high calcium-phosphate product and malnutrition were uncommon. The prevalence of proteinuria (25, 38, and 58%), anemia (16, 32, and 51%) and left ventricular hypertrophy (51, 55, and 64%) significantly increased, while hypercholesterolemia was less frequent in stage 5 (49%) than in stages 4 and 3 (59%). The vast majority of patients received multidrug antihypertensive therapy including inhibitors of renin-angiotensin system; conversely, diuretic treatment was consistently inadequate for both frequency and dose despite scarce implementation of low salt diet (19%). Statins were not prescribed in most hypercholesterolemics (78%), and epoietin treatment was largely overlooked in anemics (78%). The adjusted risk for having a higher number of uncontrolled risk factors rose in the presence of diabetes (odds ratio 1.29, 95% confidence interval 1.00-1.66), history of CV disease (odds ratio 1.48, 95% confidence interval 1.15-1.90) and CKD stages 4 and 5 (odds ratio 1.75, 95% confidence interval 1.37-2.22 and odds ratio 2.85, 95% confidence interval 2.01-4.04, respectively). In the tertiary care of CKD, treatment of hypertension is largely inadequate, whereas therapy of anemia and dyslipidemia is frequently omitted. The risk of not achieving therapeutic targets is higher in patients with diabetes, CV disease and more advanced CKD.

[Census 2004 of the Italian renal and dialysis units. Basilicata - Calabria - Puglia]

The Italian Society of Nephrology (SIN) sponsored in 2004 a National Census of the Italian renal and dialysis units. This paper presents the main structural, technical, organizational features, as well as the human resources and the activities of three South-East regions of Italy: Basilicata (B), Calabria (C), and Puglia (P).

EPIDEMIOLOGY

incidence of dialysis patients was 149 per million population (pmp) in B, 134 pmp in C and 172 pmp in P; prevalence of dialysis patients 729, 694 and 886 pmp, respectively; prevalence of transplanted patients 188 in B, 264 in C and 249 pmp in P; gross mortality rate of dialysis patients was 12.7% (B), 12.2% (C) and 10.8% (P).

TYPE OF VASCULAR ACCESS IN PREVALENT DIALYSIS PATIENTS

arteriovenous fistula: 83.9% (B), 87.7% (C) and 86.5% (P); central venous catheter: 14.2% (B), 8.4% (C) and 11.2% (P); vascular graft 1.9% (B), 3.9% (C) and 2.3% (P).

STRUCTURAL RESOURCES

nephrological beds 37, 34 and 88 pmp, respectively; dialysis stations 265, 209 and 207 pmp.

PERSONNEL RESOURCES

renal physicians 45 (B), 67 (C) and 64(P) pmp; renal nurses 189, 190 and 207 pmp; each nephrologist cares for 16 (B), 10 (C) and 14 (P) dialysis patients, whereas each renal nurse takes care of 3.8 (B), 3.7 (C) and 4.3 (P) dialysis patients.

ACTIVITY

hospitalizations 1378, 1834 and 3439 pmp, respectively; renal biopsies 40 (B), 64 (C) and 107 (P) pmp. The main goal of this project was to create a reference for benchmarking studies. Therefore, data from the Puglia region were compared to data from other regions with similar population size (such as Piemonte and Emilia-Romagna). Moreover, a Census may became a useful qualitative tool for renal registries: this report compares data from the Census with data collected by the dialysis and transplantation registry of the Puglia region. Generally speaking, prevalence for Basilicata and Calabria is close to the Italian one, whereas incidence is inferior; things are opposite in Puglia. Furthermore, compared to Basilicata, Calabria and Italy on average, the Puglia region shows a significant higher number of in-patient beds and a lower DRG weight. Compared to Piemonte, Emilia Romagna and Italy on average, all the three South-East regions do not show differences in number/pmp of dialysis centres. More physicians (nephrologists = 80%) are reported to be active in Puglia and Calabria, compared to Piemonte and Emilia Romagna. Nurses in Puglia look after a greater number of dialysis patients than in Calabria and Basilicata. The number of renal biopsies/ pmp is similar to the Italian mean only in Puglia; it is inferior in the other two regions. These data highlight many differences among these three South-East regions, as well as among Piemonte, Emilia Romagna and Puglia. A relevant inequality in health care structures and resources has been found and discussed.

[Update of the Italian Society of Nephrology Project No. 1 of the 2004-2006 SIN programme]

In the last few years the Italian Society of Nephrology has addressed many technical-scientific and management aspects to better patient satisfaction. Project No. 1 of the 2004-2006 programme on 'Quality and Accreditation of National Renal Units' focuses on four essential points. The first is the questionnaire mailed to all the Presidents and Regional Delegates on the relationship between Nephrology units, Local Government Health-System and the Regional Healthcare Agency. The results evidence that the 'political' decision-making power of nephrologists decreases in the absence of a national strategy. The second point, in collaboration with the National Census Group, includes the quality analysis and the standardization of resources (human and structural) and management of the Renal Units. The third point is based on 'Educational Courses for Quality and Accreditation' held in Rome (3-5 October 2005: L'Accreditamento all'Eccellenza dell'Unita' Operativa di Nefrologia, Dialisi e Trapianto; 17-19 October 2005: Il Manuale di Accreditamento della Specialità di Nefrologia). The courses aim at training members responsible for each region to hold courses in their specific region to create a network including each single Renal Unit to create an acceptable homogenous language on the models of analysis and on the correct use of 'The Guide for Excellence Accreditation'. The fourth point concerns both the on-line Guide for Excellence Accreditation and 'Peer Review Accreditation' and the NEQUASY (Nephrology Quality System) project. The manual must be 'user friendly' allowing each Centre to self-evaluate using national and regional standards.

[Standardization criteria to ensure the uniformity of data collection by the Italian Registry of Dialysis and Transplantation]

The Italian Registry of Dialysis and Transplantation (RIDT) collects data concerning patients in renal replacement therapy (RRT) sent from Regional Registries. Until 2003, the data were sent in summary tables. From 2004, each region has been sending patient data as single non-summarized forms (i.e. one record for each patient). This paper summarizes the collection criteria and the ideal method to codify data ensuring that data sent to the RIDT are consistent. This standardization process is necessary to ensure the statistical analyzability of the data and their comparability with data from other registries. Moreover, the standardization process is the initial step in allowing the RIDT to obtain clinical data to transform the registry from an epidemiological registry to a clinical governance instrument.

[Italian Registry of Dialysis and Transplantation: 1996-2001 experience]

The Italian Registry of Dialysis and Transplantation (RIDT) was born in 1996 under the aegis of the Italian Society of Nephrology, and it is organized as a federation of regional registries. This study aimed to completely revise the epidemiological data collected during the first 5 yrs (1996-2001) of RIDT activity to evaluate the trends of the main epidemiological features. During this period, regional registries were not always able to assure complete and exhaustive information according to RIDT requirements, owing to different levels of organization and functioning. To avoid any possible error in data analysis, information inadequately assessed was refused. The incidence of end-stage renal disease (ESRD) patients on renal replacement therapy (RRT) in Italy has increased from 114 pmp in 1996 to 139 pmp in 2001, that means an increase of 3.5%/yr, corresponding to 5718 patients during 1996 and 8000 patients during 2001. Primary renal diseases (according to the EDTA) in incident ESRD patients are vascular and diabetic nephropathy. Main dialysis modality in incident patients was hemodialysis (HD) (85%), while peritoneal dialysis (PD) was only 15%; pre-emptive transplantation was a very unusual modality. The prevalence of ESRD patients at 31 December was 693 pmp in 1996 and 827 pmp in 2001; among dialysis patients, the corresponding rates were 575 pmp and 657 pmp, respectively. Consequently, the number of dialyzed patients increased, respectively, from 28892 to 37919. The prevalent dialysis modality was bicarbonate dialysis in 74% of cases, followed by hemodiafiltration (HDF) in 15%, continuous ambulatory peritoneal dialysis (CAPD) in 7% and APD in 3%. The gross mortality rate in dialyzed patients was stable during this period, at approximately 14%, the main causes of death being cardiovascular diseases and cachexia.

Successful use of central venous catheter as permanent hemodialysis access: 84-month follow-Up in lucania

Cuffed tunneled venous access catheters are commonly used for temporary and permanent access in hemodialysis (HD) patients. These catheters serve an essential role in providing permanent access in subjects in whom all other access options have been exhausted. The predominant complications are catheter thrombosis, catheter fibrin sheating and infection. The aim of this study was to evaluate long-term survival and complications of permanent venous catheters (PVC) placed for the purpose of HD during the period from January 1992 to December 1998, at the Dialysis Units of Lucania (a southern Italian region). A total of 98 PVC were placed in 88 patients during this period. The catheters used were of three types: (a) 72 VasCath Soft Cell catheters (Bard Instrument Company, Toronto, Ont., Canada); (b) 22 PermCath catheters (Quinton Instrument Company, Seattle, Wash., USA), and (c) 4 Tesio catheters (Bellco SpA, Mirandola, Italy). Survival curves of catheters were calculated using the Kaplan-Meier product-limit estimator. The patient survival was 60% at the 78th month. Actually, 52 patients (27 males, 25 females) are still alive: 15 (26.9%) of these patients have diabetes mellitus and 1 has been transplanted. The actuarial survival rate of PVC was 89% in the whole population studied and 82% in subjects alive after 84 months. Twenty-five patients (28.4%) had PVC as the first reliable vascular access. Long-term complications occurred 27 times (1 episode every 44.81 month/patient) as: breakage (3.1%); thrombosis (10.2%); displacement (2.0%); subcutaneous tunnel bleeding (3.1%); inadequate blood flow (7.1%), and infection (10.2%). In conclusion, our data confirm that PVC might represent an effective long-term blood access route for HD. Again, PVC are getting the access of choice for selected patients (i.e., older subjects with cardiovascular diseases and cancer patients) and are enjoying a dramatic increase in use for subjects who are terrified of repetitive venopuncture.

Percent reduction in blood urea concentration during dialysis estimates Kt/V in a simple and accurate way

Urea Kt/V is an accurate tool to estimate the adequacy of hemodialysis (HD) therapy; however, the current methods of calculating Kt/V are too complex for routine clinical use and require great care in order to avoid major inaccuracies. As percent reduction in blood urea concentration during dialysis (PRU) is a function of dialyzer urea clearance, length of dialysis, and urea distribution volume of the patient, it might correlate with Kt/V. Thus, analyzing retrospectively data of 78 studies, we found that the following linear regression equation existed between Kt/V values calculated by means of direct dialysis quantification (DDQ) and PRU values: Kt/V = 0.023 x PRU - 0.284 (r = 0.92). Furthermore, a good correlation existed between Kt/V values measured both by means of DDQ and of the classical algorithm (CA) of the urea kinetic model (UKM) (r = 0.98). Then, a prospective study was started in which 145 Kt/V values calculated by means of the above equation were correlated with the corresponding ones computed by means of a modified algorithm (MA) of UKM, perfectly fitting those generated by CA of UKM. Although the relationship was exponential, it was linear in the clinically important range of PRU between 40% and 70%, corresponding to a Kt/V between 0.64 and 1.33. Furthermore, an excellent correlation (r = 0.96) and no statistically significant difference existed in this range between the two series.(ABSTRACT TRUNCATED AT 250 WORDS)