[Epidemiology of chronic kidney disease in Italy: current state and contribution of the CARHES study]

The epidemic dimensions of non-dialysis chronic kidney disease (CKD) and the associated elevated cardiovascular risk as well as the high costs of renal replacement therapy have made the identification of CKD patients and the quantification of CKD-related comorbidities a key priority in the strategies of public health agencies worldwide. Information on the CKD prevalence at a national level is still lacking in Italy, although these data are critical for planning preventive strategies and increasing the awareness of CKD as a major chronic disease. In 2008 the CARHES (CArdiovascular risk in Renal Patients of the Italian Health Examination Survey) study was started. The study - a joint venture between the Italian Society of Nephrology, the Italian Society of Cardiologists, and the National Health Institute-Cardiovascular Disease Prevention Project - will integrate the previously collected information on the cardiovascular risk profile of the adult Italian population provided by the Health Examination Survey (HES) with epidemiological data on CKD. The initial results on approximately half of the prospective sample of 9020 subjects aged 35-79 years suggest a lower CKD prevalence than that reported in other countries. The final results will allow to estimate the level of CKD in Italy and hopefully increase the awareness of this high-risk chronic disease among Italian physicians and health authorities.

[Amino acid loss during dialysis treatment]

Protein-calorie malnutrition is a widespread complication in hemodialysis (HD) patients and is associated with increased mortality. The pathogenesis of malnutrition is multifactorial. Intradialytic amino acid (AA) loss is considered one of the cofactors in the complex mechanisms that lead to malnutrition in HD patients. It has been documented that in each dialysis session there is a 6-8 gram loss of AA into the dialysate, which worsens with the use of high-flux membranes. The intradialytic AA loss is variably compensated by reduction of liver synthesis and increased AA release from muscle stores. In malnourished HD patients the serum AA concentration, especially branched-chain AA (BCAA), is correlated with nutritional status and anorexia, whereas BCAA supplementation improves the nutritional parameters and increases appetite. Further studies are necessary to clarify the role of alterations of AA metabolism in the pathogenesis of malnutrition and the potential beneficial effects of BCAA supplementation or alternative treatments in malnourished patients.

[Role of paracalcitol in the management of non-dialysis CKD: state of art and... Unmet needs]

Chronic kidney disease (CKD) is associated with a high risk of cardiovascular morbidity and mortality due to the high prevalence of traditional risk factors and the presence of factors specific to CKD. Vitamin D deficiency and secondary hyperparathyroidism are the earliest complications in CKD, and observational data show that low plasma vitamin D is an independent predictor of death in patients with CKD. Oral supplementation with active oral vitamin D appears to be associated with greater survival but a significant improvement in renal outcome has not been demonstrated, probably because of its unwanted side effects (increase in plasma calcium and phosphate levels). Oral paracalcitol, a new vitamin D receptor activator, is now available for CKD patients not yet on dialysis. It suppresses PTH with a low incidence of increased serum calcium and phosphate levels in patients treated with dialysis and when high doses are administered. Furthermore, recent data show that paracalcitol treatment in CKD patients also results in a significant reduction of albuminuria, which is a major risk factor for cardiorenal outcome. The antiproteinuric effect of paracalcitol appears to be the result of intrarenal suppression of the renin-angiotensin system (RAS). Therefore, paracalcitol may be mostly effective in reducing albuminuria in patients already treated with RAS inhibitors who show compensatory increments of RAS components. Studies in large patients series and with adequate follow-up are needed to evaluate the effects of long-term paracalcitol treatment in CKD and its potential role in improving renal outcome in comparison not only with placebo but also other vitamin D metabolites and analogues.

Effect of furosemide on left ventricular mass in non-dialysis chronic kidney disease patients: a randomized controlled trial

BACKGROUND

In chronic kidney disease (CKD), loop diuretics correct volume-dependent hypertension, but their effect on left ventricular mass index (LVMI) is unknown.

METHODS

Forty hypertensive CKD patients (estimated creatinine clearance 60-15 mL/min/1.73 m²), treated with renin-angiotensin system (RAS) inhibitors, were randomized to receive furosemide or non-diuretic antihypertensive treatment (control group). Office blood pressure (BP) < 130/80 mmHg was pursued in both groups. Primary end point was the reduction of LVMI after 52 weeks. Secondary aims were to verify safety related to furosemide treatment and its effects on ambulatory and clinic BP and body fluid volumes.

RESULTS

Office BP similarly declined in the furosemide group (from 161 ± 14/80 ± 10 to 139 ± 14/74 ± 8 mmHg) and in controls (from 159 ± 16/81 ± 10 to 137 ± 16/75 ± 10 mmHg). We detected a greater reduction (P = 0.013) of LVMI in patients receiving furosemide (-7.9, IQR from -15.8 to -1.4 g/h(2.7)) than in controls (0.0, IQR from -6.2 to + 9.5 g/h(2.7), P = 0.013). Bio-impedance analysis-derived extracellular water (ECW) significantly decreased in furosemide-treated patients (from 18.7 ± 3.9 to 17.7 ± 3.3 L) while remained unchanged in the control group (from 19.5 ± 2.2 to 19.6 ± 1.9 L). Absolute change of LVMI correlated with changes of ECW in furosemide-treated patients (r = 0.458, P = 0.042) but not in controls. In the furosemide group, no patient experienced side effects requiring drug withdrawal.

CONCLUSIONS

In hypertensive CKD patients treated with RAS inhibitors, add-on furosemide efficaciously reduces LVMI independently from BP changes. The effect is possibly mediated by better control of volume expansion.

Epidemiology of chronic kidney disease in Italy

Chronic kidney disease (CKD) is becoming a major public health problem worldwide. In Italy, only scarce and partial national data of prevalence have been obtained, from small-size cohorts in single settings not representative of the general Italian population. In this article, we review in detail the prevalence data obtained by the Gubbio study and the Italian Society of Nephrology - Health Search study, and describe the emerging problem of CKD definition in the elderly.

Anaemia management in non-dialysis chronic kidney disease: flexibility of target to target stability?

International clinical practice guidelines have recently recognized for the first time the concrete difficulty of keeping chronic kidney disease (CKD) patients within the narrow haemoglobin (Hb) target recommended of 11-12 g/dl (110-120 g/l) because of the variability of individual patient Hb levels. This emerging clinical problem has been the topic of several editorials that, however, exclusively focused on haemodialysis patients. Recently, 3 retrospective studies have been published on Hb variability in non-dialysis CKD. The studies which overall included more than 6,000 patients showed that Hb variability in non-dialysis CKD is greatly prevalent and is associated with a worse cardiorenal outcome. This minireview summarizes the results and limits of these studies and discusses the potential implications for clinical practice.

Prevalence and prognosis of mild anemia in non-dialysis chronic kidney disease: a prospective cohort study in outpatient renal clinics

BACKGROUND/AIMS

we evaluated prevalence and prognosis of mild anemia, defined as Hb (g/dl) 11-13.5 in males and 11-12 in females, in a prospective cohort of stage 3-5 chronic kidney disease (CKD) patients.

METHODS

we enrolled 668 consecutive patients in 25 renal clinics during 2003. Patients with frank anemia (Hb <11 or erythropoiesis-stimulating agents) at enrolment were excluded. Mild anemia was evaluated at two visits planned with an interval of 18 ± 6 months to identify four categories: no anemia at both visits, mild anemia at visit 1 resolving at visit 2 (RES), mild anemia persisting at both visits (PER), and progression from no anemia or mild anemia at visit 1 to mild or frank anemia at visit 2 (PRO).

RESULTS

mild anemia was present in 41.3% at visit 1 and 34.1% at visit 2. We identified PER in 22% patients, RES in 10%, and PRO in 26%. In the subsequent 40 months, 125 patients developed end-stage renal disease (ESRD) and 94 died. At competing risk model, PER predicted ESRD (hazard ratio, HR, 1.82, 95% confidence interval, CI, 1.01-3.29) while PRO predicted both ESRD (HR 1.81, 95% CI 1.02-3.23) and death (HR 1.87, 95% CI 1.04-3.37).

CONCLUSION

in non-dialysis chronic kidney disease, mild anemia is prevalent and it is a marker of risk excess when persistent or progressive over time.

Effect of a low- versus moderate-protein diet on progression of CKD: follow-up of a randomized controlled trial

BACKGROUND

Whether low-protein-diet (LPD) as opposed to moderate-protein-diet (MPD) regimens improve the long-term survival of patients with chronic kidney disease (CKD) or induce protein-caloric malnutrition is unknown.

STUDY DESIGN

Intention-to-treat analysis of follow-up data from a randomized controlled trial.

SETTING & PARTICIPANTS

423 patients with CKD (stages 4-5) were randomly assigned between January 1999 and January 2003 and followed up until December 2006 or death. The first phase of follow up was from January 1999 to June 2004; additional follow-up was from July 2004 to December 2006.

INTERVENTION

LPD versus MPD (protein intake, 0.55 vs 0.80 g/kg/d).

OUTCOMES

Protein-caloric malnutrition (defined as the occurrence of 1 of the following: loss of body weight > 5% in 1 month or 7.5% in 3 months or body mass index < 20 kg/m(2) with serum albumin level < 3.2 g/dL and normal C-reactive protein level [<0.5 mg/dL]), dialysis, death, or the composite outcome of dialysis and death.

RESULTS

Baseline mean age was 61 years, estimated glomerular filtration rate was 16 mL/min/1.73 m(2), proteinuria had protein excretion of 1.67 g/d, body mass index was 27.1 kg/m(2), protein intake was 0.95 g/kg/d, and there were 57% men. Duration of follow-up was 32 months (median, 30 months; 25th-75th percentiles, 21-39). Average protein intakes were 0.73 +/- 0.04 g/kg/d for the LPD and 0.9 +/- 0.06 g/kg/d for the MPD. 3 patients (0.7%) met criteria for protein-caloric malnutrition. 48 patients died (11%), 83 initiated dialysis therapy (20%), and 113 (27%) reached the composite outcome. In unadjusted Cox survival analyses, effects of the LPD on these outcomes were 1.01 (95% CI, 0.57-1.79), 0.96 (95% CI, 0.62-1.48), and 0.98 (95% CI, 0.68-1.42), respectively.

LIMITATIONS

Low event rates for dialysis therapy initiation and death.

CONCLUSIONS

Most patients, who were regularly followed up in CKD clinics, were acceptably adherent to the prescribed dietary protein intake restrictions; the LPD and MPD did not lead to protein wasting; and the LPD did not decrease the risk of death or dialysis therapy initiation compared with the MPD.

Assessment of nutritional practice in Italian chronic kidney disease clinics: a questionnaire-based survey

BACKGROUND

The prevention of malnutrition in patients with progressive chronic kidney disease (CKD) presents a challenge to nephrologists. We evaluated nutritional practice and routines, at a national level, related to the nutritional management of nondialyzed CKD patients.

METHODS

A questionnaire-based survey (32 open and 9 multiple-choice questions) was used to assess the evaluation of nutritional status in nondialyzed CKD outpatients at baseline and during follow-up. Data were obtained for 230 Italian public nephrology centers (63% of the total number of Italian public nephrology centers).

RESULTS

There was a dedicated dietitian at only 19% of the centers. At baseline, body weight, body mass index, and serum albumin were determined in almost all centers, nutrient intakes and bioimpedance analysis in half the centers, and subjective global assessment and skinfold thickness in a small proportion of centers. During follow-up, the rate of assessments decreased by 8% for weight, 14% for nutrient intake, and 29% for subjective global assessment and skinfold thickness. Overall, the K/DOQI minimum criteria for nutritional assessment were fulfilled in only two thirds and half of the clinics at baseline and during follow-up, respectively. Multivariate analysis showed that the number of nutritional variables evaluated was significantly related to the size of the CKD clinic and the presence of a dietitian at baseline, but only with the presence of dietitian during follow-up. Daily urinary output was collected at 90% of the centers, but urea and sodium excretions were determined in only 59% and 57% of cases, respectively. The rate of assessment for urinary solutes during follow-up was higher at centers where a very low protein diet was prescribed.

CONCLUSIONS

The indications about nutritional assessment for CKD patients are poorly translated into practice patterns, especially with respect to the evaluation of nutrient intakes and additional but simple variables such as skinfold-thickness measurement and bioimpedance analysis. The presence of a dedicated dietitian appears to improve the quality of nutritional assessment in CKD.

Hemoglobin variability in nondialysis chronic kidney disease: examining the association with mortality

BACKGROUND AND OBJECTIVES

Anemia and hemoglobin (Hb) variability are associated with mortality in hemodialysis patients who are on erythropoiesis-stimulating agents (ESA). Our aim was to describe the degree of Hb variability present in nondialysis patients with chronic kidney disease (CKD), including those who were not receiving ESA, and to investigate the association between Hb variability and mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Hb variability was determined using 6 mo of "baseline" data between January 1, 2003, and October 31, 2005. A variety of definitions for Hb variability were examined to ensure consistency and robustness.

RESULTS

A total of 6165 patients from 22 centers in seven countries were followed for a mean of 34.0 +/- 15.8 mo; 49% were prescribed an ESA. There was increased Hb variability with ESA use; the residual SD of Hb was 4.9 +/- 4.4 g/L in patients who were not receiving an ESA, compared with 6.8 +/- 4.8 g/L. Hb variability was associated with a small but significantly increased risk for death per g/L residual SD, irrespective of ESA use. Multivariate linear regression model explained only 11% of the total variance of Hb variability.

CONCLUSIONS

Hb variability is increased in patients who have CKD and are receiving ESA and is associated with an increased risk for death (even in those who are not receiving ESAs). This analysis cannot determine whether Hb variability causally affects mortality. Thus, the concept of targeting Hb variability with specific agents needs to be examined within the context of factors that affect both Hb variability and mortality.

[Treatment of HCV-associated cryoglobulinemic glomerulonephritis]

HCV-related membranoproliferative glomerulonephritis is the most common cause of hepatitis C-associated renal disease. Its treatment is still under debate and based on scant experimental evidence. The recommended therapeutic strategy depends on the severity of the kidney disease. The first-line treatment for patients with mild to moderate clinical and histological kidney damage is antiviral therapy with pegylated interferon alpha and ribavirin for 48 weeks combined with symptomatic treatment (diuretics, angiotensin converting enzyme inhibitors and angiotensin receptor blockers). In case of severe renal involvement (nephrotic syndrome, nephritic syndrome and/or progressive renal failure, high activity score of glomerulonephritis on light microscopy), the initial treatment may consist of sequential administration of immunosuppressive therapies (plasmapheresis, corticosteroids and cyclophosphamide) and antiviral agents, although no definitive data are yet available from the literature. B-cell depleting agents such as rituximab may be an alternative to conventional therapy in refractory or intolerant patients. Large randomized and controlled clinical trials are needed to establish guidelines for the treatment of HCV-related cryoglobulinemic glomerulonephritis.

[Resistant hypertension in non-dialysis chronic kidney disease]

Resistant hypertension is defined as blood pressure that remains above the target of <140/90 mm Hg in the general population and <130/80 mm Hg in people with diabetes mellitus or chronic kidney disease (CKD) in spite of the use of at least three full-dose antihypertensive drugs including a diuretic, or as blood pressure that reaches the target by means of four or more drugs. Hypertension is a frequent complication in CKD and a determining factor in the progression of renal damage, especially in proteinuric and diabetic patients, as well as contributing to a high cardiovascular risk. Clinical practice guidelines recommend blood pressure levels below 130/80 mm Hg in all CKD patients, but the target is reached in only a small proportion (10-20%), both in nephrology and non-nephrology settings. The resistance to antihypertensive treatment may be considered one of the causes of the poor achievement of blood pressure targets in CKD patients.

Epoetin therapy and hemoglobin level variability in nondialysis patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Intrapatient variability of hemoglobin (Hb) is a newly proposed determinant of adverse outcome in chronic kidney disease (CKD). We evaluated whether intensity of epoetin therapy affects Hb variability and renal survival in nondialysis CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We calculated the individual therapeutic index (TI) for epoetin (EPO; difference between rates of visits that required EPO dosage change and those with effective EPO change) from 1198 visits during the first year of EPO in 137 patients. Renal death was registered in the subsequent 18.1 mo. Analysis was made by TI tertile (lower, middle, and higher; i.e., from more to less intensive therapy).

RESULTS

Main features and visit number were similar in tertiles. Lower Hb response to first EPO dosage was an independent predictor of higher TI (P = 0.002). The area under the curve for Hb (11.56 +/- 0.87, 11.46 +/- 1.20, and 10.95 +/- 1.48 g/dl per yr; P = 0.040) decreased from lower to higher tertile. Hb variability increased in parallel, as shown by the reduction of time with Hb at target (time in target, from 9.2 +/- 2.0 to 3.0 +/- 2.2 mo; P < 0.0001) and the wider values of within-patient Hb standard deviation (from 0.70 to 0.96; P = 0.005) and Hb fluctuations across target (P < 0.0001). In Cox analyses (hazard ratio [95% confidence interval]), risk for renal death was increased in the middle and higher tertiles (2.79 [1.36 to 5.73] and 2.94 [1.40 to 6.20]) and reduced by longer time in target (0.90 [0.83 to 0.98]).

CONCLUSIONS

Lack of adjustment of EPO worsens Hb variability in CKD. Hb variability may be associated with renal survival, but further studies are needed to explore the association versus causal relationship.

[Erythropoiesis-stimulating agents in chronic kidney disease: which route of administration?]

In the last twenty years, erythropoiesis-stimulating agents (ESAs) have improved the management of renal anemia, with significant amelioration of quality of life in patients on hemodialysis. ESAs can be administered both intravenously and subcutaneously. In predialysis chronic kidney disease and in peritoneal dialysis, the administration route is necessarily subcutaneous. In hemodialysis the intravenous route was initially preferred because of the presence of ready vascular access for drug administration. Subsequent studies have demonstrated that the subcutaneous route allowed the achievement of optimal levels of hemoglobin with a reduction of mean administered dose, number of injections, and costs. A few years ago, the finding of a higher risk of pure red cell aplasia associated with subcutaneous administration of epoetin reopened the debate about the route of administration. We here review the studies on the preferable route of administration of epoetin and darbepoetin- alpha, in terms of efficacy and safety, and take a look at future perspectives.

[Hyponatremia secondary to inappropriate antidiuretic hormone secretion]

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a disorder of sodium and water balance characterized by hypotonic hyponatremia and impaired water excretion in the absence of renal insufficiency , adrenal insufficiency or any recognized stimulus for the antidiuretic hormone (ADH). An inappropriate increase in ADH release of any cause produces hyponatremia by interfering with urinary dilution, thereby preventing the excretion of ingested water. Despite being the most common cause of hyponatremia in hospitalized patients, SIADH remains a diagnosis of exclusion. SIADH should be suspected in any patient with hyponatremia, hyposmolarity, urine osmolality above 100 mosmol/hgH2O, urine sodium concentration usually above 40 mEq/L, and clinical euvolemia. a number of modalities can be used to correct hyponatremia in SIADH, with water restriction and salt administration being the most important. The rate of correction is dependent upon the degree of hyponatremia and the presence or absence of symptoms. Patients with severe neurological symptoms require prompt correction; however, excessively rapid correction should be avoided because it can lead to the late onset of neurological complications from osmotic demyelination.

Detection and awareness of moderate to advanced CKD by primary care practitioners: a cross-sectional study from Italy

BACKGROUND

Chronic kidney disease (CKD) is a strong independent predictor of cardiovascular disease. Although general practitioners (GPs) represent the first line for identification of these high-risk patients, their diagnostic approach to CKD is ill defined.

STUDY DESIGN

Cross-sectional evaluation of database of Italian GPs.

SETTING & PARTICIPANTS

Representative sample of adult Italian population regularly followed up by GPs in 2003.

OUTCOMES

Frequency of serum creatinine testing, prevalence of CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m(2)), awareness of CKD assessed from use of diagnostic codes (Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM]) for CKD, and referral to nephrologists.

RESULTS

Of 451,548 individuals in the entire practice population, only 77,630 (17.2%) underwent serum creatinine testing. Female sex (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.06 to 1.12), advanced age (OR, 2.70; 95% CI, 2.63 to 2.78), diabetes (OR, 1.31; 95% CI, 1.20 to 1.42), hypertension (OR, 1.10; 95% CI, 1.02 to 1.19), autoimmune diseases (OR, 1.42; 95% CI, 1.11 to 1.82), and recurrent urinary tract infections (OR, 1.63; 95% CI, 1.10 to 2.42) were all associated with serum creatinine testing. Conversely, use of either nonsteroidal anti-inflammatory drugs (OR, 1.03; 95% CI, 0.89 to 1.21) or aminoglycosides or contrast media (OR, 0.78; 95% CI, 0.54 to 1.14) was not associated with serum creatinine testing. In the subgroup with serum creatinine data, the age-adjusted prevalence of CKD was 9.33% (11.93% in women, 6.49% in men). However, in patients with eGFR less than 60 mL/min/1.73 m(2), serum creatinine values were apparently normal (<1.2 mg/dL in women, <1.4 mg/dL in men) in 54%, and GPs used ICD-9-CM codes for CKD in only 15.2%. Referral to nephrologists ranged from 4.9% for patients with eGFR of 59 to 30 mL/min/1.73 m(2) to 55.7% for those with eGFR less than 30 mL/min/1.73 m(2).

LIMITATIONS

The prevalence of decreased kidney function may be overestimated because of the more frequent serum creatinine testing in sicker individuals and lack of creatinine calibration.

CONCLUSIONS

In primary care, CKD stages 3 to 5 are frequent, but its awareness is scarce because of limited rates of serum creatinine testing and difficulty recognizing decreased eGFR in the absence of increased serum creatinine testing.