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.

[Native kidney ultrasound in obstructive uropathy].

The term "obstructive uropathy" refers to the complex structural and functional changes following the interruption of normal urinary runoff, which can occur at every level of the urinary tract. Depending on its origin, duration and severity, urinary tract obstructions can be acute or chronic, mono or bilateral, partial or complete. The obstruction can be localized or extended to the entire pielo-caliceal system and/or homolateral urethra. The term "hydronephrosis" indicates the dilation of the pelvis detected through imaging techniques. Among these, ultrasound is considered the gold standard in the diagnosis of obstructive uropathy: it allows to distinguish three degrees of urinary tract dilation, depending on the extent of the dilation itself and the thickness of the parenchyma. Nephrologists are confronted daily with patients who experience kidney failure and must be able to quickly distinguish between chronic and acute and, in the latter case, to discern between issues of nephrological or urological competence. This short review aims at helping them deal with this very common scenario, through the use of ultrasound.

Effectiveness of Switch to Erythropoiesis-Stimulating Agent (ESA) Biosimilars versus Maintenance of ESA Originators in the Real-Life Setting: Matched-Control Study in Hemodialysis Patients.

BACKGROUND: In hemodialysis (HD), switching from erythropoiesis-stimulating agent (ESA) originators to biosimilars is associated with the need for doses approximately 10% higher, according to industry-driven studies. OBJECTIVE: The aim of this study was to evaluate the efficacy on anemia control of switching from ESA originators to biosimilars in daily clinical practice. METHODS: We retrospectively selected consecutive HD patients receiving stable intravenous ESA doses, and who had not been transfused in the previous 6 months, from 12 non-profit Italian centers. Patients switched from originators to biosimilars (n = 163) were matched with those maintained on ESA originators (n = 163) using a propensity score approach. The study duration was 24 weeks, and the primary endpoint was the mean dose difference (MDD), defined as the difference between the switch and control groups of ESA dose changes during the study (time-weighted average ESA dose minus baseline ESA dose). RESULTS: Age (70 ± 13 years), male sex (63%), diabetes (29%), history of cardiovascular disease (40%), body weight (68 ± 14 kg), vascular access (86% arteriovenous fistula), hemoglobin [Hb] (11.2 ± 0.9 g/dL) and ESA dose (8504 ± 6370 IU/week) were similar in the two groups. Hb remained unchanged during the study in both groups. Conversely, ESA dose remained unchanged in the control group and progressively increased in the switch group from week 8 to 24. The time-weighted average of the ESA dose was higher in the switch group than in the control group (10,503 ± 7389 vs. 7981 ± 5858 IU/week; p = 0.001), leading to a significant MDD of 2423 IU/week (95% confidence interval [CI] 1615-3321), corresponding to a 39.6% (95% CI 24.7-54.6) higher dose of biosimilars compared with originators. The time-weighted average of Hb was 0.2 g/dL lower in the switch group, with a more frequent ESA hyporesponsiveness (14.7 vs. 2.5%). Iron parameters and other resistance factors remained unchanged. CONCLUSIONS: In stable dialysis patients, switching from ESA originators to biosimilars requires 40% higher doses to maintain anemia control.

Incidence of renal replacement therapy in Veneto for 2008, 2009 and 2010.

This section of the report of the Veneto Dialysis and Transplantation Registry (VDTR) provides data on the incidence of patients receiving renal replacement therapy (RRT) in the region from 2008 to 2010. Its purpose is to provide health authorities with the information they need to plan the delivery of RRT in Veneto. Data were obtained from the VDTR, defining incident patients according to the recommendations of the Italian Dialysis and Transplantation Registry. The incidence rate was calculated per million population (pmp). Variability by province and treatment center was studied by applying multilevel modeling methods. An age-period-cohort model was used to forecast the incidence rate of RRT over the years to come. The incidence of patients on RRT was 114.23 pmp in 2008, 120.15 pmp in 2009 and 107.08 pmp in 2010. The patients' median age at the time of starting RRT was 70.5 in 2008, 68.7 in 2009 and 69.5 in 2010. During these 3 years, 66.3% of patients were male, and 33.7% were female. Incidence rates were not uniformly distributed between the provinces in the region, but were significantly higher in 2. The incidence rate of patients needing RRT seems likely to remain stable in the future, until 2015 at least. Renal vascular disease was the primary cause of end-stage renal disease (ESRD), followed closely by diabetes, while the proportion due to primary glomerulonephritis has gradually decreased. Initial dialysis modality was hemodialysis (HD) for 78% of patients, while about 20% started RRT on peritoneal dialysis (PD), and a negligible proportion had a preemptive kidney transplantation. About 35% patients began dialysis with a temporary vascular catheter; this percentage remained fairly constant until 2010. The incidence of RRT in Veneto is one of the lowest in Italy and remained substantially stable over the period 1998-2010, despite the population of patients with ESRD becoming older and more severely ill. This finding could mean a heavier burden on the welfare system in the future.

Prevalence of renal replacement therapy in Veneto for 2008, 2009 and 2010.

The aim of this section is to provide descriptive data for end-stage renal disease (ESRD) in the Veneto Region (Italy). Data were obtained from the Veneto Dialysis and Transplantation Registry (VDTR). Patients were considered to be prevalent renal replacement therapy (RRT) patients if alive on 31 December of each year examined. Prevalence is expressed per million population (pmp). The trend for prevalence of each treatment in the period examined was estimated by random effects longitudinal logistic regression. Prevalence of RRT in Veneto in the years 2008, 2009 and 2010 was 888, 923 and 950 pmp, respectively. The prevalence of RRT patients by treatment modality showed a slight increase for hemodialysis, notable stability for peritoneal dialysis and a more pronounced increase for transplantation. Every year, about 10% of peritoneal dialysis patients shifted to hemodialysis, and 12% received a transplant. The transition probability from hemodialysis to peritoneal dialysis was negligible, and less than 5% of hemodialysis patients received a transplant. The probability of returning to hemodialysis after having received a transplant was less than 2% a year. Bicarbonate hemodialysis slowly increased from 1998 to 2010, both in percentage and in prevalence per million population; conversely, hemodiafiltration (HDF) showed a mild but constant decrease. Automated peritoneal dialysis (APD), which was quantitatively almost negligible in 1998, reached the same level as continuous ambulatory peritoneal dialysis (CAPD) in 2010. The prevalence of patients undergoing living donor transplants almost doubled in the period 1998-2010. The increase of prevalence over time was not proportional for the 3 modalities of RRT: hemodialysis prevalence grew slowly, peritoneal dialysis prevalence remained stable, and renal transplant prevalence quickly increased.

Mortality in the Veneto population on renal replacement therapy.

This section reports survival rates for patients on renal replacement therapy (RRT). The data obtained from the Veneto Dialysis and Transplantation Registry (VDTR) cover the whole population in the region. Patients on RRT alive on 31 December of each year were assumed to be at risk of dying in the following year. Furthermore, time-to-event analysis was used to describe the complete history of patients from when they started RRT until they died, including transitions between the 3 main treatment modalities - hemodialysis (HD), peritoneal dialysis (PD) and renal transplantation. The cohort of patients starting RRT from 1998 to 2010 was followed up until 31 December 2010. Survival rates from the first treatment to death were calculated according to the life table method. Relative survival and excess mortality rates were estimated according to the Ederer II method. A multistate model was used to describe changes in a patient's condition (changes of treatment, or death) over time. Among prevalent patients on RRT, the annual risk of death was 10.65% in 2008, 9.35% in 2009 and 8.86% in 2010. The overall mortality rate was 12.5 per 100 patient-years (95% confidence interval [95% CI], 12.1-13.0). The 5-year relative survival was 59% (95% CI, 57%-60%), and at 10 years relative survival was 41% (95% CI, 39%-43%); the estimated excess mortality rate was very high at the start of RRT (18 per 100 patient-years) but gradually decreased after the second year. On multivariate analysis, excess mortality was associated with age and primary renal diseases. Less than 10% of patients starting on PD shifted to HD in the first year of RRT, and a considerable proportion received a transplant, amounting to 6% in the first year, and thereafter increasing steadily: at the end of the fifth year, 34% of patients starting RRT on PD had received a transplant. HD patients behaved differently: any shift to PD was negligible, and the patients receiving a transplant amounted to only 2% in the first year and about 16% by the end of the fifth year. Cumulative mortality among HD patients was particularly high (already 18% at 1 year, and 70% at 10 years) by comparison with those on PD (8% at 1 year, 54% at 10 years). Although mortality on RRT is not particularly high in Veneto by comparison with countries other than Italy, this result is mainly due to an increasing number of patients receiving transplants, which makes them a favorably selected population. The mortality rate was high among those on HD, particularly in the first year. Our population on RRT is rather heterogeneous, and a description of the outcomes based only on the whole population may be misleading.

Therapy of hyperhomocysteinemia in hemodialysis patients: effects of folates and N-acetylcysteine.

OBJECTIVE: Uremia represents a state where hyperhomocysteinemia is resistant to folate therapy, thus undermining intervention trials' efficacy. N-acetylcysteine (NAC), an antioxidant, in addition to folates (5-methyltetrahydrofolate, MTHF), was tested in a population of hemodialysis patients. DESIGN: The study is an open, parallel, intervention study. SETTING: Ambulatory chronic hemodialysis patients. SUBJECTS: Clinically stable chronic hemodialysis patients, on hemodialysis since more than 3 months, undergoing a folate washout. Control group on standard therapy (n = 50). INTERVENTION: One group was treated with intravenous MTHF (MTHF group, n = 48). A second group was represented by patients treated with MTHF, and, during the course of 10 hemodialysis sessions, NAC was administered intravenous (MTHF + NAC group, n = 47). MAIN OUTCOME MEASURE: Plasma homocysteine measured before and after dialysis at the first and the last treatment. RESULTS: At the end of the study, there was a significant decrease in predialysis plasma homocysteine levels in the MTHF group and MTHF + NAC group, compared with the control group, but no significant difference between the MTHF group and MTHF + NAC group. A significant decrease in postdialysis plasma homocysteine levels in MTHF + NAC group (10.27 ± 0.94 µmol/L, 95% confidence interval: 8.37-12.17) compared with the MTHF group (16.23 ± 0.83, 95% confidence interval: 14.55-17.90) was present. In the MTHF + NAC group, 64% of patients reached a postdialysis homocysteine level <12 µmol/L, compared with 19% in the MTHF group and 16% in the control group. CONCLUSIONS: NAC therapy induces a significant additional decrease in homocysteine removal during dialysis. The advantage is limited to the time of administration.

High chronic nephropathy detection yield in CKD subjects identified by the combination of albuminuria and estimated GFR.

BACKGROUND AND OBJECTIVES: Epidemiological studies have shown that the burden of chronic kidney disease (CKD) is huge. CKD is a non-specific diagnosis, however, and it is hard to say which renal disorders comprise the body of CKD diagnosed on the strength of the combination of albuminuria and estimated glomerular filtration rate (eGFR) in epidemiological studies, or just how efficient such studies are in detecting chronic nephropathies. METHODS: The INCIPE study identified 524 CKD cases (using the K/DOQI definition based on albuminuria and eGFR) in a random sample of 4000 Italians >40 years old, 262 of whom were randomly chosen to be investigated in order to confirm their CKD and complete a diagnostic workup. We a priori defined diagnostic algorithms for 14 renal conditions based on personal family history, medical records, urine tests, kidney ultrasound with colour-Doppler and other tests. RESULTS: Among the subjects whose CKD was confirmed, a diagnosis of chronic nephropathy was reached in 68% of cases recognized as having either a specific (38%) or an undetermined (30%) kidney disease. Almost 50% of subjects with a specific chronic nephropathy had a diabetic or vascular renal disease. Abnormalities consistent with a chronic nephropathy were found in 50, 68, 70 and 100% of subjects with CKD Stages 1, 2, 3 and 4, respectively. Lone low eGFR and lone microalbuminuria were observed in 20 and 12%, respectively. CONCLUSION: In Caucasians >40 years old with a confirmed CKD condition, (i) an impressive 68% of subjects have an underlying chronic nephropathy, so eGFR and albuminuria are very efficient in detecting renal diseases; (ii) in 32%, the only disclosed renal abnormalities were a glomerular filtration rate <60 mL/min/1.73 m(2) or microalbuminuria; follow-up studies are needed to clarify whether these abnormalities do really identify a chronic nephropathy or just a cardiovascular risk condition.

Serum uric acid levels and incident chronic kidney disease in patients with type 2 diabetes and preserved kidney function.

OBJECTIVE: Recent studies have suggested an association between hyperuricemia and adverse renal outcomes in nondiabetic populations. Data on the relationship between hyperuricemia and the risk of incident chronic kidney disease (CKD) in type 2 diabetic patients with normal or near-normal kidney function are lacking. We determined whether baseline serum uric acid levels predict the subsequent development of CKD in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We followed 1,449 type 2 diabetic patients with normal kidney function and without overt proteinuria for 5 years for the occurrence of incident CKD (defined as overt proteinuria or estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m(2)). RESULTS: During a 5-year follow-up period, 194 (13.4%) patients developed incident CKD. The cumulative incidence of CKD was significantly greater in patients with hyperuricemia than in those without hyperuricemia (29.5 vs. 11.4%, P < 0.001). In univariate logistic regression analysis, the presence of hyperuricemia roughly doubled the risk of developing CKD (odds ratio [OR] 2.55 [95% CI 1.71-3.85], P < 0.001). After adjusting for age, sex, BMI, smoking status, diabetes duration, systolic blood pressure, antihypertensive treatment, insulin therapy, HbA(1c), eGFR, and albuminuria, hyperuricemia was associated with an increased risk of incident CKD (adjusted OR 2.10 [1.16-3.76], P < 0.01). In continuous analyses, a 1-SD increment in the serum uric acid level was significantly associated with a 21% increased risk of CKD. CONCLUSIONS: In type 2 diabetic individuals with preserved kidney function, hyperuricemia seems to be an independent risk factor for the development of incident CKD.

Prognosis of CKD patients receiving outpatient nephrology care in Italy.

BACKGROUND AND OBJECTIVES: Prognosis in nondialysis chronic kidney disease (CKD) patients under regular nephrology care is rarely investigated. Design, setting, participants, & measurements We prospectively followed from 2003 to death or June 2010 a cohort of 1248 patients with CKD stages 3 to 5 and previous nephrology care ≥1 year in 25 Italian outpatient nephrology clinics. Cumulative incidence of ESRD or death before ESRD were estimated using the competing-risk approach. RESULTS: Estimated rates (per 100 patient-years) of ESRD and death 8.3 (95% confidence interval [CI], 7.4 to 9.2) and 5.9 (95% CI 5.2 to 6.6), respectively. Risk of ESRD and death increased progressively from stages 3 to 5. ESRD was more frequent than death in stage 4 and 5 CKD, whereas the opposite was true in stage 3 CKD. Younger age, lower body mass index, proteinuria, and high phosphate predicted ESRD, whereas older age, diabetes, previous cardiovascular disease, ESRD, proteinuria, high uric acid, and anemia predicted death (P < 0.05 for all). Among modifiable risk factors, proteinuria accounted for the greatest contribution to the model fit for either outcome. CONCLUSIONS: In patients receiving continuity of care in Italian nephrology clinics, ESRD was a more frequent outcome than death in stage 4 and 5 CKD, but the opposite was true in stage 3. Outcomes were predicted by modifiable risk factors specific to CKD. Proteinuria used in conjunction with estimated GFR refined risk stratification. These findings provide information, specific to CKD patients under regular outpatient nephrology care, for risk stratification that complement recent observations in the general population.

Metabolic syndrome, cardiovascular disease, and risk for chronic kidney disease in an Italian cohort: analysis of the INCIPE study.

BACKGROUND: Metabolic syndrome is a frequent condition that has been linked to cardiovascular disease (CVD) and mortality. Metabolic syndrome has been extensively shown to increase the risk of chronic nephropathies in Americans and Asians, but not in European populations. Renal disease increases the risk of CVD and mortality. However, the chronic nephropathy-CVD liaison has not been analyzed in the framework of the possible role of metabolic syndrome in both. METHODS: We analyzed data from 3,757 subjects participating in the INCIPE survey (Initiative on Nephropathy, of relevance to public health, which is Chronic, possibly in its Initial stages, and carries a Potential risk of major clinical End-points), a cross-sectional study enrolling subjects from the general population in the Veneto region in Italy, and calculated the odds ratio (OR) and 95% confidence interval (CI) of the association between metabolic syndrome, and/or chronic kidney disease (CKD) and albuminuria, and/or previous CVD after adjustment for confounding factors. RESULTS: Metabolic syndrome is associated with CKD (OR 2.17; P<0.001) and albuminuria (OR 2.28; P<0.001) and CVD (OR 1.58; P=0.002). There is a direct correlation between number of metabolic syndrome traits and nephropathy and CVD. CVD and nephropathies are associated even after adjustment for metabolic syndrome (OR 2.30; P<0.001). CONCLUSIONS: In a homogeneous Caucasian European population, metabolic syndrome is associated with CKD and albuminuria, and CVD. Although metabolic syndrome is a risk factor for both CVD and nephropathy, it does not entirely explain the dangerous CVD-nephropathy liaison.

Regulation of heparanase by albumin and advanced glycation end products in proximal tubular cells.

Diabetic nephropathy is one of the main causes of end-stage renal disease, in which the development of tubular damage depends on factors such as high glucose levels, albuminuria and advanced glycation end-product. In this study, we analyzed the involvement of heparanase, a heparan sulfate glycosidase, in the homeostasis of proximal tubular epithelial cells in the diabetic milieu. In vitro studies were performed on a wild-type and stably heparanase-silenced adult tubular line (HK2) and HEK293. Gene and protein expression analyses were performed in the presence and absence of diabetic mediators. Albumin and advanced glycation end-product, but not high glucose levels, increased heparanase expression in adult tubular cells via the AKT/PI3K signaling pathway. This over-expression of heparanase is then responsible for heparan sulfate reduction via its endoglycosidase activity and its capacity to regulate the heparan sulfate-proteoglycans core protein. In fact, heparanase regulates the gene expression of syndecan-1, the most abundant heparan sulfate-proteoglycans in tubular cells. We showed that heparanase is a target gene of the diabetic nephropathy mediators albumin and advanced glycation end-product, so it may be relevant to the progression of diabetic nephropathy. It could take part in several processes, e.g. extracellular-matrix remodeling and cell-cell crosstalk, via its heparan sulfate endoglycosidase activity and capacity to regulate the expression of the heparan sulfate-proteoglycan syndecan-1.

Risk of chronic kidney disease in patients with non-alcoholic fatty liver disease: is there a link?

Non-alcoholic fatty liver disease (NAFLD) has emerged as a growing public health problem worldwide. Increasing recognition of the importance of NAFLD and its association with the features of the metabolic syndrome has stimulated an interest in its putative role in the development and progression of chronic kidney disease (CKD). Accumulating evidence suggests that NAFLD and CKD share many important cardio-metabolic risk factors and common pathogenetic mechanisms and that NAFLD is associated with an increased prevalence and incidence of CKD. This association appears to be independent of obesity, hypertension, and other potentially confounding factors, and it occurs both in patients without diabetes and in those with diabetes. Although further research is needed to establish a definitive conclusion, these observations raise the possibility that NAFLD is not only a marker of CKD but also might play a part in the pathogenesis of CKD, possibly through the systemic release of several pro-inflammatory/pro-coagulant mediators from the steatotic/inflamed liver or through the contribution of NAFLD itself to insulin resistance and atherogenic dyslipidemia. However, given the heterogeneity and small number of observational longitudinal studies, further research is urgently required to corroborate the prognostic significance of NAFLD for the incidence of CKD, and to further elucidate the complex and intertwined mechanisms that link NAFLD and CKD. If confirmed in future large-scale prospective studies, the potential adverse impact of NAFLD on kidney disease progression will deserve particular attention, especially with respect to the implications for screening and surveillance strategies in the growing number of patients with NAFLD.

[Obesity in dialysis and reverse epidemiology: true or false?]. / L'obesita' in dialisi e l'epidemiologia inversa: vero o falso?

About 50% of patients who undergo dialysis are overweight or obese. Rather than being a disadvantage, the extra weight is associated with improved survival in this patient group. However, the relationship between weight and outcome is complex among dialysis patients. In the general population obesity constitutes a clear cardiovascular risk factor. By contrast, in obese dialysis patients the nutritional status may be better, and obesity thus provides, at least in the short term, some protection against malnutrition and the associated morbidity. On the other hand, some studies suggest that mortality in the long term is directly correlated with excess weight and obesity, which indicates that fat represents a risk factor also in uremia. In the elderly, particularly those affected by end-stage renal disease, endocrine and metabolic effects on the nitrogen balance cause the loss of muscle mass despite an excess of adipose tissue, which is a condition known as sarcopenic obesity. While a good nutritional state is found in some obese dialysis patients, which probably accounts for the improved survival of the obese group as a whole, there is a sizable proportion of sarcopenic obese, which is probably increasing. Sarcopenic obesity is not only characterized by the reduction of muscle mass but also by the accumulation of fat surrounding the abdominal viscera (visceral fat syndrome), which may be associated with a greater degree of metabolic and atherosclerotic disease. Several studies have shown that malnutrition associated with obesity, including sarcopenic obesity, is the risk factor most closely correlated with morbidity and mortality both in dialysis patients and the general population. The timely identification of this condition has therefore become necessary in the dialysis population now dominated by the elderly and very elderly. Body mass index is inadequate as a measure of sarcopenic obesity since it cannot define muscle mass nor indicate the localization of the fat in the visceral compartment. Other indices must be developed and validated in well performed clinical trials to identify fat localization and the presence of sarcopenia.

Prevalence of CKD in northeastern Italy: results of the INCIPE study and comparison with NHANES.

BACKGROUND AND OBJECTIVES: Sufficiently powered studies to investigate the CKD prevalence are few and do not cover southern Europe. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: For the INCIPE study, 6200 Caucasian patients ≥40 years old were randomly selected in northeastern Italy in 2006. Laboratory determinations were centralized. The albumin to creatinine ratio in urine and estimated GFR from calibrated creatinine (SCr) were determined. A comparison with 2001 through 2006 NHANES surveys was performed. RESULTS: Prevalence of CKD was 13.2% in northeastern (NE) Italy (age and gender standardized to the U.S. 2007 Caucasian population). Prevalence of CKD in U.S. Caucasians is higher (20.3%), the major difference being in CKD 3. Risk factors for CKD are more prevalent in the United States than in Italy. With use of CKD 3a and 3b stages, CKD prevalence decreased in NE Italy (8.5%) and in the United States (12.8%). CONCLUSIONS: The prevalence of CKD is high in NE Italy, but lower than that in the United States. A large part of the difference in CKD prevalence in NE Italy versus that in the United States is due to the different prevalence of CKD 3. The higher prevalence of a number of renal risk factors in persons from the United States explains in part the different dimensions of the CKD problem in the two populations.

Early creatinine shifts predict contrast-induced nephropathy and persistent renal damage after angiography.

PURPOSE: The purpose of this study was to evaluate incidence and predictors of contrast-induced nephropathy after coronary angiography and interventions, and to assess renal function at 30 days. The prognostic value of any early shift of serum creatinine compared with baseline was investigated; such measurement, being a delta, is largely independent of creatinine variations. METHODS: There were 216 patients at risk for contrast-induced nephropathy prospectively evaluated at baseline and at 12, 24, and 48 hours after exposure to contrast media, and 190 (88%) evaluated 1 month after discharge. RESULTS: Contrast-induced nephropathy occurred in 39 patients (18%), and 30-day renal damage was detected in 15 (7%). Contrast media/kg volume predicted contrast-induced nephropathy (P=.002), and percentage change of creatinine 12 hours from baseline was significantly higher in patients with nephropathy (P <.001). At multivariate analysis, percentage change of creatinine 12 hour-basal was the best predictor of nephropathy (P <.001). A 5% increase of its value yielded 75% sensitivity and 72% specificity (area under the curve 0.80; odds ratio 7.37; 95% confidence interval, 3.34-16.23) for early contrast-induced nephropathy detection. Furthermore, it strongly correlated with the development of renal impairment at 30 days (P=.002; sensitivity 87%, specificity 70%; area under the curve 0.85; odds ratio 13.29; 95% confidence interval, 2.91-60.64). CONCLUSION: Minimal elevations of serum creatinine at 12 hours are highly predictive of contrast-induced nephropathy and 30-day renal damage after exposure to contrast media.

Long-term treatment with potassium citrate and renal stones in medullary sponge kidney.

BACKGROUND AND OBJECTIVES: Medullary sponge kidney (MSK) is a renal malformation typically associated with nephrocalcinosis and recurrent calcium stones. Incomplete distal renal tubular acidosis, hypocitraturia, and hypercalciuria are common. For stone prevention, patients with MSK generally receive the standard "stone clinic" recommendations and often receive potassium citrate (KC). However, the effect on stone recurrence of citrate treatment in these patients has never been studied. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The issue was retrospectively analyzed on an outpatient basis in 97 patients with a radiologic diagnosis of MSK: 65 had at least one stone risk factor (SRF; hypercalciuria, hypocitraturia, hyperuricosuria, hyperoxaluria) and received KC [29 +/- 8 (SD) mEq/d]; 10 patients with SRF and 22 without received only general stone clinic suggestions. Follow-up was 78 +/- 13, 72 +/- 15, and 83 +/- 14 months, respectively. The 24-hour urinary excretion of calcium, oxalate, uric acid, citrate, and morning urine pH were investigated at baseline and at the end of follow-up. RESULTS: Parallel to a significant rise in urinary citrate and decreased urinary calcium (all P < 0.001), KC led to a dramatic reduction in the stone event rate (from 0.58 to 0.10 stones/yr per patient). The existence of a group of patients with MSK, those without SRF, with a very low stone rate and no SRF was recognized. CONCLUSIONS: Treatment with KC is effective in preventing renal stones in the typical patient with MSK. It seems that two clinical phenotypes among patients showing typical MSK features during radiologic study exist.