Frequency and risk factors of contrast-induced nephropathy after cardiac catheterization in type II diabetic patients: a study among Egyptian patients

Contrast-induced nephropathy (CIN) is the third leading cause of acute kidney injury (AKI) in hospitalized patients. Diabetes mellitus remains a consistent independent predictor of contrast nephropathy. Aim: To determine frequency and predictors of contrast-induced nephropathy after cardiac catheterization in type II diabetic patients. Patients and methods: The study included 200 type II diabetic patients who underwent cardiac catheterization; serial measurement of serum creatinine and creatinine clearance (Before contrast exposure and 48?h), creatinine clearance was calculated using Cockcroft–Gault formula. Contrast-induced nephropathy was defined as rise in serum creatinine 48?h after contrast exposure of ≥0.5?mg/dL or increased >25% compared to base line creatinine. Results: incidence of CIN in type II diabetic patients was 21.5%; incidence of CIN in diabetic patients with microalbuminuria was 17%, while incidence of CIN in patients with macroalbuminuria levels was 26%. There was a statistically significant difference between the patients who suffered from CIN post-procedure and patients who did not suffer from CIN regarding the ejection fraction and age with low ejection fraction and older patients in CIN group. Multiple logistic regression analysis for CIN predictors showed that pre-contrast serum creatinine to be the strongest predictor for being at risk of contrast-related, followed by age, and lastly albumin/creatinine ratio. Conclusion: Our findings suggest that diabetic patients, despite having a normal baseline creatinine are at an increased risk of developing CIN post-coronary angiography, patients at risk of CIN are older patients with high pre-contrast serum creatinine and high urine albumin/creatinine ratio.     

Improved estimation of glomerular filtration rate by serum cystatin C in preventing contrast induced nephropathy by N-acetylcysteine or zinc--preliminary results.

BACKGROUND: Prevention of contrast media (CM) induced nephropathy (CIN) by prophylaxis (e.g. N-acetylcysteine; NAC) is controversially discussed. Up to now, assessment of kidney function has been based on measurements of serum creatinine, although this biomarker has several limitations. We investigated NAC and zinc (Zn) for the prevention of CIN by monitoring creatinine and cystatin C. METHODS: In a prospective, placebo-controlled, double blind trial, patients with moderately impaired kidney function receiving low-osmolar, non-ionic CM were randomly assigned to an oral treatment for 2 days with 1.2 g/day of NAC (n = 19), for 1 day with 60 mg/day of Zn (n = 18) or placebo (n = 17). All patients received peri-procedurally 1 ml/kg/h of 0.45% saline for 24 h. At baseline, prior to exposure of CM, 2 and 6 days after CM, creatinine and cystatin C were measured. RESULTS: There was no difference in the incidence of CIN, but a significant drop in creatinine (P < 0.05) was observed in all patients during volume expansion. Creatinine showed no increase after CM and it was normalized to the baseline values in all groups at the study end. In contrast, 2 days after CM there was a significant rise in cystatin C in the Zn (P = 0.012) and the placebo (P = 0.041) group, whereas NAC prevented this deterioration of kidney function. CONCLUSIONS: Cystatin C seems to reflect CM-induced changes in kidney function better than creatinine. NAC and Zn have no effect in preventing CIN by the standard definition, but based on cystatin C we can confirm a preventive effect of NAC. It appears mandatory to assess kidney function by cystatin C in CIN intervention trials, because relying on creatinine can be misleading.     

The association between albumin to creatinine ratio and total protein to creatinine ratio in patients with chronic kidney disease

Aims: Although albumin to creatinine ratio (ACR) and total protein to creatinine ratio (PCR) in random urine have been supposed as alternatives to 24-h urine measurements, there are few studies comparing these tests in CKD patients. Therefore, we investigated the relations between ACR and PCR in CKD patients and the factors that affect the relationship. Methods: We enrolled 808 patients with CKD prospectively and compared ACR, PCR and urine dipstick test in random urine. Results: Albuminuria was well correlated with proteinuria (β = 1.114, p < 0.001). The association between albuminuria and proteinuria was greater in patients with following characteristics: dipstick protein positive compared with negative (p < 0.001 for interaction), urine creatinine level ≥ 60 mg/dl compared with < 60 mg/dl (p = 0.024 for interaction) and estimated glomerular filtration rate < 60 ml/min/1.73 m2 compared with ≥ 60 ml/min/1.73 m2 (p = 0.040 for interaction). However, the association between albuminuria and proteinuria was not affected by sex, the presence of diabetes, or old age (≥ 60 years). Conclusions: Both ACR and PCR in random urine are correlated well and can be used for monitoring of protein excretion in CKD patients, alternatively. However, the correlation is not strong in patients with low amount of protein excretion or with low urinary creatinine concentration.     

Physical Activity Alters Urinary Albumin/ Creatinine Ratio in Type 1 Diabetic Patient

While the best way to identify microalbuminuria is to determine albumin excretion rate (AER) in a 24 h urine sample. Published data have shown that calculation of an albumin/creatinine ratio (ACR) in a spot urine sample has reasonable rate of sensitivity and specificity. We aimed to evaluate the effect of daily exercise on ACR and estimate the best time for the examination of the ACR in a spot urine sample. Sixteen eligible patients with Type 1 diabetes mellitus were asked to perform varying degree of exercise periods. Urinary albumin and creatinine excretion rates during each period were determined. ACR and AER of timed urinary samples were compared with the 24 hour urinary AER. We found significant correlations between timed and 24 hour urinary AER. According to diagnostic performance tests, ACR and AER of timed urine samples were both found to be significantly more sensitive during resting period when compared with mild or moderate active periods. It is concluded that ACR and AER of a timed urine sample are sensitive and specific methods for determining microalbuminuria, while overnight resting samples give the impression of being more diagnostic.

Key Points

• Timed urine samples can predict microalbuminuria but because of the erroneous urine collections, microalbuminuria measurement should be calculated with creatiniuria measurement.
• With increasing physical activity during urine collection diagnostic performances of the cut-off values go downhill.
• For detecting microalbuminuria best results are reached with the early-morning urine samples.

Key Words: Microalbuminuria, albumin/creatinine ratio, type 1 diabetes mellitus, exercise, nephropathy     

Use of the albumin/creatinine ratio to detect microalbuminuria: implications of sex and race

The recommended albumin (microg)/creatinine (mg) ratio (ACR) (30 microg/mg) to detect microalbuminuria does not account for sex or racial differences in creatinine excretion. In a nationally representative sample of subjects, the distribution of urine albumin and creatinine concentrations was examined by using one ACR value (> or =30 microg/mg) and sex-specific cutpoints (> or =17 microg/mg in men and > or =25 microg/mg in women) measured in spot urine specimens. Mean urine albumin concentrations were not significantly different between men and women, but urine creatinine concentrations were significantly higher (P < 0.0001). Compared with non-Hispanic whites, urine creatinine concentrations were significantly higher in non-Hispanic blacks (NHB) and Mexican Americans, whereas urine albumin concentrations were significantly higher in NHB (P < 0.0001) but not Mexican Americans. When a single ACR is used, the prevalence of microalbuminuria was significantly lower among the men compared with women (6.0 versus 9.2%; P < 0.0001) and among non-Hispanic whites compared with NHB (7.2 versus 10.2%; P < 0.0001). No significant difference in the prevalence of microalbuminuria between men and women was noted when sex-specific ACR cutpoints were used. In the multivariate adjusted model, female sex (odds ratio, 1.62; 95% confidence interval, 1.29 to 2.05) and NHB race/ethnicity (odds ratio, 1.34; 95% confidence interval, 1.12 to 1.61) were independently associated with microalbuminuria when a single ACR threshold was used. When a sex-specific ACR was used, NHB race/ethnicity remained significantly associated with microalbuminuria but sex did not. The use of one ACR value to define microalbuminuria may underestimate microalbuminuria in subjects with higher muscle mass (men) and possibly members of certain racial/ethnic groups.     

The effectiveness of N-acetylcysteine in preventing contrast-induced nephropathy in patients undergoing contrast-enhanced computed tomography: a meta-analysis of randomized controlled trials

Background

N-Acetylcysteine (NAC) is reported to have potential for preventing of contrast-induced nephropathy (CIN) in patients undergoing coronary angiography. However, the effectiveness of NAC in preventing CIN in patients undergoing contrast-enhanced computed tomography (CT) is still controversial. We conducted a meta-analysis of relevant randomized controlled trials (RCTs) to further examine this issue.

Methods

RCTs were identified by computerized searching in PubMed, EMBASE, SCOPUS, and Cochrane databases. Two reviewers independently assessed the methodological quality of each study. A meta-analysis was performed to evaluate the effectiveness of NAC in preventing CIN in patients undergoing CT. The primary outcome was the incidence of contrast-induced nephropathy, and the requirement for dialysis. The secondary outcome was the change of serum creatinine.

Results

Six randomized controlled trials were identified with a total of 496 patients meeting the criteria for this study. Prophylactic administration of NAC in patients with serum creatinine above 1.2 mg/dL undergoing contrast-enhanced CT, along with hydration, reduced the risk of CIN (relative risk 0.20; 95 % confidence interval: 0.07–0.57). Requirement for dialysis was not significantly different between the NAC group and the control group.

Conclusions

This review provides evidence of the efficacy of NAC in preventing the incidence of CIN and recommends that NAC be more widely used in high-risk patients undergoing contrast-enhanced CT. On the basis of the evidence reviewed, further research involving large RCTs may be warranted.     

Use of albumin creatinine ratio and urine albumin concentration as a screening test for albuminuria in an Indo-Asian population.

BACKGROUND: Albuminuria (>30 mg/day) based on 24 h urine albumin excretion is one of the criteria for chronic kidney disease (CKD) and a predictor of cardiovascular disease (CVD). Differences in urine albumin concentration and creatinine excretion rates between Indo-Asians and other populations may require different threshold values for detection of albuminuria. We compared the use of spot urine albumin concentration and urine albumin to creatinine excretion ratio for detection of albuminuria in this population. METHODS: A total of 577 subjects aged >or=40 years, 54% of whom were women, were recruited from the general population in Karachi, Pakistan. Albumin concentration (mg/l) and albumin to creatinine ratio (mg/g of creatinine) were determined in a spot morning urine sample, and albuminuria (30 mg/day or greater) measured in a 24 h urine collected on the subsequent day. RESULTS: The median (25-75 percentile) of urine albumin excretion was 4.8 (3.6-10.3) mg/day: 5.4 (3.7-12.5) mg/day in men and 4.5 (3.8-8.9) mg/day in women. The overall prevalence (95% CI) of albuminuria was 11.8% (7.2-12.0%): 14.8% in men and 9.2% in women (P = 0.04). The areas under the receiver operator characteristic (ROC) curves for urine albumin concentration were 0.86 (0.82-0.90) and 0.88 (0.84-0.92), respectively, in women and men. The areas under the ROC curves for albumin to creatinine ratio were 0.86 (0.82-0.89) and 0.90 (0.86-0.93), respectively, in women and men. For urine albumin concentration, the sensitivity and specificity were 37 and 97%, respectively, in women and 69 and 94%, respectively, in men at the conventionally recommended value of 2 mg/dl. The discriminator value of urine albumin concentration identified in the analysis was 0.5 mg/dl in women (sensitivity of 87% and specificity of 75%) and 1.7 mg/dl in men (sensitivity of 74% and specificity of 93%). For the albumin to creatinine ratio, the sensitivity and specificity were 46 and 95%, respectively, in women and 60 and 97%, respectively, in men at cut-off value of 30 mg/g. CONCLUSION: Both urine albumin concentration and albumin to creatinine ratio are acceptable tests for population screening for albuminuria in Indo-Asians. While sensitivities may be suboptimal, particularly in women, lowering the existing thresholds would compromise specificity. Those who screen positive need evaluation and management of CKD and prevention of CVD.     

The effect of N-acetylcysteine on renal function, nitric oxide, and oxidative stress after angiography

BACKGROUND: Renal failure induced by radiographic contrast agents is a known complication of coronary angiography, especially among patients with chronic renal failure. Recently, treatment with N-acetylcysteine (NAC) has been shown to have a protective effect but the mechanisms are unknown. We examined the hypothesis that NAC protected against contrast-induced renal impairment through effects on nitric oxide metabolism and oxidative stress. METHODS: Patients with a serum creatinine concentration above 10(6) micromol/L undergoing coronary angiography were randomly assigned to receive either NAC 1 g (N= 24) or placebo (N= 29) twice daily 24 hours before and after angiography with 0.45% saline hydration in a double-blind study. Creatinine clearance was calculated and urinary nitric oxide and F2-isoprostane excretion were measured at baseline, 24 and 96 hours after angiography. RESULTS: Treatment with NAC significantly improved the effect of contrast media on creatinine clearance, and maximal beneficial effect was observed 24 hours after angiography. Creatinine clearance (mL/min) was 59.5 +/- 4.4, 64.7 +/- 5.8, and 58.7 + 3.9 at baseline, 24, and 96 hours after angiography in the NAC group, respectively, and 65.2 +/- 3.2, 51.5 +/- 3.7, and 53.6 +/- 3.9 in the placebo group, respectively (P < 0.0001). NAC treatment prevented the reduction in urinary nitric oxide after angiography. The urinary nitric oxide/creatinine ratio (micromol/mg) was 0.0058 +/- 0.0004, 0.0057 +/- 0.0004, and 0.0052 +/- 0.0004 at baseline, 24, and 96 hours after angiography in NAC group, respectively, and 0.0057 +/- 0.0007, 0.0031 +/- 0.0005, and 0.0039 +/- 0.0005 in the placebo group, respectively (P= 0.013). NAC had no significant effect on urinary F2-isoprostanes. CONCLUSION: NAC treatment has renoprotective effect in patients with mild chronic renal failure undergoing coronary angiography that may be mediated in part by an increase in nitric oxide production.     

Effects of sulodexide in patients with type 2 diabetes and persistent albuminuria.

BACKGROUND: Urinary albumin excretion frequently persists in diabetic patients who are treated with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB). Sulodexide, a glycosaminoglycan mixture of 80% heparan sulfate and 20% dermatan sulfate, has been hypothesized to reduce persistent albuminuria. We have conducted a multi-center randomized double-blind pilot study in order to determine the effect of 6 months' therapy with sulodexide on urinary albumin excretion and to address logistical issues for a full-scale trial. METHODS: A total of 149 patients with type 2 diabetes and an albumin:creatinine ratio (ACR) between 20 and 300 mg/g were randomized with equal allocation to either placebo, 200 mg of sulodexide or 400 mg of sulodexide. The primary endpoint was the achievement, at 6 months, of either 3(1) return to normoalbuminuria (ACR < 20 mg/g with a decrease of at least 25%) or (2) a decrease in ACR of at least 50% from the baseline value. All patients used a maximum tolerated recommended FDA approved dose of an ACEI or ARB for at least 60 days and had stable blood pressure prior to randomization. RESULTS: The primary efficacy endpoint was achieved in 25.3% of the patients in the two sulodexide groups combined versus 15.4% of the placebo-treated patients (P = 0.26). The primary endpoint was achieved in 33.3% (P = 0.075 for the comparison to placebo) in the sulodexide 200 mg group and 18.4% (P = 0.781) in the sulodexide 400 mg group. (No consistent patterns of side effects were observed. CONCLUSION: Based on the experience gained in this pilot study, one full-scale trial is currently being conducted to evaluate the effects of sulodexide on change in ACR in patients with persistent microalbuminuria, and a longer-term trial is underway to evaluate the effects of sulodexide on long-term renal disease progression in patients with overt proteinuria.     

N-Acetylcysteine does not artifactually lower plasma creatinine concentration.

BACKGROUND: All randomized controlled trials of N-acetylcysteine (NAC) in contrast media-induced nephropathy used creatinine as a marker of renal function. However, it has been suggested that NAC may lower plasma creatinine levels independent of any effects on glomerular filtration rate (GFR). METHODS: At a tertiary hospital 110 cardiac surgical patients were randomly allocated to peri-operative infusion of NAC (300 mg/kg over 24 h, N = 30) or placebo (N = 80). We compared the plasma concentrations of creatinine, cystatin C and urea, the plasma creatinine/plasma cystatin C ratio and the estimated GFR at baseline and at 24 and 72 h after commencement of the infusion. We measured urinary creatinine concentration at 24 h. RESULTS: At baseline, the plasma creatinine/plasma cystatin C ratio did not differ between the NAC and placebo group (0.90 versus 0.92; P = 0.94). There was no significant difference in the plasma creatinine/plasma cystatin C ratio for the NAC and placebo group either during or after NAC infusion at 24 h (1.03 versus 1.00; P = 0.78) and 72 h (0.94 versus 0.89; P = 0.09). Those allocated to NAC showed no difference in urinary creatinine excretion when compared to placebo (P = 0.24). CONCLUSIONS: The results of our study do not demonstrate that NAC artifactually lowers creatinine measured using the Jaffé method. (ClinicalTrials.gov, NCT00332631, NCT00334191).     

Clinical evaluation of the albumin/creatinine ratio in outpatients with diabetes

For the early diagnosis of diabetic nephropathy, it is best to use the albumin excretion rate (AER). However, it is a complicated test to perform in the outpatient setting, and it is sometimes affected by inaccurate urine collection. Therefore, we have used the albumin/creatinine ratio, which is measured simply with randomly collected urine, for evaluation of microalbuminuria and found it to be of equal diagnostic value to the AER. The AER, albumin/creatinine ratio, and creatinine excretion rate were measured in 86 patients with NIDDN who were negative for proteinuria. Urine was obtained after bed rest and in the outpatients department (without rest). 1) The reproducibility of time-restricted urine sampling was investigated using the rate of creatinine excretion. The mean coefficient of variation was found to be 42%, and inaccurate urine sampling appeared to cause variation in the AER. 2) The AER and albumin/creatinine ratio obtained in the outpatient setting were higher than those after bed rest, and urine collection at the time of outpatient examination was considered to be more useful than that after bed rest. To check variations in urine collection at the time of outpatient examination, the albumin/creatinine ratio in random urine samples was superior on the basis of the correlation coefficients to urine obtained after bed rest. 3) The urinary creatinine excretion rate showed a significant sex difference (males: 0.823 +/- 0.152 mg/g. creat., females: 0.577 +/- 0.194 mg/g. creat) (p less than 0.001), but there was no significant difference for BMI and age. The relationship between each level of microalbuminuria and the creatinine excretion rate did not change significantly. 4) The following formula was used to calculate the albumin/creatinine ratio corresponding to the AER. Albumin/creatinine ratio formula; (see text) An AER of 30 micrograms/min thus corresponds to an albumin/creatinine ratio of 36 mg/g. creat. for males and 51 mg/g. creat. for females. 5) The percentage of positive results for microalbuminuria in patients with NIDDM showed that the albumin/creatinine ratio and the AER were equal as diagnostic criteria, when the sex difference was taken into consideration. Thus, the albumin/creatinine ratio is equal to the AER for evaluation of microalbuminuria, and it is a simple and convenient test to use in daily clinical practice.     

The validity of screening based on spot morning urine samples to detect subjects with microalbuminuria in the general population

BACKGROUND: No study has yet investigated the validity of prescreening by albumin measurements in a spot morning urine sample to identify in the general population subjects with microalbuminuria. We therefore tested the diagnostic performance of urinary albumin concentration (UAC) and albumin-creatinine ratio (ACR), measured in a spot morning urine sample, in predicting a urinary albumin excretion (UAE) > or =30 mg in subsequent 24-hour urines (microalbuminuria). METHODS: Subjects (2527) participating in the PREVEND study, a representative sample from the general population, collected a spot morning urine sample and, on average, 77 days later, two 24-hour urine collections. RESULTS: The ROC curve of UAC in predicting microalbuminuria has an area-under-the-curve of 0.92 with a discriminator value of 11.2 mg/L. Using this cut-off value for UAC, sensitivity in predicting microalbuminuria is 85.0%, and specificity 85.0%. For ACR these values are, respectively: area-under-the-curve 0.93, discriminator value 9.9 mg/g, sensitivity 87.6%, and specificity 87.5%. Sensitivity for UAC in predicting microalbuminuria does not differ significantly from the sensitivity for ACR, whereas the difference between the specificities of UAC and ACR reaches statistical significance, but is numerically very small. In various subgroups characterized by differences in urinary creatinine excretion, the area-under-the-ROC curve, sensitivity, as well as specificity, do not increase relevantly compared to the results in the overall study population. This holds true for ACR as well as UAC. CONCLUSION: The diagnostic performance of measuring UAC in a spot morning urine sample in predicting microalbuminuria in subsequent 24-hour urine collections is satisfactory, and, moreover, comparable to that of measuring ACR. In order to keep the burden and costs involved in population screening for microalbuminuria as low as possible, we therefore propose prescreening by measuring UAC in a spot morning urine sample. Those subjects with a UAC above a certain predefined level (e.g., 11 mg/L) should be asked to collect timed urine samples.     

N-acetylcysteine for the prevention of contrast-induced nephropathy in patients with pre-existing renal insufficiency or diabetes: a systematic review and meta-analysis

Abstract

Purpose: To identify benefit of N-acetylcysteine (NAC) on patients with pre-existing renal insufficiency or diabetes. Background: NAC administration is a common method for prevention of contrast-induced nephropathy (CIN). Nevertheless, its benefit on patients with pre-existing renal insufficiency or diabetes remains uncertain and controversial. Methods: Randomized controlled trials (RCTs) to evaluate the efficacy of NAC for the prevention of CIN in patients with pre-existing renal insufficiency or diabetes were searched from the databases of MEDLINE, EMBASE, and Cochrane library. Pooled odds ratio (OR) with 95% confidence interval (95% CI) were calculated using fixed-effects model by the Mantel–Haenszel test. Results: Twenty RCTs involving 3466 subjects (1756 assigned to NAC and 1710 assigned to the control) were included in the pre-existing renal dysfunction group. Pooled analysis suggested a significant reduction in CIN among this group (OR, 0.76; 95% CI, 0.61–0.93; p?=?0.008). However, the nine trials comparing NAC versus control among patients with diabetes (NAC, 367 subjects; control, 358 subjects) showed no benefit of NAC for prevention of CIN (OR?=?0.87; 95% CI, 0.58–1.30; p?=?0.50). No significant heterogeneity was detected (p?=?0.07; I²?=?34% for the group of pre-existing renal dysfunction; p?=?0.40; I²?=?5% for the group of diabetes). Conclusion: Our results suggest that NAC decreases the incidence of contrast-induced nephropathy among patients with pre-existing renal insufficiency. The benefit was not existed in patients with diabetes.     

Microproteinuria predicts the severity of systemic effects of reperfusion injury following infrarenal aortic aneurysm surgery

Noncardiogenic pulmonary dysfunction can be demonstrated in all patients following elective aortic aneurysm repair and is a cause of postoperative morbidity. Aortic clamping and reperfusion initiate a systemic inflammatory response producing endothelial damage and increases in vascular permeability. In the lung this is manifest as pulmonary edema and in the kidney as detectable increases in urinary protein excretion (microproteinuria). Immunoassay of low-level protein excretion appears to provide an index of the systemic effects of local reperfusion injury and may allow early prediction of complications such as pulmonary edema. Hourly urinary albumin and IgG excretion was measured in 40 patients undergoing infrarenal aortic aneurysm repair and expressed as ratios to urinary creatinine (albumin/creatinine ratio [ACR] and IgG/creatinine ratio [IgGCR]). These were compared to clinical outcome. Pulmonary dysfunction was assessed according to Pao₂Fio₂ ratios and chest radiography. Within 180 minutes of beginning surgery all patients had significant increases in ACR and IgGCR. Ten patients who manifested respiratory dysfunction had significantly higher ACRs at 4 hours (median 84.8, 95% confidence intervals, range 47.7 to 136) than patients who made uneventful recoveries (median 16.6, 95% confidence intervals, range 7.9 to 31.7). IgGCR increases paralleled that of ACRs. Differences persisted for 24 hours. Urinary protein excretion rises rapidly during aortic surgery. The degree of increase appears to predict development of pulmonary dysfunction. This simple test may provide a rational basis for evaluation of therapeutic modalities to limit reperfusion injury in these patients.Presented at the Eighteenth Annual Meeting of the Peripheral Vascular Surgery Society, Washington, D.C., June 6, 1993.     

中国汉族人以尿白蛋白肌酐比值诊断微量白蛋白尿的界值研究

目的 探讨中国汉族人群以晨尿白蛋白肌酐比值（ACR）诊断微量白蛋白尿（MA）的界值。 方法 本研究对象来自于北京平谷区代谢综合征肾损害流行病学调查,随机整群抽取的部分受试者除外脓尿或者镜下血尿后自愿留取8 h过夜尿。以8 h尿白蛋白排泄率（UAE）作为诊断标准,应用受试者工作特征曲线（ROC）方法确定MA的诊断界值。 结果 （1）共1056人（男性494人、女性562人,年龄20~75岁）纳入本研究,MA的患病率为12.5%,临床蛋白尿患病率为1.7%。（2）ROC确定诊断MA的ACR下界值：男性1.95 g/mol（敏感性97.6%,特异性88.6%）,女性3.62 g/mol（敏感性83.8%,特异性89.1%）,总体受试者ACR下界值为2.78 g/mol（敏感性88.7%,特异性86.0%）;上界值：总体受试者ACR上界值为22.59 g/mol（敏感性100.0%,特异性98.8%）。（3）与8 h尿UAE诊断MA的一致性检验显示本研究按性别区分的诊断界值敏感性91.3%,特异性88.2%,阳性及阴性似然比为7.96和0.10,阳性及阴性预测值为56.9%和98.4%。 结论 晨尿诊断MA的ACR下界值存在性别差异,男性1.95 g/mol,女性3.62 g/mol,较目前国际推荐的性别特异性ACR诊断值偏高,具有良好的诊断性。     

Role of N-acetylcysteine on renal function in patients after orthotopic heart transplantation undergoing coronary angiography

INTRODUCTION: The aim of this study was to assess nephroprotective influence of intravenous N-acetylcysteine (NAC) on renal function after radiocontrast use in calcineurin inhibitor-treated patients after orthotopic heart transplantation (OHT). MATERIALS AND METHODS: We analyzed the results of 112 consecutive coronary angiography examinations (CAG). All patients received intravenous 500 mL multielectrolyte fluid (PWE) before catheterization. Group I of 55 randomly selected cases in addition were treated with 300 mg of NAC. The other 57 cases (group II) received only hydration. After catheterization, we administered 500 mL 0.9% saline with 20 mg furosemide. A nonionic, low-osmolality contrast agent (OPTIRAY) was used for all catheterizations. All patients underwent measurements of serum creatinine and creatinine clearance levels before and after the procedure (CREA0, CREA1, CC0, and CC1, respectively). We assessed the influence of NAC on CREA1 and the relative change of CREA1/CREA0 and CC1/CC0 ratios. RESULTS: In groups I and II we noticed decreased CC0 in 17 versus 22 cases (31% vs 39%), a relative change of CREA1/CREA0 ratio of 0% versus -3.95% and of CC1/CC0 ratio 0% versus 4, 11%, respectively. CIN was not recognized in any patient. None of the differences was significant. CONCLUSION: Intravenous NAC (300 mg) along with hydration before radiocontrast use had no impact on renal function in OHT patients undergoing CAG. It seems that there is no need for an additional preventive strategy apart from hydration and a small volume of low osmolar contrast in the majority of patients.     

Microalbumin measurement alone or calculation of the albumin/creatinine ratio for the screening of hypertension patients?

BACKGROUND: Spot urine sampling seems to be a reliable screening method for the detection of microalbuminuria in hypertensive patients. It remains unclear whether microalbumin measurement alone or calculation of the albumin/creatinine ratio (ACR) are more reliable for the detection of microalbuminuria in non-selected hypertensive patients. METHODS: Following collection of a spot, midstream urine sample, urine was collected for 24 h for the measurement of microalbumin in 264 hypertensive patients. We compared microalbumin concentration in the spot urine with microalbumin measured in the 24-h urine sample and examined the utility of the ACR in evaluating microalbuminuria in hypertensive patients. Pathologic microalbuminuria was assumed when the microalbumin concentration exceeded 30 mg/l in the 24-h urine sample. Diagnostic performance is expressed in terms of specificity, sensitivity, positive (PPV) and negative predictive value (NPV), and area under receiver operating characteristics curve (AUC). RESULTS: A total of 47 samples (17.8%) showed pathologic microalbuminuria in the 24-h urine sample. The diagnostic performance expressed as AUC was 0.94 (95% CI 0.90-0.98) for microalbumin measurement alone and 0.94 (95% CI 0.89-0.97) for ACR. The PPV and NPV were 44.2 and 97.9% for microalbumin measurement alone. ACR revealed a PPV of 29.3% and a NPV of 96.2% for males and 42.9 and 98% for females, if a cut-off value of 2.5 mg/mmol for males and of 4.0 mg/mmol for females was used. CONCLUSIONS: The ACR did not provide any advantage compared with microalbumin measurement alone, but requires an additional determination of creatinine and the use of gender-specific cut-off values. Therefore, measurement of microalbuminuria alone in the spot urine sample is more convenient in daily clinical practice and should be used as the screening method for hypertensive patients.     

Urinary excretion of vitamin A in critically ill patients complicated with acute renal failure

OBJECTIVE: Study the possible excretion of vitamin A in urine of critically ill patients complicated with acute renal failure. PATIENTS AND METHODS: Nine Intensive Care Unit patients, age 71.2 +/- 15.7 (mean +/- SD) with acute renal failure were studied. Urinary retinol, creatinine, protein, albumin, and serum creatinine were measured. RESULTS: All patients excreted retinol in urine; individual values ranged from 0.007 to 0.379 micromol retinol/mmol creatinine. There was no correlation of urinary retinol/creatinine ratio with serum creatinine or with urinary protein/creatinine and albumin/creatinine ratios. CONCLUSION: Excretion of retinol in urine may be indicative of acute renal failure in critically ill patients.     

Metabolic syndrome as a risk factor for contrast-induced nephropathy in non-diabetic elderly patients with renal impairment

BACKGROUND/AIMS: Metabolic syndrome (MS) as a risk factor for contrast-induced nephropathy (CIN) has not been studied. The aim of the present study was to assess the influence of MS on the development of CIN in patients undergoing coronary angiography. METHODS: This was a prospective cohort study. A total of 219 non-diabetic patients with reduced kidney function and age >or=60 years were divided into two groups (MS, n = 107 and non-MS, n = 112). CIN was defined as an increase of >or=25% in creatinine over the baseline value within 48 h of angiography. RESULTS: CIN occurred in 14% of the MS group and 3.6% of the non-MS group (p = 0.006). Serum creatinine increased from 1.06 +/- 0.17 to 1.12 +/- 0.27 mg/dl in the MS group and from 1.03 +/- 0.17 to 1.09 +/- 0.23 mg/dl in the non-MS group (p < 0.001). MS was a risk indicator of CIN [odds ratio (OR) 4.26; 95% confidence interval (95% CI) 1.19-15.25; p = 0.026). Impaired fasting glucose (OR 4.72; 95% CI 1.53-14.56; p = 0.007), high triglyceride (OR 4.06; 95% CI 1.22-13.44; p = 0.022), and multivessel involvement (OR 3.14; 95% CI 1.07-9.82; p = 0.038) in the MS group were predictors of CIN. CONCLUSION: Our data support the hypothesis that patients with MS are at risk of developing CIN.     

Rise in serum albumin and creatinine in the first half year on hemodialysis

Rise in serum albumin and creatinine in the first half year on hemodialysis. BACKGROUND: Serum albumin and creatinine have been reported to rise in new hemodialysis patients; however, these trends have not been quantitated in a stable cohort, and their determinants and prognostic value are unknown. METHODS: This study examined the changes in monthly values of serum albumin and creatinine over the first half year of hemodialysis in 115 patients who survived to the start of the sixth month. After verifying that the trends were approximately linear, we calculated the rates of rise (slope) of six predialysis values of serum albumin (months 1 through 6) and of creatinine (months 2 through 7) and examined their associations with age, diabetes, race, baseline 24-hour urine protein and creatinine excretion, and survival during the latter half of the first year. RESULTS: Serum albumin rose by 13% over months 1 through 6 [0.08 +/- 0.12 (SD) g/dl/month, P < 10-9 vs. zero slope]. Patients who survived the entire year had higher mean values for both serum albumin (month 1, P < 0.003; months 3 through 6, P < 10-3) and rate of rise of albumin (0.09 +/- 0.11 g/dl/month vs. 0.01 +/- 0.13 g/dl/month, P < 0.005) than patients who died during months 6 through 12, but the slope was not an independent predictor of survival after adjusting for serum albumin concentration. Baseline proteinuria correlated inversely with serum albumin measured at the first and second months (P < 0.005) and directly with the albumin slope (r = 0.49, P < 10-5). Serum creatinine rose by 12% between months 2 through 7 (0.12 +/- 0.47 mg/dl/month, P < 0.02). Survivors had a significantly higher mean baseline creatinine excretion (P < 0. 03) and serum creatinine (month 2, P < 0.03; months 3 through 7, P < 0.01) but only a marginally higher rate of rise of serum creatinine (0.16 +/- 0.47 mg/dl/month vs. -0.07 +/- 0.48 mg/dl/month, P < 0.06) than patients who died during the second half of the year. Baseline urinary creatinine excretion correlated directly with serum creatinine at month 2 (P < 0.01) and more strongly at months 3 through 7 (P < 10-3), as well as correlating with the creatinine slope (r = 0.26, P < 0.03). CONCLUSIONS: Serum albumin and creatinine rose by 12 to 13% during the first half year of hemodialysis in a stable cohort. The slope of serum albumin versus time predicted survival, but it was not as predictive as the absolute albumin concentration. The pattern of correlations of baseline urinary protein and creatinine excretion with the respective monthly serum values of albumin and creatinine and their slopes is consistent with the hypothesis that as residual renal function declines, progressive retention of protein and creatinine contributes to the respective rises in serum albumin and creatinine.