Comparison of serum creatinine and cystatin C for early diagnosis of contrast-induced nephropathy after coronary angiography and interventions.

BACKGROUND: The diagnostic accuracy of serum creatinine and cystatin C (Cys) as early predictors of contrast-induced nephropathy (CIN) has been debated. We investigated the diagnostic sensitivities, diagnostic specificities, and variations from baseline for serum creatinine and Cys in CIN. METHODS: We prospectively evaluated 166 patients at risk for CIN at baseline, and at 12, 24, and 48 h after exposure to contrast media. CIN occurred in 30 patients (18%). Changes (Δ) compared to baseline in serum creatinine and Cys were evaluated at the predefined time points. ROC curve analysis was performed for the Δ 12-h basal serum creatinine and Cys. RESULTS: The Δ serum creatinine at 12 h from baseline was the earliest predictor of CIN [area under the ROC curve (AUC) = 0.80; P < 0.001]. The Δ serum creatinine 15% variation [0.15 mg/dL (13.2 µmol/L)] yielded 43% diagnostic sensitivity and 93% diagnostic specificity. The ΔCys at 12 h from baseline performed significantly worse than serum creatinine (AUC = 0.48; P = 0.74). CONCLUSIONS: Variations from the serum creatinine baseline offer better diagnostic accuracy for predicting CIN at an earlier stage than similar variations in Cys. An additional diagnostic value of Cys over the determination of serum creatinine in the setting of CIN was not observed.

Diagnostic accuracy of a reagent strip for assessing urinary albumin excretion in the general population.

BACKGROUND: Albuminuria is a sensitive marker of renal derangement and has been included in a number of studies investigating chronic kidney diseases (CKDs). This study is aimed to evaluate the diagnostic performances of a strip for measuring the albumin/creatinine ratio (ACR) in the general population and to compare it with those found in a diabetic population. METHODS: Urine samples were obtained from 201 consecutive subjects enrolled in an epidemiological study and from 259 type 2 diabetic patients. Urine was tested for albumin and creatinine using the strip (Clinitek Microalbumin) and laboratory methods. A hundred samples were stored under various conditions to assess analyte stability. RESULTS: In the general population, the strip test reached a 90% sensitivity and 91% specificity, considering the laboratory method as the 'gold standard', sparing >80% of subjects the laboratory tests at the expense of a 1% false negative rate and an 8% false positive rate. Regarding sensitivity and specificity, the ACR test performs very similarly in the general population and in the diabetics. The stability study showed that storage at -20 degrees C induced a significant decrease in the albumin concentration with both methods, such that 5% of the samples were re-classified in the lower ACR class. Storage at -80 degrees C for up to 12 months did not affect the measurement with both methods. CONCLUSION: Clinitek Microalbumin strips can be used for screening purposes in the general population since they correctly classify a significant percentage of subjects, particularly those with a normal albuminuria. Storage at -80 degrees C does not affect strip results. Screening with the strip and confirming positive results with a wet chemistry method are an efficient strategy for detecting albuminuria 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.

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.

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.