Gai Milo

The effect of cardiac angiography timing, contrast media dose, and preoperative renal function on acute renal failure after coronary artery bypass grafting.

OBJECTIVE Our objective was to assess the effect of the timing of cardiac angiography, contrast media dose, and preoperative renal function on the prevalence of acute renal failure after cardiac surgery. METHODS Data on 395 consecutive patients who underwent coronary artery bypass grafting were prospectively collected. Creatinine clearance was estimated by the Cockcroft-Gault equation. Patients were divided into 3 groups according to the time between cardiac angiography and surgery (group A, < or = 1 day; group B, > 1 day and < or = 5 days; group C, > 5 days). Patients who underwent a salvage operation or were receiving dialysis before surgery were excluded. Acute renal failure was defined as 25% decrease from baseline of estimated creatinine clearance and estimated creatinine clearance of 60 mL/min or less on postoperative day 3. Owing to differences in preoperative characteristics between groups, propensity score analysis was used to adjust those differences. RESULTS Acute renal failure developed in 13.6% of patients. Hospital mortality was 3.3% and was higher in patients in whom acute renal failure developed (22%) versus those in whom it did not (0.3%; P < .001). Multivariable analysis identified preoperative estimated creatinine clearance of 60 mL/min or less (odds ratio [OR], 7.1), operation within 24 hours of catheterization (OR = 3.7), use of more than 1.4 mL/kg of contrast media (OR = 3.4), lower hemoglobin level (OR = 1.3), older age (OR = 1.1), and lower weight (OR = 0.95) as independent predictors of postoperative acute renal failure. Analysis of interaction between contrast dose and time of surgery revealed that high contrast dose (>1.4 mL/kg) predicted acute renal failure if surgery was performed up to 5 days after angiography. CONCLUSIONS Whenever possible, coronary bypass grafting should be delayed for at least 5 days in patients who received a high contrast dose, especially if they also have preoperative reduced renal function.

Proximal Tubular Hypertrophy and Enlarged Glomerular and Proximal Tubular Urinary Space in Obese Subjects with Proteinuria

Background Obesity is associated with glomerular hyperfiltration, increased proximal tubular sodium reabsorption, glomerular enlargement and renal hypertrophy. A single experimental study reported an increased glomerular urinary space in obese dogs. Whether proximal tubular volume is increased in obese subjects and whether their glomerular and tubular urinary spaces are enlarged is unknown. Objective To determine whether proximal tubules and glomerular and tubular urinary space are enlarged in obese subjects with proteinuria and glomerular hyperfiltration. Methods Kidney biopsies from 11 non-diabetic obese with proteinuria and 14 non-diabetic lean patients with a creatinine clearance above 50 ml/min and with mild or no interstitial fibrosis were retrospectively analyzed using morphometric methods. The cross-sectional area of the proximal tubular epithelium and lumen, the volume of the glomerular tuft and of Bowman’s space and the nuclei number per tubular profile were estimated. Results Creatinine clearance was higher in the obese than in the lean group (P=0.03). Proteinuria was similarly increased in both groups. Compared to the lean group, the obese group displayed a 104% higher glomerular tuft volume (P=0.001), a 94% higher Bowman’s space volume (P=0.003), a 33% higher cross-sectional area of the proximal tubular epithelium (P=0.02) and a 54% higher cross-sectional area of the proximal tubular lumen (P=0.01). The nuclei number per proximal tubular profile was similar in both groups, suggesting that the increase in tubular volume is due to hypertrophy and not to hyperplasia. Conclusions Obesity-related glomerular hyperfiltration is associated with proximal tubular epithelial hypertrophy and increased glomerular and tubular urinary space volume in subjects with proteinuria. The expanded glomerular and urinary space is probably a direct consequence of glomerular hyperfiltration. These effects may be involved in the pathogenesis of obesity-related renal disease.

Association between the body mass index and chronic kidney disease in men and women. A population-based study from Israel

BACKGROUND Any association between the body mass index (BMI) and chronic kidney disease (CKD) has so far proved inconclusive. Most studies have estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) equation. This has recently been replaced by the more accurate Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. METHODS In a cross-sectional study, data from a screening centre in Israel, n = 21880 (32% women) were used to assess the prevalence of CKD defined as eGFR < 60 mL/min/1.73 m(2) in relation to BMI categories. The CKD-EPI equation was used to assess the eGFR. RESULTS CKD was found in 167 men and 45 women. Subjects with a BMI of 25-29.9 kg/m(2), compared with those with a BMI of <25 kg/m(2), had an odds ratio (OR; 95% confidence intervals) for CKD of 1.8 (1.2-2.7) and 3.4 (1.5-7.7) for men and women, respectively. Subjects with a BMI of 30-35 kg/m(2) had an OR of 2.5 (1.6-4.0) and 4.5 (1.7-11.7) for men and women, respectively. In comparable data, for subjects with a BMI > 35 kg/m(2) the OR was 2.7 (1.3-5.5) and 15.4 (6.4-36.7) for men and women, respectively. After multivariate adjustment for age, hypertension and diabetes mellitus, no association was found in men yet it persisted for women. This correlation in women, between the BMI and CKD, was attributed to the subcategory of severely obese women with a BMI of >35 kg/m(2). CONCLUSIONS Our study is the first to suggest that morbid obesity may be an independent factor related to CKD in women.

Duration of Antibacterial Treatment for Uncomplicated Urinary Tract Infection in Women

Background Uncomplicated urinary tract infection (UTI) is a common disease, occurring frequently in young sexually active women. In the past, seven day antibiotic therapy was recommended while the current practice is to treat uncomplicated UTI for three days. Objectives TO compare the efficacy and safety of three-day antibiotic therapy to multi-day therapy (five days or longer) on relief of symptoms and bacteriuria at short-term and long-term follow-up. Search strategy The Cochrane Library (Issue 1, 2004), the Cochrane Renal Group’s Register of trials (July 2003), EMBASE (January 1980 to August 2003), and MEDLINE (January 1966 to August 2003) were searched. We scanned references of all included studies and contacted the first or corresponding author of included trials and the pharmaceutical companies. Selection criteria Randomised controlled trials comparing three-days oral antibiotic therapy with multi-day therapy (five days and longer) for uncomplicated cystitis in 18 to 65 years old non-pregnant women without signs of upper UTI. Data collection and analysis Data concerning bacteriological and symptomatic failure rates, occurrence of pyelonephritis and adverse effects were extracted independently by two reviewers. Relative risk (RR) and their 95% confidence intervals (CI) were estimated. Outcomes were also extracted by intention-to-treat analysis whenever possible. Main results Thirty-two trials (9605 patients) were included. For symptomatic failure rates, no difference between three-day and 5-10 day antibiotic regimen was seen short-term (RR 1.06, 95% CI 0.88 to 1.28) and long-term follow-up (RR 1.09, 95% CI 0.94 to 1.27). Comparison of the bacteriological failure rates showed that three-day therapy was less effective than 5-10 day therapy for the short-term followup, however this difference was observed only in the subgroup of trials that used the same antibiotic in the two treatment arms (RR 1.37, 95% CI 1.07 to 1.74, P = 0.01). This difference was more significant at long-term follow-up (RR 1.43, 95% CI 1.19 to 1.73, P = 0.0002). Adverse effects were significantly more common in the 5-10 day treatment group (RR 0.83, 95% CI 0.74 to 0.93, P = 0.0010). Results were consistent for subgroup and sensitivity analyses. Authors’ conclusions Three days of antibiotic therapy is similar to 5-10 days in achieving symptomatic cure during uncomplicated UTI treatment, while the longer treatment is more effective in obtaining bacteriological cure. In spite of the higher rate of adverse effects, treatment for 5-10 days could be considered for treatment of women in whom eradication of bacteriuria is important. 1 Duration of antibacterial treatment for uncomplicated urinary tract infection in women (Review) Copyright

GFR in Patients with β-Thalassemia Major

BACKGROUND AND OBJECTIVES Patients with β-thalassemia major (TM) may have tubular dysfunction and glomerular dysfunction, primarily hyperfiltration, based on eGFR. Assessment of GFR based on serum creatinine concentration may overestimate GFR in these patients. This study sought to determine GFR by using inulin clearance and compare it with measured creatinine clearance (Ccr) and eGFR. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS Patients followed up in an Israeli thalassemia clinic who had been regularly transfused for years and treated with deferasirox were included in the study. They were studied by inulin clearance, Ccr, the CKD Epidemiology Collaboration and the Modification of Diet in Renal Disease equations for eGFR, and the Cockcroft-Gault estimation for Ccr. Expected creatinine excretion rate and tubular creatinine secretion rate were calculated. RESULTS Nine white patients were studied. Results, given as medians, were as follows: serum creatinine was 0.59 mg/dl (below normal limits); GFR was low (76.6 ml/min per 1.73 m(2)) and reached the level of CKD; Ccr was 134.9 ml/min per 1.73 m(2), higher than the GFR because of a tubular creatinine secretion rate of 30.3 ml/min per 1.73 m(2) (this accounted for 40% of the Ccr); and eGFR calculated by the CKD Epidemiology Collaboration and Modification of Diet in Renal Disease equations and Cockcroft-Gault-estimated Ccr were 133, 141, and 168 ml/min per 1.73 m(2), respectively. These latter values were significantly higher than the GFR, reaching the hyperfiltration range, and indicated that the estimation techniques were clinically unacceptable as a method for measuring kidney function compared with the GFR according to Bland and Altman analyses. CONCLUSIONS Contrary to previous reports, patients in this study with TM had normal or reduced GFR. The estimating methods showed erroneous overestimation of GFR and were clinically unacceptable for GFR measurements in patients with TM by Bland and Altman analysis. Therefore, more accurate methods should be used for early detection of reduced GFR and prevention of its further decline toward CKD in these patients.