Predictive risk factors for chronic renal failure in primary high-grade vesico-ureteric reflux

Impact of Urinary Tract Infection on Progression of Renal Scars and Formation of New Scars in Patients with Primary Vesicoureteric Reflux

INTRODUCTION

Primary vesicoureteric reflux (VUR) is a prevalent cause of end-stage renal failure in children. Scars on radionuclide imaging indicate irreparable damage to the growing kidneys. This study aims to determine whether a urinary tract infection (UTI) associated with primary VUR promotes the development of new renal scars or progression in the pre-existing ones.

MATERIALS AND METHODS

Children with primary VUR on continuous antibiotic prophylaxis at a tertiary teaching hospital's paediatric nephrourology clinic were observed prospectively. At recruitment, a renal cortical (dimercaptosuccinic acid [DMSA]) scan was done, and the children were followed up every 3 months. Breakthrough UTIs were documented, and follow-up DMSA scans were performed to document new scarring/grade advancement of existing scars in the renoureteric units (RUUs).

RESULTS

Seventy-two RUUs in 36 patients were monitored. Fifty-four (75%) RUUs were exposed to VUR of different grades, and 46 (85.1%) had a UTI. On the DMSA scan, these showed new scar development in 10/18 (55%) RUUs and scar progression in 13/28 (46.4%) RUUs. Of the 8 RUUs with VUR and without UTI, new scars manifest in 4/5 (80%) and progressed in 1/3 (33%). On univariate analysis, there was no significant difference in the formation of new scars or scar advancement on the DMSA scan between RUU with VUR and UTI and those without UTI. There was a significant positive correlation between the scarring on DMSA scan and the grade of reflux (P < 0.001).

CONCLUSION

Primary VUR patients had fresh or progressed scarring regardless of urinary infection. A higher VUR grade at presentation was a significant risk factor for scarring.

Vesicoureteral reflux is associated with increased risk of chronic kidney disease: A nationwide cohort study

The association between vesicoureteral reflux (VUR) and chronic kidney disease (CKD) risk remains unestablished. We investigated the incidence of CKD in children with VUR in Taiwan and evaluated whether they had a higher risk of CKD than the general population. A nationwide population-based cohort study was conducted among children with VUR identified using Taiwan's National Health Insurance Research Database from 2000 to 2013. VUR was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes. We identified the children with VUR and randomly selected comparison children according to a 1:1 ratio, matching them by age, gender, index year and comorbidity using data from the National Health Insurance Research Database. In total, 8648 children with VUR and 8648 comparison children were included. All children were followed from the study date until a diagnosis of CKD, termination of insurance, or the end of 2013. Cox proportional hazards regressions were performed to compare the hazard ratios for CKD between the 2 cohorts. Incident cases of CKD were identified. After adjustment for potential confounders, the study cohort was independently associated with a higher risk of CKD (adjusted hazard ratio, 3.78; 95% confidence interval, 2.10-7.18). This population-based cohort study indicated that children with VUR have a higher risk of CKD than those without VUR.

The long-term prognosis of nephropathy in operated reflux

OBJECTIVE

To investigate the postoperative long-term prognosis and the factors predicting the renal function of patients with reflux nephropathy. As the serum creatinine (s-Cr) level tends to increase during infancy, the degree of reflux and renal parenchymal damage are thought to be more important factors in pediatric patients than in older patients.

MATERIALS AND METHODS

This study examined s-Cr, urinary protein, and blood pressure of patients who underwent anti-reflux surgery 10 years before. It also calculated the postoperative estimated glomerular filtration rate (eGFR) and examined the correlation between the eGFR and preoperative factors (age, gender, number of urinary tract infections [UTIs], primary diagnosis, reflux grade, percentage of dimercaptosuccinic acid uptake, degree of renal parenchymal damage, s-Cr abnormality, proteinuria, and hypertension), and analyzed the factors associated with the long-term prognosis.

RESULTS

The study population was 51 infants (37 boys and 14 girls). The mean age of the patients before surgery and at the follow-up examination was 3.41 ± 3.61 and 14.63 ± 3.74 years, respectively. After surgery, the s-Cr, urinary protein, and blood pressure values showed (44.7%, 26.7%, and 18.2%, respectively) were abnormal. The postoperative eGFR was a mean 90.27 ± 20.42 ml/min/1.73 m² and primary correlated with an older age (P = 0.0361), no UTI at the primary diagnosis (P = 0.0044), reflux grade ≥8 (P = 0.0180), degree of renal parenchymal damage (group ≥2b, P < 0.0001), s-Cr abnormality (P < 0.0001), and proteinuria (P = 0.0001) at baseline. A total of 20 patients had chronic kidney disease (CKD; Fig. 1). The multiple regression analysis of these factors revealed that an older age (P = 0.0021), reflux grade ≥8 (P = 0.0134), and degree of renal parenchymal damage (group ≥2b, P < 0.0001) were significantly associated with the long-term postoperative prognosis of reflux nephropathy. Using these three factors, this study derived a multiple regression equation estimating eGFR in the 10th year after surgery (Fig. 1).

DISCUSSION

In this study, severe vesico-ureteral reflux (reflux grade ≥8) and severe renal parenchymal damage (group ≥2b) were associated with a long-term decrease in the eGFR. In particular, renal parenchymal damage was closely correlated with the postoperative eGFR; thus, this was clearly a critical factor. The age at surgery showed a better correlation with the postoperative eGFR in the multiple regression analysis; thus, age was regarded as an independent prognostic factor.

CONCLUSIONS

The age, reflux grade, and degree of renal parenchymal damage at baseline were factors that affected the long-term postoperative prognosis of reflux nephropathy. Patients with high-grade reflux and severe renal parenchymal damage were more likely to show a reduced CKD level at 10 years after anti-reflux surgery.

Predictors of Renal Dysfunction in Adults with Childhood Vesicoureteral Reflux after Long-Term Follow-Up

BACKGROUND:

Triad of childhood vesicoureteral reflux (VUR), urinary infection (UTI) and renal scarring might initiate potentially serious consequences that lead to renal dysfunction manifested at the second or third decade of life.

AIM:

To identify the risk factors predictive for renal dysfunction in adults with primary VUR after long-term follow-up.

METHODS:

We evaluated the records of 101 children (94.1% female, 5.9% male) at a median age of 5.2 ± 2.3 years (1-12 years), suffering from UTI and VUR. The patients were interviewed after mean 21 years from the first episodes of VUR (8 to 32 years). Renal function was determined from the estimated glomerular filtration rate (eGFR).

RESULTS:

Renal scarring was detected in 68.3% out of 82 patients and bilateral one in 7.3% patients. Linear regression analysis revealed that presence of proteinuria (B = -33.7, p=0.0001), the greater number of years from VUR diagnosis (B = -1.6, p = 0.002) and renal scarring (B = -14.8, p = 0.005) appeared as independent predictors of reduced global eGFRcreat. The same variables plus microalbuminuria (B = -1.0, p = 0.012) appeared as independent predictors of reduced global eGFRcreat-cys. Bilateral scarring (OR=25.5, p = 0.003) appeared as independent predictor of greater risk for CKD assessed using eGFRcreat while greater number of years from VUR diagnosis (OR = 1.7, p = 0.092), microalbuminuria (OR = 1.3, p = 0.047) and again bilateral scarring (OR = 31.3, p = 0.040) appeared as predictors of risk for CKD assessed using eGFRcreat-cys.

CONCLUSION:

Identification of those with an increased risk of progression to CKD should be the goal in all patients with childhood VUR. Their systematic follow-up should be till adulthood and older age.

Renal development in the fetus and premature infant

Congenital abnormalities of the kidney and urinary tract (CAKUT) are one of the leading congenital defects to be identified on prenatal ultrasound. CAKUT represent a broad spectrum of abnormalities, from transient hydronephrosis to severe bilateral renal agenesis. CAKUT are a major contributor to chronic and end stage kidney disease (CKD/ESKD) in children. Prenatal imaging is useful to identify CAKUT, but will not detect all defects. Both genetic abnormalities and the fetal environment contribute to CAKUT. Monogenic gene mutations identified in human CAKUT have advanced our understanding of molecular mechanisms of renal development. Low nephron number and solitary kidneys are associated with increased risk of adult onset CKD and ESKD. Premature and low birth weight infants represent a high risk population for low nephron number. Additional research is needed to identify biomarkers and appropriate follow-up of premature and low birth weight infants into adulthood.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

Predictive Factors of Chronic Kidney Disease in Patients with Vesicoureteral Reflux Treated Surgically and Followed after Puberty

PURPOSE

We delineated clinical features and determined predictors of chronic kidney disease during long-term postpubertal followup in patients with vesicoureteral reflux treated surgically.

MATERIALS AND METHODS

We analyzed the data of 101 patients who were surgically treated for vesicoureteral reflux and had gone through puberty. Patients underwent preoperative and postoperative voiding cystourethrography to assess reflux status, and dimercaptosuccinic acid scan to assess renal cortical defects. We compared several variables preoperatively and postpubertally, including body mass index; blood urea nitrogen, creatinine and uric acid levels; estimated glomerular filtration rate; microalbuminuria; blood pressure; renal function and renal scarring. Kaplan-Meier analysis was used to predict chronic kidney disease-free survival rates throughout the followup periods. Cox regression model was adopted to identify independent predictors of chronic kidney disease. We defined chronic kidney disease as estimated glomerular filtration rate less than 60 ml/minute/1.73 m(2).

RESULTS

Median followup was 100.0 months (IQR 69.0 to 136.5). Median age was 16 years at last followup (IQR 14 to 18). A total of 11 patients (10.9%) were diagnosed with de novo chronic kidney disease during postpubertal followup. It is noteworthy that serum uric acid levels (HR 1.96) and presence of high grade reflux (HR 7.40) were significant predictors of chronic kidney disease on multivariate analysis.

CONCLUSIONS

In children who were treated surgically for vesicoureteral reflux preoperative uric acid levels and high grade reflux were independent predictors of de novo chronic kidney disease during postpubertal followup. Our results offer valuable information for predicting long-term renal outcomes in patients with vesicoureteral reflux treated surgically.

Vesicoureteral Reflux in Pediatric Age: Where are we Today?

Although the diagnosis of vesicoureteral reflux and of reflux nephropathy is a well-established and shared procedure, its treatment nowadays is still very controversial. New developments on the knowledge of pathophysiology of renal damage associated to reflux opened the way towards a different diagnostic work-up and different therapeutic approaches.

Recently, the “top-down” diagnostic approach has gained wider interest, versus the “down-top” protocol. The attention has recently focused on the renal parenchyma damage and less interest has been given to the presence and the radiological degree of vesicoureteral reflux.

The review criteria were based on an in-depth search of references conducted on PubMed, using the terms “vesicoureteral reflux”, “children”, “incidence”, “etiology”, “diagnosis”, “treatment” and “outcomes”. The selection of the papers cited in this review was influenced by the content and the relevance to the points focused in the article.

Conservative approaches include no treatment option with watchful waiting, long-term antibiotic prophylaxis and bladder rehabilitation. The operative treatment consists of endoscopic, open, laparoscopic and robotic procedures to stop the refluxing ureter.

No final consensus has been achieved in literature yet, and further studies are necessary in order to better define the subset of children at risk of developing progression of renal damage.

This review aims to clarify the diagnostic management and the urological-nephrological treatment of reflux in pediatric age, on the basis of a review of the best-published evidence.

Differences in urodynamic variables for vesicoureteral reflux depending on the neurogenic bladder type

Objective

To compare the urodynamic study variables at the onset of vesicoureteral reflux (VUR) between the overactive and underactive bladders in patients with spinal cord injury who presented with VUR.

Methods

A total of 28 (13 cases of detrusor overactivity and 15 detrusor underactivity) men were enrolled. We compared the urodynamic variables between the two groups; detrusor pressure and bladder compliance, the infused volume at the onset of VUR measured on a voiding cystourethrography and cystometric capacity, maximum detrusor pressure, and bladder compliance during filling cystometry were recorded.

Results

At the onset of VUR, the bladder volume and compliance, except for the detrusor pressure, showed a significant difference between the two groups. The detrusor pressure, bladder volume, and bladder compliance relative to the cystometric capacity showed a significant difference between the two groups. The detrusor pressure, bladder volume, and bladder compliance at the onset of VUR relative to the cystometric bladder capacity did not show any significant difference between the two groups.

Conclusion

There were differences in some variables at the onset of VUR depending on the type of neurogenic bladder. The VUR occurred at a lower capacity in neurogenic bladder with detrusor overactivity than in neurogenic bladder with detrusor underactivity at the same pressure. VUR occurred at a lower intravesical pressure compared to that known as the critical detrusor pressure (≥40 cm H₂O) required for the development of VUR. The results of our study demonstrate that the detrusor pressure should be maintained lower than the well known effective critical detrusor pressure for the prevention and treatment of VUR.

Prognostic factors of endoscopic treatment of vesicoureteral reflux in spinal cord injured patients

INTRODUCTION

Vesicoureteral reflux (VUR) is an important complication in patients with spinal cord injury due to its frequency and morbidity. One of the most extended therapeutic options is endoscopic injection of obliteration substances in the urethral meatus.

OBJECTIVE

To analyze the prognostic factors of VUR treatment using obliterative substances in patients with spinal cord injury.

MATERIAL AND METHODS

A prospective study was performed in a cohort of 76 patients (age 48.9±14.4 years), of both genders, with spinal cord injuries, who underwent endoscopic treatment of the VUR during the years 2008 to 2011. In all the patients, a clinical history was obtained and a pre-operative videourodynamic study was performed. Another study was carried out at 7.32 months (standard deviation: 6.28 months) of the intervention. Treatment consisted in endoscopic injection of dextranomer/hyaluronic acid copolymer (62 cases) and polydimethylsiloxane (14). The statistical tests applied were the Fisher's exact test and the Student's T test comparing the means. Bilateral significance level was established at 95%.

RESULTS

Resolution of VUR was achieved in 46 cases (61%). The statistically significant prognostic factors were age (younger aging cured patients), bilaterality and reflects great (greater grade in bilaterality in the cases with persistence of reflux) and presence of neurogenic detrusor overactivity (greater percentage in the cases of reflux persistence). Stress urinary incontinence (greater percentage in cured patients), contractile potency (lower percentage in cured patients) and urethral resistance (greater percentage in cured patients) were also statistically significant prognostic factors.

CONCLUSIONS

Among the prognostic factors that affected the endoscopic treatment results of the VUR in patients with neurogenic lower urinary tract dysfunction (NLUTD), anatomical as well as functional factors were found.

Risk factors for renal scarring and deterioration of renal function in primary vesico-ureteral reflux children: a long-term follow-up retrospective cohort study

BACKGROUND AND PURPOSE

The aim was to identify the risk factors for renal scarring and deteriorating renal function in children with primary vesico-ureteral reflux (VUR).

MATERIALS AND METHODS

Patients with primary VUR admitted to the National Cheng Kung University Hospital were retrospectively analyzed. The outcomes were renal scarring, assessed by technetium-99 m dimercaptosuccinic acid scanning, and renal function, assessed by estimated glomerular filtration rate. Univariate and multivariate models were applied to identify the corresponding independent predictors.

RESULTS

A total of 173 patients with primary VUR were recruited. The median age of VUR diagnosis was 10.0 months (IQR: 4.0-43.0 months). After adjusting for confounding factors, it was found that older age of VUR diagnosis (≥5 years vs. <1 year, adjusted OR = 2.78, 95% CI = 1.00-7.70, p = 0.049), higher grade of VUR (high grade [IV-V] vs. none, adjusted OR = 15.17, 95% CI = 5.33-43.19, p<0.0001; low grade [I-III] vs. none, adjusted OR = 5.72, 95% CI = 2.43-13.45, p<0.0001), and higher number of UTI (≥2 vs. 0, adjusted OR = 3.21, 95% CI = 1.06-9.76, p = 0.039) were risk factors for renal scarring, whereas a younger age of VUR diagnosis (≥5 years vs. <1 year, adjusted HR = 0.16, 95% CI: 0.05-0.51, p = 0.002), renal scarring (yes vs. no, adjusted HR = 3.66, 95% CI: 1.32-10.16, p = 0.013), and APN (yes vs. no, adjusted HR = 3.10, 95% CI: 1.05-9.14, p = 0.041) were risk factors for developing chronic kidney disease stage 2 or higher.

CONCLUSIONS

Our findings expand on the current knowledge of risk factors for renal scarring and deteriorating renal function, and this information can be used to modify the management and treatment of VUR.

[Primary vesicoureteral reflux]

The never ending discussion about the diagnostics and treatment of vesicoureteral reflux (VUR) now includes arguments for diagnostic nihilism as well as invasive diagnostics and therapy, which is reminiscent of the debate on prostate cancer in adulthood. The common goal of all currently competing diagnostic strategies and approaches is the prevention of renal scars by the most effective and least burdensome approach. There is a difference between acquired pyelonephritic scars with VUR (acquired reflux nephropathy) and congenital reflux nephropathy (primary dysplasia) which cannot be influenced by any therapy.The VUR can be verified by conventional radiological voiding cystourethrography (VCUG), by urosonography, radionuclide cystography or even by magnetic resonance imaging (MRI). The guidelines of the European Association of Urology/European Society for Paediatric Urology (EAU/ESPU) recommend radiological screening for VUR after the first febrile urinary tract infection. Significant risk factors in patients with VUR are recurrent urinary tract infections (UTI) and parenchymal scarring and the patients should undergo patient and risk-adapted therapy. Infants with dilating reflux have a higher risk of renal scarring than those without dilatation of the renal pelvis. Bladder dysfunction or dysfunctional elimination syndrome represents a well-known but previously neglected risk factor in combination with VUR and should be treated prior to any surgical intervention as far as is possible.Certainly not every patient with VUR needs therapy. The current treatment strategies take into account age and gender, the presence of dysplastic or pyelonephritic renal scars, the clinical symptoms, bladder dysfunction and frequency and severity of recurrent UTI as criteria for the therapy decision. The use of an antibacterial prophylaxis as well as the duration is controversially discussed. Endoscopic therapy can be a good alternative to antibacterial prophylaxis or a surveillance strategy in patients with low grade VUR. In patients with dilating VUR and given indications for surgery, endoscopic treatment can be offered. However, parents should be completely informed about the significantly lower success rate of endoscopic therapy compared to open surgical procedures. The open surgical techniques guarantee the highest success rates and should be used in patients with a dilating VUR and high risk of renal damage.

Predicting factors of breakthrough infection in children with primary vesicoureteral reflux

PURPOSE

Many pediatric urologists still favor using prophylactic antibiotics to treat children with vesicoureteral reflux (VUR). However, breakthrough infection sometimes occurs, leading to significant increases in morbidity as a result of renal scarring. Therefore, we tested whether abnormal renal scan and other factors are predictive of breakthrough infection using univariate analyses.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 163 consecutive children who were diagnosed with vesicoureteral reflux between November 1997 and June 2010. Clinical parameters for the statistical analysis included form of presentation, gender, age, VUR grade, laterality, presence of intrarenal reflux, class of antibiotic drug, and presence of abnormal renal scan by Dimercapto-succinic acid. Clinical parameters used for prognostic factors were established by univariate analyses. Fisher's exact test and unpaired t-test were done using SPSS software [SPSS ver. 12.0 (SPSS Inc., Chicago, IL, USA)].

RESULTS

Breakthrough infection developed in 61 children (48.0%). A total of 58 children (45.7%) had abnormal renal scans. Time to development of breakthrough infection was significantly longer in girls (9.0±8.2 months) than in boys (5.8±4.8 months, p<0.05). On univariate analysis, though statistically not significant, the most predictive factor of breakthrough infection was abnormal renal scan (p=0.062). In patients with abnormal renal scans, breakthrough infection was not associated with mode of presentation, gender, grade or prophylactic antibiotics. However, there was a significant difference between patients younger than 1 year and those 1 year old or older. Mean±SD age at diagnosis of VUR in patients with breakthrough infection (1.14±3.14) was significantly younger than in those without breakthrough infection (5.05±3.31, p=0.009). There was also a significant difference between patients with bilateral or unilateral reflux (p=0.028).

CONCLUSION

Our data showed that abnormal renal scan was the most predictive factor of breakthrough infection and demonstrated statistical significance in patients under the age of 1 year. Parents and physicians should remain aware that these patients are at high risk of breakthrough urinary tract infection, which may potentially lead to renal damage.

Is a routine voiding cystourethrogram necessary in children after the first febrile urinary tract infection?

AIM

The aim of this study was to estimate the value of identifying vesicoureteral reflux (VUR) on a voiding cystourethrogram (VCUG) and the benefit of VUR management according to imaging strategies at the first febrile urinary tract infection (UTI).

METHODS

Children aged 1-144 months (n = 618) with the first febrile UTI admitted at our hospital from 2000 to 2009 were enrolled. In all patients, renal sonogram (US), (99m) Tc-dimercaptosuccinic acid (DMSA) renal scanning and VCUG were performed. Retrospective analyses per patient and per renal unit were performed.

RESULTS

Abnormal US or DMSA scans had a sensitivity of 100% and a negative predictive value (NPV) of 100% to detect high-grade reflux. In hydronephrotic kidneys, DMSA scanning had a sensitivity of 88.2% and a NPV of 97.1% to detect high-grade reflux.

CONCLUSION

Routine VCUG is not required after the first febrile UTI in patients with normal US or normal DMSA scan. Even if the US reveals hydronephrosis, routine VCUG is not necessary if the DMSA findings are normal. It is recommended that children who did not receive both a DMSA scan and VCUG after the first febrile UTI should be followed up over the long term.

Urological disorders in chronic kidney disease in children cohort: clinical characteristics and estimation of glomerular filtration rate

PURPOSE

Urological disorders are the most common cause of pediatric chronic kidney disease. We determined the characteristics of children with urological disorders and assessed the agreement between the newly developed bedside glomerular filtration rate estimating formula with measured glomerular filtration rate in 586 patients in the Chronic Kidney Disease in Children study.

MATERIALS AND METHODS

The Chronic Kidney Disease in Children study is a prospective, observational cohort of children recruited from 48 sites in the United States and Canada. Eligibility requirements include age 1 to 16 years and estimated glomerular filtration rate by original Schwartz formula 30 to 90 ml/min/1.73 m(2). Baseline demographics, clinical variables and glomerular filtration rate were assessed. Bland-Altman analysis was conducted to assess agreement between estimated and measured glomerular filtration rates.

RESULTS

Of the 586 participants with at least 1 glomerular filtration rate measurement 348 (59%) had an underlying urological diagnosis (obstructive uropathy in 118, aplastic/hypoplastic/dysplastic kidneys in 104, reflux in 87 and other condition in 39). Among these patients median age was 9 years, duration of chronic kidney disease was 7 years and age at first visit with a urologist was less than 1 year. Of the patients 67% were male, 67% were white and 21% had a low birth weight. Median height was in the 24th percentile. Median glomerular filtration rate as measured by iohexol plasma disappearance was 44.8 ml/min/1.73 m(2). Median glomerular filtration rate as estimated by the Chronic Kidney Disease in Children bedside equation was 44.3 ml/min/1.73 m(2) (bias = -0.5, 95% CI -1.7 to 0.7, p = 0.44).

CONCLUSIONS

Underlying urological causes of chronic kidney disease were present in 59% of study participants. These children were diagnosed early in life, and many had low birth weight and growth delay. There is good agreement between the newly developed Chronic Kidney Disease in Children estimating equations and measured glomerular filtration rate in this population.

Acute Tc-99m DMSA scan for identifying dilating vesicoureteral reflux in children: a meta-analysis

Controversy exists regarding the type and/or sequence of imaging studies needed during the first febrile urinary tract infection (UTI) in young children. Several investigators have claimed that because acute-phase Tc-99m dimercaptosuccinic acid (DMSA) renal-scan results are abnormal in the presence of dilating vesicoureteral reflux, a normal DMSA-scan result makes voiding cystourethrography (VCUG) unnecessary in the primary examination of infants with UTI. To evaluate the accuracy of acute-phase DMSA scanning in identifying dilating (grades III through V) vesicoureteral reflux documented by VCUG in children with a first febrile UTI, we performed a meta-analysis of the accuracy of diagnostic tests as reported from relevant studies identified through the PubMed and Scopus databases. Patient-based and renal unit-based analyses were performed. Overall, 13 cohort studies were identified. Nine studies involved patients younger than 2 years, 3 involved children aged 16 years or younger, and 1 involved exclusively neonates. Girls constituted 22% to 85% of the involved children. Pooled (95% confidence intervals) sensitivity and specificity rates of DMSA scanning were 79% and 53%, respectively, for the patient-based analysis (8 studies) and 60% and 65% for the renal unit-based analysis (5 studies). The respective areas under the hierarchical summary receiver operating curves were 0.71 and 0.67. Marked statistical heterogeneity was observed in both analyses, as indicated by I(2) test values of 91% and 87%, respectively. Acute-phase DMSA renal scanning cannot be recommended as replacement for VCUG in the evaluation of young children with a first febrile UTI.

Urodynamics investigation on children with vesicoureteral reflux identifies overactive bladder and poor compliance in those with voiding dysfunction

BACKGROUND

Up to 50% of children with vesicoureteral reflux (VUR) may have associated voiding dysfunction. It is thought to be an important determinate of the severity and resolution of VUR; however, to date there has been no objective measurement defining the impact of voiding dysfunction in children with VUR. The purpose of this study is to compare the urodynamic parameters of children with VUR who have and do not have symptomatic voiding dysfunction.

METHODS

We performed a retrospective study of 138 children with a diagnosis of primary VUR who underwent urodynamic investigations. Information regarding patient demographics, grade and laterality of VUR and clinical history of bladder dysfunction were assessed. Urodynamic parameters recorded included detrusor overactivity, early and late compliance, voiding pressure, post-void residual volume and functional bladder capacity. Statistical analysis was performed using t Student analysis, Pearson's χ(2) test or Fischer's exact test, with a p < 0.05 as being significant.

RESULTS

The mean age of the patients at the time of urodynamic evaluation was 5.8 years (SD 4.4). 30% had symptomatic voiding dysfunction based on the clinical history. Children without a history of voiding dysfunction had higher grades of VUR as compared to those with it (p = 0.002). Bladder hypertone, detrusor overactivity, detrusor hypereflexia and poor late bladder compliance presented a statistically significant higher incidence the incidence of bladder overactivity and poor late bladder compliance was higher in children with bladder dysfunction than those without it.

CONCLUSION

Our findings suggest that voiding dysfunction does have objective and quantifiable effects on bladder dynamics. Urodynamic evaluation may play a role in the management of children with VUR by identifying those with bladder dysfunction secondary to abnormal voiding habits.

Prenatal diagnosis: what do we know of long-term outcomes?

Although prenatal diagnosis has been a prominent feature of Paediatric Urology for more than two decades the published literature has been largely characterized by studies reporting short to medium-term follow up. This deficiency is now being addressed by the growing availability of published and unpublished long-term outcome data for a range of prenatally detected anomalies. This review analyses the evidence on long-term outcomes which is provided by studies with mean or median follow- up exceeding 5 years, with particular emphasis on the small number of studies reporting follow -up at 10 years and beyond. The natural history and outcome of conservatively managed uropathies is considered in conjunction with an appraisal of evidence- based indications for surgical intervention. This review evaluates the relative benefits and drawbacks of prenatal diagnosis for children and their parents and also considers the impact of prenatal diagnosis on the delivery of Paediatric Urological services and specialist training.

Controversies in the management of vesicoureteral reflux: the rationale for the RIVUR study

The current management of vesicoureteral reflux (VUR) focuses on the prevention of urinary tract infections (UTI), with curative surgery being limited to those children that fail conservative measures. This is based on the assumption that UTIs are preventable with the use of prophylatic antibiotics, leading to reduction of renal scarring, and the possibility that VUR in children can resolve spontaneously.

METHODS

Review of the recent literature has demonstrated a growing concern that antibiotic prophylaxis may not lead to prevention of UTIs. Additionally, data indicate that renal scarring may not be preventable with antibiotic prophylaxis or even surgical correction of VUR. An overview of all of the current controversies is presented in this paper.

RESULTS

Does antibiotic prophylaxis lead to reduction in UTIs in children with VUR? To address this question, the National Institutes of Health have developed a randomized placebo-controlled study of children with VUR (the RIVUR Study), identified following the development of a UTI.

CONCLUSIONS

There are far reaching consequences of the results of the RIVUR Study. If antibiotic prophylaxis does not prevent UTI in children with VUR, or lead to reduction in renal scarring, does identification of VUR provide any benefits? Perhaps appropriate treatment of UTI may be all that is necessary for preserving renal function. Final answers will have to wait until the completion of this study.

Predictors of renal scar in children with urinary infection and vesicoureteral reflux

We evaluated the predictors of renal scar in children with urinary tract infections (UTIs) having primary vesicoureteral reflux (VUR). Data of patients who were examined by dimercaptosuccinic acid (DMSA) scintigraphy between 1995 and 2005 were evaluated retrospectively. Gender, age, reflux grade, presence/development of scarring, breakthrough UTIs, and resolution of reflux, were recorded. The relation of gender, age and VUR grade to preformed scarring and the relation of gender, age, VUR grade, presence of preformed scarring, number of breakthrough UTIs and reflux resolution to new scarring were assessed. There were 138 patients [male/female (M/F) 53/85]. Multivariate analysis showed that male gender [odds ratio (OR) 2.5], age > or = 27 months in girls (OR 4.2) and grades IV-V reflux (OR 12.4) were independent indicators of renal scarring. On the other hand, only the presence of previous renal scarring was found to be an independent indicator for the development of new renal scar (OR 13.4). In conclusion, while the most predictive variables for the presence of renal scarring among children presenting with a UTI were male gender, age > or = 27 months in girls, and grades IV-V reflux, the best predictor of new scar formation was presence of previous renal scarring.

Vesicoureteral reflux, reflux nephropathy, and end-stage renal disease

Objective. To review the contribution of vesicoureteral reflux and reflux nephropathy to end-stage renal disease. Data Source. Published research articles and publicly available registries. Results. Vesicoureteral reflux (VUR) is commonly identified in pediatric patients and can be associated with reflux nephropathy (RN), chronic kidney disease (CKD), and rarely end-stage renal disease (ESRD). Patients with reduced GFR, bilateral disease, grade V VUR, proteinuria, and hypertension are more likely to progress to CKD and ESRD. Because progression to ESRD is rare in VUR and often requires many decades to develop, there are limited prospective, randomized, controlled trials available to direct therapy to prevent progression to ESRD. Conclusions. Identification of patients with increased risk of progression to CKD and ESRD should be the goal of clinical, biochemical, and radiological evaluation of patients with VUR. Treatment of patients with VUR should be directed at preventing new renal injury and preserving renal function.

Prenatally diagnosed urinary tract abnormalities: long-term outcome

The long-term outcomes of prenatally detected uropathies are poorly documented. Limited data on fetal intervention show a possible reduction in early mortality from pulmonary hypoplasia, but no beneficial effect on long-term prognosis for renal function. Prenatally detected vesicoureteric reflux (VUR) is characterised by males with high-grade primary reflux, who are at long-term risk of renal impairment. Prenatal diagnosis and surgical intervention have contributed to a reduction in long-term morbidity in children with pelviureteric junction (PUJ) obstruction. By the same token, many children have almost certainly undergone unnecessary early pyeloplasty for an obstruction that would have resolved spontaneously. Multicystic dysplastic kidney (MCDK) carries a low (1%) risk of hypertension in childhood. The limited evidence on the long-term outcome of mild dilatation (pelvicaliectasis) indicates this is a largely innocent finding, which carries no increased risk of morbidity.

Significance of the renal functional reserve in reflux nephropathy: an evaluation according to the degree of glomerular damage

OBJECTIVE

In the treatment of progressive reflux nephropathy (RN), the therapeutic benefit and prognosis of the renal function in RN patients appears to be influenced by the degree of renal functional reserve. We designed this study to determine the presence and characteristics of the renal functional reserve in RN patients.

MATERIALS AND METHODS

In the 35 RN patients with renal scars (19 males; mean age 16.1 years), an exogenous renal clearance test was performed to measure the glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF). In the second half of this test, the renal functional reserve was estimated by measuring the GFR and ERPF during low-dose dopamine infusion. These measurements were then compared with the glomerular size, which had been previously determined by a renal biopsy.

RESULTS

Among the patients with a normal glomerular size (-2SD to +2SD), the GFR markedly increased after low-dose dopamine infusion (from 112.15 +/- 52.51 to 182.07 +/- 69.95 mL/min, p < 0.0001), whereas an increase in ERPF was not significant. Among the patients with an enlarged glomerular size (+2SD to +4SD), the GFR and ERPF increased significantly over the baseline values (from 54.60 +/- 32.90 to 114.00 +/- 65.48 mL/min, p = 0.0076; from 281.01 +/- 152.54 to 622.43 +/- 392.73 mL/min, p = 0.0155, respectively). Among the patients with an extremely enlarged glomerular size (>+4SD), both the GFR and ERPF remained almost completely unchanged.

CONCLUSION

The renal functional reserve was present even among progressive RN patients with a glomerular size ranging between +2SD and +4SD.

The quality of ambulatory care delivered to children in the United States

BACKGROUND

Little is known about the magnitude of deficits in the quality of care delivered to children, since comprehensive studies have been lacking.

METHODS

We assessed the extent to which care processes recommended for pediatric outpatients are delivered. Quality indicators were developed with the use of the RAND-UCLA modified Delphi method. Parents of 1536 children who were randomly selected from 12 metropolitan areas provided written informed consent to obtain medical records from all providers who had seen the children during the 2-year period before the date of study recruitment. Trained nurses abstracted these medical records. Composite quality scores were calculated by dividing the number of times indicated care was documented as having been ordered or delivered by the number of times a care process was indicated.

RESULTS

On average, according to data in the medical records, children in the study received 46.5% (95% confidence interval [CI], 44.5 to 48.4) of the indicated care. They received 67.6% (95% CI, 63.9 to 71.3) of the indicated care for acute medical problems, 53.4% (95% CI, 50.0 to 56.8) of the indicated care for chronic medical conditions, and 40.7% (95% CI, 38.1 to 43.4) of the indicated preventive care. Quality varied according to the clinical area, with the rate of adherence to indicated care ranging from 92.0% (95% CI, 89.9 to 94.1) for upper respiratory tract infections to 34.5% (95% CI, 31.0 to 37.9) for preventive services for adolescents.

CONCLUSIONS

Deficits in the quality of care provided to children appear to be similar in magnitude to those previously reported for adults. Strategies to reduce these apparent deficits are needed.

Therapy Insight: what nephrologists need to know about primary vesicoureteral reflux

Vesicoureteral reflux (VUR) is the abnormal, retrograde flow of urine from the bladder to the upper urinary tract. This disease affects about 1% of otherwise normal children, 30-50% of those who present with urinary tract infections, and approximately 10% with prenatally diagnosed hydronephrosis. Over the past 50 years, tremendous progress has been made in the diagnosis, treatment and management of VUR. The realization that VUR is probably a component of generalized dysfunction of the lower urinary tract (i.e. dysfunctional elimination syndrome) has further enhanced understanding of the disease. This Review covers basic pathogenesis, diagnosis, management, clinical presentation, and current controversies surrounding VUR.

Significance of age-specific creatinine levels at presentation in posterior urethral valve patients

OBJECTIVE

Determination of prognostic factors is of great importance in decision making on therapies and informing parents about the probable outcome of disease. The present study aims to evaluate and assess the prognostic factors in posterior urethral valve (PUV) patients.

MATERIALS AND METHODS

The data of 68 patients treated between 1996 and 2004 were evaluated retrospectively. The mean age at diagnosis was 36.4 months. The serum creatinine levels were standardized using the age-specific creatinine reference (ASCR) levels. The age at diagnosis, clinical presentation, initial serum creatinine, method of treatment, presence of vesicoureteral reflux (VUR) and hydroureteronephrosis (HUN), all of which may effect the prognosis, were evaluated.

RESULTS

The analysis revealed that, of the 36 patients whose initial serum creatinine levels were within ASCR, only one (2.8%) had a final serum creatinine higher than ASCR values. In contrast, of the 32 patients whose initial serum creatinine levels were not within ASCR, 19 (59.4%) had final serum creatinine levels higher than ASCR (P<0.001). The distribution of final serum creatinine according to treatment method, presence of UTI before treatment and age at diagnosis was not statistically significant; however, the difference in distribution for initial serum creatinine (P<0.001), mode of clinical presentation (0.016), presence of HUN (0.019) and state of VUR (0.037) before treatment was statistically significant.

CONCLUSION

Final outcome with regard to renal function in PUV patients is affected by bilateral VUR and most significantly by serum creatinine levels higher than ASCR.

Predictive factors of chronic kidney disease in severe vesicoureteral reflux

The aim of this retrospective cohort study was to evaluate independent predictive factors of chronic kidney disease (CKD) in children with severe bilateral primary vesicoureteral reflux (VUR). Between 1970 and 2004, 184 patients were diagnosed with VUR (grades III-V) and were systematically followed up at a single tertiary renal unit. CKD was defined as estimated glomerular filtration rate <75 ml/min per 1.73 m2 body surface area in two consecutive examinations. Risk of CKD was analyzed by the Kaplan-Meier method and Cox's regression model. The probability of CKD for patients with bilateral severe reflux was estimated at 15% by 10 years after VUR diagnosis. After adjustment, four variables remained independently associated with CKD during follow-up: age at diagnosis >24 months [relative risk (RR)=4.8, 95% confidence interval (95%CI), 1.8-12.7, P<0.001], VUR grade V (RR=3.5, 95%CI, 1.5-7.9, P=0.002), bilateral renal damage (RR=2.86, 95%CI, 1.3-6.1, P=0.007), and decade of admission after 1990 as a protective factor (RR=0.16, 95%CI 0.06-0.43, P<0.001). A delay in the diagnosis of VUR more than 12 months after urinary tract infection (UTI) was also a predictive factor in an alternative model (RR=2.2, 95%CI, 1.1-6.6, P=0.03). Prognosis regarding renal function was relatively poor after a long-term follow-up of patients with bilateral severe reflux.

Prognostic significance of the number of renal glomeruli in reflux nephropathy

OBJECTIVE

To monitor the decrease in the number of glomeruli in reflux nephropathy (RN) and to investigate its association with glomerular hypertrophy or clinical data, as some cases of RN progress to end-stage renal failure, although the mechanism of progression remains unknown and is generally thought to depend on remnant normal renal tissue mass, i.e. the number of remnant renal glomeruli (functional nephrons).

PATIENTS AND METHODS

From 1987 onward, a renal biopsy was taken in 71 patients (mean age 8.08 years) in two institutions to estimate the prognosis of patients with RN.

RESULTS

The number of glomeruli per unit area and glomerular size in grossly normal renal tissue specimens were determined to explore the potential association between these variables and the total renal scars, renal function (glomerular filtration rate, GFR), or daily urinary protein excretion. The number of glomeruli was closely correlated with the actual size of glomeruli (y = 14.783 - 0.052x, R = 0.782). To a lesser extent, the number of glomeruli was also closely correlated with the size of glomeruli expressed in sds (y = 6.264 - 0.832x, R = 0.630). There was a good correlation between the number of glomeruli and the extent of renal scarring, renal function, or daily urinary protein excretion, although its association with renal function (GFR) was least evident.

CONCLUSION

There was an association between the decrease in the number of glomeruli and glomerular hypertrophy, decreased renal function, or increased proteinuria. A renal biopsy taken from radiographically and macroscopically normal regions can be useful for assessing RN, and the size and number of glomeruli in the specimens might provide an important measure for estimating the prognosis of RN.

Vesicoureteric reflux and renal malformations: a developmental problem

Vesicoureteric reflux (VUR) is a congenital urinary tract defect caused by the failure of the ureter to insert correctly into the bladder. It occurs in up to 1% of the general population and is associated with recurrent urinary tract infections and renal failure. Despite treatment of affected children for the past 40 years, the incidence of end-stage renal disease secondary to VUR has not decreased. Twin and family studies reveal that VUR has a genetic basis. Some of the gene candidates that have been identified regulate the position of ureteric budding, a critical step in both kidney and urinary tract development. Analysis of data from humans and mice suggests that some of the renal damage associated with VUR is congenital and is due to a kidney malformation. Therefore, in these cases, the association of VUR and renal failure may be caused by a genetic defect affecting the formation of the kidney and the urinary tract.

Renal damage in vesico-ureteric reflux

OBJECTIVE

To detect the different extent of renal parenchymal involvement in primary vesico-ureteric reflux (VUR), and to evaluate the relationship between VUR grade, patient age and different patterns of parenchymal damage.

PATIENTS AND METHODS

This blinded retrospective study included 197 consecutive children (mean age 4.26 years, range 1 month to 13 years) with primary VUR detected by voiding cysto-urethrography (VCUG), 99mTc-dimercaptosuccinic acid (DMSA; 120 MBq/1.73 m2) renal scintigraphy, with scanning for 3 h after intravenous injection. An abnormal DMSA scan was classified into three subtypes: cortical defects as a single scar (SS), multiple cortical scarring (MS) and diffuse reduced uptake with small renal size. Renal absolute uptake (AU), and split-kidney relative uptake were evaluated in refluxing and nonrefluxing renal units, and correlated with parenchymal damage and patient age. Student's t-test and the chi-square test were used for the statistical analysis.

RESULTS

In all, 282 refluxing and 112 nonrefluxing units were assessed. Renal damage was detected in 188 of 282 units with VUR (67%) and in 18 of 112 (16%) contralateral nonrefluxing kidneys. The mean AU was 18.7% in kidneys with VUR and 29% in nonrefluxing units (P < 0.001). The mean (SD) AU decreased from lower to higher grades of VUR, i.e. grade 0 VUR (group A), 28.97 (9.71); grade 1-3 (group B), 21.28 (8.33); grade 4-5 (group C), 14.78 (8.02). The differences were statistically significant (A vs B, B vs C, both P < 0.001). Renal damage was differently distributed in the three groups: 69 of 109 kidneys (63%) in group C (MS prevalent), 39 of 173 (22.5%) in group B (SS prevalent) and 17 of 112 (15.2%) in group A. There was no significant difference in the distribution of renal damage subtypes in patients aged < or > 2 years (SS 19.6% vs 17.9%, MS 29.6% vs 30.1%, small size 48.2% vs 46.3%). The VUR was severe (group C) in 65% of patients aged < 2 years and in 46% aged > 2 years (chi-square, P = 0.016).

CONCLUSIONS

VUR is commonly associated with renal damage. Age (< or > 2 years) did not significantly influence the kidney lesion subtype. Reduced parenchymal function (AU) progressively decreased with the severity of VUR. Focal MS, reduced size and relative uptake were significantly more common in severe VUR, leading to multifocal lesions and hypo-dysplasia. Renal scarring was present in up to 15% of contralateral nonrefluxing kidneys. Severe VUR behaved differently from lesser VUR in the renal scan parenchymal uptake.