Risk factors associated with chronic kidney disease in patients with posterior urethral valves without prenatal hydronephrosis

Comparison of outcomes of prenatal versus postnatal presentation of posterior urethral valves: a systematic review and meta-analysis

OBJECTIVE

To determine through a comprehensive systematic review and meta-analysis the differences in the outcomes of prenatally versus postnatally diagnosed posterior urethral valves (PUV) to ascertain if prenatal detection of PUV has superior outcomes.

METHODS

We conducted a systematic review and meta-analysis in March 2022 (PROSPERO ID - CRD42021243546) and included all studies that reported outcomes of prenatally and postnatally diagnosed PUV. However, for meta-analysis, only those studies that described both groups were included. The main outcomes of interest included progression of chronic kidney disease (CKD), need for renal replacement therapy (RRT) and renal transplant, and bladder dysfunction as determined by initiation of clean intermittent catheterization (CIC). Time to event analyses were completed when possible.

RESULTS

The systematic review included 49 studies (3820 patients). The pooled effect estimates for progression to CKD (OR 0.75 [95% CI 0.43, 1.31]), need for RRT (OR 1.39 [95% CI 0.64, 2.99]) and need for renal transplant (OR 1.64 [95% CI 0.61, 4.42]) between prenatal and postnatal groups was not different. CICs rates were as high as 32% in the prenatal group and 22% in the postnatal group. Most studies had a moderate or serious risk of bias.

CONCLUSION

The existing comparative literature on prenatal versus postnatal presentation of PUV is very heterogeneous. The diagnostic and treatment protocols have not been reported in majority of the studies. The outcome variables are also reported inconsistently. Based on the current evidence, prenatal diagnosis of PUV does not appear to improve the long-term outcomes of these patients.

Posterior urethral valves: Role of prenatal diagnosis and long-term management of bladder function; a single center point of view and review of literature

Posterior Urethral Valves (PUV) are the most common cause of lower urinary tract obstruction. More severe forms are detected early in pregnancy (mainly type I), while other forms are usually discovered later in childhood when investigating lower urinary tract symptoms. Bladder dysfunction is common and is associated with urinary incontinence in about 55% (0%-72%). Despite the removal of the obstruction by urethral valve ablation, pathological changes of the urinary tract can occur with progressive bladder dysfunction, which can cause deterioration of the upper urinary tract as well. For this reason, all children with PUV require long-term follow-up, always until puberty, and in many cases life-long. Therefore, management of PUV is not only limited to obstruction relief, but prevention and treatment of bladder dysfunction, based on urodynamic observations, is paramount. During time, urodynamic patterns may change from detrusor overactivity to decreased compliance/small capacity bladder, to myogenic failure (valve bladder). In the past, an aggressive surgical approach was performed in all patients, and valve resection was considered an emergency procedure. With the development of fetal surgery, vesico-amniotic shunting has been performed as well. Due to improvements of prenatal ultrasound, the presence of PUV is usually already suspected during pregnancy, and subsequent treatment should be performed in high-volume centers, with a multidisciplinary, more conservative approach. This is considered to be more effective and safer. Primary valve ablation is performed after clinical stability and is no longer considered an emergency procedure after birth. During childhood, a multidisciplinary approach (pediatric urologist, nephrologist, urotherapist) is recommended as well in all patients, to improve toilet training, using an advanced urotherapy program with medical treatments and urodynamic evaluations. The aim of this paper is to present our single center experience over 30 years.

Association of Renal Glomerular and Tubular Function With Renal Outcome in Patients With Posterior Urethral Valves

OBJECTIVE

To analyze renal glomerular and tubular function and their association in patients operated for posterior urethral valves and to prognosticate the risk for end-stage kidney disease (ESKD) METHODS: Sixty-three previously treated patients were evaluated for renal function during 1987-1991. The patients' age at evaluation was 11 years (range 2-24). Glomerular function was assessed by measuring glomerular filtration rate (GFR) and urine albumin excretion. Tubular function was determined by measuring urine concentration capacity and excretion of electrolytes (Na, K, Cl, Ca, P, Mg) and β-2-microglobulin. Additionally, the prevalence of hypertension and serum parathyroid hormone and aldosterone values were registered. Tubular function was compared with GFR and the risk of developing ESKD before November 2018.

RESULTS

Twenty of the study patients (32%) had decreased GFR. In addition, 19% had proteinuria and 56% were hypertensive. Those without proteinuria or hypertension had better GFR values (P < .01 for both). There was a significant correlation between GFR and all the tubular function (P < .05) variables (except excretion of chloride) measured. Compared to the patients with favorable renal outcome, the patients (n = 10) who later developed ESKD had significantly (P < .01) lower GFR and reduced urinary excretion of all measured electrolytes except calcium. Consistently, urine β-2 microglobulin and serum parathyroid hormone and aldosterone values were significantly higher in the patients who developed ESKD (P ≤ .01).

CONCLUSION

Both glomerular and tubular function decline was common and several parameters were likely to predict ESKD in posterior urethral valves patients.

Primary Infertility Secondary to Posterior Urethral Valve

A 34-year-old civil servant presented to our facility, following a referral from a gynecologist who was also seeing the wife. The man presented with a history of anejaculation and the inability to impregnate his wife after 23 months of marriage. History, physical examination, and ancillary investigation led to a diagnosis of primary infertility secondary to posterior urethral valve which was subsequently ablated. Three weeks after ablation, he started ejaculating, and 2 months later, the wife became pregnant.

Renal Replacement Therapy and Intermittent Catheterization Risk in Posterior Urethral Valves

OBJECTIVES

Posterior urethral valves predispose children to renal replacement therapy (RRT) and bladder dysfunction. Researchers of single-institutional series were unable to refine risk stratification because of rarity of the disease. We aimed to identify clinical variables associated with the risk of RRT and clean intermittent catheterization (CIC) in a large multicenter cohort study.

METHODS

Children with posterior urethral valves born between 1995 and 2005 who were treated before 90 days of life at 5 children's hospitals were retrospectively reviewed. Outcomes included RRT and recommendation for CIC. Predictors and outcomes were assessed by using survival analysis.

RESULTS

A total of 274 patients were managed for a median of 6.3 years, and 42 progressed to RRT. On survival analysis, 16% progressed to RRT by 10 years of age. RRT varied by the serum nadir creatinine level in the first year of life (SNC1) (log-rank P < .001). After stratifying by the SNC1, the estimated risk of progressing to RRT by 10 years of age was 0%, 2%, 27%, and 100% for an SNC1 of <0.4, an SNC1 of 0.4 to 0.69, an SNC1 of 0.7 to 0.99, and an SNC1 of ≥1.0 mg/dL, respectively. CIC was recommended in 60 patients, which translated on survival analysis to a risk of 26% by 10 years of age.

CONCLUSIONS

Risk of RRT and CIC recommendation increased with age. The SNC1 strongly predicted need for RRT. These results allow for both improved family counseling and the potential for more appropriate screening and intervention strategies for those identified in higher-risk groups.

A clinical predictive model of chronic kidney disease in children with posterior urethral valves

BACKGROUND

Posterior urethral valves (PUVs) are associated with severe consequences to the urinary tract and are a common cause of chronic kidney disease (CKD). The aim of this study was to develop clinical predictive model of CKD in a cohort of patients with PUVs.

METHODS

In this retrospective cohort study, 173 patients with PUVs were systematically followed up at a single tertiary unit. The primary endpoint was CKD ≥ stage 3. Survival analyses were performed by Cox regression proportional hazard models with time-fixed and time-dependent covariables.

RESULTS

Mean follow-up time was 83 months (SD, 70 months). Sixty-five children (37.6%) developed CKD stage ≥ 3. After adjustment by the time-dependent Cox model, baseline creatinine, nadir creatinine, hypertension, and proteinuria remained as predictors of the endpoint. After adjustment by time-fixed model, three variables were predictors of CKD ≥ stage 3: baseline creatinine, nadir creatinine, and proteinuria. The prognostic risk score was divided into three categories: low-risk (69 children, 39.9%), medium-risk (45, 26%), and high-risk (59, 34.1%). The probability of CKD ≥ stage 3 at 10 years age was estimated as 6%, 40%, and 70% for patients assigned to the low-risk, medium-risk, and high-risk groups, respectively (P < 0.001). The main limitation was the preclusion of some relevant variables, especially bladder dysfunction, that might contribute to a more accurate prediction of renal outcome.

CONCLUSION

The model accurately predicts the risk of CKD in PUVs patients. This model could be clinically useful in applying timely intervention and in preventing the impairment of renal function.

Predicting and Modifying Risk for Development of Renal Failure in Boys with Posterior Urethral Valves

PURPOSE OF REVIEW

The purpose of this review is to bring the reader up to date on the current risk factors for the development of renal deterioration in the boys with posterior urethral valves (PUV) and approaches to modify this risk.

RECENT FINDINGS

Renal bladder ultrasound (RBUS) is routinely performed in boys with PUV and recent advancements allow imaging processing that can more accurately quantify renal parenchyma and correlate this with risk for renal loss. Refinement of urine studies may improve our ability to stratify patients into renal loss categories. Use of videourodynamics (VUDS) allows refined assessment of the valve bladder to identify those who might benefit from secondary procedures and/or the addition of targeted pharmacotherapy to improve bladder emptying or dangerous storage pressures. All boys with a history of PUV are at a significant long-term risk of renal deterioration. The literature suggests that several technical advances have improved our ability to predict this risk, although there needs to be further refinement and validation before widespread use. Utilization of close follow-up, VUDS, pharmacotherapy, and bladder drainage provide the best methods to improve care to this group of patients and if more studies confirm their utility, adoption of these as part of standard of care protocols may be warranted.

[Is there an outcome difference between posterior urethral valves diagnosed prenatally and postnatally at the time of antenatal screening?]

PURPOSE

Posterior urethral valves (PUV) diagnosed during childhood have classically been associated with a better outcome than antenatally diagnosed PUV. The aim of our study was to compare long-term outcome of these two patients' groups.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of boys with PUV managed between 1990 and 2010. Patient demographics, clinical background, radiographic data (including prenatal ultrasonography data when available), renal and bladder functional outcomes, surgical procedures and urinary tract infections (UTI) were abstracted. Impaired renal function (IRF) was defined as glomerular filtration rate less than 90 mL/min/1.73 m(2) at last follow-up.

RESULTS

We identified 69 patients with confirmed PUV. Thirty-eight were diagnosed prenatally (group 1) at 30.5 weeks of gestation and 31 had a delayed diagnosis (group 2) at a median age of 6.31 years. At diagnosis, 20 patients in group 1 had renal insufficiency versus two in group 2 (P<0.05). At the end of mean follow-up of 7.2 ± 0.5 years, in group 1, 26.3% developed IRF versus 6.3% in group 2 (mean follow-up 2.3 years). Mean age at last follow-up was 7.3 years in group 1 versus 8.3 in group 2 (P>0.05). In group 1, 27% had voiding dysfunction versus 30% in group 2 (NS). In group 1, 35% had UTI during follow-up versus 10% (P=0.01).

CONCLUSION

During the follow-up, the patients with delayed diagnosis VUP have developed fewer complications related to the initial obstruction than the population who was detected antenatally and managed from the early hours of life. However, the rate of IRF and voiding disorders in our study, associated with the data of the literature, highlights the potential persistence and worsening of these conditions. That is why, whatever the age at diagnosis, VUP patients require a close monitoring.