Risk Assessment of Severe Congenital Anomalies of the Kidney and Urinary Tract (CAKUT): A Birth Cohort

External validation and reliability assessment of posterior urethral morphology on initial voiding cystourethrogram as a predictor for infants with posterior urethral valves

INTRODUCTION

The morphology of the bladder and posterior urethra on initial voiding cystourethrogram (VCUG) in posterior urethral valve (PUV) has been proposed as a meaningful early metric for short- and long-term kidney outcomes. Here, we seek to externally validate the proposed association and assess the reliability of PUV morphology characteristics.

MATERIALS AND METHODS

We reviewed our institutional database for patients managed for PUV between 2000 and 2022 and included those treated with primary ablation with at least 1 year of follow-up for kidney function. Each VCUG was evaluated by three independent raters for the height-width ratio of the bladder (HW-B), height-width ratio of the posterior urethra (HW-PU), and posterior-anterior urethral ratio (PA-UR), and trabeculation (none, fine, or coarse). We assessed the reliability in these with intra-class coefficient and Fleiss kappa for continuous and categorical data, respectively. We performed univariate analysis with nadir creatinine and five-year follow-up glomerular filtration rate (GFR).

RESULTS

In total, 98 patients met inclusion criteria. The median age at diagnosis and ablation was 10 and 21 days, respectively. Patients with nadir creatinine <0.8 mg/dL had higher follow-up GFR (101 vs. 20 ml/min/1.73 m2, p = 0.04), and lower risk of CKD (odds ratio 14.7, p = 0.002). The median value for HW-B was 1.4, median HW-PU was 2.1, and median PA-U was 4.7, There was significant inter-class agreement between all three measures of 0.80, 0.51, and 0.70 (p < 0.001). The inter-rater agreement for bladder trabeculation was fair (Fleiss K = 0.40, p < 0.001). There was no statistically significant correlation between HW-B, HW-PU, PU-A with nadir creatinine (p = 0.07, 0.33, 0.91) or 5-year GFR (0.27, 0.45, 0.62), respectively.

DISCUSSION

There is significant interest in determining prognostic factors and metrics in PUV. The morphological characteristics on VCUG are reliable and is available information for all boys diagnosed with PUV, resulting in an attractive metric. While we do not demonstrate correlation with kidney outcomes, VCUG features warrant further attention as prognostic factors in PUV.

CONCLUSIONS

PUV morphology on initial VCUG is a reliable metric of lower urinary tract deformity but is not associated with 5-year kidney outcomes.

Congenital Anomalies of the Kidneys and Urinary Tract

Congenital anomalies of the kidneys and urinary tract encompass the spectrum of disorders that include the kidneys, ureters, bladder, and urethra. These abnormalities often lead to altered renal size and location, dysplastic changes in the kidney parenchyma, and anomalies in the collecting system. Though the etiology of each of these conditions can be variable, it is known that the collection of these defects represent 40% to 50% of all pediatric end-stage renal disease worldwide. The multifaceted management of these conditions is aimed at preserving kidney function and ultimately delaying the need for transplantation. With the advancement of prenatal ultrasonographic techniques, these conditions are more likely to be diagnosed before birth, which often leads to rapid postnatal intervention and better outcomes.

Early predictive factors for progression to kidney failure in infants with severe congenital anomalies of the kidney and urinary tract

BACKGROUND

Severe congenital anomalies of the kidney and urinary tract (CAKUT) progress to infantile kidney failure with replacement therapy (KFRT). Although prompt and precise prediction of kidney outcomes is important, early predictive factors for its progression remain incompletely defined.

METHODS

This retrospective cohort study included patients with CAKUT treated at 12 centers between 2009 and 2020. Patients with a maximum serum creatinine level ≤ 1.0 mg/dL during the first 3 days, patients who died of respiratory failure during the neonatal period, patients who progressed to KFRT within the first 3 days, and patients lacking sufficient data were excluded.

RESULTS

Of 2187 patients with CAKUT, 92 were finally analyzed. Twenty-five patients (27%) progressed to KFRT and 24 (26%) had stage 3-5 chronic kidney disease without replacement therapy during the median observation period of 52.0 (interquartile range, 22.0-87.8) months. Among these, 22 (24%) progressed to infantile KFRT. The kidney survival rate during the infantile period was significantly lower in patients with a maximum serum creatinine level during the first 3 days (Cr-day3-max) ≥ 2.5 mg/dL (21.8%) compared with those with a Cr-day3-max < 2.5 mg/dL (95.2%) (log-rank, P < 0.001). Multivariate analysis demonstrated Cr-day3-max (P < 0.001) and oligohydramnios (P = 0.025) were associated with higher risk of infantile KFRT. Eighty-two patients (89%) were alive at the last follow-up.

CONCLUSIONS

Neonatal kidney function, including Cr-day3-max, was associated with kidney outcomes in patients with severe CAKUT. Aggressive therapy for severe CAKUT may have good long-term life outcomes through infantile dialysis and kidney transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of Maternal and Neonatal Birth Outcomes With Subsequent Pediatric Transplants

BACKGROUND

We identified maternal and neonatal birth characteristics that were associated with organ or tissue transplants during childhood.

METHODS

We designed a retrospective cohort study of the population of children born between 2006 and 2019 in Quebec, Canada. The exposure included birth complications such as congenital anomaly, neonatal blood transfusion, and oligohydramnios. The main outcome measure was organ or tissue transplantation before 14 y of age. We categorized transplants according to type (major organs versus superficial tissues). To determine the association of birth characteristics with risk of pediatric transplant, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards models adjusted for potential confounders.

RESULTS

The cohort comprised 1 038 375 children with 7 712 678 person-years of follow-up, including 436 children who had transplants before 14 y of age. Birth complications were predominantly associated with major organ transplants. Congenital anomaly was associated with heart or lung (HR, 10.41; 95% CI, 5.33-20.33) and kidney transplants (HR, 13.69; 95% CI, 7.48-25.06), compared with no anomaly. Neonatal blood transfusion was associated with all major organ transplants, compared with no transfusion. Maternal complications were not as strongly associated with the risk of childhood transplant, although oligohydramnios was associated with 16.84 times (95% CI, 8.09-35.02) the risk of kidney transplant, compared with no oligohydramnios.

CONCLUSIONS

Adverse birth outcomes such as congenital anomaly, neonatal blood transfusion, and maternal oligohydramnios are associated with a greater risk of transplantation before 14 y of age. Maternal and neonatal birth outcomes may be useful predictors of transplantation.

Congenital anomalies of the kidney and urinary tract (CAKUT) in critically ill infants: a multicenter cohort study

BACKGROUND

The aim of the study was to determine the prevalence of congenital anomalies of the kidney and urinary tract (CAKUT) in the neonatal intensive care unit (NICU) and to evaluate risk factors associated with worse outcomes. We hypothesized that infants with CAKUT with extra-renal manifestations have higher mortality.

METHODS

This is a cohort study of all inborn infants who were diagnosed with any form of CAKUT discharged from NICUs managed by the Pediatrix Medical Group from 1997 to 2018. Logistic and linear regression models were used to analyze risk factors associated with in-hospital mortality.

RESULTS

The prevalence of CAKUT was 1.5% among infants hospitalized in 419 NICUs. Among the 13,383 infants with CAKUT analyzed, median gestational age was 35 (interquartile range [IQR] 31-38) weeks and median birth weight was 2.34 (IQR 1.54-3.08) kg. Overall in-hospital mortality for infants with CAKUT was 6.8%. Oligohydramnios (adjusted odds ratio [aOR] 4.5, 95% confidence interval [CI] 2.2-9.1, p < 0.001), extra-renal anomalies (aOR 2.5, 95% CI 2.0-3.1, p < 0.001), peak SCr (aOR 1.02, 95% CI 1.01-1.03, p < 0.001) and exposure to nephrotoxic medications (aOR 1.4, 95% CI 1.1-1.7, p = 0.01) were associated with increased mortality, while a history of urological surgery or intervention was associated with lower mortality (aOR 0.6, 95% CI 0.4-0.7, p < 0.001).

CONCLUSIONS

Infants hospitalized in the NICU who have CAKUT and the independent risk factors for mortality (e.g., oligohydramnios and presence of extra-renal anomalies) require close monitoring, minimizing of exposure to nephrotoxic drugs, and timely urological surgery or intervention. A higher resolution version of the Graphical abstract is available as Supplementary information.

Predictors of advanced chronic kidney disease in infancy after definitive vesicoamniotic shunting for congenital lower urinary tract obstruction

BACKGROUND

Severe congenital lower urinary tract obstruction (cLUTO) is associated with poor postnatal outcomes, including chronic and end stage kidney disease, and high mortality. Studies of the impact of fetal intervention through vesicoamniotic shunting are marred by a device malfunction rate of up to 60%. In this study, we delineate the postnatal course and infant kidney function following definitive urinary diversion in utero.

MATERIALS AND METHODS

This is a retrospective, single-center cohort study of 16 male infants who survived the fetal intervention to birth, from 2010 to 2014 at a single center. All had patent shunts in place at birth. Perinatal and biochemical characteristics were collected with patients followed for one year, or until demise, with serial measures of serum creatinine (SCr) and serum cystatin C (CysC).

RESULTS

Of the 16 males, 81% were non-white (38% black, 43% Hispanic). Shunts were placed at a median of 20 weeks (IQR 19,23) gestation, with median fetal bladder volume of 39 cm³ (IQR 9.9,65). All neonates were born preterm [median 34 weeks (IQR 31,35)] and the majority with low birth weight [median 2340 grams (1,895, 2,600)]. 63% required positive pressure ventilation. Advanced chronic kidney disease stage 4-5 at 1 year of age was predicted by neonatal characteristics: peak SCr ≥2 mg/dl, time to peak SCr > 6 days, discharge SCr ≥1.0 mg/dl, CysC ≥2.5 mg/l, urine protein:creatinine ≥4.8 mg/mg, urine microalbumin:creatinine ≥2.2 mg/mg. In infancy, a nadir SCr ≥0.5 mg/dl occurring before 160 days (5.3 months) of age was also predictive of advanced chronic kidney disease stage 4-5 at 1 year. Three patients died in the neonatal period, with 1 receiving kidney replacement therapy (KRT). Three additional patients required KRT before 12 months of age.

CONCLUSIONS

Even with definitive vesicoamniotic shunting for cLUTO, postnatal morbidity and mortality remain high, emphasizing the role of renal dysplasia, in spite of urinary diversion, in postnatal kidney dysfunction. Neonatal and infant biochemical parameters exhibit distinct trends that offer families and physicians a better understanding of the prognosis of childhood kidney function.

The incidence of transient infantile pseudohypoaldosteronism in Ireland: A prospective study

AIM

To review the clinical course, outcome and incidence of infantile salt wasting associated with urinary tract infection (UTI) and/or urinary tract malformation (UTM) over a two-year surveillance period on the island of Ireland.

METHODS

A two-year (2013-14) prospective surveillance undertaken via the Irish and Ulster Paediatric Surveillance Units. Monthly prepaid postcards were circulated to consultant paediatricians (n = 260) at all paediatric units on the island of Ireland. Infants under one year of age presenting for the first time with hyponatraemia (Na < 130 mmol/L) and/or hyperkalaemia (K > 5.0 mmol/L) associated with urosepsis/UTM were reported.

RESULTS

All 7 reported patients (6 male) had culture-proven UTI, and 5 (71%) also had an underlying UTM (one diagnosed antenatally). Four (57%) patients had a documented elevated serum aldosterone supporting secondary pseudohypoaldosteronism (PHA) as the underlying diagnosis. Data on aldosterone were not reported in the other 3 patients, but clinical features were suggestive of secondary PHA. The estimated incidence for the Irish population of transient PHA is 1 per 13,200 total live births per year.

CONCLUSIONS

Salt wasting is a rare complication of UTI, especially if associated with underlying UTM. Boys appear to be at particular risk.

Congenital Anomalies of the Kidney and Urinary Tract in Children with Congenital Heart Defects

BACKGROUND/AIMS

To investigate the incidence and clinical characteristics of congenital anomalies of the kidney and urinary tract (CAKUT) in children with congenital heart defects (CHD).

METHODS

We retrospectively analyzed the clinical data of children with CHD with CAKUT admitted to the Shanghai Children's Medical Center affiliated with the Shanghai Jiao Tong University School of Medicine between September 2018 and March 2019. Patients underwent routine examinations for liver, kidney, and coagulation function, and urinary tract ultrasonography, and we summarized patients' clinical manifestations and imaging abnormalities.

RESULTS

A total of 1,410 children with CHD were diagnosed and treated in our hospital. The total number of patients with abnormal urogenital systems was 104, and hydronephrosis was the most common abnormality, followed by vesicoureteral reflux and duplication of the kidney and ureter. The overall prevalence of CAKUT was 7.4%. There was no statistically significant difference for maternal age, sex, parity, gestational age, and history of medication during pregnancy between the patients with CAKUT and those without CAKUT.

CONCLUSION

The incidence of CAKUT in our patients with CHD was significantly higher than that in the general population. We recommend urinary ultrasonography as a routine examination for children with CHD for early detection of CAKUT, to avoid missed diagnoses, and to initiate appropriate treatment.