Kidney disease documented in 1 in 4 children with Bardet-Biedl syndrome
Study finds kidney surveillance testing inconsistent in children with BBS
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Kidney disease is a major complication of Bardet-Biedl syndrome, and a new study highlights gaps in kidney surveillance among affected children. (Image by iStock)
One quarter of children with Bardet-Biedl syndrome (BBS) had documented chronic kidney disease, but testing for kidney problems by ultrasound and urine tests was not consistently documented, according to a large multicenter study.
These findings prompted researchers to call for more standardized kidney surveillance testing as part of BBS care management.
The study also found that children with BBS-associated kidney disease had higher rates of obesity, sleep apnea, and kidney cysts than children with kidney disease caused by structural kidney abnormalities, supporting the idea that multiple factors may contribute to kidney disease in BBS rather than a single cause.
The study, “Kidney disease and surveillance testing in children with Bardet–Biedl syndrome: an administrative data study,” was published in Pediatric Nephrology.
How BBS can affect the kidneys
BBS is caused by genetic mutations that disrupt the function of cilia, the specialized, tiny, hair-like structures found on cells throughout the body. This leads to a wide range of symptoms, including obesity, vision problems, and learning disabilities.
Kidney impairment is one of the most serious complications of BBS and is a major contributor to illness and death in affected children. Despite this, data on chronic kidney disease (CKD) in children with BBS in the U.S. and how kidney health is monitored are limited.
In March 2023, a new diagnostic code specific to BBS was introduced, giving researchers a new way to identify children with the syndrome across large hospital databases.
So, a team led by researchers at the Ann & Robert H. Lurie Children’s Hospital of Chicago used that code to identify children with BBS and examine documented CKD, kidney surveillance testing, and related health conditions. Data came from the Pediatric Health Information System (PHIS), a database that includes records from many children’s hospitals.
The search identified 294 children, ages 0 to 17, with BBS across 44 pediatric centers. CKD was documented in 75 children (26%), including 18 (6%) with stage 5 CKD, or kidney failure. The median age at first documented CKD was 5.9 years, while the median age at first documented stage 5 CKD was 11.8 years.
Within PHIS, kidney surveillance testing was variably documented. Slightly more than half (55%) of children with BBS had a kidney ultrasound documented, and about one-fifth had documented urine protein testing (21%) or urine creatinine testing (20%).
The researchers then compared 74 children with BBS-associated CKD with 296 age- and sex-matched children whose CKD was due to structural kidney abnormalities rather than BBS.
Obesity, sleep apnea, and kidney cysts higher in BBS-related CKD
Here, obesity was about five times as high in the BBS-associated CKD group as in the comparison group (72% vs. 14%). Also, more common among children with BBS-associated CKD were obstructive sleep apnea (32% vs. 17%), a sleep disorder in which the throat muscles relax and block the airway, and renal cysts (54% vs. 32%), fluid-filled pouches that form on or inside the kidney.
The rates of high blood pressure were similar between the BBS-associated CKD and comparison groups (31% vs. 35%), whereas type 2 diabetes was numerically more common in the BBS-associated CKD group (7% vs. 3%). However, the difference in diabetes rate was not statistically significant, meaning it may have occurred by chance due to the small number of cases.
The authors noted that more frequent metabolic problems, like obesity and sleep apnea, among children with BBS-associated CKD are in line with emerging research suggesting BBS-related CKD may arise from multiple factors rather than a single cause.
Among the study’s limitations, it relied on administrative data from participating pediatric hospitals, which may not capture children with BBS who receive care elsewhere. The team also noted that their findings represent a snapshot of coded CKD and related data within this hospital network, and not a complete picture of the full range of kidney problems in BBS, which can vary widely from child to child.
The researchers concluded that their findings “support consideration of more standardized kidney surveillance within multidisciplinary BBS care.”
