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Kidney volume, kidney function, and ambulatory blood pressure in children born extremely preterm with and without
Alexander Rakow1, Åsa Laestadius2, Ulrika Liliemark3
1Neonatal Unit, Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, 17176, Stockholm, Sweden. alexander.rakow@ki.se.
Insights
Extreme prematurity (EPT) reduces kidney volume and function in school-aged children. Neonatal nephrocalcinosis (NC) may worsen kidney growth, and EPT children show abnormal blood pressure regulation.
Area of Science:
- Pediatric Nephrology
- Neonatal Medicine
- Developmental Pediatrics
Background:
- Reduced kidney volume (KV) in premature infants is linked to adult hypertension and kidney disease.
- Extreme prematurity (EPT) may impact long-term kidney health and function.
- The role of neonatal nephrocalcinosis (NC) in EPT kidney development needs further investigation.
Purpose of the Study:
- To assess the effects of EPT on kidney volume, function, and blood pressure in school-aged children.
- To determine if neonatal NC exacerbates these effects.
- To evaluate circadian blood pressure patterns in EPT children.
Main Methods:
- Study included 60 children: 20 EPT with NC (NC+), 20 EPT without NC (NC-), and 19 full-term controls.
- Kidney volume measured by ultrasound; renal function assessed via blood and urine tests.
- Office and 24-h ambulatory blood pressure monitoring (ABPM) were performed.
Main Results:
- EPT children had smaller kidneys and lower glomerular filtration rates than controls.
- No significant differences in KV or function between NC+ and NC- groups.
- Abnormal circadian blood pressure regulation (blunted nocturnal dip) observed in 50% of EPT children.
Conclusions:
- EPT significantly impacts kidney growth and volume, with NC potentially worsening outcomes.
- Abnormal circadian blood pressure regulation is a concern in EPT-born children.
- Long-term monitoring of kidney health and blood pressure is crucial for EPT survivors.
Background:
Reduced kidney volume (KV) following prematurity is a proxy for reduced nephron number and is associated with the development of hypertension and end-stage renal disease in adults. We investigated whether extreme prematurity affects KV, function, and blood pressure in school-aged children and if nephrocalcinosis (NC) developed during the neonatal period had additional effects.
Methods:
We investigated 60 children at a mean age of 7.7 years: 20 born extremely preterm (EPT < 28 weeks gestational age with NC (NC+)), 20 born EPT without NC (NC-), and 19 born as full-term infants (control). We measured KV by ultrasound, collected blood and urine samples to evaluate renal function, and measured office and 24-h ambulatory blood pressure (ABPM).
Results:
Children born EPT had significantly smaller kidneys (EPT (NC+ NC-) vs control (estimated difference, 11.8 (CI - 21.51 to - 2.09 ml), p = 0.018) and lower but normal cystatin C-based glomerular filtration rate compared with control (estimated difference, - 10.11 (CI - 0.69 to - 19.5), p = 0.035). KV and function were not different between NC+ and NC- groups. Change in KV in relation to BSA (KV/BSA) from the neonatal period to school age showed significantly more EPT children with neonatal NC having a negative evolution of KV (p = 0.01). Blood pressure was normal and not different between the 3 groups. Fifty percent of EPT had a less than 10% day-to-night decline in ABPM.
Conclusions:
Kidney growth and volume is affected by EPT birth with NC being a potential aggravating factor. Circadian blood pressure regulation seems abnormal in EPT-born children.
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