Children with chronic kidney disease (CKD) who show normal blood pressure (BP) at the doctor's clinic have high BP when tested at home, indicating many of them are not appropriately treated for hypertension, exposing them to risk of developing heart disease.

Such children who have hypertension often develop an enlarged heart, yet many CKD children who have normal BP when taken in the doctor's office also develop the condition.

Mark Mitsnefes, of the Cincinnati Children's Hospital Medical Center (CCHMC), and his colleagues wondered if these children actually have elevated blood pressure not detected in the clinic.

The researchers analysed information from nearly 200 children in the Chronic Kidney Disease in Children (CKiD) study, a prospective observational study of children with mild to moderate CKD.

Children were asked to wear devices that collect BP readings periodically round the clock. Mitsnefes and his team found that monitoring BP in this way revealed that a third of children with CKD who had normal BP readings in the doctor's office actually had elevated blood pressure (called masked hypertension).

Some of these children were not taking any BP medications, meaning they had unrecognised hypertension, while some were being treated with low doses of anti-hypertensive medications, meaning they had undertreated hypertension.

More importantly, children with masked hypertension were four times as likely to have an enlarged heart as children with normal BP, says a release of the American Society of Nephrology (ASN).

These results support the case for early heart tests and BP readings outside the clinic as a part of standard care to screen for enlarged hearts and hypertension in children with mild to moderate CKD, said Mitsnefes.

These findings will appear in the Journal of the American Society of Nephrology (JASN).