US researchers have flagged problems with the types of diagnostic tests being used in adolescents with hypertension that could have implications in Australia.

The study, which was published in the Archives of Pediatrics & Adolescent Medicine, found that guideline-recommended diagnostic tests ― echocardiograms and renal ultrasonography ― were being underused in adolescents with essential hypertension. (1)

The researchers found that electrocardiogram (ECG) was the test of choice, even though US paediatric hypertension guidelines do not recommend it.

The researchers looked at data on adolescents from Michigan in the US who had 3 or more years of Medicaid eligibility, a diagnosis of essential hypertension and one or more antihypertensive medication pharmacy claims.

They found that, of these, 24% had echocardiograms, 22% had renal ultrasonography and 50% had ECGs.

They said the preferential use of ECGs was understandable because ECGs were less expensive and more readily available to physicians at the point of care.

However, they wrote that these patterns “raise questions about the level of familiarity, awareness, or agreement with pediatric hypertension guideline recommendations and the rationale behind these recommendations among physicians who provide primary care for children and adolescents”.

Dr Chi Le-Ha, from the School of Medicine and Pharmacology at the University of Western Australia, said that despite methodological limitations, the study findings were important and relevant to Australian practice.

The paper had raised several questions that needed to be answered in future research internationally and in Australia, he said.

Associate Professor Gad Kainer, a paediatric nephrologist at Sydney Children’s Hospital, said the study was a little simplistic as it did not analyse possible differences between children for whom medical practitioners did or did not order tests.

However, he noted the important role that ultrasonography played in determining end-organ effects and investigating causes of hypertension.

The authors also noted a number of limitations to their findings, including the exclusion of privately insured patients. They concluded that the choice of diagnostic tests to evaluate essential hypertension in adolescents warranted further study.

An accompanying editorial published in the Archives of Pediatrics & Adolescent Medicine, said the methodological issues probably accounted for only a modest proportion of underuse of ultrasonography implied by the study’s findings. (2)

“The answers to the many questions raised here are unclear, pointing to the need for more information about the extent to which the BP guidelines overall, and recommended diagnostic testing in particular, are implemented”, the editorial said. “It is important to get these answers.”

Dr Le-Ha agreed that more information was needed about implementing guidelines to evaluate and treat adolescent hypertension.

“In general, adolescents with hypertension should be screened for cardiovascular risk factors such as obesity, diabetes mellitus and dyslipidemia, and should be evaluated for target organ damage with a retinal examination, an echocardiography and particularly renal ultrasonography”, he said.

Dr Le-Ha said these examinations could help identify the causes of hypertension and assess the extent of end-organ damage.

“For example, cardiac ultrasonography is important because it is more sensitive and specific in assessing left ventricular hypertrophy compared with the commonly used ECG”, he said.

– Amanda Bryan

1. Arch Pediatr Adolesc Med 2012; Published online: July 23

2. Arch Pediatr Adolesc Med 2012; Published online: July 23

 

Posted 30 July 2012

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