Diagnostic tests underused in adolescents with hypertension

Most adolescents with essential hypertension do not get the recommended diagnostic imaging tests, according to a study of a Medicaid population.

Pediatric guidelines recommend renal ultrasonography to rule out renal disease and echocardiography to assess possible target organ damage for all pediatric patients with hypertension. To determine patterns of use of these recommended tests in relation to use of electrocardiograms, which are not recommended in the pediatric guidelines, researchers conducted a longitudinal analysis of Medicaid claims in Michigan and pharmacy data from 2003 to 2008 for adolescents aged 12 to 18 years. The study population included 951 adolescents with 3 or more years of Medicaid eligibility, a diagnosis of essential hypertension, and at least 1 antihypertensive pharmacy claim.

During the study period, more than a third of the adolescents on antihypertensive medication had none of the diagnostic tests, whereas only 6% had all 3. Fifty percent had an electrocardiogram, but only 24% had an echocardiogram, and only 22% had renal ultrasonography.

The researchers found that there were sex and age differences in use of echocardiograms. Males, younger adolescents, and those who had had electrocardiograms or renal ultrasonography were more likely than other patients to have an echocardiogram.

The preferential use of electrocardiography is understandable, the researchers explain, because it is readily available at the point of care and less expensive than echocardiography or renal ultrasonography. In pediatric patients, however, electrocardiography’s sensitivity for detection of left ventricular hypertrophy (LVH), which can guide treatment decisions, is low, and target organ damage cannot be ruled out based on the absence of LVH on electrocardiogram alone.

The findings raise questions about the level of familiarity, awareness, and agreement with the pediatric hypertension guidelines among family physicians and general pediatricians, and the researchers suggest that there may be missed opportunities in the treatment of adolescents with hypertension who are at high risk for developing cardiovascular disease as adults.

Hospitalizations of children with hypertension more than doubled in the 10-year period from 1997 to 2006, with 68% of cases occurring in children aged 10 to 18 years.

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