Pilot Study of Blood Pressure in Girls With Turner Syndrome

Systemic hypertension, ischemic heart disease, and stroke are the major factors that reduce lifespan in Turner syndrome. Importantly, high blood pressure (BP) is the most readily treatable risk factor for aortic dissection and rupture that occurs in young women with Turner syndrome. A review of 65 cases of aortic dissection in girls and women with Turner syndrome identified concomitant congenital heart disease and hypertension in 89%, with half of cases occurring before age 30. Unfortunately, systemic hypertension occurs frequently in Turner syndrome with prevalence estimates of 25% to 40% in girls and an even larger percentage in affected women. Having few overt symptoms, high BP can easily go unrecognized. Elevated BP by casual BP measurement is common in the general child and adolescent population, with estimates of 10% to 17%; however, the overall burden of true hypertension (defined by BP ≥95th% on at least 3 separate assessments) is relatively low with estimates of 1% to 4% of all girls. In Turner syndrome, however, the prevalence may be many times that of the general population, making recognition of the problem particularly important. We sought to identify the factors associated with hypertension in girls with Turner syndrome by studying the prevalence of elevated systemic BP, awareness of the problem, and its clinical associations in a large cohort of girls with Turner syndrome while attending the annual meeting of the Turner Syndrome Society of the United States over a 9-year period. Subjects and Methods The protocol was approved by the Institutional Review Board at Oregon Health & Science University. As part of the ongoing Turner Syndrome Healthy Heart Project at the annual meeting of the Turner Syndrome Society of the United States from 2003 to 2011, 168 volunteer subjects aged 2 to 17 years with Turner syndrome participated in cardiovascular health screening. Written consent was obtained from all subjects or their legal guardians, and a written assent obtained from children capable of reading the form. Subjects completed a standardized questionnaire documenting karyotype (45,X versus non-45,X), history of growth hormone use, thyroid disease, renal/urologic disease, surgical repair of aortic coarctation, and self-reported history of a diagnosis of hypertension. Height and weight were measured. A single screening BP was measured after a short period of rest (3–5 minutes) in seated position on the right upper arm by automatic oscillometry (Dynamap, GE Healthcare) using methods consistent with American Heart Association recommendations. Taking the BP on the right arm minimized the possibility of or erroneous measurement in subjects who had previous aortic coarctation operations. Focused 2-dimensional echocardiography was performed with a Philips Sonos 5500 or IE 33 (Philips Medical Systems, Bothell, WA) ultrasound system. Age and height-adjusted systolic BP percentiles (n=168) and age-adjusted body mass index percentiles (n=166; 2 subjects not weighed) were calculated. BP ≥95th% was considered evidence of potential hypertension (consistent with definition of stage 1 hypertension or greater). Body mass index ≥95th% was considered to be obesity. Statistical analysis was conducted using SAS software. Univariate comparisons were made by χ and Fisher exact test to identify factors associated with hypertension. P<0.05 was chosen as the level of statistical significance. Abstract—Cardiovascular disease is the major factor that reduces lifespan in Turner syndrome. High blood pressure (BP) is common in Turner syndrome and is the most easily treatable cardiovascular risk factor. We studied the prevalence of elevated screening systemic BP, awareness of the problem, and its clinical associations in a large group of girls attending the annual meeting of the Turner Syndrome Society of the United States. Among 168 girls aged 2 to 17 years, 42% had elevated screening BP (systolic and diastolic), yet only 8% reported a previous diagnosis of hypertension. History of aortic coarctation repair (17%) was positively associated with elevated systolic BP (52% versus 32%; P<0.05). Elevated systolic BP was positively associated with obesity (56% versus 31%; P<0.05). Because the prevalence of obesity in the studied population was similar to Center for Disease Control published data for obesity in all girls and the prevalence of increased BP is approximately twice that of the general population, the Turner syndrome phenotype/genotype probably includes an intrinsic risk for hypertension. Obesity and repaired aortic coarctation increase this risk further. There seems to be a BP awareness gap in girls with Turner syndrome. Because girls living with Turner syndrome are a sensitized population for hypertension, further study may provide clues to genetic factors leading to a better understanding of essential hypertension in the general population. (Hypertension. 2016;68:133-136. DOI: 10.1161/HYPERTENSIONAHA.115.07065.)