What components of the clinical history, physical examination, and laboratory testing are useful for differentiating primary from secondary hypertension in children and adolescents?
A family history of secondary hypertension, a history of prematurity, age 6 years or younger, low body weight (10% or lower for age and sex), microalbuminuria, and serum uric acid concentration of 5.5 mg/dL or less are the most useful findings for an increased likelihood of secondary hypertension in children and adolescents. Obesity, family history of primary hypertension, and absence of hypertension-related symptoms (eg, headache, blurry vision, dizziness, chest pain, edema) are the most useful findings for ruling out secondary hypertension.
Self-funded or unfunded
The optimal management approach (avoiding overuse) for children and adolescents with newly diagnosed hypertension remains uncertain. These investigators thoroughly searched multiple databases, including MEDLINE, PubMed Central, Embase, Web of Science, and the Cochrane Library without language restrictions for studies describing clinical characteristics of children and adolescents (21 years or younger) who underwent evaluation for secondary causes of hypertension (defined as kidney, renovascular, cardiac, endocrine, or genetic causes, or due to medication exposure). Study quality assessment occurred using a standard validated scoring system based on sample size, method of enrollment, prospective vs retrospective design, comparison method with reference standard, and independent measurement resulting in levels 1 to 4 (highest to lowest quality). Two individuals independently assessed all trials for eligibility and quality; disagreements were resolved by consensus discussion.
Thirty studies met the initial inclusion criteria with 23 used for pooling of data (N = 4210 children and adolescents) after excluding 7 level 4 studies. Of these, 1 study remained with level 1 evidence, 3 studies with level 2 evidence, and 19 studies with level 3 evidence. Studies conducted at primary care or school-based screening clinics reported a lower prevalence of secondary hypertension (9.0%; 95% CI 4.5% - 15%) than those conducted at subspeciality clinics (44%; 36% - 53%). Demographic findings most associated with secondary hypertension included a family history of secondary hypertension (positive likelihood ratio [LR+] 4.7; 2.9 - 7.6), a history of prematurity (LR+ range 2.3 - 2.8), and age 6 years or younger (LR+ range 2.2 - 2.6). A family history of primary hypertension was associated with a lower likelihood of secondary hypertension (negative likelihood ratio [LR-] 0.49; 0.32 - 0.73). Clinical and laboratory findings most associated with secondary hypertension included a body weight at the 10% or lower level for age and sex (LR+ 4.5; 1.2 - 18), microalbuminuria (LR+ 13; 3.1 - 53), and a serum uric acid concentration of 5.5 mg/dL or lower with normal renal function (LR+ range 2.1 - 6.3). Clinical findings associated with a decreased likelihood of secondary hypertension included obesity (LR- 0.34; 0.13 - 0.90) and the absence of hypertension-related symptoms (eg, headache, blurry vision, dizziness, chest pain, edema; LR- range 0.19 - 0.36). Factors often considered, but not associated with, secondary hypertension included sex, race, hypertension stage, and left ventricular hypertrophy. There is minimal evidence of the accuracy of common physical maneuvers (including delayed femoral pulses, differences between upper- and lower-extremity blood pressure, and abdominal bruits) as well as commonly ordered blood tests (including serum electrolytes, creatinine, and blood urea nitrogen).
David C. Slawson, MD
Professor and Vice Chair of Family Medicine for Education and Scholarship
Professor of Family Medicine, UNC Chapel Hill