Background: With the goal of averting future cardiovascular disease, the Affordable Care Act of 2010 mandates population-wide identification of children with high blood pressure (BP). Since children are prone to white coat (reactive) hypertension and masked hypertension, ambulatory blood pressure monitoring (ABPM) may be a cost-effective confirmatory test and therefore of high relevance to this mandate. Using actual patient data we evaluated the role of ABPM in patients referred to specialty clinic for evaluation of elevated blood pressure.
Methods: From an unselected group of consecutive referral patients all receiving ABPM (n=58), we collected ABPM results, clinic auscultative BP and subsequent work-up patterns. Pre-elevated (90-95% referenced to age-sex-height) and elevated (>95%) clinic BP (CBP) were defined per NHLBI 2011 integrated guidelines. ABPM stratified patients into a) normal (mean 24 systolic BP (SBP) < 95%; SBP load <25%);b) pre-elevated (mean 24 SBP 25%); and c)elevated (mean 24 hour SBP >95%; SBP load >25%). ABPM was treated as the gold standard. We then compared 3 high BP confirmation strategies: 1. Average CBP alone to stratify into normal, pre-elevated, or elevated BP; 2. CBP followed by ABPM for CBP > 90%ile, using CBP and ABPM to stratify; 3. ABPM alone to stratify. The scenarios were compared by a) proportion elevated BP children appropriately identified; b) charges incurred. Charges included NHLBI 2011 recommended evaluation for elevated BP, extended secondary etiology work-up when indicated, target organ damage assessment in all pre-elevated, and screening for co-morbidities in obese pre-elevated patients. Rates of secondary etiology work-up and proportion obese were derived from the clinical cohort. We used an average cost approach with charges gleaned from our institution rate book.
Results: CBP alone, CBP + ABPM, and ABPM alone identified 33.3% (3/9), 44.4% (4/9), and 100% (9/9) hypertensive cases respectively. Cost per hypertensive patient identified in each scenario was $28,994; $14,312; and $11,336 respectively.
Conclusion: Given pediatric high BP is uncommon with many false positives and negatives, ABPM as a universal confirmatory test identifies more true hypertensives at a lower average cost.