One of the biggest problems with evidence-based medicine is translating that evidence into everyday practice. This article is a nice example of making it easier for child healthcare providers to identify children with blood pressure problems.
Source: Banker A, Bell C, Gupta-Malhotra M, et al. Blood pressure percentile charts to identify high or low blood pressure in children. BMC Pediatr. 2016;16:98; doi:10.1186/s12887-016-0633-7. See AAP Grand Rounds commentary by Dr. Pamela Singer (subscription required).
The so-called "Fourth Report" (this always sounds like some Grisham novel off the bestseller lists, but it wasn't), from 2004, identified blood pressure (BP) norms for children. It's a great resource for anyone screening children for hypertension, but unfortunately the tables for BP are very complex, making their use very cumbersome for front-line practitioners. This likely has resulted in poor implementation of recommended hypertension screening in practice. Well, 12 years later, those front-line practitioners might have something to help them implement good clinical practice.
The study itself may not be rocket science exactly, but the fact that this took 12 years is a good indication that it wasn't that easy a problem to approach. The authors went back to their own database of BP measurements in Houston schoolchildren and developed nice graphical representations of BP by height (the strongest determinant of BP in children) for boys and girls ages 3 years and up. They designed their charts to be screening tools, with the main caveat that they are intended to be highly sensitive, with the resultant loss of specificity that we learn to accept with screening tools. Stated differently, we'll have some false positives, children identified as hypertensive or prehypertensive, who need to be sorted out subsequently, but it's better than the alternative of missing some children who truly should be categorized into those groups. Using the Fourth Report measurements as the gold standard, sensitivities were 100%, with specificities for systolic and diastolic measurements of 94.7% and 99.3% for hypertension and 95.4% and 98.3% for prehypertension, respectively. Inexplicably, the authors didn't include confidence intervals around these estimates, my one complaint about the article.
Dr. Singer pointed out in her commentary that the BP measurement methods differed between the Fourth Report (by auscultation) and the current study (oscillometry), which could contribute to some inaccuracies. However, if these new charts aid clinicians in implementing BP measurement guidelines, the net effect likely will be positive.
Another nice feature of this article is that it was published in an open-source journal, meaning that any of you has access to the boys and girls charts to try out tomorrow. If any of you do, let me know what you think by commenting on my main blog site.
