The authors of this study did a great job of explaining their results and potential study limitations. Frontline pediatric providers would do well to compare their own practices to those of this large managed-care practice.
Source: Koebnick C, Mohan Y, Li X, et al. Failure to confirm high blood pressures in pediatric care- quantifying the risks of misclassification. J Clin Hypertens (Greenwich). 2018;20(1):174-182; doi:10.1111/jch.13159. See AAP Grand Rounds commentary by Dr. Pamela Singer (subscription required).
The study originates from the Kaiser Permanente of Southern California health system which, because of its large patient population and electronic health record system, has the ability to measure practice and health outcomes with large study sample size. In this instance, investigators looked at 4 years' worth of blood pressure measurements in children between 3 and 17 years of age. After excluding various conditions that could be associated with hypertension or high blood pressure recordings, they focused on 186,732 children who had at least 1 BP reading at the 95th percentile or above, looking mainly to see how well practitioners adhered to screening guidelines* and how this might affect eventual health outcomes. Their discussion section alone is worth the price of reading the article.
The study's key findings were that only about half of the children had correct BP classifications based on the initial visit, with the remainder classified as a false-positive high BP, false-negative low BP, or unknown. Eighty percent of the group with initial high measurements did not even have a repeat measurement performed at the same visit; this occurred even though the Kaiser system automatically translates the readings into percentiles, which I (and the authors) would have thought would be a great help to the providers. That failure to repeat the measurement at the same visit accounted for half of the false-positive results in the study. That would certainly cause problems by requiring unnecessary follow-up visits to repeat BP measurement, though perhaps sadly not as big a problem as expected with this group since only one-third of those children completed the follow-up within 3 months of the initial measurement.
I mentioned some helpful take-home messages for primary care providers.
1. Take time now to review the current AAP blood pressure screening guidelines, linked above.
2. Ensure office staff are trained and re-certified annually in blood pressure measurement. (However, the Kaiser staff did have this condition in place and still ended up with these problems.)
3. Assess your office sphygmomanometers. Automated digital devices are widely used now, including in this study, but do have a tendency to overestimate true BP. I'm not suggesting we return to those manual sphygmomanometers with glass tubes filled with toxic liquid mercury, but aneroid (from the Greek meaning "without water") devices require frequent recalibration due to being dropped or other trauma.
4. Watch out for implicit bias in BP screening. (Note that implicit bias applies to any form of stereotyping; it is any bias that we are not aware of in a conscious manner.) I mention this because the authors found that children with high BP were more likely to have repeat measurements performed if they were male, older, and obese. This meant that younger, non-obese female patients had poorer care for this particular screening, which suggests implicit bias was in play.
