Paediatric blood pressure guideline changes issued in 2017 increase the number of children diagnosed with high blood pressure, a new study finds.
That means more kids will be identified as having a higher risk of developing heart disease in adulthood, researchers point out.
After analysing data on nearly 4,000 adults who had their blood pressure recorded in childhood, researchers concluded that the new guidelines would have done a better job at identifying the kids who would later, as adults, have hypertension, an enlarged heart and metabolic syndrome, according to a report in Hypertension.
“When you compare the old versus the new guidelines in this population, 8% of the kids would get up-classified as having hypertension,” said study co-author Dr Lydia Bazzano, an associate professor and director of the Centre for Lifespan Epidemiology Research at the Tulane University School of Public Health and Tropical Medicine. “Those kids were more likely to have metabolic syndrome, enlarged hearts and hypertension as adults.”
The children who would have been added to the ranks of those with hypertension might also be at a higher risk of having heart attacks, but it will be years before that data can be collected since most of the people in those in the study are now in their mid-30s to mid-50s, Bazzano said.
Unlike adults for whom there are specific blood pressure thresholds for a diagnosis of hypertension, cutoffs for high blood pressure in children depend on their age, sex and height, Bazzano explained.
The old guidelines were drawn up based on data from all children, including those who were overweight and obese, which led to a higher cut-point than the new charts which exclude information on overweight and obese children. Although it’s only a degree or two difference, 8% more kids would end up with a diagnosis of hypertension under the new guidelines, Bazzano said.
The data for the new report came from the Bogalusa Heart Study, a long-term series of studies that began in 1973. Between 1973 and 2016, there were nine cross-sectional surveys of children between three and 18 years old and 11 surveys of adults who had been previously examined as children.
The 3,940 people in the new study were examined as children and were followed for 36 years. When the researchers compared how the old and new guidelines would have played out in this population, they found that the newer ones would have caught a much larger number of children who would eventually develop left ventricular hypertrophy. “That condition develops when the left ventricle enlarges because it is fighting against a higher pressure than it should be,” Bazzano said. “Just as weight lifter’s muscles get bigger, the heart gets bigger and that makes it more vulnerable to not getting enough oxygen.”
The changes also identified would have identified more children who would eventually develop metabolic syndrome and hypertension in adulthood.
The new study is assessing “how good this guideline change was at helping identify the kids who were truly at risk,” said Dr Tammy Brady, an associate professor of paediatrics and medical director of the Pediatric Hypertension Program at Johns Hopkins University. “It’s fascinating. It showed that when kids were reclassified as hypertensive according to the new guidelines they did in fact seem to have more cardiovascular risk factors. So it does seem to do a better job of identifying those who are at risk of developing long term complications.”
By having a lower threshold for hypertension in children, the new guidelines may give paediatricians more ammunition when they try to convince parents to get their kids to make lifestyle changes that would result in lower blood pressure, Brady said. Sometimes parents are resistant when the physician says, “we need to minimise weight gain,” she added. “They’ll sometimes respond: ‘He looks fine to me. He looks like me.’”
But with an actual diagnosis of hypertension, “an alarm bell can go off,” Brady said. “And I can say we really, really need to work on this.”