Blood Pressure Measurement in Pediatrics

In this issue, Dr Patel and colleagues1 assess pediatric blood pressure (BP) measurement in two medical practices using a retrospective chart review. Hypertension is a leading precursor to cardiovascular morbidity and mortality. Propelled by the wave of childhood obesity, primary BP abnormalities are expected to increase. This study shows that BP is being frequently measured, and while many children have abnormal readings, there is wide variation in recognition, appropriate evaluation, and confirmation per current guidelines from the National Heart, Lung, and Blood Institute (NHLBI)/fourth report from the National High Blood Pressure Education Program (NHBPEP) Working Group on Blood Pressure in Children and Adolescents.2 These guidelines recommend that children older than 3 years have BP measured at each medical encounter. If BP is above the 90th percentile for age, height, and sex, measurement should be repeated to confirm abnormal findings. Children with persistently elevated BP should undergo further evaluation to rule out secondary causes and to assess for comorbid conditions.

Patel's findings in the current study are both reassuring and concerning at the same time. The number of patients who appropriately have BP measured at routine pediatric visits (97%) is impressive. Previous studies indicate that in most pediatric offices, BP is measured much less frequently.3, 4, 5 A 2012 study by Shapiro and colleagues6 looked at data from a 10‐year period between 2000 and 2009 and revealed that in up to one third of primary care visits, BP was not even measured. Soon after these results were published, the US Preventative Task Force released a statement that there was not enough evidence to recommend routine BP screening in pediatric patients to prevent future cardiovascular disease.7 Definitively proving such a long‐term link is problematic, and BP screening guidelines from the American Academy of Pediatrics and NHLBI have not changed. In addition, most pediatric providers recognize that there are more immediate reasons to assess pediatric BP that warrant continued measurement. There was concern, however, that following the task force statement, many primary pediatric offices would skip this vital diagnostic screening test.8 Patel's finding that over 97% of office visits included a BP check is certainly reassuring that, at least in these offices, providers are still taking the time to screen for BP abnormalities. So much for the good news.

The remaining findings in the current Patel study are also concerning. Although BP was being measured in the study population, the methods of obtaining BP readings were variable and inconsistent. The Fourth Working Group recommends BP be measured in a quiet room using the right arm of a seated patient (with back supported) whose feet are flat on the floor.2 The use of auscultatory BP is also recommended but this study used oscillometric devices to measure BP. Comparison of auscultatory to oscillometric values is complex, especially when only a single value is measured.9 While this study did not evaluate the degree to which the Working Group recommendations were followed regarding BP measurement technique, at least half of the patients had BP measured inappropriately in the left arm. Whether these methodologic issues in BP measurement affected the study findings is unclear, but certainly a more standardized BP measurement technique is required to obtain reproducible BP values that are comparable to the national threshold standards.

Another concerning, although not surprising, finding in the current Patel study is the high prevalence of abnormal BP readings. At each of the two study sites, almost 20% of children were found to have abnormally elevated BP levels at some point. This is almost identical to our findings at school‐based BP screenings in the Houston area.10 Certainly not all of these children will have persistently elevated BP. Patel showed that when BP measurement was repeated, many of the children's BP values normalized either at the initial visit or by the next recheck. This finding is also consistent with previous findings.11 While most providers will excuse a single high BP reading, children with elevated BP require follow‐up. Even when subsequent BP measurements normalize, it seems these children may be at increased risk for developing sustained hypertension within a few years.12 This point leads to the most concerning of Patel's findings. For many children with elevated BP, abnormal BP is not recognized.

Most of the time, even when BP was measured in this study, the offices were neither recognizing the abnormalities nor ordering appropriate follow‐up. One potential explanation might be that recognition of BP abnormalities in childhood remains complex. The design of the current BP tables by the Fourth Working Group make accurate recognition of normal and abnormal BP onerous and unintuitive. By current Fourth Working Group guidelines, BP is standardized not only to sex but also to both age and height. The additional variable does not allow for a graphical two‐dimensional display such as the ubiquitous stature for age or weight for age charts. In order to address this complexity, we recently used data from the Fourth Working Group to develop simple charts to help graphically identify BP percentiles in the same manner that providers use to track growth parameters.13 Although not as accurate as the official tables (since they remove age as a factor in determining BP thresholds), the charts are less cumbersome and provide the ability to track BP changes over time. These sex‐specific charts use BP for stature to show exact percentiles as derived from the Fourth Working Group. Despite their ease, we have yet to test the charts in practice to evaluate whether they will improve recognition of abnormal BP in our practice. Admittedly, using such paper charting is becoming increasingly anachronistic.

Since most practitioners no longer use paper charts during office visits, the introduction of an electronic medical record (EMR) has the potential to bring in a new era of automatic recognition of abnormal findings of all kinds, including BP. While it should certainly not be hard to program automated alerts into EMR platforms to notify physicians (and staff) when BP is abnormal, not all EMR systems have this functionality. In this study, one of the investigator's sites used EpicCare (Epic Systems Corp, Verona, Wisconsin, USA), with automatic display of BP percentiles, while the other site used Allscripts (Allscripts Healthcare Solutions, Inc., Chicago, Illinois, USA), without automatically displayed percentiles. Not surprisingly, there was significantly more recognition of BP abnormalities at the site with automatically calculated BP percentiles in the EMR (74% vs 9.5%) that displayed these values for the practitioner.

Although the Fourth Working Group guidelines are a dozen years old, there still seems to be difficulty in their adoption. Instead of diagnosis and evaluation, practitioners continue to under‐recognize elevations in BP even when it is appropriately measured. EMR technology has the potential to vastly improve medical care, and the current study highlights how important this programing is to the identification of elevated BP. Only continued attention from providers will ensure that children are correctly screened, diagnosed, and evaluated for BP abnormalities.