Unattended automated office blood pressure measurement in children

To the Editor,

In our most recent study on unattended automated office blood pressure (uAOBP) measurement in children and adolescents published in Blood Pressure last year [1] we have demonstrated that the uAOBP was significantly lower than office BP (OBP) both for systolic and diastolic values (−13.6 and −7.6 mmHg, p < 0.0001). This was different from the results from the first study on AOBP in children published by Hanevold et al. three years ago who found less pronounced differences between AOBP and OBP values (−4.5 and −1.0 mmHg for systolic and diastolic BP, respectively) [2]. In our discussion we have hypothesized that the discrepant results between our and Hanevold´s study could be due to the lack of a rest period in the first subgroup of children investigated in the later study however we didn´t have the data comparing AOBP between children with and without a 5 min rest period before the AOBP measurement as they were not published.

Hanevold et al. showed in their Letter to the Editor these unpublished data on the AOBP and OBP in their study (Table 1 in the Letter to the Editor [3]). These data showed only non-significantly lower similar differences in AOBP values in comparison to OBP in the early cohort with a 5 min rest period before AOBP measurement in comparison to the late cohort without rest period (difference 1.5 mmHg for systolic and 1.5 mmHg for diastolic BP). These formerly unpublished results show that the reason for the discrepant results between our and Hanevold et al. study lies possibly in another factor that than in a 5 min rest before the AOBP measurements. This factor could be a different BP measurement technique (oscillometric vs. auscultatory), other clinical setting of the BP measurements (e.g. OBP first, followed by AOBP vs. AOBP first, followed by OBP measurement), other selection of children (e.g. hypertensive vs. normotensive, new patients in the clinic with higher level of stress vs. patients who are familial with the clinic, nurses and physicians and behave more calm) or other still unknown factor.

We fully agree with Hanevold et al. that further research on this quite new and promising method of BP measurement in children is indicated. We suggest that the research should concentrate not only on the question what is the reason for discrepant results between our studies but also whether other AOBP devices (BpTRU is no more producing) such as Omron 907XL can lead similar results, whether children younger than 6 years, who did not tolerate unattended AOBP measurements without their parents in our study can obtain reasonable AOBP measurements with the presence of their parents, whether six AOBP measurements (BpTRU) delivers similar results as three AOBP measurements (e.g. OMRON XL), whether AOBP can predict systolic white-coat hypertension also in a larger prospective trial and diastolic white-coat hypertension, why children´s AOBP is, in contrary to adults, lower than daytime ambulatory BP, whether attended AOBP (e.g. presence of a nurse/physician or even only a parent) is similar to unattended AOBP or whether AOBP values are associated with hypertensive target organ damage such as left ventricular mass or albuminuria similar to OBP or ABP values. The clinical utility of AOBP measurements in paediatrics still needs to be determined. And last but not least the currently lacking normative values for AOBP and AOBP thresholds for diagnosing hypertension in children are urgently needed.

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The author(s) reported there is no funding associated with the work featured in this article.