Journal of the American Society of Hypertension 8(9) (2014) 668–669
Commentary
Pediatric ambulatory blood pressure monitoring grows up Joseph T. Flynn, MD, MS* Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
In 1997, the largest set of ‘‘normative’’ data for pediatric ambulatory blood pressure monitoring (ABPM) studies was published by Soergel et al1 in Germany. Consisting of carefully performed and analyzed ABPM studies in approximately 1100 midEuropean children, this was the first large-scale attempt to establish normal values for pediatric ABPM that could be used to apply the technique to the routine evaluation of elevated blood pressure in children and adolescents. That publication was accompanied by an editorial with the provocative title ‘‘Twenty-four-hour ABPM: now that technology has come of age—we need to catch up2’’. So, nearly 20 years later, what is the state of pediatric ABPM, and have we ‘‘caught up?’’ The article by Davis et al3 in this issue of the Journal of American Society of Hypertension indicates that, at least in larger referral centers, practitioners interested in childhood hypertension have indeed moved pediatric ABPM beyond the experimental stage and are now routinely applying the technique to evaluate elevated childhood blood pressure. The investigators retrospectively examined their clinical experience with pediatric ABPM to address two questions: First, can a level of office blood pressure be identified that could help choose which children should undergo ABPM; and second, what is the potential economic impact of routine application of ABPM in the evaluation of children with elevated blood pressure? Although both of these questions have been examined previously, the findings of Davis et al3 should prove useful to those interested in advocating for wider application of ABPM in pediatrics. Differentiation between white-coat and sustained hypertension is the most wellaccepted indication for performance of ABPM in both adults and children.4,5 The high frequency of white-coat hypertension in patients seen at pediatric hypertension referral centers—typically 30%–40%5—makes ABPM an indispensable tool for evaluating such children. On the other end of the spectrum, however, are children and adolescents with more severe, sustained hypertension, who may require immediate therapy and/or advanced diagnostic studies. It can be argued that such children do not need ABPM at all, but should instead proceed to an immediate evaluation seeking the etiology of their hypertension. In fact, Sorof et al6 demonstrated that in children with systolic blood pressure 20% above the 95th percentile, white-coat hypertension was an uncommon finding, implying that ABPM could possibly be omitted in their evaluation. In contrast, Davis et al3 did not find an office BP level that was predictive of sustained hypertension on ABPM. They did have a similar proportion of children with white-coat hypertension as in prior studies (22% by their analysis, 29% if eliminate children studied by ABPM who had normal office BP), but they were unable to predict which patients would have confirmed hypertension by ABPM based on office BP levels. This may have been a consequence of the fact that this group of clinicians performed ABPM in a large number of patients with normal office BP and included those patients in their analysis. Although the rationale for studying those children by ABPM may have *Corresponding author: Joseph T. Flynn, MD, MS, Division of Nephrology, Seattle Children’s Hospital, 4800 Sand Point Way NE, Seattle, WA 98105. Tel: (206) 987-2524; Fax: (206) 987-2636. E-mail: [email protected] 1933-1711/$ - see front matter Ó 2014 American Society of Hypertension. All rights reserved. http://dx.doi.org/10.1016/j.jash.2014.07.001
J.T. Flynn / Journal of the American Society of Hypertension 8(9) (2014) 668–669
669
been valid (eg, to identify potential cases of masked hypertension), it is likely that doing this reduced the investigators’ ability to identify ambulatory hypertension based on office BP levels. With respect to the economic impact of ABPM on the evaluation of childhood hypertension, Davis et al3 examined the costs of identifying children with confirmed hypertension based on three possible approaches, ranging from office BP measurement only to universal use of ABPM. They found that universal ABPM was the most cost-effective strategy, leading to lower costs per child with ABPM-confirmed hypertension. This approach was sensitive to the prevalence of white-coat hypertension—a higher percentage of children with white-coat hypertension would result in lower per-patient costs, as fewer patients would require a full diagnostic evaluation. These findings are similar in some ways to those of Swartz et al7, who found that use of ABPM would result in significant cost savings because fewer expensive diagnostic tests (echocardiograms, renal ultrasounds) would be ordered if only those children with ABPM-confirmed hypertension underwent the full work-up usually recommended by consensus organizations.8 Thus, clinical application of pediatric ABPM does seem not only to have ‘caught up’ with the technology, but the evidence base has also ‘grown up’ over the past two decades. However, there is a need for even stronger evidence, including prospective studies that could more definitively address the questions examined by Davis et al. Additionally, there is still the need for more robust normative data that would be more broadly applicable to non-Caucasian children.5,9 Despite these issues, the time is right for widespread application of ABPM in the evaluation of childhood hypertension and incorporation of the evidence generated by this and future studies into new clinical practice guidelines for pediatric hypertension.
References 1. Soergel M, Kirschstein M, Busch C, Danne T, Gellermann J, Holl R, et al. Oscillometric twenty-fourhour ambulatory blood pressure values in healthy children and adolescents: a multicenter trial including 1141 subjects. J Pediatr 1997;130:178–84. 2. Alpert BS, Daniels SR. Twenty-four-hour ambulatory blood pressure monitoring: now that technology has come of age—we need to catch up. J Pediatr 1997;130:167–9. 3. Davis ML, Ferguson MA, Zachariah JP. Clinical predictors and impact of ambulatory blood pressure monitoring in pediatric hypertension referrals. J Am Soc Hypertens 2014;8:660–7. 4. Parati G, Stergiou G, O’Brien E, Asmar R, Beilin L, Bilo G, et al. European Society of Hypertension practice guidelines for ambulatory blood pressure monitoring. J Hypertens 2014;32:1359–66. 5. Flynn JT, Daniels S, Hayman L, Maahs DM, McCrindle BW, Mitsnefes M, et al. Update: ambulatory blood pressure monitoring in children and adolescents.
6.
7.
8.
9.
A scientific statement from the American Heart Association. Hypertension 2014;63:1116–35. Sorof JM, Poffenbarger T, Franco K, Portman R. Evaluation of white coat hypertension in children: importance of the definitions of normal ambulatory blood pressure and the severity of casual hypertension. Am J Hypertens 2001;14:855–60. Swartz SJ, Srivaths PR, Croix B, Feig DI. Costeffectiveness of ambulatory blood pressure monitoring in the initial evaluation of hypertension in children. Pediatrics 2008;122:1177–81. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 2004;114:555–76. Flynn JT. Ambulatory blood pressure monitoring in children: imperfect, yet essential. Pediatr Nephrol 2011;26: 2089–94.
Commentary
Pediatric ambulatory blood pressure monitoring grows up Joseph T. Flynn, MD, MS* Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
In 1997, the largest set of ‘‘normative’’ data for pediatric ambulatory blood pressure monitoring (ABPM) studies was published by Soergel et al1 in Germany. Consisting of carefully performed and analyzed ABPM studies in approximately 1100 midEuropean children, this was the first large-scale attempt to establish normal values for pediatric ABPM that could be used to apply the technique to the routine evaluation of elevated blood pressure in children and adolescents. That publication was accompanied by an editorial with the provocative title ‘‘Twenty-four-hour ABPM: now that technology has come of age—we need to catch up2’’. So, nearly 20 years later, what is the state of pediatric ABPM, and have we ‘‘caught up?’’ The article by Davis et al3 in this issue of the Journal of American Society of Hypertension indicates that, at least in larger referral centers, practitioners interested in childhood hypertension have indeed moved pediatric ABPM beyond the experimental stage and are now routinely applying the technique to evaluate elevated childhood blood pressure. The investigators retrospectively examined their clinical experience with pediatric ABPM to address two questions: First, can a level of office blood pressure be identified that could help choose which children should undergo ABPM; and second, what is the potential economic impact of routine application of ABPM in the evaluation of children with elevated blood pressure? Although both of these questions have been examined previously, the findings of Davis et al3 should prove useful to those interested in advocating for wider application of ABPM in pediatrics. Differentiation between white-coat and sustained hypertension is the most wellaccepted indication for performance of ABPM in both adults and children.4,5 The high frequency of white-coat hypertension in patients seen at pediatric hypertension referral centers—typically 30%–40%5—makes ABPM an indispensable tool for evaluating such children. On the other end of the spectrum, however, are children and adolescents with more severe, sustained hypertension, who may require immediate therapy and/or advanced diagnostic studies. It can be argued that such children do not need ABPM at all, but should instead proceed to an immediate evaluation seeking the etiology of their hypertension. In fact, Sorof et al6 demonstrated that in children with systolic blood pressure 20% above the 95th percentile, white-coat hypertension was an uncommon finding, implying that ABPM could possibly be omitted in their evaluation. In contrast, Davis et al3 did not find an office BP level that was predictive of sustained hypertension on ABPM. They did have a similar proportion of children with white-coat hypertension as in prior studies (22% by their analysis, 29% if eliminate children studied by ABPM who had normal office BP), but they were unable to predict which patients would have confirmed hypertension by ABPM based on office BP levels. This may have been a consequence of the fact that this group of clinicians performed ABPM in a large number of patients with normal office BP and included those patients in their analysis. Although the rationale for studying those children by ABPM may have *Corresponding author: Joseph T. Flynn, MD, MS, Division of Nephrology, Seattle Children’s Hospital, 4800 Sand Point Way NE, Seattle, WA 98105. Tel: (206) 987-2524; Fax: (206) 987-2636. E-mail: [email protected] 1933-1711/$ - see front matter Ó 2014 American Society of Hypertension. All rights reserved. http://dx.doi.org/10.1016/j.jash.2014.07.001
J.T. Flynn / Journal of the American Society of Hypertension 8(9) (2014) 668–669
669
been valid (eg, to identify potential cases of masked hypertension), it is likely that doing this reduced the investigators’ ability to identify ambulatory hypertension based on office BP levels. With respect to the economic impact of ABPM on the evaluation of childhood hypertension, Davis et al3 examined the costs of identifying children with confirmed hypertension based on three possible approaches, ranging from office BP measurement only to universal use of ABPM. They found that universal ABPM was the most cost-effective strategy, leading to lower costs per child with ABPM-confirmed hypertension. This approach was sensitive to the prevalence of white-coat hypertension—a higher percentage of children with white-coat hypertension would result in lower per-patient costs, as fewer patients would require a full diagnostic evaluation. These findings are similar in some ways to those of Swartz et al7, who found that use of ABPM would result in significant cost savings because fewer expensive diagnostic tests (echocardiograms, renal ultrasounds) would be ordered if only those children with ABPM-confirmed hypertension underwent the full work-up usually recommended by consensus organizations.8 Thus, clinical application of pediatric ABPM does seem not only to have ‘caught up’ with the technology, but the evidence base has also ‘grown up’ over the past two decades. However, there is a need for even stronger evidence, including prospective studies that could more definitively address the questions examined by Davis et al. Additionally, there is still the need for more robust normative data that would be more broadly applicable to non-Caucasian children.5,9 Despite these issues, the time is right for widespread application of ABPM in the evaluation of childhood hypertension and incorporation of the evidence generated by this and future studies into new clinical practice guidelines for pediatric hypertension.
References 1. Soergel M, Kirschstein M, Busch C, Danne T, Gellermann J, Holl R, et al. Oscillometric twenty-fourhour ambulatory blood pressure values in healthy children and adolescents: a multicenter trial including 1141 subjects. J Pediatr 1997;130:178–84. 2. Alpert BS, Daniels SR. Twenty-four-hour ambulatory blood pressure monitoring: now that technology has come of age—we need to catch up. J Pediatr 1997;130:167–9. 3. Davis ML, Ferguson MA, Zachariah JP. Clinical predictors and impact of ambulatory blood pressure monitoring in pediatric hypertension referrals. J Am Soc Hypertens 2014;8:660–7. 4. Parati G, Stergiou G, O’Brien E, Asmar R, Beilin L, Bilo G, et al. European Society of Hypertension practice guidelines for ambulatory blood pressure monitoring. J Hypertens 2014;32:1359–66. 5. Flynn JT, Daniels S, Hayman L, Maahs DM, McCrindle BW, Mitsnefes M, et al. Update: ambulatory blood pressure monitoring in children and adolescents.
6.
7.
8.
9.
A scientific statement from the American Heart Association. Hypertension 2014;63:1116–35. Sorof JM, Poffenbarger T, Franco K, Portman R. Evaluation of white coat hypertension in children: importance of the definitions of normal ambulatory blood pressure and the severity of casual hypertension. Am J Hypertens 2001;14:855–60. Swartz SJ, Srivaths PR, Croix B, Feig DI. Costeffectiveness of ambulatory blood pressure monitoring in the initial evaluation of hypertension in children. Pediatrics 2008;122:1177–81. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 2004;114:555–76. Flynn JT. Ambulatory blood pressure monitoring in children: imperfect, yet essential. Pediatr Nephrol 2011;26: 2089–94.
