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Increased nocturnal heart rate in children with renal scars
bone pain, and daily life function must play a prominent role in both the decisions to begin therapy, as well as the ongoing determination of therapy duration. The comment of Drs Bachrach and Gandrud regarding our reported use of bisphosphonate therapy based solely on densitometry raises a valid concern. Indeed, we agree with the points raised by the writers. In particular, they took issue with the decision to treat four persons who had a corrected lumbar spine lumbar mineral density Z scores between ÿ1 to ÿ2. However, we must point out that the decision to treat these patients was not based solely on BMD reading, though we may have erroneously given that impression in the manuscript. Two of the four persons in this group had OI. Persons with OI have fractures, even in the face of BMD within ÿ2 SDs of normal.2 Therefore, in patients with OI and active fracturing, the use of bisphosphonates can lead to dramatic clinical improvement. The remaining two persons had a history of long-term and ongoing glucocorticoid exposure, with no expectation for reduction in the glucocorticoid dosage. Bisphosphonates are currently considered the treatment of choice for glucocorticoid-induced osteoporosis in adults and have been shown to have efficacy in primary prevention of bone loss in adults exposed to glucocorticoids. Given the successful experience with the use of bisphosphonates in improving fragility in children with long-standing glucocorticoid-induced osteoporosis, the decision was made to treat these children to prevent worsening of their bone strength. Thus, this treatment was undertaken in light of a combination of BMD and the expectation of further deterioration, not, as may have appeared, in response to the BMD reading alone. The treatment of osteoporosis in children remains in its infancy and we agree with the writers that the decision to undertake this treatment must take into account many aspects of the particular patient’s presentation. This certainly includes careful analysis of BMD, but also fracture history, as the best measure of overall bone health and predictor of future fractures. Furthermore, treatment requires a careful consideration of the etiology of the fragility, the likelihood that the particular etiology will continue to affect the child’s bone health, the alternative treatment options available, and the anticipated benefits of improved bone strength for the particular patient. Furthermore, we agree that such treatment should be undertaken by clinicians experienced in the evaluation and treatment of pediatric osteoporosis and in a setting that allows accumulation of data, both observational and prospective, so that our understanding of this disorder can continue to progress. Joel Steelman, MD Division of Pediatric Endocrinology Vanderbilt University Medical Center Nashville, TN 37232 YMPD643 10.1016/j.jpeds.2003.11.020
286 Letters
REFERENCES 1. Whyte M, Wenkert D, Clements K, McAlister W, Mumm S. Bisphosphonate-induced osteopetrosis. N Engl J Med 2003;349:457-63. 2. Lee Y, Low S, Lim L, Loke K. cyclic pamidronate infusion improves bone mineralization and reduces fracture incidence in osteogenesis imperfecta. Eur J Pediatr 2001;11:641-4.
Increased nocturnal heart rate in children with renal scars To the Editor: We read with interest the article by Patzer et al1 and the accompanying editorial by Portman2 regarding day- and night-time blood pressure (BP) elevation in children with renal scarring as studied using ambulatory blood pressure monitoring (ABPM). The authors’ findings were a significant increase of mean systolic day-time BP in girls and a significant increase of both mean systolic and diastolic night-time BP in both girls and boys compared with healthy controls. Their conclusion was that night-time elevation in BP might be the most sensitive indicator of a raised BP in these children. We would like to draw the authors’ attention to a previous publication of ours reporting on 10 children with renal scars similarly studied by ABPM.3 Our results differ somewhat in that average daytime and night-time BP were not significantly different from those of controls. Moreover, the physiologic decrease in BP during sleep was observed in both study subjects and controls and was of equal magnitude between these groups. Our main finding, however, was a significant increase of mean and minimal night-time heart rates in children with renal scars. The importance of an increased nocturnal heart rate due to a disturbed sympathovagal balance has recently been reported as an independent risk factor in diverse conditions, such as progression of diabetic retinopathy4 or visual field loss in normal-tension glaucoma.5 In the manuscript by Patzer et al, no mention is made of heart rate. It would be interesting to know if their data corroborate our finding. If indeed this is the case, the earliest and most sensitive indicator of hypertension, either present or impending, in children with renal scars is likely to be nocturnal tachycardia. This alteration of the normal physiological dip of heart rate during sleep will probably also prove to be true in other clinical settings. Ze’ev Korzets, MBBS Department of Nephrology Avishalom Pomeranz, MD Department of Pediatrics Meir Hospital, Sapir Medical Center University of Tel-Aviv Tel-Aviv, Israel YMPD640 10.1016/j.jpeds.2003.11.017
REFERENCES 1. Patzer L, Seeman T, Luck C, Wu¨hl E, Janda J, Misselwitz J. Day- and night-time blood pressure elevation in children with higher grades of renal scarring. J Pediatr 2003;142:117-22.
The Journal of Pediatrics
February 2004
2. Portman RJ. While you were sleeping. . .. J Pediatr 2003;142:93-5. 3. Pomeranz A, Korzets Z, Regev A, Wolach B, Bernheim J. Is greater than normal nocturnal heart rate in children with renal scars a predictor of reflux nephropathy? Blood Press Monit 1998;3:369-72. 4. Imano E, Miyatsuka T, Motomura M, Kanda T, Matsuhisa M, Kajimoto Y, et al. Heart rate elevation and diabetic retinopathy in patients with type 2 diabetes mellitus and normoalbuminuria. Diabetes Res Clin Pract 2001;52:185-91. 5. Kashiwagi K, Hosaka O, Kashiwagi F, Taguchi K, Mochizuki J, Ishii H, et al. Systemic circulatory parameters. Comparison between patients with normal tension glaucoma and normal subjects using ambulatory monitoring. Jpn J Ophthalmol 2001;45:388-96.
Reply To the Editor: We read with interest the letter by Korzets and Pomeranz regarding changes of heart rate in children with renal scars. The authors draw the attention to previously published findings of a significant increase of mean and minimal night-time heart rates in 10 children with renal scars.1 We analyzed median SDS heart rate according to height in our 61 patients and 934 controls after correction by the LMS method, as given in the paper. The median SDS for 24-hour day heart rate and night heart rate are given in the Table. Although we found a tendency to higher heart rate SDS in patients, we did not find any significant differences of mean heart rate between patients and healthy controls on the basis of SDS according to height. We could not find any significant correlation between SDS heart rate and severity of renal scars detected by DMSA scan either. In conclusion, median heart rate measured by an oscillometric ABPM device was not influenced by renal scarring in our group of patients compared with a large group of healthy controls. The difference to the data of Pomeranz
et al are probably caused by the number of patients and the use of the LMS method. Only this method allows calculation of exact SDS values in a non-normal distributed reference group. Nevertheless, we do agree with the authors’ opinion that a disturbed sympathovagal balance needs to be addressed in further studies as a possible cardiovascular risk factor already in childhood. Ludwig Patzer, MD Department of Pediatrics, Friedrich-Schiller-University Jena, Germany Tomas Seeman, MD Department of Pediatrics, University Hospital Prague-Motol, Czech Republic Carmen Luck, MD Department of Nuclear Medicine, Friedrich-Schiller-University Jena, Germany Elke Wu¨hl, MD Department of Pediatrics, Ruprecht-Karls-University Heidelberg, Germany Jan Janda, MD Department of Pediatrics, University Hospital Prague-Motol, Czech Republic Joachim Misselwitz, MD Department of Pediatrics, Friedrich-Schiller-University Jena, Germany YMPD641 10.1016/j.jpeds.2003.11.018
REFERENCE 1. Pomeranz A, Korzets Z, Regev A, Wolach B, Bernheim J. Is greater than normal nocturnal heart rate in children with renal scars a predictor of reflux nephropathy? Blood Press Monit 1998;3:369-72.
Table. Median heart rate SDS in patients and controls
Boys Controls (n = 458) Patients (n = 13) Patients vs controls Girls Controls (n = 476) Patients (n = 48) Patients vs controls
Median 24-h heart rate SDS
Median day heart rate SDS
Median night heart rate SDS
0.006 ÿ11.8/3.1 0.06 ÿ1.2/1.2 NS
0.04 ÿ3.0/3.3 0.13 ÿ1.5/1.0 NS
0.02 ÿ3.0/3.0 0.1 ÿ1.1/1.3 NS
ÿ0.05 ÿ3.5/3.7 0.1 ÿ2.0/3.1 NS
ÿ0.01 ÿ3.0/2.8 0.24 ÿ2.0/3.3 NS
0.01 ÿ3.2/3.9 ÿ0.3 ÿ2.3/3.2 NS
Data are given as median and range; significance was tested by Mann-Whitney U test.
Letters
287
286 Letters
REFERENCES 1. Whyte M, Wenkert D, Clements K, McAlister W, Mumm S. Bisphosphonate-induced osteopetrosis. N Engl J Med 2003;349:457-63. 2. Lee Y, Low S, Lim L, Loke K. cyclic pamidronate infusion improves bone mineralization and reduces fracture incidence in osteogenesis imperfecta. Eur J Pediatr 2001;11:641-4.
Increased nocturnal heart rate in children with renal scars To the Editor: We read with interest the article by Patzer et al1 and the accompanying editorial by Portman2 regarding day- and night-time blood pressure (BP) elevation in children with renal scarring as studied using ambulatory blood pressure monitoring (ABPM). The authors’ findings were a significant increase of mean systolic day-time BP in girls and a significant increase of both mean systolic and diastolic night-time BP in both girls and boys compared with healthy controls. Their conclusion was that night-time elevation in BP might be the most sensitive indicator of a raised BP in these children. We would like to draw the authors’ attention to a previous publication of ours reporting on 10 children with renal scars similarly studied by ABPM.3 Our results differ somewhat in that average daytime and night-time BP were not significantly different from those of controls. Moreover, the physiologic decrease in BP during sleep was observed in both study subjects and controls and was of equal magnitude between these groups. Our main finding, however, was a significant increase of mean and minimal night-time heart rates in children with renal scars. The importance of an increased nocturnal heart rate due to a disturbed sympathovagal balance has recently been reported as an independent risk factor in diverse conditions, such as progression of diabetic retinopathy4 or visual field loss in normal-tension glaucoma.5 In the manuscript by Patzer et al, no mention is made of heart rate. It would be interesting to know if their data corroborate our finding. If indeed this is the case, the earliest and most sensitive indicator of hypertension, either present or impending, in children with renal scars is likely to be nocturnal tachycardia. This alteration of the normal physiological dip of heart rate during sleep will probably also prove to be true in other clinical settings. Ze’ev Korzets, MBBS Department of Nephrology Avishalom Pomeranz, MD Department of Pediatrics Meir Hospital, Sapir Medical Center University of Tel-Aviv Tel-Aviv, Israel YMPD640 10.1016/j.jpeds.2003.11.017
REFERENCES 1. Patzer L, Seeman T, Luck C, Wu¨hl E, Janda J, Misselwitz J. Day- and night-time blood pressure elevation in children with higher grades of renal scarring. J Pediatr 2003;142:117-22.
The Journal of Pediatrics
February 2004
2. Portman RJ. While you were sleeping. . .. J Pediatr 2003;142:93-5. 3. Pomeranz A, Korzets Z, Regev A, Wolach B, Bernheim J. Is greater than normal nocturnal heart rate in children with renal scars a predictor of reflux nephropathy? Blood Press Monit 1998;3:369-72. 4. Imano E, Miyatsuka T, Motomura M, Kanda T, Matsuhisa M, Kajimoto Y, et al. Heart rate elevation and diabetic retinopathy in patients with type 2 diabetes mellitus and normoalbuminuria. Diabetes Res Clin Pract 2001;52:185-91. 5. Kashiwagi K, Hosaka O, Kashiwagi F, Taguchi K, Mochizuki J, Ishii H, et al. Systemic circulatory parameters. Comparison between patients with normal tension glaucoma and normal subjects using ambulatory monitoring. Jpn J Ophthalmol 2001;45:388-96.
Reply To the Editor: We read with interest the letter by Korzets and Pomeranz regarding changes of heart rate in children with renal scars. The authors draw the attention to previously published findings of a significant increase of mean and minimal night-time heart rates in 10 children with renal scars.1 We analyzed median SDS heart rate according to height in our 61 patients and 934 controls after correction by the LMS method, as given in the paper. The median SDS for 24-hour day heart rate and night heart rate are given in the Table. Although we found a tendency to higher heart rate SDS in patients, we did not find any significant differences of mean heart rate between patients and healthy controls on the basis of SDS according to height. We could not find any significant correlation between SDS heart rate and severity of renal scars detected by DMSA scan either. In conclusion, median heart rate measured by an oscillometric ABPM device was not influenced by renal scarring in our group of patients compared with a large group of healthy controls. The difference to the data of Pomeranz
et al are probably caused by the number of patients and the use of the LMS method. Only this method allows calculation of exact SDS values in a non-normal distributed reference group. Nevertheless, we do agree with the authors’ opinion that a disturbed sympathovagal balance needs to be addressed in further studies as a possible cardiovascular risk factor already in childhood. Ludwig Patzer, MD Department of Pediatrics, Friedrich-Schiller-University Jena, Germany Tomas Seeman, MD Department of Pediatrics, University Hospital Prague-Motol, Czech Republic Carmen Luck, MD Department of Nuclear Medicine, Friedrich-Schiller-University Jena, Germany Elke Wu¨hl, MD Department of Pediatrics, Ruprecht-Karls-University Heidelberg, Germany Jan Janda, MD Department of Pediatrics, University Hospital Prague-Motol, Czech Republic Joachim Misselwitz, MD Department of Pediatrics, Friedrich-Schiller-University Jena, Germany YMPD641 10.1016/j.jpeds.2003.11.018
REFERENCE 1. Pomeranz A, Korzets Z, Regev A, Wolach B, Bernheim J. Is greater than normal nocturnal heart rate in children with renal scars a predictor of reflux nephropathy? Blood Press Monit 1998;3:369-72.
Table. Median heart rate SDS in patients and controls
Boys Controls (n = 458) Patients (n = 13) Patients vs controls Girls Controls (n = 476) Patients (n = 48) Patients vs controls
Median 24-h heart rate SDS
Median day heart rate SDS
Median night heart rate SDS
0.006 ÿ11.8/3.1 0.06 ÿ1.2/1.2 NS
0.04 ÿ3.0/3.3 0.13 ÿ1.5/1.0 NS
0.02 ÿ3.0/3.0 0.1 ÿ1.1/1.3 NS
ÿ0.05 ÿ3.5/3.7 0.1 ÿ2.0/3.1 NS
ÿ0.01 ÿ3.0/2.8 0.24 ÿ2.0/3.3 NS
0.01 ÿ3.2/3.9 ÿ0.3 ÿ2.3/3.2 NS
Data are given as median and range; significance was tested by Mann-Whitney U test.
Letters
287