Journal of Pediatric Urology (2006) 2, 436e438
MrNomogram: A web-based multivariable pediatric renal nomogram John J. Chen a,*, Jizu Zhi b, Wenyang Mao a, George F. Steinhardt c a
Department of Preventive Medicine, Stony Brook University, Stony Brook, NY 11794-8036, USA b School of Medicine, Stony Brook University, Stony Brook, NY 11794-8036, USA c Pediatric Urology, DeVos Children’s Hospital, Grand Rapids, MI 49503-2530, USA Received 16 August 2005; accepted 4 October 2005 Available online 21 November 2005
KEYWORDS Multivariable; Renal length; Renal nomogram
Abstract Multivariable Pediatric Renal Nomogram, or MrNomogram, is a webbased clinical tool for the evaluation of pediatric renal length. Unlike other available age-adjusted renal nomograms, MrNomogram takes into consideration the fact that the renal length is influenced by multiple demographic variables. It provides a more accurate prediction of pediatric renal length, given the patient’s demographic characteristics, such as age, gender, height, etc. (Availability: https:// www.prevmed.sunysb.edu/jjc/MrNomogram). ª 2005 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
Introduction Evaluation of renal length is an important parameter in the diagnosis and management of most pediatric urologic and renal disorders. Previous renal size nomograms have been univariate in nature, such as age-adjusted nomograms. Even though these age-adjusted renal nomograms are * Corresponding author. Department of Preventive Medicine, Health Sciences Center Level 3, Room 086, Stony Brook University School of Medicine, Stony Brook, NY 11794-8036, USA. Tel.: þ1 631 444 2191; fax: þ1 631 444 7525. E-mail address:
[email protected] (J.J. Chen).
easy to implement and use, they are unable to explain a large portion of the variation demonstrated with renal measurements. Besides age, pediatric renal size is influenced by many other factors, such as gender, ethnicity, height, and weight [1,2]. Recently, we developed a multivariable renal size model, adjusting for these multiple patient demographic variables [2]. This multivariable approach to evaluate renal length has been successfully applied to the evaluation of the well-being of scarred kidneys in pediatric patients [3]. Since publishing this nomogram, we have received many worldwide inquiries from clinicians on
1477-5131/$30 ª 2005 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jpurol.2005.10.003
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how to utilize this clinical tool. We present here a web-based software tool, called MrNomogram (Multivariable pediatric renal Nomogram), implementing this multivariable approach. This webbased tool allows easy access and interactive exploration by pediatric urologists and other clinicians around the globe.
Overview of MrNomogram The original multivariable pediatric renal nomogram was built based on renal ultrasound measurements from 707 children with normal renal anatomy and no VUR, using a multivariable regression technique [2]. This nomogram was implemented here as a web-based clinical tool using Microsoft ASP.NET technology. Anyone with an internet connection and a web browser, such as Internet Explorer, Firefox, or Netscape, will be able to get access to MrNomogram (website: https://www.prevmed. sunysb.edu/jjc/MrNomogram).
Intended use The web-based program, MrNomogram, is intended for use by pediatric urologists or other treatment specialists who are evaluating the renal well-being of pediatric patients. The multivariable renal length model behind MrNomogram explains more variability among ultrasound measurements and allows individualized renal size evaluation. It assists the clinician in making renal outcome assessments thereby justifying various management decisions. By entering a
Figure 1
patient’s relevant information (age, gender, ethnicity, height, and weight), clinicians can receive an individualized renal evaluation (predicted renal length, 95% prediction interval, percentile among children with similar demographic characteristics) by a single mouse click. Although this nomogram provides clinicians with an indication of what a patient might expect, no nomogram can provide absolute predictions. The results need to be interpreted by the patient’s physician in conjunction with a complete medical history and evaluation.
User interface Input The input screen requests entries of relevant demographic information on the patient (Fig. 1). The user can select the option of using either Metric or English units. The user should have access to information on the following variables (required input fields): laterality of the kidney(s) (left, right, or both), age of the patient (years and months, maximum 18 years and 11 months), gender (male versus female), ethnicity (African origin, Caucasian, other), height (centimeters or feet and inches), and weight (kilograms or pounds). The user enters patient data either through selecting options from drop-down lists, clicking on radio buttons, or keying in corresponding text values. The program verifies user inputs and prompts error messages if required parameters are missing or invalid values are entered. By providing the optional information of patient name and actual
MrNomogram patient data entry screen.
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Figure 2
MrNomogram renal length evaluation output screen.
renal length measurement, an individually tailored evaluation can be generated. Output The output includes a summary of the information entered in the input screen (Fig. 2). It also dynamically generates a normal distribution for renal lengths of subjects with similar demographic characteristics as the patient of interest. The percentile of the observed renal length among these subjects is shown by the red-shaded left tail area. The predicted renal lengths and the values of upper and lower 95% prediction intervals are shown below the normal graph. The result page can be printed through the built-in print menu provided by most browsers.
Acknowledgement We thank Kevin Henderson for his expert technical assistance.
References [1] Zerin JM, Blane CE. Sonographic evaluation of renal length in children: a reappraisal. Pediatr Radiol 1994;24:101e6. [2] Chen JJ, Pugach J, Patel M, Luisiri A, Steinhardt GF. The renal length nomogram: a multivariable approach. J Urol 2002;168:2149e52. [3] Chen JJ, Mao W, Rongviriyapanich C, Luisiri A, Steinhardt GF. A multivariable assessment of renal size and growth of scarred kidneys in children. J Urol 2005; 174:2358e62.