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Predicting the outcome of chronic kidney disease by the estimated nephron number: the rationale and design of PRONEP, a prospective, multicenter, observational cohort study.

Imasawa T, Nakazato T, Ikehira H, Fujikawa H, Nakajima R, Ito T, Ando Y, Yoshimura M, Nakayama M, Yahata K, Sasaki O, Yaomura T, Katafuchi R, Yamamura T, Kawaguchi T, Nishimura M, Kitamura H, Kenmochi T, Shimatsu A - BMC Nephrol (2012)

Bottom Line: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient.The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR.The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Hospital Organization Chiba-East Hospital, Chiba, Japan. imasawa@cehpnet.com

ABSTRACT

Background: The nephron number is thought to be associated with the outcome of chronic kidney disease (CKD). If the nephron number can be estimated in the clinical setting, it could become a strong tool to predict renal outcome. This study was designed to estimate the nephron number in CKD patients and to establish a method to predict the outcome by using the estimated nephron number.

Methods/design: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient. This will be a multicenter, prospective (minimum 3 and maximum 5 years follow-up) study. The subjects will comprise CKD patients aged over 14 years who have undergone a kidney biopsy. From January 2011 to March 2013, we will recruit 600 CKD patients from 10 hospitals belonging to the National Hospital Organization of Japan. The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR. The secondary parameter is the rate of eGFR decline per year. The nephron number will be estimated by the glomerular density in biopsy specimens and the renal cortex volume. This study includes one sub-cohort study to establish the equation to calculate the renal cortex volume. Enrollment will be performed at the time of the kidney biopsy, and the data will consist of a medical interview, ultrasound for measurement of the kidney size, blood or urine test, and the pathological findings of the kidney biopsy. Patients will continue to have medical consultations and receive examinations and/or treatment as usual. The data from the patients will be collected once a year after the kidney biopsy until March 2016. All data using this study are easily obtained in routine clinical practice.

Discussion: This study includes the first trials to estimate the renal cortex volume and nephron number in the general clinical setting. Furthermore, this is the first prospective study to examine whether the nephron number predicts the outcome of CKD patients. The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

Trial registration: UMIN-Clinical Trial Registration, UMIN000004784.

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Related in: MedlinePlus

A hypothetical sphere of a glomerulus.
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Figure 6: A hypothetical sphere of a glomerulus.

Mentions: We assume that glomeruli less than 5 micrometers in diameter cannot be counted. A sphere 2r in diameter is cut off at both ends in parallel so that the diameter of a section may be set to 2ro(5 μm). We observe only circles parallel to the section of this solid, whose height is defined as 2 h. Considering a 2 h-high cylinder whose volume is equal to this solid, the cylindrical base area is equal to the average cross-sectional area of this solid cut at random parallel to the base of the solid (Figure 6).


Predicting the outcome of chronic kidney disease by the estimated nephron number: the rationale and design of PRONEP, a prospective, multicenter, observational cohort study.

Imasawa T, Nakazato T, Ikehira H, Fujikawa H, Nakajima R, Ito T, Ando Y, Yoshimura M, Nakayama M, Yahata K, Sasaki O, Yaomura T, Katafuchi R, Yamamura T, Kawaguchi T, Nishimura M, Kitamura H, Kenmochi T, Shimatsu A - BMC Nephrol (2012)

A hypothetical sphere of a glomerulus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376039&req=5

Figure 6: A hypothetical sphere of a glomerulus.
Mentions: We assume that glomeruli less than 5 micrometers in diameter cannot be counted. A sphere 2r in diameter is cut off at both ends in parallel so that the diameter of a section may be set to 2ro(5 μm). We observe only circles parallel to the section of this solid, whose height is defined as 2 h. Considering a 2 h-high cylinder whose volume is equal to this solid, the cylindrical base area is equal to the average cross-sectional area of this solid cut at random parallel to the base of the solid (Figure 6).

Bottom Line: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient.The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR.The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Hospital Organization Chiba-East Hospital, Chiba, Japan. imasawa@cehpnet.com

ABSTRACT

Background: The nephron number is thought to be associated with the outcome of chronic kidney disease (CKD). If the nephron number can be estimated in the clinical setting, it could become a strong tool to predict renal outcome. This study was designed to estimate the nephron number in CKD patients and to establish a method to predict the outcome by using the estimated nephron number.

Methods/design: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient. This will be a multicenter, prospective (minimum 3 and maximum 5 years follow-up) study. The subjects will comprise CKD patients aged over 14 years who have undergone a kidney biopsy. From January 2011 to March 2013, we will recruit 600 CKD patients from 10 hospitals belonging to the National Hospital Organization of Japan. The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR. The secondary parameter is the rate of eGFR decline per year. The nephron number will be estimated by the glomerular density in biopsy specimens and the renal cortex volume. This study includes one sub-cohort study to establish the equation to calculate the renal cortex volume. Enrollment will be performed at the time of the kidney biopsy, and the data will consist of a medical interview, ultrasound for measurement of the kidney size, blood or urine test, and the pathological findings of the kidney biopsy. Patients will continue to have medical consultations and receive examinations and/or treatment as usual. The data from the patients will be collected once a year after the kidney biopsy until March 2016. All data using this study are easily obtained in routine clinical practice.

Discussion: This study includes the first trials to estimate the renal cortex volume and nephron number in the general clinical setting. Furthermore, this is the first prospective study to examine whether the nephron number predicts the outcome of CKD patients. The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

Trial registration: UMIN-Clinical Trial Registration, UMIN000004784.

Show MeSH
Related in: MedlinePlus