MDRD.Rmd

---
title: "MDRD"
author: "kou"
date: "12/27/2017"
output: html_document
---

## Modification of Diet in Renal Disorders (MDRD) formula

 In 1999, Leveys proposed MDRD formula by stufy of chronic kidney disease (CKD) patients.  
***MDRD formula*** are proposed to determine the grade of CKD.

* MDRD formula  
    * caucasians male
$$
eGFR_{(male)}   = 186\times (Age)^{-0.203}\times (Scr)^{-1.154}
$$
    * caucasians female
$$
eGFR_{(female)} = 186\times (Age)^{-0.203}\times (Scr)^{-1.154}\times 0.742
$$

This formula determine GFR at standard body surface area (BSA) (1.73$m^{2}$).  
The muscle volume is propotional to BSA (creatinine is metabolic product from muscle).  
So, the production of creatinine is propotional to BSA.  

This value from MDRD is need to adjust by BSA.  

$$
eGFR_{(adj-BSA)}=GFR\times \frac{BSA}{1.73}
$$

 In 2005, MDRD formula is adjusted to modify the difference between race.  
For blacks, GFR is multiplied by a coefficient (1.212). 

* MDRD formula adjusted by race  
    * blacks male
$$
GFR_{(male)}   = 186\times (Age)^{-0.203}\times (Scr)^{-1.154}\times 1.212
$$
    * blacks female
$$
GFR_{(female)} = 186\times (Age)^{-0.203}\times (Scr)^{-1.154}\times 0.742\times 1.212
$$


* This is reference of MDRD (NCBI)

[Levey AS, Bosch JP, Lewis JB, et.al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Intern Med; 130: 461-70, 1999.](https://www.ncbi.nlm.nih.gov/pubmed/10075613)