How to create scalar function of SQL Server in order to define nPNA?

The Japanese Society for Dialysis Therapy (JSDT) recommends PCR as an indicator of protein intake. Otherwise K/DOQQI recommends nPNA. If you calculate Kt/V with Daugirdas’ method, you can also define nPNA.

\displaystyle \mathrm{nPNA} = \frac{C_0}{36.3 + 5.48\times\mathrm{Kt/V} + 53.5/\mathrm{Kt/V}} + 0.168 \\  = \frac{\mathrm{preBUN}}{36.3 + 5.48\times\mathrm{Kt/V} + 53.5 / \mathrm{Kt/V}} + 0.168 \cdots(4)

Execute the following procedure.

Reference: Simplified nutritional screening tools for patients on maintenance hemodialysis

How to define Kt/V, an indicator of the efficiency of dialysis, as scalar function of SQL Server?

In Japan, Shinzato’s fomula for calculating Kt/V, an indicator of efficiency of dialysis, is recommended by JSDT. Since integral equation is used to solve Shinzato’s method, you couldn’t solve algebraically. In K/DOQQI, it is usual to solve Kt/V with Daugirdas’ method. Shinzato has described that Daugirdas’ Kt/V is similar to Shinzato’s Kt/V.

\displaystyle \mathrm{Kt/V} = - LN( R - 0.08 \times t ) + \left[ 4 - \left( 3.5 \times R \right) \right] \times\frac{\mathrm{UF}}{\mathrm{W}}\\  = - LN \left( \frac{\mathrm{postBUN}}{\mathrm{preBUN}} - 0.008 \times t \right) + \left[ 4 - \left( 3.5 \times \frac{\mathrm{postBUN}}{\mathrm{preBUN}} \right) \right] \times \frac{\mathrm{preWeight} - \mathrm{postWeight}}{\mathrm{postWeight}} \cdots(1)
\displaystyle \mathrm{Gw} = \mathrm{G}\cdot\mathrm{Tw} = \mathrm{Kd}\int_{0}^{Td}C_1dt + \mathrm{Kd}\int_{0}^{Td}C_2dt + \mathrm{Kd}\int_{0}^{Td}C_3dt \cdots(2)
\displaystyle \mathrm{Ce} = \mathrm{Cs} Exp\left( - \frac{\mathrm{Kt}}{\mathrm{V}} \right) + \frac{\mathrm{G}}{\mathrm{K}}\left[ 1 - Exp\left( - \frac{\mathrm{Kt}}{\mathrm{V}} \right) \right] \cdots(3)

Execute the procedure as following;

References: JSDT 29 (12): 1511-1516, 1996

Second Generation Logarithmic Estimates of Single-Pool Variable Volume

How to create scalar function of SQL Server in order to calculate GNRI?

Malnutrition in elder people increases the risk of death. Geriatric Nutrition Risk Index (GNRI) is the tool to detect malnutrition easily in hemodialysis patients, too. The definition is as following;

\displaystyle \mathrm{GNRI} = 14.89\times\mathrm{Albumin (g/dL)} + 41.7\times\frac{\mathrm{Body Weight}}{\mathrm{Ideal Body Weight}}

where ideal body weight is given by multiplying 22 the square of height. But body weight should be replaced with ideal body weight if body weight is greater than ideal body weight. Then the second term is equal to 1.

Table is defined as following procedure. It is based on the survey list of the Japanese Society for Dialysis Therapy in 2013.

We need height, body weight and albumin in the table. Execute following procedure to create function.

Execute following query to calculate GNRI.

Reference: Simplified nutritional screening tools for patients on maintenance hemodialysis