BMI Zscore Calculation and its json file

Is there a file (json) that holds the zscore for bmi ? and also, what is the calculation needed in the form to do that like z-score,

And is that easy or hard to setup ?

Thanks and God Bless.

Hi @Marcelo_De_Guzman could you please elaborate more on the problem and the issue you are facing?

Hi @Marcelo_De_Guzman,
For calculation of z-score in the form for a patient given their sex, age, and weight is as follows:

z-score('weight-for-age', ../my_sex, ../my_age, ../my_weight)

CHT documentation provides more information about z-score which can be found here

But I think that z-score is only for malnutrition right?

Right now, we are developing the form that will also included to measure BMI.

Is that zscore can also use for calculating BMI and not only malnutrition ?

The z-score can be used for calculating anything. In the documentation that @niraj linked you can see the document that needs to be added to CouchDB as a lookup table. The first parameter of the z-score calculation has to match the charts.id property in the doc. This should be reasonably easy to set up. Please give that a try and let me know if you get stuck!

I’ve tried but it gives me blank values.

When I was checking the calculation for BMI Z score, it needs

  • weight (should be in kg)
  • height (in centimeter but need to convert it to meter squared)
  • age (in months)
  • gender (male or femal)

for getting bmi index = ( kg / m2) , so, it was like ( weight / (height * height)

then for bmi zscore, it was based on the WHO data for boys and girls.

So, it would look like

{
  "id" : "bmia-zscore",
  "data" : {
       "male": [  
          {
               key: {patient age in months}, 
               points: {bmi index from -4SD to +4SD}
           }
}

So, is it possible to include this on zscore-charts.json (that i have and added on couchdb) ?

and in the form for formula is round(z-score('bmia-zscore'(${patient_gender},${patient_age_in_months},${bmi_index}),3) or there is another file that I need to update ?

Hi @gareth and @marc, do you have any suggestions on what might be the issue?

hi @niraj ,

Thanks, it was working now.

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@Marcelo_De_Guzman great to hear it is working. could you please mark the issue as solved? It would be helpful for future reference if others face similar issue.