extended BMI SDS

[eatyourpeas]

A suggestion from Mars Skae, endocrinologist is for more SDS lines on the centile charts for children of high BMI She cites the CDC

[statist7]

The questions to ask are: which extra SDS lines would they be, and in what circumstances would they be drawn?

The current centiles are spaced 2/3 SDS up to 2 2/3, so it would be plausible to continue on that basis with the same spacing, as 3 1/3 and 4 etc. Another alternative would be to space them more widely at say 2 SDS apart, i.e. at 4 and 6 to match 2, which I think would be better. It would be straightforward to interpolate or extrapolate using the +2 and +4 lines.

In terms of drawing the lines, it would be good to develop an algorithm which drew them when required and not otherwise. This would avoid having to customise the chart. Perhaps when the BMI SDS is sufficiently far above the 99.6th centile it triggers the +4 or even the +6 line being plotted.

[dc2007git]

@eatyourpeas is this issue still open for discussion?

[eatyourpeas]

Discussion at Project Board 22.8.24 BMI charts should have SDS lines at:

• [ ] +2.67 SDS
• [ ] +3.33 SDS
• [ ] +3.67 SDS
• [ ] +4.0 SDS There is already an API endpoint that can generate custom lines against an SDS, so we can use this for this purpose.