Growth Charts for Turner's Syndrome patients

[snield1150]

Apologies if this is not the correct place to ask this kind of question, but not sure where else to post. This isn't an issue as such with the Chart Component, but a question about implementation.

I wondered if any integrators/implementers of the Growth Charts API and/or Growth Charts component have taken account for Turner's patients? I note from your Demo application that you don't allow the submission of Turners measurements for weight, BMI or head circumference.

I'd be interested to know how others might have implemented this use case where a user wants to record height measurements by calling the Turners API end point, and plotting a height chart with Turner's Syndrome reference data. But for weight and head circumference, use the UK-WHO API end point and plot a chart using UK-WHO reference data. Additionally, how should the BMI calculation be handled? Presumably, from a clinical perspective, the BMI couldn't be calculated and plotted?

Thanks for any ideas about how best to approach this use case.

[pacharanero]

Hi @snield1150 and thanks for asking this great question. I can't answer the whole question as I am not experienced enough clinically with caring for Turner's patients. Experts like @eatyourpeas may have clinical experience of this, and we have non-clinical experts such as @statist7 who might know what the UK accepted position is on this.

I can say that (as far as I am aware) none of our implementers have yet encountered the use-case of how to manage the weight, head-circ, and BMI aspects of managing Turner growth charts. A pragmatic view, given that we don't have Turner-specific data for weight, head-circ etc, would be to use UK-WHO reference data for these but ensure that the UI alerted the user that there may be a requirement to take expert advice, to account for the Turner syndrome when comparing Turner children to the non-Turner UK-WHO population.

I suspect clinically it is safer to be comparing the children against something (even UK-WHO), as opposed to not measuring weight and head-circ, or not charting them.

BMI can still be calculated and plotted on a BMI centile chart, but again, I'd say a large UI flag needs to remind users that the child has Turner syndrome and that interpretation of a UK-WHO BMI centile in such circumstances needs a growth/TS expert. TS tends to result in short stature so the BMI is likely to be elevated compared to the background population, a TS expert will know from experience and judgement when this is BMI elevation is 'normal for TS' and when it is problematic/pathological in its own right.

[eatyourpeas]

Turner reference data only exists for height - mostly useful because Turner syndrome is an indication for growth hormone and so having a reference for height gives a better steer on what normal is. Note that there is no adolescent growth spurt on the turner chart and this is because of the impact of streak ovaries which goes with XO.

For sure it would be great to have a reference for BMI to see how the obesity epidemic we are living in reflects on people with Turner, but actually this is not possible since there is no weight reference. So the answer to the question is that it is not possible to get a reference for weight, OFC and BMI in Turner's, and what we tend to do in clinical practice is use the standard charts but disregard the normal curves and look at the trend.

[raspberrycodes]

Keeping an eye on this log - we are currently discussing our implementation of measurements for Turner's and can share once we figure it out on open health hub.

[eatyourpeas]

As an update, conversation with colleagues in Scotland about this on 8/2/24 - their clinicians are finding in their implementation that once a child has been labelled as having Turner, they are unable to enter data for height in the under 1s, weight or BMI or head circumference (of course because there is no reference data). Even for height, they make the good point that growth hormone treatment is entirely to improve final height for those with Turner against the general population, so actually it is helpful to see height in those with Turner on Turner charts, but also see how their height compares with the general population, using UK-WHO.

This is not entirely an issue for the chart component, more an implementation question, on which chart is presented to the user and under what circumstances. I wonder if the following implementations might be recommended?

Those with Turner
Growth data would be plotted on UKWHO chart for all metrics, but a toggle might be applied to render heights > 1 y in the Turner chart. This would mean therefore storing 2 sets of results in the clinical record - centiles and SDS scores for Turner where valid, and centiles and SDS scores in UK-WHO for all measurements. A conditional would need to be applied based on user request with respect to height (position of the toggle) but would otherwise default to UK-WHO for all measurements.
There would need to be some signposting below the chart to notify users to use caution in interpreting centile and SDS scores given that the underlying reference data apply to children without Turner

Those with Trisomy 21
Reference data here exist only from 40 weeks gestation for height/weight and BMI, up to 18y for head circumference. Those that are premature therefore are not catered for. In these circumstances it might be acceptable to plot preterm growth data (<37 weeks) on UK-WHO with appropriate warnings, and then switch to Trisomy references once they are term. Babies born born preterm might continue to be plotted on UK-WHO until 0 decimal age, swapping to T21 reference at that point, but those born >37 weeks and above might be plotted against T21 reference at birth.

Those with extreme prematurity < 23 weeks
Some babies are born at the threshold of survivability where there is currently no reference data. It is necessary to be able to plot them nonetheless and their growth trajectory will be come clearer as they grow older.

Development implications for RCPCH

1. Babies born in this latter category (Trisomy 21 at term but < 40 weeks) would need to be able to be plotted for corrected ages in blank space before reference data begins. Data points need to be allowed to 'hang in midair' for the 3 weeks 37 to 40 weeks before the Trisomy data starts.
2. A similar approach needs to be included for those babies that are extremely preterm <23 weeks. Data points need to be plottable, even though no data exists.

As an aside, a previous experimental implementation I did mash the trisomy and UK-WHO references together exactly to allow for prematurity in Trisomy 21. The lines do not match up and are very messy. Better therefore to keep the datasets separate.