Recombinant human growth hormone (GH) has been available since 1986 for the treatment of short staturebut there is a paucity of final height data. The aims of this study were to determine the final height achieved following GH therapy under Australian dosage schedules at a single centre. As many had left our care and were unlikely to return to the hospital for a final height measurement, we needed a standardised measuring tool to be used at home. It needed to be accurate to 0.5cms, easy to use, and able to be posted.
Selection criteria included GH therapy commenced after 1985 and a diagnosis of familial short stature, maturational delay, idiopathic short stature (collectively non-GHD), GH deficiency, intrauterine growth retardation (IUGR), Turner syndrome (TS), Russell Silver syndrome (RS) or Noonan syndrome (NS). Growth hormone deficient patients were further divided into congenital/idiopathic (GHD) and those secondary to childhood cancer (GHD-onc). Non-GHD patients were also subdivided into those with a bone age delay of >2 years (non-GHD-delay) or appropriate bone age (non-GHD). Final height was defined at (1) a bone age >17 years (male) or >15 years (female), (2) males >18 years or females >16 years with a growth velocity <2cm/year, or (3) patients >30 years of age with a recent height measurement. Additional measurements of final height were obtained from the home measuring device posted to past patients of the Growth Clinic and these were validated by comparing parental heights already on file.
Final height was available for 428 patients (Table 1). Mean age at start of treatment was 10.9 years and mean duration of treatment was 4.7 years for all groups. Median starting dose of GH was the same for all groups (5.0mg/m2/week) apart from TS (8.6mg/m2/week). Similarly, median final dose was 7.3mg/m2/week for all groups apart from TS (9mg/m2/week). GHD-onc patients started GH at a higher start height SDS compared to other patients. GHD patients had a better first year response to GH compared to other patients and achieved a higher final height SDS. They were also closer to their mid parental height (MPH). Despite having similar first year responses, patients with IUGR and RS had the lowest overall response to GH therapy. Regression analysis showed that the first year response to GH and commencement before puberty were associated with better final height responses in all patient groups.
Final height outcomes were significantly lower than target heights (MPH) for all groups. While this is expected for syndromic short stature (especially TS), for other conditions it highlights the need to re-evaluate GH dose and treatment duration.
The measuring device was assessed as being easy to assemble and the instructions clear. By demonstrating the device to families prior to them leaving our care, we hope to be able to capture more accurate final height data.
This will assist in providing valuable information on the final height of those treated with growth hormone.
In turn this will facilitate the evaluation of optimal treatment and contribute to predicting outcomes for patients in the future.
|
n |
Mean start height SDS |
First year delta SDS |
Mean final Height SDS |
Final height relative to MPH (cm) |
|
|
GHD |
61 |
-3.0 ± 1.0 |
0.9 ± 0.5 |
-0.8 ± 1.2 |
-2.8 ± 8.0^ |
|
GHD-onc |
86 |
-2.0 ± 1.0* |
0.3 ± 0.4* |
-1.7 ± 1.4* |
-10.3 ± 9.9^ |
|
NonGHD |
55 |
-2.6 ± 0.4 |
0.4 ± 0.3* |
-1.6 ± 0.7* |
-2.9 ± 6.4^ |
|
NonGHD-delay |
86 |
-3.0 ± 0.5 |
0.5 ± 0.3* |
-1.5 ± 0.7* |
-4.1 ± 6.0^ |
|
IUGR |
16 |
-3.5 ± 1.2 |
0.4 ± 0.3* |
-2.6 ± 1.1* |
-13.3 ± 10^ |
|
TS |
110 |
-2.8 ± 0.9 |
0.4 ± 0.3* |
-1.7 ± 0.7* |
-10.5 ± 5.8^ |
|
RS |
4 |
-3.8 ± 1.2 |
0.3 ± 0.2* |
-3.1 ± 1.2* |
-19.3 ± 11.3^ |
|
NS |
10 |
-3.3 ± 0.7 |
0.4 ± 0.3* |
-1.6 ± 1.1* |
-7.2 ± 8.3^ |
Table 1: Final Height Outcome
Values represent mean±SD
* p<0.05 compared to GHD for the same variable. ^p<0.05 compared to corresponding MPH.