ESPE Abstracts

The many false-positive diagnoses of IIGHD do not automatically imply that re-testing is needed. Instead, the diagnostic procedure should be improved. Still, re-testing of children can be useful. Regarding the timing, re-testing within 1-2 months would only extend the diagnostic procedure. Re-testing after one year may be a useful option if the growth response appears insufficient. The current approach of re-testing at near-adult height (NAH) is associated with highest GH waste and patient burden. Testing at mid-puberty has the benefit of long-term physiological exposure to sex steroids, and a lower GH waste and patient burden than current practice. However, decisions are needed about which GHST should be used, whether sex hormone priming is indicated, the optimal cut-off for the GH peak, and possible adjustment for BMI SDS. The effect of discontinuation of rhGH treatment on adult height in an adolescent with a normal GH peak at re-testing in mid-puberty is uncertain. Two small uncontrolled (and potentially biased) studies showed a 0.4-0.5 SD lower NAH adjusted for target height. The reported positive effect by doubling the rhGH dose in puberty on NAH suggests that pubertal growth is GH dependent. The benefit of re-testing is a reduction of GH waste and patient burden. Risks include uncertainty about the effect on adult height and potential patient anxiety. Further, the physician’s credibility may be at stake and a repeat test will be necessary at NAH if the GH peak in mid-puberty is low. I propose a stricter diagnostic phase associated with full explanation of the re-testing schedule; re-testing after 1 year if the growth response insufficient; re-testing at mid-puberty in all; discontinuation of rhGH treatment if the GH peak is sufficient; and careful long-term follow-up.