Growth hormone deficit. Does the first year of treatment influence adult height?

INTRODUCTION: Short stature is the most frequent reason for Pediatric Endocrinology consultations and sometimes requires treatment with growth hormone.

OBJECTIVE: The possible correlation of a good response to any early response factor with a better final response was studied, and also whether there was a difference in response to treatment according to the type of deficit.

PATIENTS AND METHODS: This was a longitudinal, retrospective and observational study of 139 patients treated for idiopathic growth hormone deficiency up to adult height. There were good response criteria in the first year of treatment: a) an increase in growth rate ≥3 cm/year, b) a growth rate ≥1 standard deviation (SD), c) an increase in height ≥0.5 SD, d) an increase in height ≥0.3 SD. Study of the Index of Responsiveness to treatment in the first and second year. Final response variables: adult height with respect to target height, adult height with respect to initial growth prediction and adult height with respect to initial height at the start of treatment. The possible correlation of a good response to any of the early response factors with a better final response to treatment was studied, and also whether there was a difference in the response to treatment according to the type of deficit.

RESULTS: The treatment produced a gain in adult height with respect to genetic height of 0.06 ± 0.7 SD. Patients considered good responders in the first year of treatment presented a better final response (growth rate ≥3 cm: p = 0.000, growth rate ≥1 SD: p = 0.008, height gain ≥0.5 SD: p = 0.007, height gain ≥0.3 SD: p = 0.006), as well as patients with a severe deficit (p = 0.04). The index of responsiveness to treatment during the first year was associated with a better final response (r = 0.249, p = 0.003), with this correlation being maintained in the second year (r = 0.294, p = 0.01).

CONCLUSIONS: Growth hormone treatment increased height in the genetic target. The percentage of good responders varied depending on the criteria used. The response in the first year of treatment and a severe deficit were determining factors for achieving a good long-term response.