Growth hormone treatment of children with neural tube defects: results from 6 months to 6 years

OBJECTIVE: Patients with neural tube defects (myelomeningocele) have severe growth retardation, and treatment with recombinant human growth hormone (rHGH) for 6 months accelerates growth velocity. We examined patients treated for longer periods to determine whether accelerated growth persists, and whether patients demonstrated to be growth hormone deficient have a greater response to rHGH therapy. METHODS: We retrospectively evaluated the growth rate and length standard deviation score (SDS) of 22 patients in response to treatment with 0.3 mg/kg per week of rHGH for 7 to 72 months. Nine of 22 patients were growth hormone deficient (nocturnal and provocative growth hormone responses < 7 ng/ml). Treatment success was defined as an increase of length SDS of > 0.2 SD per year. RESULTS: Fourteen patients (64%) had treatment successes, and eight had treatment failures. Length SDS improved from a pretreatment value of -2.9 (+/- 1.2) to the most recent length SDS of -1.9 (+/- 1.4) (p < 0.001). The growth rate was significantly increased through year 4 of treatment. The annualized growth rate after 6 months of rHGH treatment was significantly different for the success and failure groups (11.0 +/- 2.6 cm/yr vs 5.1 +/- 3 cm/yr, p < 0.001). The annualized 6-month growth rate during treatment was related to the probability of treatment success. CONCLUSION: Treatment with rHGH significantly improves the growth rate and length SDS of children with neural tube defects. The 6-month annualized growth velocity during treatment was predictive of long-term treatment response. The effect on adult stature is unknown.