Growth hormone therapy and respiratory disorders: long-term follow-up in PWS children.

CONTEXT: Adenotonsillar tissue hypertrophy and obstructive sleep apnea have been reported during short-term GH treatment in children with Prader-Willi syndrome (PWS). OBJECTIVE: We conducted an observational study to evaluate the effects of long-term GH therapy on sleep-disordered breathing and adenotonsillar hypertrophy in children with PWS. DESIGN: This was a longitudinal observational study. PATIENTS AND METHODS: We evaluated 75 children with genetically confirmed PWS, of whom 50 fulfilled the criteria and were admitted to our study. The patients were evaluated before treatment (t0), after 6 weeks (t1), after 6 months (t2), after 12 months (t3), and yearly (t4-t6) thereafter, for up to 4 years of GH therapy. The central apnea index, obstructive apnea hypopnea index (OAHI), respiratory disturbance index, and minimal blood oxygen saturation were evaluated overnight using polysomnography. We evaluated the adenotonsillar size using a flexible fiberoptic endoscope. RESULTS: The percentage of patients with an OAHI of >1 increased from 3 to 22, 36, and 38 at t1, t4, and t6, respectively (χ(2) = 12.2; P < .05). We observed a decrease in the respiratory disturbance index from 1.4 (t0) to 0.8 (t3) (P < .05) and the central apnea index from 1.2 (t0) to 0.1 (t4) (P < .0001). We had to temporarily suspend treatment for 3 patients at t1, t4, and t5 because of severe obstructive sleep apnea. The percentage of patients with severe adenotonsillar hypertrophy was significantly higher at t4 and t5 than at t0. The OAHI directly correlated with the adenoid size (adjusted for age) (P < .01) but not with the tonsil size and IGF-1 levels. CONCLUSION: Long-term GH treatment in patients with PWS is safe; however, we recommend annual polysomnography and adenotonsillar evaluation.