Sleep-related breathing disorders in prepubertal children with Prader-Willi syndrome and effects of growth hormone treatment

Context: Recently, several cases of sudden death in GH-treated and non-GH-treated, mainly young Prader-Willi syndrome (PWS), patients were reported. GH treatment in PWS results in a remarkable growth response and an improvement of body composition and muscle strength. Data concerning effects on respiratory parameters, are however, limited. Objective: The objective of the study was to evaluate effects of GH on respiratory parameters in prepubertal PWS children. Design: Polysomnography was performed before GH in 53 children and repeated after 6 months of GH treatment in 35 of them. Patients: Fifty-three prepubertal PWS children (30 boys), with median (interquartile range) age of 5.4 (2.1-7.2) yr and body mass index of +1.0 SD score (-0.1-1.7). Intervention: Intervention included treatment with GH 1 mg/m(2)-d. Results: Apnea hypopnea index (AHI) was 5.1 per hour (2.8-8.7) (normal 0-1 per hour). Of these, 2.8 per hour (1.5-5.4) were central apneas and the rest mainly hypopneas. Duration of apneas was 15.0 sec (13.0-28.0). AHI did not correlate with age and body mass index, but central apneas decreased with age (r = -0.34, P = 0.01). During 6 months of GH treatment, AHI did not significantly change from 4.8 (2.6-7.9) at baseline to 4.0 (2.7-6.2; P = 0.36). One patient died unexpectedly during a mild upper respiratory tract infection, although he had a nearly normal polysomnography. Conclusions: PWS children have a high AHI, mainly due to central apneas. Six months of GH treatment does not aggravate the sleep-related breathing disorders in young PWS children. Our study also shows that monitoring during upper respiratory tract infection in PWS children should be considered.