Hypothalamic GH releasing hormone (GHRH) has hypnotic actions by increasing slow wave sleep (SWS) (non-rapid eye movement sleep, non-REM), which account for about 75% of sleep. Conversely, GH may stimulate the rapid eye movement sleep (REM). Patients with GH deficiency (GHD) often exhibit sleep problems leading to daytime fatigue and reduced quality of life (QoL). We have described a cohort of patients with isolated GHD (IGHD) due to GHRH resistance caused by a homozygous null mutation (c.57+1G>A) in the GHRH receptor gene. They have normal QoL and no obvious complaints of chronic tiredness. The aim of this study was to determine objectively and subjectively the sleep quality in these subjects, who have never received GH therapy. A cross sectional study was carried out on 21 adult IGHD subjects, and 21 matched controls. Objective sleep assessment included polygraphic records of the stages wake (W), non-REM: N1 (drowsiness), N2 and N3 (already sleeping) and R (REM). Subjective evaluation included the Pittsburgh Sleep Quality Index, Insomnia Severity Index, and Epworth Sleepiness Scale. Compared to controls, IGHD subjects exhibited lower sleep efficiency (77.7 (27.5) vs 87.5 (10.1) %, P=0.007), total sleep time (330.0 (127.5) vs 385.5 (56.0) min, P=0.028) and higher percentage of the non-REM 1 stage (14.6 (18.9) vs 7.3 (8.1) %, P=0.022). There was no difference between the groups in REM sleep and in quality questionnaires. These data show an extension of the drowsiness period, with a reduction in the total sleep time, suggesting a preponderant role of GHRH resistance over GHD in the sleep quality of these IGHD subjects. The objective reduction in the sleep efficiency and total sleep time seem have minimal subjective consequences, as it was not reflected in differences of quality sleep questionnaires.
20 - 23 May 2017
European Society of Endocrinology