Endocrine Abstracts

Aim: To evaluate sleep architecture of patients with Cushing’s disease (CD) and to explore whether agouti-related peptide (AgRP) leptin, and interleukin-6 (IL-6) play a permissive role in sleep alterations.

Methods: We performed polysomnography on 26 patients with active CD and age 26 age- and sex-matched control subjects. Blood samples were obtained from all participants for the analyses of AgRP, leptin, and IL-6. The laboratory and sleep-related parameters were compared.

Results: The groups were similar in age, gender, and body mass index. Plasma AgRP (13.2±7.4 pg/ml vs 9±3.1, P=0.029), leptin (59.5 mg/l, [IQR] 32.6-94.6)vs 25.3 mg/l, [IQR] 12.9-57.5, P=0.007) and IL-6 levels (1.2 pg/ml, [IQR] 0.5-2.7 vs 0.6 pg/ml, [IQR] 0.5-2.7, P=0.058) were higher in CD group. The CD group had reduced sleep efficiency (71.6±12.1% vs 78.8±12.6%, P=0.042) and increased wake after sleep onset % (WASO%) (24.7±13.1% vs. 17.4±11.6%, P=0.040) as compared to control group. AgRP and leptin correlated negatively with total sleep time, sleep efficiency, N2%, and positively with WASO%. In multiple regression analyses, AgRP emerged as a significant predictor of sleep efficiency (β= 0.481 and P<0.05) and WASO% (β=0.452 and P<0.05) among other confounders. Seventeen patients with CD and 18 control subjects had obstructive sleep apnea (OSAS).

Conclusion: Active CD hampers sleep efficiency and continuity which may be associated with increased plasma AgRP. Leptin may correlate negatively with sleep efficiency and continuity. More than half of patients with CD may suffer from OSAS. Therefore, patients with CD who complain of impaired sleep or have symptoms attributable to OSAS should undergo polysomnographic evaluation.