Katalin Z Ronai1, Andras Szentkiralyi2, Alpar S Lazar3, Zsolt I Lazar4, Istvan Papp4, Ferenc Gombos5, Rezso Zoller6, Maria E Czira7, Anett V Lindner8, Istvan Mucsi9, Robert Bodizs1, Miklos Z Molnar10, Marta Novak11. 1. Inst. of Behavioural Sciences, Semmelweis University, Budapest, Hungary. 2. Inst. of Behavioural Sciences, Semmelweis University, Budapest, Hungary; Inst. of Epidemiology and Social Medicine, University of Muenster, Muenster, Germany. 3. Inst. of Behavioural Sciences, Semmelweis University, Budapest, Hungary; Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK. 4. Dept. of Physics, Babes-Bolyai University, Cluj-Napoca, Romania. 5. Dept. of General Psychology, Pázmány Péter Catholic University, Budapest, Hungary. 6. 1st Dept. of Internal Medicine, Semmelweis University, Budapest, Hungary. 7. Inst. of Epidemiology and Social Medicine, University of Muenster, Muenster, Germany. 8. Klinikum Landkreis Erding, Interdisciplinary Pain Center, Erding, Germany. 9. Inst. of Behavioural Sciences, Semmelweis University, Budapest, Hungary; Dept. of Medicine, Division of Nephrology, University Health Network, University of Toronto, Toronto, Canada. 10. Dept. Transplantation and Surgery, Semmelweis University, Budapest, Hungary; Division of Nephrology, Department of Medicine, University of Tennessee Health Science Center, TN, USA. 11. Inst. of Behavioural Sciences, Semmelweis University, Budapest, Hungary; Centre for Mental Health, University Health Network and Dept. of Psychiatry, University of Toronto, Toronto, Canada. Electronic address: marta@nefros.net.
Abstract
OBJECTIVE: Insomnia complaints are frequent among kidney transplant (kTx) recipients and are associated with fatigue, depression, lower quality of life and increased morbidity. However, it is not known if subjective insomnia symptoms are associated with objective parameters of sleep architecture. Thus, we analyze the association between sleep macrostructure and EEG activity versus insomnia symptoms among kTx recipients. METHODS: Participants (n1=100) were selected from prevalent adult transplant recipients (n0=1214) followed at a single institution. Insomnia symptoms were assessed by the Athens Insomnia Scale (AIS) and standard overnight polysomnography was performed. In a subgroup of patients (n2=56) sleep microstructure was also analyzed with power spectral analysis. RESULTS: In univariable analysis AIS score was not associated with sleep macrostructure parameters (sleep latency, total sleep time, slow wave sleep, wake after sleep onset), nor with NREM and REM beta or delta activity in sleep microstructure. In multivariable analysis after controlling for covariables AIS score was independently associated with the proportion of slow wave sleep (β=0.263; CI: 0.026-0.500) and REM beta activity (β=0.323; CI=0.041-0.606) (p<0.05 for both associations). CONCLUSIONS: Among kTx recipients the severity of insomnia symptoms is independently associated with higher proportion of slow wave sleep and increased beta activity during REM sleep but not with other parameters sleep architecture. The results suggest a potential compensatory sleep protective mechanism and a sign of REM sleep instability associated with insomnia symptoms among this population.
OBJECTIVE:Insomnia complaints are frequent among kidney transplant (kTx) recipients and are associated with fatigue, depression, lower quality of life and increased morbidity. However, it is not known if subjective insomnia symptoms are associated with objective parameters of sleep architecture. Thus, we analyze the association between sleep macrostructure and EEG activity versus insomnia symptoms among kTx recipients. METHODS:Participants (n1=100) were selected from prevalent adult transplant recipients (n0=1214) followed at a single institution. Insomnia symptoms were assessed by the Athens Insomnia Scale (AIS) and standard overnight polysomnography was performed. In a subgroup of patients (n2=56) sleep microstructure was also analyzed with power spectral analysis. RESULTS: In univariable analysis AIS score was not associated with sleep macrostructure parameters (sleep latency, total sleep time, slow wave sleep, wake after sleep onset), nor with NREM and REM beta or delta activity in sleep microstructure. In multivariable analysis after controlling for covariables AIS score was independently associated with the proportion of slow wave sleep (β=0.263; CI: 0.026-0.500) and REM beta activity (β=0.323; CI=0.041-0.606) (p<0.05 for both associations). CONCLUSIONS: Among kTx recipients the severity of insomnia symptoms is independently associated with higher proportion of slow wave sleep and increased beta activity during REM sleep but not with other parameters sleep architecture. The results suggest a potential compensatory sleep protective mechanism and a sign of REM sleep instability associated with insomnia symptoms among this population.