Abstract
ObjectivesResearch has shown that sleep disturbances can negatively influence the progression of chronic inflammatory diseases, including chronic inflammatory bowel disease (IBD). More specifically, poor sleep quality is strongly related to the clinical activity of the disease. Nevertheless, some patients suffer from sleep disorders even when the disease is clinically inactive. Psychological factors, such as depression and anxiety, are also known to contribute to poor sleep quality. Depression and anxiety are common in chronic diseases. In addition, while the link between depression or anxiety and sleep disorders is well-known, the link between sleep disorders and inflammation has only been studied recently. Sleep studies in IBD patients have generally excluded patients with clinically diagnosed depression or anxiety in order to neutralize their effects on the relationship between inflammation and sleep disorders. Nevertheless, there is no consensus on the relationship between depression and anxiety and the clinical activity of the disease. When a patient with chronic inflammatory bowel disease (Crohn's disease here) complains of fatigue or poor sleep, the subjective aspects of these complaints therefore lead the clinician to consider them simply as: a characteristic of IBD, exhaustion related to the chronicity of the disease, unsatisfactory sleep quality, a manifestation of a depressive mood, or a consequence of an anxious state. When a patient reports a subjective complaint of poor sleep or fatigue in a complex, multi-determined clinical situation, it can thus be difficult to identify its most likely cause and to establish the best possible therapeutic intervention.Patients, materials and methodsThe aim of this work was to determine which element (disease activity, inflammation, depression, anxiety) is most closely related to sleep disorders in patients with Crohn's disease (CD) referred for outpatient psychological assessment. Ninety-seven patients with CD participated in this study. Their mean age was 34.70 (± 10.85) years. They were asked about their sleep (IQSP, ISI, ESD) and mood (HADS). They also provided details of clinical disease activity (Harvey–Bradshaw Index) and inflammation (CRP). In order to determine the nature and extent of the relationship between the variables, Spearman correlation coefficients were calculated, supplemented by multiple regression analyses to determine the variables that could explain the sleep disorders.ResultsThe results show that sleep quality (IQSP) was significantly predicted by the Harvey–Bradshaw score (β = 0.21; β standardized = 0.24; t = 2.6; P = 0.01) and depression (β = 0.45; β standardized = 0.41; t = 4.55; P < 0.001). The Harvey–Bradshaw score (β = 26; β standardized = 2; t = 2.27; P = 0.026) and depression score (β = 75; β standardized = 47; t = 5.34; P < 0.001) were related to the insomnia score (ISI). Finally, daytime sleepiness (DSA) was predicted by the depression score (β = 42; β standardized = 432; t = 3.17; P = 0.002) and by the CRP (β = − 0.05; β standardized = − 0.21; t = − 2.13; P = 0.036). The results show that the severity of clinical activity of the disease was associated with poor sleep quality and insomnia. However, there was a stronger association between the intensity of depression and sleep disturbances than between these variables and clinical disease activity. It therefore seems important that sleep disorders and their management should be considered first from the perspective of depression. However, it is important that CD is not assumed to be the sole cause of depression: other factors (dispositional or situational) should also be taken into consideration. Nevertheless, while our results show a weaker link between inflammation and sleep disorders than other studies, they confirm the link between sleep disorders and disease activity.ConclusionsIn order to predict the likelihood and nature of relapses, it seems important that future research should take into account not only disease activity and inflammation, but also disorders of arousal and nocturnal awakenings experienced by the patient.