Fatigue and sleep patterns in systemic lupus erythematosus : correlation with disease activity, depression and serum levels of interleukin-6

Abstract EN

Objective : to assess fatigue and sleep disturbances in SLE patients and their correlation with disease activity index, depression, health related quality of life and serum IL-6 levels.

Methodology : The study included 20 SLE female patients.

Six apparently healthy females served as control.

They were subjected to full history taking, thorough clinical examination, assessment of: disease activity using SLE Disease Activity Index (SLEDAI), disease damage using SLE International Collaborating Clinics Damage Index (SLICC), sleep pattern with Pittsburgh sleep quality index [PSQI] and polysomnography [PSG]), fatigue using Fatigue Severity Scale (FSS), depression with Montgomery Asberg Depression Rating Scale (MADRS), health related quality of life (HRQL) using Medical Outcomes Study 36 item Short Form health survey (SF-36), pain using visual analogue scale for pain (VAS-P).

Serum interleukin-6 (IL-6) levels were measured with ELISA technique.

Results : there was no statistically significant difference between patients and controls regarding age (t = 0.49).

Serum IL-6 levels were significantly higher in SLE patients versus controls and in active versus inactive SLE patients (t = 2.1, t = 2.2 respectively).

SLE patients showed poor sleep quality as detected by significant increase in PSQI score in patients compared to controls and in active SLE patients versus those in remission (t=2.9, t = 2.9 respectively).

Using polysomnography, SLE patients experienced high significant reduction in sleep efficiency, REM latency, SWS% (t = 4.3, t =4.6, t = 5.2 respectively), high significant increase in stage II %, periodic leg movement index (t = 7.02, t = 3.9 respectively) and significant increase in arousal index (t = 2.9) when compared to controls.

Active SLE patients showed high significant decrease in sleep efficiency (t = 6.1), significant reduction in REM latency and SWS% (t = 2.6, t = 2.1 respectively) and high significant increase in arousal index and periodic leg movement index (t = 4.9, t = 4.5 respectively) in comparison to those with quiescent disease.

60% and 65% of SLE patients experienced fatigue and depressive symptoms respectively.

Most of the SF-36 components for health related quality of life were highly significantly reduced in patients versus controls while all the components of SF-36 were highly significantly reduced in active SLE patients when compared to those in remission.

SLE patients experienced highly significantly more pain on VAS-P when compared to controls (t = 4.1).

In SLE patients high significant positive correlation could be found between SLEDAI and PSQI score (r = 0.74), arousal index (r = 0.87) PLMI (r = 0.67), FSS score (r = 0.79), VAS–P (r = 0.91) while it showed high significant negative correlation with all components of SF-36.

Among SLE patients, PSQI score showed high significant positive correlation with FSS score (r = 0.85), MADRS score (r = 0.80), serum IL-6 levels (r = 0.73), VAS-P (r = 0.76).

There was high significant positive correlation between increased FSS scores and MADRS scores (r = 0.82), VAS-P (r = 0.79) and significant positive correlation with serum IL-6 levels (r = 0.51) in SLE patients.

Conclusion : SLE patients experience fatigue and sleep disturbances.

These are correlated to each other and to disease activity, depression ; health related quality of life, serum levels of IL-6.

Early and proper control of SLE disease process may lead to improvement in fatigue and sleep problems and prevent the development of a vicious cycle which may lead to depression, reduced quality of life.

Proper assessment and control of sleep and psychological problems is mandatory in SLE patients.