Fatigue, Nonrestorative Sleep and Associated Factors Among Sudanese Patients with Type 2 Diabetes: A Case-Control Study

Background: Fatigue, nonrestorative sleep, and other sleep disorders could be pointers to serious medical problems like obstructive sleep apnea; when present in patients with diabetes, they exacerbate each other deleterious consequences. The present study aimed to assess fatigue, nonrestorative sleep, sleep duration, and daytime sleepiness among patients with type 2 diabetes.
Methods: This cross-sectional descriptive study was conducted among 103 consecutive patients with type 2 diabetes and 121 healthy controls attending an outpatient clinic in Omdurman, Sudan during the period from December 2015 to June 2016. All participants signed a written informed consent and were interviewed using a questionnaire based on Epworth Sleepiness Scale to assess subjective nonrestorative sleep, sleep duration, and snoring. A blood sample was taken for the HbA1c. The local ethical committee approved the research, and chi-square test and t-test were used for data analysis.
Results: Highly significant statistical differences were observed between the diabetic patients and the control subjects regarding fatigue, nonrestorative sleep, sleep duration, snoring, and excessive daytime sleepiness (P-value < 0.001). Patients with fatigue had higher nonrestorative sleep than those without, no significant differences were found between patients with the symptoms of fatigue and those without regarding excessive daytime sleepiness, snoring, sleep duration, and the HbA1c (P-value > 0.05).
Conclusions: Fatigue, nonrestorative sleep, sleep duration, excessive daytime sleepiness, and snoring were common among patients with type 2 diabetes than their healthy counterparts, diabetic patients with fatigue had more nonrestorative sleep than those without. The reliance on a self-administered questionnaire is a limitation of the study. 
Keywords: fatigue, nonrestorative sleep, excessive daytime sleepiness, diabetes mellitus, Sudan