Daytime Functioning in People with Type 2 Diabetes and Insomnia Symptoms: A Comparison-Correlational Study

Abstract

Background Sleep disturbances showed negative impact on self-care and diabetes outcomes for people with type 2 diabetes. However, there is a need to understand to what extent insomnia symptoms impact daytime functioning in people with type 2 diabetes. This study compared common daytime functioning outcomes including fatigue, daytime sleepiness, and quality of life related to vitality and physical function in people with type 2 diabetes with and without insomnia symptoms. Methods This study was a cross-sectional comparison design which used validated instruments to assess common daytime functioning outcomes (i.e. fatigue severity scale, daytime sleepiness, and quality of life related to vitality and physical function domains) in 60 participants with type 2 diabetes with and without symptoms of insomnia. Insomnia Severity Index was used to stratify participants into an insomnia group and non-insomnia control group. Multivariate linear model and partial correlations tests were utilized to examine the relationships between outcomes in the two groups after controlling for age and depression symptoms. Results Levels of fatigue severity, and quality of life related vitality and physical function were worse in the insomnia group compared to non-insomnia group (P<.004). After controlling for age, the multivariate linear model showed that the insomnia group had greater fatigue severity (R 2 =0.15, p=.003), and lower quality of life related to vitality and physical function (R 2 =0.25, p<.001; and R 2 =0.11, p=.004, respectively). Partial correlation showed that daytime sleepiness was correlated with Insomnia Severity Index in the full sample after controlling for age ( r =.35, p =.006). When added depression symptoms into the models, the differences or relationships were not observed. Conclusion Fatigue, and quality of life related vitality and physical function were worse in people with both type 2 diabetes and insomnia symptoms compared to people with type 2 diabetes only. Depression symptoms may have an independent contribution for the daytime functioning.