The Association between Biochemical Parameters and Sleep Related Disorders in Hemodialysis Patients

BACKGROUND: Sleep disorders in long-term hemodialysis patients with comorbidities are common. They affect the quality of life and physical well-being of patients. However, little attention has been paid to this phenomenon. METHODS: Thirty-nine long-term hemodialysis patients with ＞ 3 months of care at Taipei Medical University Hospital were prospectively enrolled. Participants’ biochemical data and sleep disorder scores were collected for analysis using questionnaire. Laboratory data were evaluated and scored by association, and further analyzed by both univariate and multivariate binary logistic regression analyses. RESULTS: The age range of the study population was 55.2 ± 11.1 years. In the correlation study, insomnia, determined by a higher Pittsburgh Sleep Quality Index (PSQI) score, was directly correlated with the severity of restless legs syndrome. After adjusting for age and sex in the multivariate analysis, a low serum creatinine level did not correlate with insomnia (P = 0.05); low serum sodium, potassium, and chloride levels strongly correlated with the severity of restless legs syndrome (P = 0.04, 0.02, and 0.003, respectively). Furthermore, elevated uric acid and fasting blood glucose levels were associated with depressed mood according to the Beck Depression Inventory (P = 0.012 and 0.024 respectively). However, only blood glucose level was associated with depressed mood according to the Center for Epidemiologic Studies Depression Scale (CESD) (P = 0.03). CONCLUSION: Biochemical differences exist between patients with sleep disorders and those without. In addition to impaired renal function and related electrolyte imbalance, metabolic problems such as hyperlipidemia and hyperuricemia may also affect the diagnosis of sleep disorders in hemodialysis patients. However, further research is warranted to confirm these results.