Serum Interleukin-6 is Not Linked with Sleep-Quality, Restless Legs Syndrome, and Depression, But with 6-Month Survival in Hematological Malignancies

BACKGROUND: Serum interleukin (IL)-6 has been found to be associated with sleep quality, mood, and survival in patients with solid tumors. Results in these studies were confounded by knowledge of diagnosis to study subjects. Moreover, such data among subjects with hematological malignancies and data regarding restless legs syndrome is limited. The present study was, therefore, conducted to assess the sleep quality, depression, and restless leg syndrome in hematological malignancies and to study if there is any role of IL6 associated with it. METHODS: Sixty-six subjects having hematological malignancy were included in this study after excluding the potential confounders. Sleep quality was examined using Pittsburg Sleep Quality Index, depression by the Patient Health Questionnaire-9. Diagnosis of RLS was made through clinical examination. Serum for measurement of IL-6 was collected at baseline and after 1 month of initiation of chemotherapy. Patients were followed up for 6 months. RESULTS: Average age of study subjects was 50.16 years with male predominance. Nearly 22.7% had clinical depression, 28.8% had poor quality sleep, and restless legs syndrome (RLS) was reported in 6.1% cases. Nearly 22.7% patients died at 6 months. Disturbed sleep at baseline was associated with depression (odds ratio [OR] =7.89) and poor 6 months survival. Serum IL-6 did not show any association with sleep quality, restless-legs-syndrome, and depression. However, baseline high level of serum IL-6 (OR = 26.06) and low level after chemotherapy (OR = 0.03) were associated with poor survival at 6 months. CONCLUSION: Poor quality sleep, depression, and RLS are prevalent among adult subjects with hematological malignancies. Sleep disturbance, high pretreatment inflammatory and lowering of inflammatory load after chemotherapy increase likelihood for poor prognosis. Serum IL-6 did not show any association with sleep quality, restless legs syndrome and depression.