2.3 Assessment of dialysis symptom index
The DSI is a validated instrument consisting of 30 questions to assess the severity of discomfort and unpleasant emotions in patients on MHD, with each question addressing a specific physical or emotional symptom7,15. The 30 questions can be summarized into eight groups of symptoms: 1) gastrointestinal, 2) musculoskeletal and fluid volume, 3) neurological symptoms, 4) irritation of the mucous membranes and skin, 5) depression, 6) sleep disturbance, 7) sexual symptoms, and 8) anemia. Patients were asked to report symptoms that occurred in the last week, answering “yes” or “no” to each symptom. Severity was assessed on a five-point Likert scale, with scores ranging from 0 to 4 for each answer (i.e., a response of ”0” means ”no,” whereas a response of ”4” means ”yes: very much”). The total DSI score represents the sum of individual scores (ranging from 0 to 120), with higher total scores indicating higher overall symptom severity.