Symptom clusters in patients on dialysis and their association with quality-of-life outcomes.

Background: Patients who are on dialysis report multiple symptoms. The aim of the study was to explore and identify symptom clusters (co-occurring symptoms) in patients on dialysis and their possible associations with depressive symptoms and health-related quality-of-life (HRQOL) outcomes.

Methods: In a cross-sectional study of 301 prevalent patients on dialysis, physical symptoms, depressive symptoms and HRQOL were assessed using the Beck Depression Inventory (BDI) and the Kidney Disease and Quality-of-Life-Short Form version 1.3 (KDQOL-SF36) questionnaires. Symptom clusters were identified using principal component analysis with varimax rotation. Multivariate linear regression analyses were carried out to evaluate the relationships between symptom clusters and depressive symptoms and HRQOL outcomes.

Results: The majority of patients (63.5%) rated their symptoms in the 'very much' to 'extremely bothersome' range, and 29.4% had significant depressive symptoms. Three symptom clusters were identified and were named uraemic (nausea, lack of appetite, dizziness/faintness, feeling squeezed out, shortness of breath, chest pain), neuromuscular (numbness in extremities, sore muscles, cramps) and skin (itching, dry skin) clusters. The three clusters were associated with BDI, physical component summary (PCS) and mental component summary (MCS) scores. After multiple adjustments, the uraemic and neuromuscular clusters remained independently associated with BDI and PCS scores and the uraemic and skin clusters with MCS scores.

Conclusion: The strong associations between symptom clusters and depressive symptoms and the physical and mental domains of HRQOL should lead to an increased focus on symptom-alleviating interventions. Additional research is warranted to determine whether treatment of symptom clusters rather than single symptoms will improve HRQOL.