Symptom clusters in incident dialysis patients: associations with clinical variables and quality of life

Background. To date, the pathophysiology underlying symptomsin renal patients is still unclear. Symptom management researchsuggests that identification of related clusters of symptomscould provide insight into underlying determinants associatedwith multiple symptom experience. Theoretically, symptoms withina cluster could have a synergistic relationship. We aimed toidentify symptom clusters in incident dialysis patients, andinvestigated associations between symptom clusters, clinicalvariables, functional status as measured by the Karnofsky Indexand quality of life. Methods. 1553 haemodialysis (HD) and peritoneal dialysis (PD)patients completed the Kidney Disease Quality of Life ShortForm symptom/problem list at 3 months after the start of dialysis.Principal component analysis using varimax rotation was usedto identify symptom clusters. Results. Patients were bothered by an average of 2.8 (±2.4)symptoms of ‘moderate bother’ or more. Three clusterswere identified, explaining 49% of the total variance. All clustersshowed strong negative associations with the SF-36 quality oflife dimensions (–0.142 to –0.593) and with functionalstatus (–0.130 to –0.332) in HD and PD patients.In contrast, only the clinical variables serum albumin (–0.084to –0.232) and haemoglobin (–0.068 to –0.126)were associated with all clusters in HD patients, and Kt/V_urea(–0.089 to –0.125) in PD patients. Conclusions. Symptom clustering does not explain the lack ofmeaningful associations between symptoms and clinical variables.Strong associations of symptom clusters with quality of lifedimensions suggest that psychological factors could better explainsymptom burden. Patients’ perceptions of symptoms shouldbe routinely assessed as part of clinical care to improve self-managementstrategies.