Objectives: To define the concept of a symptom cluster, evaluate the evidence base in support of it, and address research and clinical implications.
Data sources: Review of descriptive research that examined fatigue, insomnia, pain, or depression in relation to other symptoms.
Conclusion: More investigation is needed. There is evidence of overlapping variance indicative of a relationship between or among symptoms. Few studies have addressed the outcomes of symptom clusters. There is limited evidence of symptom concurrence or a common biological pathway for clustered symptoms.
Implications for nursing practice: Consideration should be given to assessment and management of fatigue, insomnia, pain, and depression as potential "sentinel symptoms" that could affect patient outcomes.