Fatigue and the prediction of negative health outcomes: A systematic review with meta-analysis

•30 papers included providing information on the relationship between fatigue and health outcomes.•Fatigue increases the risk for developing negative health outcomes (OR 1.3–3.1 HR/RR 1.0–1.5).•Fatigue-related physical decline occurs earlier than hospitalization, disease & mortality. Fatigue is a common complaint among older adults. Evidence grows that fatigue is linked to several negative health outcomes. A general overview of fatigue and its relationship with negative health outcomes still lacks in the existing literature. This brings complications for healthcare professionals and researchers to identify fatigue-related health risks. Therefore, this study gives an overview of the prospective predictive value of the main negative health outcomes for fatigue in community-dwelling older adults. PubMed, Web of Knowledge and PsycINFO were systematically screened for prospective studies regarding the relationship between fatigue and negative health outcomes resulting in 4595 articles (last search 5th March 2020). Meta-analyses were conducted in RevMan using Odds ratios (ORs), Hazard ratios (HRs) and relative risk ratios (RR) that were extracted from the included studies. Subgroup-analyses were performed based on (1) gender (male/female), (2) length of follow-up and (3) fatigue level (low, medium and high). In total, thirty articles were included for this systematic review and meta-analysis encompassing 152 711 participants (age range 40–98 years), providing information on the relationship between fatigue and health outcomes. The results showed that fatigue is related to an increased risk for the occurrence of all studied health outcomes (range OR 1.299–3.094; HR/RR 1.038–1.471); for example, mortality OR 2.14 [1.74–2.63]; HR/RR 1.44 [1.28–1.62]), the development of disabilities in basic activities of daily living (OR 3.22 [2.05–5.38]), or the occurrence of physical decline (OR 1.42 [1.29–1.57]). Overall fatigue increases the risk for developing negative health outcomes. The analyses presented in this study show that fatigue related physical decline occurs earlier than hospitalization, diseases and mortality, suggesting the importance of early interventions.