Associations between loneliness and physical frailty in community-dwelling older adults: A systematic review and meta-analysis

Objectives: Older adults may be at increased risk of loneliness. Frailty is also common in older adults, however, associations between loneliness and frailty have been understudied. This systematic review and meta-analysis aimed to explore evidence on how loneliness and frailty are correlated. Methods: A systematic search of the literature was conducted using 4 electronic databases in February 2022 for any studies published in 2000 or later that provided cross-sectional or longitudinal associations between lone-liness and physical frailty in community-dwelling older adults. A meta-analysis was attempted to combine data when possible. Results: From 1386 studies identified by the initial search, 16 studies were included for this review. Standardized mean difference (SMD) meta-analysis based on mean loneliness score across 3 frailty groups provided by 6 cross-sectional studies showed that worse frailty status was significantly associated with a higher degree of loneliness (SMD between frail and robust, frail and prefrail, and prefrail and robust were 0.77 (95% confidence interval (CI)= 0.57-0.96), 0.37 (95%CI=0.25-0.50), and 0.30 (95%CI=0.20-0.40), respectively.) Meta-analyses combining cross-sectional data from 6 studies revealed that frailty was significantly associated with a higher risk of loneliness compared with robustness (3 studies: pooled OR=3.51, 95%CI=2.70-4.56 for frailty, pooled OR=1.88, 95%CI=1.57-2.25 for prefrailty) and compared with non-frailty (4 studies: pooled OR=2.05, 95% CI=1.76-2.39). A meta-analysis involving two longitudinal studies showed that baseline loneliness was associated with a significantly higher risk of worsening frailty (2 studies: pooled OR=1.41, 95%CI=1.16-1.72). Conclusions: This systematic review and meta-analysis was the first, to our knowledge, to quantitatively demonstrate significant cross-sectional and longitudinal associations between loneliness and frailty in community-dwelling older adults.