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

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.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 loneliness and physical frailty in community-dwelling older adults. A meta-analysis was attempted to combine data when possible.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).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.