Prevalence of multidimensional frailty and pre-frailty in older people in different settings: A systematic review and meta-analysis.

Frailty is a common condition in older people. The epidemiological data available, however, are mainly based on the physical frailty phenotype. An extensive literature has suggested that frailty should be identified using a multidimensional approach. Based on these recommendations, we estimated the prevalence of frailty and pre-frailty in the older population, using the multidimensional prognostic index (MPI), a common tool for defining multidimensional frailty. We searched several databases until 10th May 2021 for studies reporting the prevalence of frailty according to MPI values. MPI was categorized, where possible, in < 0.33 (robustness), 0.33-0.66 (pre-frailty) and > 0.66 (frailty) or using a RECursive Partition and AMalgamation approach. A meta-analysis of the prevalence, with the correspondent 95% confidence intervals (CIs) of pre-frailty and frailty was performed stratified by setting (population-based, ambulatory, nursing home, and hospital). Among 177 papers initially screened, we included 57 studies for a total of 56,407 older people. The mean age was 78.6 years, with a slight prevalence of women (58%). The overall prevalence of multidimensional frailty (MPI-3) was 26.8% (95%CI: 22.1-31.5), being higher in nursing home setting (51.5%) and lower in population-based studies (13.3%). The prevalence of pre-frailty (MPI-2) was 36.4% (95%CI: 33.1-39.7), being higher in hospital setting (39.3%) and lower in nursing home (20%). In conclusion, frailty and pre-frailty, according to a multidimensional definition, are common in older people affecting, respectively, one person over four and one over three. Our work further strengths the importance of screening frailty in older people using a multidimensional approach.