Can multimorbidity lead to frailty among older people? A systematic review of longitudinal studies.

To systematically review longitudinal studies examining the evidence of multimorbidity on the incidence of frailty. The systematic review with meta-synthesis we searched four databases Scopus, PubMed, Virtual Health Library, Web of Science, and CINAHL for literature published prior to December 2023 using a prespecified search strategy. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale for longitudinal studies. Three studies examining the role of multimorbidity on frailty incidence were included. All the included studies assessed patterns of multimorbidity, and frailty was operationalized through Fried's phenotype. Two of the three studies indicated that multimorbidity was associated with an increased risk of frailty and the most prevalent patterns of multimorbidity linked with the incidence of frailty were cardiometabolic and dementia-neuro patterns. In conclusion, two of the three included studies suggest that multimorbidity is a risk factor for frailty.