Persistent pain is a risk factor for frailty: a systematic review and meta-analysis from prospective longitudinal studies

Background: pain is prevalent in frail older adults; however, the association of pain and frailty has not been evaluated yet by a systematic assessment of prospective longitudinal studies. Objective: we aimed to assess the association of persistent pain as a risk factor for frailty incidence, using data from longitudinal studies in a systematic review and meta-analysis. Methods: publications were identified using a systematic search on PubMed, Embase, Cochrane Library and clinicaltrials. gov databases from inception to October 2017. Since heterogeneity across studies was high, we used random-effects metaanalysis to calculate the pooled relative risk for the association between persistent pain and the incidence of frailty. We investigated sources of heterogeneity among studies using meta-regression and stratified analyses. Results: we included five prospective longitudinal studies with 13,120 participants (46% women, mean age from 59 to 85 years old). Participants with persistent pain at baseline had twice the risk of developing frailty during the follow-up (pooled RR = 2.22, 95% CI = 1.14-4.29). No variables were related to study heterogeneity in sensitivity analyses. Conclusion: persistent pain was a risk factor for the development of frailty in a meta-analysis of longitudinal studies. Better understanding of the association between pain and frailty with proper evaluation of potential confounders could allow the development of targeted interventions.