Persistent pain and cognitive decline in older adults: a systematic review and meta-analysis from longitudinal studies

Both persistent pain and cognitive decline prevalence increase with advancing age and are associated with functional decline. However, the association of pain and cognitive decline has not been evaluated yet by a systematic assessment of longitudinal studies. We aimed to assess the association of persistent pain as a risk factor for cognitive decline in community older adults, using data from longitudinal studies in a systematic review and meta-analysis. Publications were identified using a systematic search on PubMed, EMBASE, and Cochrane Library databases from inception to June 2019. Because heterogeneity across studies was high, we used random-effects meta-analysis to calculate the pooled relative risk (RR) for the association between persistent pain and cognitive decline incidence. We investigated sources of heterogeneity among studies using meta-regression and stratified analyses. We included 10 prospective longitudinal studies with 57,495 participants with a mean age at the baseline ranging from 61.8 to 88.4 years and mean follow-up times ranging from 2.75 to 11.8 years. Persistent pain at baseline was not associated with the development of cognitive decline during the follow-up (pooled RR = 1.05, 95% confidence interval = 0.92-1.21). In sensitivity analyses, only length of follow-up time ≤4.5 years was associated with a higher risk of cognitive impairment (pooled RR = 1.19, 95% confidence interval = 1.10-1.28). Persistent pain was not associated with the incidence of cognitive decline.