Persistent moderate to severe pain and long-term cognitive decline.

Abstract

The longitudinal association between persistent moderate to severe pain and subsequent long-term cognitive decline remains inconclusive. Study population came from the English Longitudinal Study of Ageing, an ongoing prospective and nationally representative cohort of community-dwelling adults aged ≥50years in England. At waves 1 (2002/2003) and 2 (2004/2005) of the study, pain severity was measured based on pain intensity scores ranged from 0 to 10. We defined moderate to severe pain as pain intensity scores ≥5 points. Persistent moderate to severe pain was defined as participants reported moderate to severe pain at both waves 1 and 2. Standardized global cognitive Z scores derived from verbal memory, temporal orientation and semantic fluency were used as the primary outcome. A total of 6,869 individuals (3,896 women; mean age: 63.9±9.5years) who have accepted twice measurements of pain at waves 1 and 2 (baseline), and at least one reassessment of cognitive function at waves 3 (2006/2007) to 8 (2016/2017), were included in this study. Each 5-point increase in the sum of pain intensity scores was associated with a faster rate of -0.009 (95% CI: -0.013 to -0.006, p<.001) in global cognitive Z scores. Compared with no pain group, persistent moderate to severe pain group was associated with a significantly faster decline rate of -0.031 SD/year (95% CI: -0.043 to -0.018), in global cognitive Z scores. The relationships of persistent moderate to severe pain with verbal memory, temporal orientation and semantic fluency were similar. Cognitive function should be monitored in individuals with persistent moderate to severe pain. Persistent moderate to severe pain in adults age 50 and older was associated with accelerated cognitive decline over a median follow-up of 12 years. More severe pain was associated with faster cognitive decline in a dose-response pattern, and the relationship was demonstrated throughout multiple cognitive domains. While the overall effect was subtle, clinicians should be aware that older adults with persistent pain are at risk of faster cognitive decline.