Pain and Mortality in Older Adults: The Influence of Pain Phenotype.

Abstract

Moderate to severe chronic pain affects 1 in 5 adults. Pain may increase the risk of mortality, but the relationship is unclear. This study investigated whether mortality risk was influenced by pain phenotype, characterized by pain extent or pain impact on daily life. The study population was drawn from 2 large population cohorts of adults ages ≥50 years, the English Longitudinal Study of Ageing (n = 6,324) and the North Staffordshire Osteoarthritis Project (n = 10,985). Survival analyses (Cox's proportional hazard models) estimated the risk of mortality in participants reporting any pain and then separately according to the extent of pain (total number of pain sites, widespread pain according to the American College of Rheumatology [ACR] criteria, and widespread pain according to Manchester criteria) and pain impact on daily life (pain interference and often troubled with pain). Models were cumulatively adjusted for age, sex, education, and wealth/adequacy of income. After adjustments, the report of any pain (mortality rate ratio [MRR] 1.06 [95% confidence interval (95% CI) 0.95-1.19]) or having widespread pain (ACR 1.07 [95% CI 0.92-1.23] or Manchester 1.16 [95% CI 0.99-1.36]) was not associated with an increased risk of mortality. Participants who were often troubled with pain (MRR 1.29 [95% CI 1.12-1.49]) and those who reported quite a bit of pain interference (MRR 1.38 [95% CI 1.20-1.59]) and extreme pain interference (MRR 1.88 [1.54-2.29]) had an increased risk of all-cause mortality. Pain that interferes with daily life, rather than pain per se, was associated with an increased risk of mortality. Future studies should investigate the mechanisms through which pain increases mortality risk.