Measuring pain in older adults: new considerations about the Fifth Vital Sign

Abstract

We evaluated measures of pain location and severity in relation to mobility in the MOBILIZE Boston Study which enrolled 749 participants aged 70 and older. Pain location was measured by the McGill Pain Map (MPM) and a questionnaire on chronic joint and back pain (JPQ). Pain severity was measured using the 4-item Brief Pain Inventory (BPI) severity subscale and the JPQ pain severity scale; both scales used the 0-10 rating scales. Self-reported mobility difficulty was defined as a lot of difficulty or inability in walking 1/4 mile or climbing stairs. In one model predicting mobility difficulty, we compared the 2 pain location measures; in the second model we compared the pain severity measures, using multivariable logistic regression. Standard errors showed no evidence of collinearity. On the BPI, 62% of elders rated their pain "now" as 0, on the 0-10 rating scale. However, 45% of the same elders reported pain in the previous week that interfered with their daily activities (BPI). For pain "on average", only 26% of all participants rated their pain as 0 on the 0-10 scale. In the pain location model, number of painful joints (JPQ) was independently associated with mobility difficulty (p < 0.007); number of sites on the MPM was weakly associated (p = 0.07). In the second model, the JPQ severity scale (p = 0.0006) and the BPI severity subscale (p = 0.02) were each independently associated with mobility difficulty. Modest differences in wording of pain assessment items using the 0-10 pain severity rating led to differing conclusions regarding the burden of pain in older adults. Summary measures of chronic joint pain location and severity may offer the most relevant assessments related to functional burden of pain in older adults. (Supported by National Institute on Aging Grant #P01AG004390.)