Association between the number of chronic pain sites and neuropathic-like symptoms in community-dwelling older adults with chronic pain: a cross-sectional study

Objectives We investigated the relationship between the number of chronic pain sites and the prevalence and severity of neuropathic-like symptoms in community-dwelling older Japanese adults with chronic pain. Design Cross-sectional study. Setting The data analysed are from a study conducted in the city of Itoshima, Japan in 2017. Participants The study population was 988 participants (age 65–75 years) not in need of long-term care who completed questionnaires assessing sociodemographic factors, psychological factors and chronic pain. Primary outcome measures The primary outcome was the participants’ neuropathic-like symptoms evaluated by the PainDETECT Questionnaire (PD-Q). We classified the participants into mild and moderate-to-severe pain groups according to the pain intensity on the PD-Q. The number of chronic pain sites was categorised into groups with 1, 2–3 and ≥4 sites. Results The age-adjusted and sex-adjusted prevalence of neuropathic-like symptoms was significantly higher among the participants with 2–3 or ≥4 sites compared with the single-site group. In the binomial logistic regression analyses, the multivariable-adjusted ORs and 95% CIs for neuropathic-like symptoms among the participants with 2–3 and ≥4 sites were 1.94 (1.13 to 3.33) and 3.90 (2.22 to 6.85), respectively compared with the participants with single-site pain. The ORs for moderate-to-severe neuropathic-like symptoms increased significantly with the increase in the number of chronic pain sites. Conclusions The number of chronic pain sites was positively associated with the presence and severity of neuropathic-like symptoms in community-dwelling older Japanese adults with chronic pain.