Categorization of chronic pain subtypes and contributing biomarkers in heart failure

AIMS: Pain is common among adults with heart failure (HF), but pain subtypes and associated biomarkers are understudied. The aims were to (i) characterize chronic pain severity, neuropathic pain quality, locations, and subtypes and (ii) compare pain severity and levels of biomarkers among pain subtypes. An exploratory aim was to correlate levels of biomarkers with pain severity. METHODS AND RESULTS: This pilot descriptive study included cross-sectional data from 60 adults with HF and chronic pain. Pain was evaluated using the PainDETECT questionnaire. Blood biomarkers included interleukin (IL)-10, IL-18, IL-1β, IL-33, IL-6, IL-8, tumour necrosis factor (TNF)-α, brain-derived neurotrophic factor, leptin, adiponectin, and C-reactive protein. Descriptive statistics, chi-square test of homogeneity, one-way analysis of variance, and Spearman correlation were used for analyses. The mean age was 70.45 (SD 7.92) years. The sample consisted of 63.3% women and 65.0% White race. Participants primarily reported nociceptive pain only (73.3%) with fewer reporting neuropathic pain only (6.7%) and mixed pain (20.0%). Current and 4-week mean pain severity scores were highest in the mixed pain subtype (P both < 0.05). No biomarkers were significantly different across the pain subtypes, but lower lL-10 (P = 0.049), and IL-33 (P = 0.014), were associated with higher pain severity. CONCLUSION: In this study, chronic pain and its association with underlying biomarkers were characterized. Future research with a larger sample is needed to understand the unique contributions of biomarkers with targeted pain phenotypes.