Archetypal analysis of pain measures in a diverse population-based cohort: Exploring cross-sectional relationships with outcomes.

OBJECTIVE

Pain experiences are complex, multifactorial, and subjective. Pain phenotyping can provide a holistic view of pain experiences by identifying distinct pain profiles. This study aimed to characterize chronic pain phenotypes using multiple validated osteoarthritis (OA) pain measures and assess their associations with functional and psychological outcomes.

DESIGN

Participants were from the Johnston County Health Study (JoCoHS), a population-based cohort of non-Hispanic White, non-Hispanic Black, and Hispanic adults aged 35-70 years. Fourteen validated pain measures were administered. Archetypal analysis, a soft clustering technique, was applied to identify pain archetypes. Associations between pain phenotypes and varying functional and psychological characteristics were examined using Dirichlet regression for modeling archetype membership proportions. Results were validated in an independent cohort.

RESULTS

Among 834 participants (33% male, 27% with symptomatic knee OA, mean age 55 ± 9.6 years, mean BMI 33 ± 8 kg/m2), five pain archetypes emerged: (1) Low Pain, (2) High Somatization and Catastrophizing, (3) Widespread Pain, Aching, and Stiffness (PAS), (4) Knee Pain, and (5) High Pain and Distress. The Low Pain archetype was associated with better physical performance, higher functional status, and lower anxiety and depression, while the High Pain and Distress and Knee Pain archetypes were associated with worse outcomes. Pain-related anxiety and depression were associated with higher membership in the High Somatization archetype.

CONCLUSIONS

Pain phenotyping using brief self-reported measures identified distinct profiles with varying functional and psychological characteristics. These findings highlight the potential of phenotyping for improved understanding of the pain experience.