Circadian-Psychosocial Profiling of Cancer Pain: A Mixed-Methods Study on Heterogeneous Subgroups and Personalized Analgesic Efficacy.

OBJECTIVE

To identify distinct cancer pain subgroups using integrated circadian, physiological and psychosocial data and assess subgroup-specific analgesic responses.

METHODS

This explanatory sequential mixed-methods study included 191 adult inpatients with cancer pain from a tertiary care hospital. Quantitative measures included 24-h blood pressure, salivary melatonin, pain beliefs, coping styles, social support, and clinical variables. Mixed-type cluster analysis (K-prototypes) identified subgroups. Analgesic efficacy was evaluated using multiple linear regression, with changes in mean pain intensity and pain variability as the outcomes. The qualitative phase involved semi-structured interviews analyzed thematically.

RESULTS

Four distinct patient subgroups (Cluster 0-3) were identified. Cluster 0 (elderly reverse-dipper, n = 44) showed moderate pain, poor sleep quality, emotional lability, and social withdrawal. Analgesics exerted no significant effect on mean pain intensity (coefficient = 0.063, 95% confidence interval [CI]: -0.585 to 0.711, p = 0.856) or pain variability (coefficient = -1.466, 95% CI: -4.178 to 1.246, p = 0.335). Cluster 1 (non-dipper severe pain, n = 54) exhibited disrupted circadian rhythm, negative pain cognition, and avoidant coping. Analgesics significantly reduced pain variability (coefficient = -2.333, 95% CI: -4.001 to -0.665, p = 0.008) but not mean pain intensity (coefficient = 0.072, 95% CI: -0.300 to 0.444, p = 0.712). Cluster 2 (dipper mild pain, n = 74) maintained normal circadian rhythm, positive mental status, and active social interaction. Analgesics significantly decreased pain variability (coefficient = -3.427, 95% CI: -5.391 to -1.463, p = 0.002) but not mean pain intensity (coefficient = -0.248, 95% CI: -0.682 to 0.186, p = 0.274). Cluster 3 (high-melatonin, n = 19) achieved significant reductions in mean pain intensity (coefficient = -1.259, 95% CI: -2.031 to -0.487, p = 0.001) and pain variability (coefficient = -5.602, 95% CI: -8.664 to -2.540, p = 0.001), with passive coping and emotional suppression.

CONCLUSIONS

Patients with cancer pain exhibit marked heterogeneity in circadian rhythm, endocrine function, and psychosocial profiles. Interactions among these factors may contribute to distinct pain mechanisms and variable analgesic responses. Comprehensive multidimensional assessment may facilitate more accurate patient subtyping and support individualized pain management.

REGISTRATION: This study was registered with the Chinese Clinical Trial Registry (ChiCTR) under registration number ChiCTR2500096806.