RESUMO
OBJECTIVE: To compare the impact of chronic pain physiopathology on health-related quality of life (HR-QoL), considering the influence of pain features and psychosocial adjustment (intensity, interference, psychological comorbidities, and sleep quality). DESIGN: A cross-sectional study involving 1,025 noncancer patients with predominantly neuropathic, nociceptive, or mixed chronic pain conditions was conducted in 88 pain clinics within Spain. The EuroQol-5 Dimensions instrument (EQ-5D) was used to measure HR-QoL. The Brief Pain Inventory (BPI), Hospital Anxiety and Depression Scale (HADS), and sleep scale developed for the MOS study (MOS-SQ) were used to measure pain features and psychosocial adjustment. Multivariate analyses were used to model HR-QoL measures. RESULTS: All patients reported very low HR-QoL. The mean EQ-5D index scores were 0.33, 0.36, and 0.37 in the mixed, neuropathic, and nociceptive pain groups, respectively. The differences did not reach statistical significance (P = 0.057). Patients with nociceptive pain had less pain (least pain intensity score: 4.7 vs. 5.2 in the other groups; P = 0.006), less interference with daily activities (BPI average interference score: 6.3 vs. 6.6 and 6.7 in the neuropathic and mixed pain groups, respectively; P = 0.013), less anxiety (HADS score: 8.5 vs. 9.6 and 9.7 in the same respective groups; P = 0.001), and fewer sleep problems (MOS-SQ sleep problems index: 46.8 vs. 52.2 and 50.2 in the same respective groups; P = 0.005). In the adjusted analyses, HR-QoL measures were explained by pain intensity, anxiety, and sleep quality, but not by physiopathological pain type. CONCLUSIONS: Pain features, particularly intensity, have a greater impact than pain physiopathology on HR-QoL. Distinct physiopathological mechanisms give rise to different pain features that, in turn, may mediate the HR-QoL of patients with chronic pain. This could be used to improve pain management strategies.