Relationship between diabetic neuropathic pain and comorbidity. Their impact on pain intensity, diabetes complications and quality of life in patients with type-2 diabetes mellitus

Objective: To compare cognitive function, mood and sleep status in patients with and without diabetic neuropathic pain (DNP) and their relationship with pain intensity, diabetes complications, and quality of life. To determine whether these relationships differ depending on the sensorial phenotype.

Methods: Cross-sectional study performed on patients with type-2 diabetes-mellitus and neuropathy. Presence of DNP, pain intensity and phenotype, mood status, sleep characteristics and quality of life were measured.

Results: A total of 130 patients (65 with DNP) were included. DNP was related to poor sleep quality (OR = 1.03;CI95%:1.02-1.05), pain treatment (OR = 3.00,CI95%:1.24-7.29) or previous anxiety (OR = 2.70,CI95%:1.05-6.99). Patients with specific phenotypes or depression (=0.82,CI95%:-0.02-1.67) referred more severe pain. More complications were related to older age (OR = 1.40,CI95%:1.12-1.66), higher pain intensity (OR = 1.51,CI95%:1.00-2.28), lower cognitive performance (OR = 1.25,CI95%:1.09-1.43), previous anxiety (OR = 10.48,CI95%:1.46-75.24) and insulin treatment (OR = 124.50,CI95%:6.64-2335.06). Decrease in mental quality of life was associated with sleep disorders (β = -0.33,CI95%:-0.48,-0.23), physical comorbidities (β = -9.73,CI95%:-18.15, -1.31) and previous anxiety (β = -7.91,CI95%:-13.04, -2.77). Lower scores in physical quality of life were related to sleep disorders (β = -0.12,CI95%:-0.21, -0.18), obesity (β = -8.35,CI95%:-13.16, -3.55), longer time since diagnosis (β = -0.72,CI95%:-1.44;0.01) and disability (β = -14.58,CI95%:-24.69; -4.48).

Conclusions: The results support the idea that mental comorbidity and sleep disorders are factors associated with DNP and greater pain intensity, more diabetes complications and lower quality of life. Moreover, they highlight the relationship between sensorial phenotypes and pain intensity, and lower cognitive performance and diabetes complications.