Diabetic peripheral neuropathic pain is a stronger predictor of depression than other diabetic complications and comorbidities

Aims: To investigate the independent effect on depression of painless diabetic polyneuropathy (DPN), painful DPN (PDPN), and general and diabetes-related comorbidities. Methods: In 181 patients the presence of DPN, PDPN, comorbidities, and depression was assessed using the Michigan Neuropathy Screening Instrument Questionnaire (MNSI-Q), the Michigan Diabetic Neuropathy Score (MDNS), Nerve Conduction Studies (NCS), the Douleur Neuropathique en 4 Questions (DN4), the Charlson Comorbidity Index, and the Beck Depression Inventory-II (BDI-II) Results: Forty-six patients met the criteria of confirmed painless DPN, and 25 of PDPN. BDI-II scores indicative of mild-moderate-severe depression were reached in 36 patients (19.7%). In a multiple logistic regression analysis (including age, sex, BMI, being unemployed, duration, HbA1c, insulin-treatment, systolic blood pressure, nephropathy, retinopathy, Charlson Comorbidity Index and PDPN), female sex (odds ratio 5.9, P=0.005) and PDPN (odds ratio 4.6, P=0.038) were the only independent predictors of depression. Multiple regression analysis, including DN4 and MDNS instead of PDPN, showed that DN4, in addition to female sex, was a significant predictor of depressive symptoms severity (P=0.005). Conclusions: PDPN is a greater determinant of depression than other diabetes-related complications and comorbidities. Painful symptoms enhance depression severity more than objective insensitivity.