Diabetic peripheral neuropathy and depressive symptoms

OBJECTIVE - We examined the association between severity of diabetic peripheral neuropathy and depressive symptoms and investigated the potential mediators of this association. RESEARCH DESIGN AND METHODS - The Hospital Anxiety and Depression Scale (HADS) was used to assess depressive symptoms in 494 patients (mean age 62 years; 70% male; 72% type 2 diabetic) with diabetic neuropathy diagnosed by the Neuropathy Disability Score (NDS) and the Vibration Perception Threshold (VPT). Diabetic neuropathy symptoms, activities of daily living (ADLs), and social self-perception were measured by the neuropathy and foot ulcer-specific quality-of-life instrument, NeuroQoL; perceptions of diabetic neuropathy symptom unpredictability and the lack of effective treatment were assessed by the revised Illness Perception Questionnaire. RESULTS - Both the NDS and VPT were significantly associated with the HADS after controlling for demographic and disease variables. Although diabetic neuropathy symptoms mediated this association, with unsteadiness being most strongly associated with HADS, the relationship between foot ulceration and depression was nonsignificant. The association between diabetic neuropathy symptoms and HADS was partially mediated by two sets of psychosocial variables: 1) perceptions of diabetic neuropathy symptom unpredictability and the lack of treatment control and 2) restrictions in ADLs and changes in social self-perception. CONCLUSIONS - These findings establish the association between diabetic neuropathy and depressive symptoms and identify potential targets for interventions to alleviate depressive symptoms in persons affected by diabetic peripheral neuropathy.