Although the association between diabetes and co-morbid depression is much researched, the specific relationship between depression and diabetic foot disease remains unclear. This study investigates the hypothesis that diabetic foot complications are associated with elevated rates of depression.
A cross-sectional sample of 110 outpatients with type 1 or 2 diabetes was recruited from the Diabetes Centre High Risk Foot Service (n = 94) and the outpatient podiatry clinic (n = 16) at Royal Prince Alfred Hospital, Sydney. The self-administered Patient Health Questionnaire-9 (PHQ-9) was used to screen for major depression (MDD), defined here as a PHQ-9 score ≥ 10. Demographic and clinical characteristics were assessed by medical record review. The association between diabetic foot complications and MDD, the primary outcome measure, was determined using logistic regression models.
Of 110 patients, including 22 with Charcot neuroarthropathy and 82 with active foot ulceration, 32 (29.1%) met the screening criteria for MDD. 29 (35.4%) patients with active ulceration and 11 (50.0%) with Charcot neuroarthropathy screened positive for MDD. Of those without active ulceration and without Charcot neuroarthropathy, the number with MDD was n = 3 (10.7%) and n = 21 (24.7%) respectively. The mean lifetime ulceration frequency was 7.04±5.34 in patients with MDD, and 3.89±5.56 in those without. Active ulceration (P = 0.020), lifetime ulceration frequency (P = 0.037) and Charcot neuroarthropathy (P = 0.024) were positively associated with MDD on univariate analysis. After multivariate adjustment, Charcot neuroarthropathy remained significantly associated with MDD (odds ratio [OR] = 6.36 [95% confidence interval 1.27-31.85]). Other clinical characteristics associated with MDD in the multivariate model include prior depression (OR = 4.93 [1.26-19.27]), other diabetic complications (OR = 2.27 [1.30-3.98]) and painful neuropathy (OR = 6.17 [1.53-24.89]).
Patients with diabetic foot complications represent a population with high rates of coexisting depression, as determined by screening questionnaire. Those with Charcot neuroarthropathy are at particular risk, and are significantly more likely to have depression than others with diabetes and diabetic foot disease.