Necrobiosis lipoidica diabeticorum: association with background retinopathy, smoking, and proteinuria. A case controlled study.

In order to evaluate patients with necrobiosis lipoidica diabeticorum and to compare them with age, sex, and duration of diabetes matched controls, 15 patients with necrobiosis were each matched with 5 control subjects with diabetes mellitus. Complications of diabetes, glycaemic control, and proteinuria were measured. Patients with necrobiosis (mean age 40, range 18-74 years) had a mean duration of diabetes of 14 (range 3-36) years; 8 patients were male, and 7 were female. For necrobiosis versus controls, background retinopathy (67% vs 27%, p = 0.009), proteinuria (53% vs 17%, p = 0.006), and smoking (60% vs 20%, p = 0.003) were all more common with necrobiosis. There were no significant differences between patients with necrobiosis and control patients in the prevalence of vascular disease and neuropathy. Glycosylated haemoglobin concentrations were higher in patients with necrobiosis (p = 0.02). Blood pressure measurements were similar in both groups. We conclude that smoking, proteinuria, and retinopathy were more prevalent in diabetic patients with necrobiosis; the skin lesion may therefore share common aetiological factors which affect the microvascular circulation, leading to damage to basement membranes and vascular endothelial cells.