Risk factors for lower limb complications in diabetic patients. The Italian Study Group for the Implementation of the St. Vincent Declaration.
Diabetic lower extremity complications may be influenced by a number of factors, including those related to the interaction between patients and the health-care system. Our objective is to identify risk factors for the development of lower limb complications, by looking for classical clinical variables and those related to quality of care. A case-control study was carried out between December 1993 and June 1994 by interviewing 348 patients with lower-limb diabetic complications and 1050 controls enrolled from 35 diabetes outpatient clinics and 49 general practitioner's offices in Italy. Among sociodemographic characteristics associated with increased risk of lower limb complications were male gender [odds ratio (OR) = 2.5, confidence interval (CI) 1.6-3.9], age between 50 and 70 years as opposed to younger than 50 (OR = 3.6, CI 2.1-6.3) and being single as opposed to married (OR = 1.4, CI 1.1-1.8). Among clinical variables, treatment with insulin for IDDM and NIDDM patients was an important predictor of lower extremity complications compared to NIDDM patients not being treated with insulin. Cardio-cerebrovascular disease and presence of diabetic neuropathy were associated with a higher risk of being a case (OR = 1.4, CI 1.2-1.8 and OR = 3.0, CI 2.1-4.2, respectively). Patients who needed help to reach the health facility before the onset of the complications and those who did not attend health facilities regularly were more liable to develop complications (OR = 1.5, CI 1.1-2.2 and OR = 2.0, CI 1.3-3.0, respectively). Patients who had never received educational intervention had a threefold risk of being a case as compared to those who received health information regularly. The study identifies factors most likely to be related to adverse outcome and permits to discriminate between avoidable and unavoidable factors.