Aims: Data concerning the relative risk of amputations in diabetic patients compared with the general population are scarce. Therefore, we carried out a case control study to quantify the relationship between diabetes and amputations.
Methods: In 20 hospitals in seven German cities and counties we obtained complete lists of non-traumatic lower limb amputations performed in 1990 and 1991. CONTROLS were selected from patients of the same surgical departments operated on in the same years. We drew a random sample of patients with procedures not likely to be associated with diabetes. Diabetic status was determined from patients' records in both cases and controls. We calculated age- and sex-specific and, using logistic regression, adjusted odds ratios (OR) and attributable risks.
Results: N = 2400, mean age 61.7 (SD 16.3) years.
Cases: n = 729; 486 (66.7%) of them had diabetes.
Controls: n = 1671; 127 (7.6%) of them had diabetes. Adjusted OR: 18.2 (confidence interval (CI) 14.2-23.6). Adjusted attributable risk among exposed (ARE): 0.95 (CI 0.93-0.96). Adjusted population attributable risk (PAR): 0.62 (CI 0.57-0.66).
Conclusions: This study has demonstrated a strong association between the risk of amputation and diabetes. The odds ratios and attributable risks for diabetic individuals are higher in the younger than in the older age groups. Population attributable risks are great. We conclude that the reduction of amputations in the general population will be achieved by improving foot care in people with diabetes.