Introduction
Diabetic foot is an important long-term complication among patients with diabetes and represents the most frequent cause of non-traumatic lower-extremity amputation (LEA), with diabetic foot ulcers preceding more than 80% of amputations in people with diabetes.1 Diabetic foot is a rising health problem due to increasing prevalence of diabetes worldwide2; it is estimated that 15%–25% of people with diabetes will be affected by a foot ulcer at some point in their lives.3 After a first amputation, patients with diabetes are at high risk to undergo other amputations, with a major impact on quality of life and an increase in illness-related costs. Algorithms to manage diabetic foot and different revascularization techniques have become available, contributing to the observed reduction in the incidence of diabetes-related major limb amputations.4–7 However, amputation rates in the diabetic population remain relatively high even with a significant regional variation, suggesting variability in availability and standard of care.7 8 Late referral to vascular specialist and lack of agreement on factors to consider when choosing intervention strategies have been suggested as possible causes of the still high amputation rates.8 In spite of improvements in perioperative risk assessment and preoperative and postoperative medical care, robust evidence is available on the extremely high mortality after amputation in patients with diabetes.9 10 The 30-day mortality risk among patients with diabetes with primary LEA is higher than among individuals undergoing open infrainguinal revascularization, ranging between 6% and 8%.11 12 A recent review considering long-term mortality after LEA reported an overall mortality rate of 48%, 61%, and 71%, at 1-year, 2-year, and 3-year follow-up, respectively, among patients with diabetes and peripheral vascular disease.13 Some clinical characteristics are well known as risk factors for mortality after LEA, such as coronary artery disease, cerebrovascular disease, renal dysfunction, and dyslipidemia. Anyway, few studies, and often single center-based, analyzed factors associated with mortality after LEA among individuals with diabetes.8 14 15 In particular, characteristics other than clinical features have been less extensively investigated, as well as long-term mortality. Hoffstad et al16 reported a high risk of death among patients with diabetes and LEA compared with individuals with diabetes but no LEA. Interestingly, they also found that mortality excess was not fully explained by diabetes complications, such as cardiovascular diseases and renal insufficiency, and therefore it was suggested that other individual factors might contribute to increasing mortality risk in this particularly fragile population.17 Actually, the identification of risk factors for mortality among patients with diabetes with foot ulcers is crucial to define preventive strategies to lower the risk of death after LEA and to appraise comprehensively the risk-benefit profile of the amputation.18 19
In the Lazio region (the third most populated region of Italy, including Rome, the capital and largest Italian city), health information systems (HIS) are comprehensive and contains high-quality information and therefore allow measurement of the occurrence of acute and chronic diseases and monitor quality of care and healthcare outcomes.20 21
The aims of our study were to investigate survival time after different types of LEA (major and minor) among patients with diabetes and to identify the sociodemographic and clinical factors associated with death. For this study, we used data collected by different HIS available in the Lazio region.