Excess risk of lower extremity amputations in people with type 1 diabetes compared with the general population: amputations and type 1 diabetes

OBJECTIVE

This study investigates how the excess risk of lower extremity amputations (amputations) in people with type 1 diabetes mellitus (DM) differs from the general population by diabetes duration, glycemic control, and renal complications.

RESEARCH DESIGN AND METHODS

We analyzed data from people with type 1 DM from the Swedish National Diabetes Register without prior amputation from January 1998 to December 2013. Each person (n=36 872) was randomly matched with five controls by sex, age, and county (n=184 360) from the population without diabetes. All were followed until first amputation, death or end of follow-up.

RESULTS

The overall adjusted HR for all amputation was 40.1 (95% CI 32.8 to 49.1) for type 1 DM versus controls. HR increased with longer diabetes duration. The incidence of amputation/1000 patient-years was 3.18 (95% CI 2.99 to 3.38) for type 1 DM and 0.07 (95% CI 0.05 to 0.08) for controls. The incidence decreased from 1998-2001 (3.09, 95% CI 2.56 to 3.62) to 2011-2013 (2.64, 95% CI 2.31 to 2.98). The HR for major amputations was lower than for minor amputations and decreased over the time period (p=0.0045). Worsening in glycemic control among patients with diabetes led to increased risk for amputation with an HR of 1.80 (95% CI 1.72 to 1.88) per 10 mmol/mol (1%) increase in hemoglobin A1c.

CONCLUSIONS

Although the absolute risk of amputation is relatively low, the overall excess risk was 40 times that of controls. Excess risk was substantially lower for those with good glycemic control and without renal complications, but excess risk still existed and is greatest for minor amputations.

Diabetic foot syndrome in patients with diabetes. A multicenter German/Austrian DPV analysis on 33 870 patients

AIMS

The diabetic foot syndrome (DFS) is a serious complication in patients with diabetes increasing the risk for minor/major amputations. This analysis aimed to examine differences in diabetes patients with or without DFS stratified by type 1 (T1D) or type 2 diabetes (T2D).

MATERIAL AND METHODS

Adult patients (≥20y of age) with diabetes from the German/Austrian diabetes patients follow-up registry (DPV) were included. The cross-sectional study comprised 45 722 subjects with T1D (n_DFS  = 2966) and 313 264 with T2D (n_DFS  = 30 904). In DFS, minor/major amputations were analysed. To compare HbA_1C , neuropathy, nephropathy, cardiovascular disease risk factors, and macrovascular complications between patients with or without DFS, regression models were conducted. Confounders: age, sex, diabetes duration.

RESULTS

In patients with DFS, a minor amputation was documented in 27.2% (T1D) and 25.9% (T2D), a major amputation in 10.2% (T1D) and 11.3% (T2D). Regression models revealed that neuropathy was more frequent in subjects with DFS compared with patients without DFS (T1D: 70.7 vs 29.8%; T2D: 59.4% vs 36.9%; both P < 0.0001). Hypertension, nephropathy, peripheral vascular disease, stroke, or myocardial infarction was more common compared with patients without DFS (all P < 0.0001). In T1D with DFS, a slightly higher HbA_1C (8.11% vs 7.95%; P < 0.0001) and in T2D with DFS a lower HbA_1C (7.49% vs 7.69%; P < 0.0001) was observed.

CONCLUSIONS

One third of the patients with DFS had an amputation of the lower extremity. Especially neuropathy or peripheral vascular disease was more prevalent in patients with DFS. New concepts to prevent DFS-induced amputations and to reduce cardiovascular risk factors before the occurrence of DFS are necessary.