Increased risk for lower extremity amputation with type 1 vs type 2 diabetes
medwireNews: People with diabetes have a higher incidence of lower extremity amputation (LEA) than those without, and individuals with type 1 diabetes have a particularly high risk, research suggests.
In their analysis of a US claims database covering the years 2010–2014, Anouk Déruaz-Luyet (Boehringer Ingelheim International GmbH, Ingelheim am Rhein, Germany) and co-researchers found that crude incidence rates (IRs) of LEA per 1000 person–years were 5.79 for the 183,889 people with type 1 diabetes, 1.62 for the 2,300,411 with type 2 diabetes, and 0.08 for the 27,688,393 without diabetes.
Compared with the no diabetes group, these rates translated into a 72-fold increased risk for LEA among people with type 1 diabetes and a 20-fold increased risk among those with type 2 diabetes in an unadjusted analysis, report the study authors in Diabetes, Obesity and Metabolism.
They note that these associations were “substantially attenuated” after matching for calendar date, sex, and age group, and reduced further after adjustment for known risk factors for amputation, but remained statistically significant in all analyses.
Indeed, in the matched analysis, the IRs per 1000 person–years were 6.02 for the 120,129 people with type 1 diabetes and 0.14 for the same number of matched individuals without diabetes, with a hazard ratio (HR) of 42.15 prior to adjustment and 22.47 after accounting for a raft of further variables including cardiovascular and cerebrovascular disease, peripheral polyneuropathy, and foot deformities.
And for the 1,679,877 people with type 2 diabetes, the IR for LEA was 1.90, compared with 0.23 for the same number of matched people without diabetes, with unadjusted and adjusted HRs of 8.10 and 4.64, respectively.
These findings highlight a “substantial increase in the IR of LEA among T1D [type 1 diabetes] patients compared to T2D [type 2 diabetes] patients, a trend that would have been masked if T1D and T2D patients were combined due to the T2D majority,” say Déruaz-Luyet and team.
They note that the greatest between-group differences were seen for minor LEA, with an adjusted HR of 33.80 for type 1 diabetes versus no diabetes and 5.50 for type 2 diabetes vs no diabetes, followed by toe amputations, with adjusted HRs of 33.32 and 5.42, respectively.
The team also demonstrated that people with type 1 diabetes were more likely that their matched counterparts without diabetes to have experienced precipitating factors for LEA in the 30 days preceding surgery, including foot and leg ulcers (86.5 vs 41.5%), foot and leg cellulitis (74.6 vs 46.3%), and gangrene (35.3 vs 24.4%). Similar differences occurred, but were smaller, among people with type 2 diabetes versus no diabetes.
These results point to “the necessity of proper diabetic care to handle these precipitating factors early,” conclude Déruaz-Luyet and colleagues.
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