Incidence of lower extremity amputations among patients with type 1 and type 2 diabetes in the United States between 2010 and 2014.

OBJECTIVE: Compare the incidence of lower extremity amputations (LEAs) among patients with type 1 (T1D) and type 2 diabetes (T2D) to those without using US commercial claims and assess the presence of key comorbidities and precipitating factors at the time of the LEA.

METHODS: Cohorts were defined via IBM MarketScan databases for beneficiaries with T1D and T2D 2010-2014. For each T1D and T2D patient, 1 patient without a prior diabetic claim matched on calendar time, sex, and age was randomly selected. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals.

RESULTS: Among the matched cohorts of 120 129 T1D and 1.7 m T2D patients, the incidence of LEA was higher among patients with T1D than T2D patients with the most frequent cases being minor LEA (4.85 and 1.53 per 1000 PY) - largely toe amputations (4.49 and 1.43 per 1000 PY). Compared to non-diabetic patients matched on age, sex and calendar time, T1D and T2D patients had more comorbidities and a higher incidence of LEA [6.02 vs 0.14 per 1000 PY; aHR, 22.47 (16.42-30.73) and 1.90 vs 0.23 per 1000 PY; aHR, 4.64 (4.32-4.98)].

CONCLUSIONS: Our data showed higher incidence of LEA, especially minor LEA, in patients with T1D and T2D compared to those without, with a greater risk among T1D than T2D. Accounting for known and measurable risk factors for LEA reduced the relative hazard by nearly one-half; the majority of LEA cases were minor LEA toe amputations. This article is protected by copyright. All rights reserved.