Impact of Diabetes Mellitus on the Progression of Lower Extremity Amputations

Abstract Background Diabetes mellitus (DM) has been shown to increase risk of lower extremity amputations (LEA), but it remains unclear how DM affects the need for consecutive amputations thereafter. This study evaluates whether patients with DM, delineated by HbA1c, experience increased rates of progression to higher-level amputations. Methods A retrospective observational study of patients (N=554) that underwent LEA between September 2020 and May 2024 was performed. Amputation procedure codes, demographics, comorbidities and operative details were extracted from Vizient's clinical database and chart review. Below-ankle amputations were considered "minor" and above-ankle were considered "major" amputations. Subgroups included well-controlled, borderline-controlled and poorly-controlled DM (HbA1c<7, =7-8.9, ≥9, respectively). The risk of progression from minor to major amputation associated with both the DM diagnosis and with the degree of glycemic control was estimated. Multivariable analysis was used to assess the specificity of DM effect on amputation progression. Results 554 patients underwent LEA. Mean age was 56 (SD 13.3) and 73% (404) were male. All DM patients were more likely to have multiple LEA (p<0.01), progress from minor to major LEA (p=0.04), and have repeat ipsilateral minor LEA (p<0.01) compared to non-DM patients. Subgroup stratification showed HbA1c ≥ 9 had a borderline significant impact on risk of progression from minor to major LEA compared to the non-DM control (p=0.05). On multivariable regression analysis assessing DM, PAD, and CAD, DM was specific for repeat ipsilateral minor amputation progression. Conclusions Diabetic patients are more likely to progress from minor to major amputations and require multiple procedures compared to non-diabetics. After multivariable regression analysis accounting for PAD and CAD, DM was specific for repeat ipsilateral minor amputation progression.