Burden of Infected Diabetic Foot Ulcers on Hospital Admissions and Costs

Abstract

Background: Costs related to diabetic foot ulcer (DFU) care are greater than $1 billion annually and rising. We sought to describe the impact of diabetes mellitus (DM) on foot ulcer admissions in the United States, and to investigate potential explanations for rising hospital costs.

Methods: The Nationwide Inpatient Sample (2005-2010) was queried using International Classification of Diseases, 9th Revision (ICD-9) codes for a primary diagnosis of foot ulceration. Multivariable analyses were used to compare outcomes and per-admission costs among patients with foot ulceration and DM versus non-DM.

Results: In total, 962,496 foot ulcer patients were admitted over the study period. The overall rate of admissions was relatively stable over time, but the ratio of DM versus non-DM admissions increased significantly (2005: 10.2 vs. 2010: 12.7; P < 0.001). Neuropathy and infection accounted for 90% of DFU admissions, while peripheral vascular disease accounted for most non-DM admissions. Admissions related to infection rose significantly among DM patients (2005: 39,682 vs. 2010: 51,660; P < 0.001), but remained stable among non-DM patients. Overall, DM accounted for 83% and 96% of all major and minor amputations related to foot ulcers, respectively, and significantly increased cost of care (DM: $1.38 vs. non-DM: $0.13 billion/year; P < 0.001). Hospital costs per DFU admission were significantly higher for patients with infection compared with all other causes ($11,290 vs. $8,145; P < 0.001).

Conclusions: Diabetes increases the incidence of foot ulcer admissions by 11-fold, accounting for more than 80% of all amputations and increasing hospital costs more than 10-fold over the 5 years. The majority of these costs are related to the treatment of infected foot ulcers. Education initiatives and early prevention strategies through outpatient multidisciplinary care targeted at high-risk populations are essential to preventing further increases in what is already a substantial economic burden.

Fig. 1.

Temporal trends in the number of foot ulcer admissions and the ratio of diabetic to nondiabetic foot ulcer admissions from 2005 to 2010. There were 962,496 foot ulcer admissions over the 6-year study period. The overall number of foot ulcer admissions was relatively stable between 2005 and 2010, but the ratio of diabetic to nondiabetic foot ulcer admissions increased significantly over time from 10.2 in 2005 to 12.7 in 2010 (P < 0.001).

Fig. 2.

Proportion of diabetic versus nondiabetic inpatients with foot ulcers stratified by limb pathology. More than half of foot ulcer admissions among diabetic patients were for simple neuropathic foot ulcers, followed by infection. In contrast, foot ulcer admissions among nondiabetic patients were most frequently related to PVD. Overall, infection accounted for 31.5% of all foot ulcer admissions (n = 303,246). Note: Numbers may add up to more than 100% because patients may have had >1 limb pathology diagnosis.

Fig. 3.

Trends in foot ulcer admissions related to infection over time for patients with diabetes versus no diabetes. Admissions related to infection rose significantly over time among DM patients (P < 0.001), but remained stable among non-DM patients (P = NS).