Trends and determinants of costs associated with the inpatient care of diabetic foot ulcers

Abstract

Objective: The cost of care for diabetic foot ulcers is estimated to be more than $1.5 billion annually. The aim of this study was to analyze inpatient diabetic foot ulcer cost changes over time and to identify factors associated with these costs.

Methods: The Nationwide Inpatient Sample (2005-2010) was queried using the International Classification of Diseases, Ninth Revision codes for a primary diagnosis of foot ulceration. The primary outcomes were changes in adjusted total hospital charges and costs over time. Multivariable analysis was performed to assess relative increases (RIs) in hospital charges per patient in 2005 vs 2010 adjusting for demographic characteristics, income, comorbidities (Charlson Comorbidity Index ≥3), insurance type, hospital characteristics, diagnostic imaging, revascularization, amputation, and length of stay.

Results: Overall, 336,641 patients were admitted with a primary diagnosis of diabetic foot ulceration (mean age, 62.9 ± 0.1 years, 59% male, 61% white race). The annual cumulative cost for inpatient treatment of diabetic foot ulcers increased significantly from 2005 to 2010 ($578,364,261 vs $790,017,704; P < .001). More patients were hospitalized (128.6 vs 152.8 per 100,000 hospitalizations; P < .001), and the mean adjusted cost per patient hospitalization increased significantly over time ($11,483 vs $13,258; P < .001). The proportion of nonelective admissions remained stable (25% vs 23%; P = .32) and there were no differences in mean hospital length of stay (7.0 ± 0.1 days vs 6.8 ± 0.1 days; P = .22). Minor (17.9% vs 20.6%; P < .001), but not major amputations (3.9% vs 4.2%; P = .27) increased over time. Based on multivariable analysis, the main factors contributing to the escalating cost per patient hospitalization included increased patient comorbidities (unadjusted mean difference 2005 vs 2010 $3303 [RI, 1.08] vs adjusted $15,220 [RI, 1.35]), open revascularization (unadjusted $15,145 [RI, 1.25] vs adjusted $30,759 [RI, 1.37]), endovascular revascularization (unadjusted $17,662 [RI, 1.29] vs adjusted $28.937 [RI, 1.38]), and minor amputations (unadjusted $9918 [RI, 1.24] vs adjusted $18,084 [RI, 1.33]) (P < .001, all).

Conclusions: Hospital charges and costs related to diabetic foot ulcers have increased significantly over time despite stable hospital length of stay and proportion of emergency admissions. Risk-adjusted analyses suggest that this change might be reflective of increasing charges associated with a progressively sicker patient population and attempts at limb salvage. Despite this, the overall incidence of major amputations remained stable.

Fig 1

Risk-adjusted annual cumulative costs for inpatient treatment of diabetic foot ulcers in the United States increased significantly from 2005 to 2010 (P < .001).

Fig 2

Multivariable risk-adjusted analysis demonstrated that the main factors contributing to the escalating cost per patient hospitalization for diabetic foot ulcers included increased patient comorbidities, open revascularization, endovascular revascularization, and minor amputations (P < .001). Osteomyelitis, diagnostic testing, and major amputations did not significantly affect cost increases after risk-adjustment (P = not significant).