2,500,000 Troubled Soles: Ten-Year Analysis of Diabetic Foot Infections in the United States

Abstract

Assess charges, case complexity and use of revascularization among inpatient hospital admissions for diabetic foot infections (DFIs) and associated amputations in the U.S. over 10 years. Inpatient discharge records from the Agency for Healthcare Research and Quality Healthcare Cost and Utilization Project were used in this retrospective cohort study spanning 2001-2010. We reviewed all-listed diagnoses of inpatient DFIs, stratified by open bypass (Open) or endovascular therapy (EVT) and major (above ankle) or minor amputation. Revascularization, length of stay (LOS), case complexity and hospital charges were analyzed on a per admission basis. During the study period, 2.5 million inpatient DFI cases were observed, of which 412,051 (16.5%) involved amputation (34.8% major, 61.2% minor). Overall, 211,534 (8.5%) of DFI cases underwent revascularization (43.5% Open, 51.1% EVT, 5.4% both). From 2001 versus 2010, the volume of Open procedures decreased to 34.9%, while EVT volume rose to 297.1%. Some 6.7% of the 143,470 major amputations involved revascularization during the same hospital stay (29.8% Open, 63.5% EVT, 6.7% combination) versus 15.1% of the 268,520 minor amputations (44.9% Open, 44.2% EVT, 6.9% combination). In amputation-only cases, from 2001 versus 2010, Open volume fell 27.3% but EVT increased 280.3%. Minor amputations increased 48.5%, but major amputations only rose 7.7%. Notably, an increasing case-mix severity was seen for amputations with associated vascular procedures, with a 25.5% increase in unadjusted mean charges ($104,839 vs $131,554, US2012). However, mean LOS decreased 22.5% (18.4 vs 14.2 days; P < .05). Inpatient amputation-related mortality was 1.8%, falling by 19.1% from 749 (2.2%) in 2001 to 606 (1.3%) in 2010. This nationally representative investigation found that DFI admissions are common, long, and ever more costly (> $100,000/case), likely due to increasing case severity mix. More DFI patients are undergoing revascularization (8.5% per admission), with a dramatic shift from Open bypass to EVT. Despite these unfavorable factors, hospital mortality and LOS have fallen significantly. Major amputation for DFI also appears to be flattening, with a marked rise in minor amputations (high:low ratio = 0.57).