Is HBOT Cost-Effective For Diabetic Foot Ulcers?
It is estimated that Medicare spends $1.5 billion annually to treat diabetic foot ulcers (DFU).1 The debate continues on the cost effectiveness of immediate amputation in comparison with “conservative treatment” using a variety of modalities.
The cost of healing a DFU is related to its severity but detailed “cost to heal” data stratified by Wagner grade are sparse. Primary amputation is costly not so much because of the expense of the surgical procedure itself but because of the consequences of amputation (e.g. rehabilitation and institutional care).
Couch et al., found that following a major amputation, only 76 percent of unilateral above-knee amputees could be rehabilitated. Furthermore, the surgical mortality of major leg amputation is 11 to 13 percent.2 The post-amputation five-year survival rates of 30.9 percent among patients with diabetes without renal failure and 14.4 percent among patients with diabetes and renal failure are similar to an aggressive cancer.3
“Limb salvage” usually requires revascularization and, regardless of whether the method is surgical or endovascular, secondary revascularization is likely to be necessary in three to five years. This is a substantial cost factor. The fact is that primary amputation can save costs and improve rehabilitation in patients who are likely to fail limb salvage interventions. Accordingly, ensuring proper patient selection is critical to the discussion of cost effectiveness. Hopf and Fife recently addressed whether HBOT has a role in limb salvage.4
What You Should Know About Hypoxia And Revascularization
Patients with purely neuropathic diabetic foot ulcers are not candidates for HBOT and one can usually manage such ulcers with aggressive offloading. Even so, diabetic foot ulcers are hard to heal. Margolis, et al., demonstrated that even with adequate arterial inflow, diabetic foot ulcers have only a 24 percent closure rate at 12 weeks and a 31 percent closure rate at 20 weeks.5
However, diabetes is a major risk factor for vascular disease leading to tissue hypoxia. Cutaneous perfusion is the critical physiological determinant of diabetic ulcer healing. Pecoraro, et al., showed there was a 39-fold increased risk of early healing failure when the average periwound TcPO2 is less than 20 mmHg.6
The appropriate treatment for hypoxia due to vascular disease is revascularization whenever possible but results of revascularization are disappointing. Among chronic limb ischemia (CLI) patients undergoing bypass for ischemic tissue loss, 63 percent required more than three months for complete healing with the mean time to healing being 86 days. More than 7 percent of these patients never healed.7
What Randomized Controlled Trials Reveal About HBOT
In an upcoming paper, we reviewed all randomized, controlled trials in the area of wound healing over a 10-year period from 1996 to 2006.8 All the trials excluded patients with significant vascular disease except those involving HBOT. After reviewing more than 1,000 papers, we found that only the HBOT studies tackled ischemic diabetic foot ulcers and/or DFUs with Wagner grades higher than II. While HBOT studies have been criticized for being small, they nevertheless stand alone in the literature.
In 1987, Baroni et al., demonstrated the efficacy of HBOT in reducing the incidence of major amputation in patients with diabetic gangrene (11 percent in the HBOT group versus 40 percent in controls).9 In 1990, Oriani, et al., reported a major amputation rate of 5 percent in patients who received HBOT in comparison to 33 percent in similar patients who either refused or had contraindications to HBOT therapy.10