Perspectives in Circulation Today

Evidence-Based Medicine and

National Diabetes Surveillance System

Hospitalizations for Nontraumatic Lower Extremity Amputation

Number (in Thousands) of Hospital Discharges for Nontraumatic Lower Extremity Amputation with Diabetes as a Listed Diagnosis, United States, 1980-2002

In general, the annual number of diabetes-related hospital discharges with lower extremity amputation (LEA) as a reported procedure increased from about 33,000 in 1980 to 84,000 in 1997.  Although large increases in the number of LEA discharges occurred in the early 1990s, the number of LEA discharges leveled off afterward. In 2002, there were about 82,000 diabetes-related hospital discharges with LEA.

The above data and commentary is taken verbatim from the National Diabetes Surveillance System. It is seen that only in four of the last 23 years did the number of amputations decrease. Infection, neuropathy and ischemia have long been identified as the major risk factors for amputation. Arteriosclerosis is a diffuse disease and may be likened to a snow storm. Removing the snow from the turnpikes does not help if snow is still falling and all of the secondary roads remain snowbound. Thus, bypassing or dilating a stenotic region in a major vessel may not have short or long term benefit if other stenoses and thromboses exist and risk factors for arteriosclerosis remain uncorrected. Linton's ten requirements for a successful bypass still exist today (In: Linton RR,  Atlas of Vascular Surgery, p394-6. WB Saunders. Phildelphia 1973): an accurate arteriogram; an available saphenous vein; adequate inflow at a point where the artery is healthy enough to initiate a graft; adequate runoff from an artery healthy enough to receive a graft; aseptic technique and pre- and post-operative antibiotics; heparin anticoagulation during the procedure;  blood bank support; a skilled surgeon; expert anesthesia avoiding hypotension; and adequate time. To these requirements are commonly added reasonable cardiopulmonary reserve, stable cerebrovascular status and absence of significant infection at the operative sites. Few  clinics require that pre-operative vascular testing show that healing would be unlikely without the benefit of a successful revascularization procedure. When these conditions allow in the diabetic foot, the skills of the vascular surgeon are enlisted to attempt a revascularization procedure. Various clinics and academic centers have then published their results; so many procedures were successful in providing a patent new vascular channel, so many of these channels were patent at 5 years and at 10 years; so many of the procedures were attended by complications (hematomas, infection, myocardial infarctions etc). The public is asked to believe that the leg survived because the procedure was accomplished. The patients were never randomized into an operative and non-operative group. If a "control" group is hypothesized, it may include those patients who did not meet the criteria allowing revascularization; they were too compromised to undergo surgery. Thus, if a prospective controlled clinical trial is the gold standard for the care of diabetic feet,  there is insufficient evidence  to justify the care our patients receive in most hospitals today.

            The data from the National Diabetes Surveillance System above  and that corrected for age shown in our first newsletter do not suggest that an effective form of therapy has been introduced in the last 25 years. Further, various authors have also reported that revascularization attempts have been unsuccessful in reducing the rate of amputations. Abstracts from the following authors may be found in the literature section of our website (www.circulatorboot.com):

• Morris PE et al: Surgery and the progression of the occlusive process in patients with peripheral vascular disease. Radiology 124:343, 1977
• Eickhoff HJ, Hanson B, Lorentzen JE: The effect of arterial reconstruction on lower limb amputation rate. Acta Chir Scand 502: 181-187, 1980.
• Humpfrey LL, Baillard DJ, Butters MA, Palumbo PJ and Hallett JW: The epidemiology of lower extremity amputation in diabetes: a population based study in Rochester, Minnesota. Diabetes 38: suppl 2:33A, 1989.
• Tunis ER, Bass EB and Steinberg EP: The use of angioplasty, bypass surgery and amputation in the management of peripheral vascular disease. N Engl J Med 325: 556-62, 1991.
• Sayers RD, Thompson MM, Varty K, Jager C and Bell PFR: Changing trends in the management of lower limb ischemia: a 17 year review. Br J Surg 80: 1269-1273, 1993.
• Connelly J, Airey M and Chell S:.Variation in clinical decision making is a partial explanation for geographical variation in lower extremity amputation rates. Br J Surg 88(4):529-35, 2001.
• Trautner C, Haastert B, Spraul M, Giani G and Berger M: Unchanged incidence of lower-limb amputations in a German city, 1990-1998. Diabetes Care 24:855-859, 2001.

Circulator Boot Clinics have generally dealt with patients who were not suited for other means of therapy and commonly were offered major amputations or boot therapy. Enlisting such patients in a study as "controls" is close to impossible. The following links will take the interested reader to areas where these issues have been discussed.

http://www.circulatorboot.com/literature/EBMVasS.html

http://www.circulatorboot.com/literature/MEthics.html

http://www.circulatorboot.com/literature/Bailar.html

http://www.circulatorboot.com/literature/Insurcoverage.html

www.icmje.org

The last reference provides information on the role of data bases in clinical research. Circulator Boot is willing to collaborate with parties interested in the outcome of treatments of the leg at risk of amputation.

Perspectives in Circulation Today

Volume 1, Number 2