Outcomes and Cost Implications of Amputation Prevention in
Patients with Diabetes
"In the thirty-ninth year of his reign, King Asa was afflicted
with a disease in his feet. Though this disease was severe, even in
his illness he did not seek help from the Lord, but only from the
physicians. Then in the forty-first year of his reign Asa died and
rested with his fathers" -- 2 Chronicles 16:12-44
Diabetes is a challenge for the people who have it, for the
health care professionals who care for them, and for the third party
carriers who have to pay for the care. The goal of reducing
amputations in this population remains elusive, although the steps
necessary seem intuitive when considered in terms of "pathways to
amputation." Simple strategies should be able to achieve the twin
goals of managed care--improving outcomes while decreasing costs.
When prophylactic care fails and the foot breaks down, aggressive
wound care, aggressive vascular surgery and the multidisciplinary
diabetic foot clinic can often retrieve the situation, achieving the
same goals. This presentation analyzes the cost implications of
lower extremity amputation prevention in this difficult population.
Magnitude of the problem:
There is a huge expense associated with diabetic foot problems.
Feet account for 16% of hospital admissions for diabetes. Feet
account for 23% diabetic hospital days. Foot ulcers occur in 15% of
diabetics. Almost half of diabetics are neuropathic at 20 years.
Traditional wound care is not very effective in healing the ulcers
that become chronic. Many of these result in amputation. Over half
of the major amputations occur in diabetics, and at least a third of
these amputees loose the opposite leg within the next 3 years. The
direct medical costs are high enough to mandate definitive action.
The social costs, in terms of time off work, disability and
dependency, although not the subject of this analysis, are even
greater. In spite of these statistics only 12% of physicians
routinely examine the feet.
Pathways to amputation:
The pathophysiology of the diabetic foot is interesting, but
beyond the scope of this presentation. Suffice it to say that the
diabetic foot not only looses its protective sensation, but it also
looses motor innervation of the small muscles of the foot (the hand
is affected as well). It also looses sympathetic innervation leading
to a foot which is physically warm but it is ischemic. The unwary
physician is commonly misled. Glycosylation of the tissues makes
them less flexible and compounds the problem of neuropathy.
Analyzing strategies for amputation prevention in terms of
specific complications of diabetes is a daunting task. Analyzing
strategies for amputation prevention in terms of the "Pathways to
Amputation" is easier. Each pathway has an intervention point early
on which is inexpensive and quite effective.
Pathway #1: Arterial Insufficiency, Minor Injury,
Gangrene, Amputation. In this pathway early intervention is the key.
Diagnosis is made early in the Vascular Laboratory. Aggressive
diagnosis and vascular surgery by experts should prevent 70% of
amputations. "Diabetic microvascular disease" is a misnomer.
Surgeons who believe that the tibial vessels cant be bypassed should
not be trusted with these patients. Aggressive diagnosis and
vascular surgery by experts should prevent 70% of the amputations
that occur at the end of this path.
Pathway #2: Poor Care, Callus, Neuropathy, Blister under
Callus, Infection, Osteomyelitis, Amputation. The key to this
pathway is good foot care. All of the amputations that occur at the
end of this path should be preventable.
Pathway #3: Neuropathy, Structural Deformity, Minor
Trauma, Poor Healing, Infection, Gangrene, Amputation. The key to
this pathway is use of the Semmes monofilament wire to detect the
absence of protective sensation coupled with early intervention with
education, foot care and protective foot gear. Almost all of the
amputations that occur at the end of this path should be
preventable.
Pathway #4: Renal Insufficiency, Poor Tissue, Poor
Healing, Minor Injury, Infection, Amputation. This is a difficult
group of patients. Amputation prevention in these patients is
possible only in patients whose functional state is good and whose
medical condition is good. Only about half of these amputations are
preventable. There is little hope for the patients who are
approaching life's end whose gangrenous leg is the first step in a
terminal condition.
Pathway #5: Autosympathectomy, Poor Care, Dry Skin,
Fissuring, Infection, Amputation. Good skin care with over the
counter emollients should prevent all of these amputations. Don't
forget superglue to close early cracks.
Managing the cost of diabetes.
Most of the effective strategies for managing the cost of the
complications of diabetes are intuitive. Much can be said about the
importance of glycemic control in the prevention of complications.
Treatment of micro proteinuria is equally important. Routine foot
care self-provided by the patient and routine patient examination of
his or her own feet is important as well. It should also be
intuitive that complex problems managed early are associated with
less morbidity and less cost. Futile care for a patient with a major
foot infection should be avoided. A determination should be made
early on as to whether a wound is healable, whether the patient is a
candidate for limb salvage surgery, or if the patient is a candidate
for amputation. Amputations when done should done early after
infection is controlled, and should be guided by the vascular
laboratory to insure that the initial amputation will heal.
Consideration should be given to two stage amputations when
infection is uncontrolled. Patients who do not use an extremity are
candidates for early amputation rather than limb salvage. Both money
and suffering are saved by this strategy.
Unfortunately all medical care is not equal. Compliance is a
problem as well. Some patients do not comply with treatment
recommendations. Some physicians do not comply with effective
management protocols. The following cost analysis assumes that care
is being provided by competent, well trained teams of providers.
Unfortunately not all internists are qualified to care for diabetes.
Not all people holding themselves out as vascular surgeons have
specific training and certification in that specialty. Not all self
styled wound care specialists have the requisite diagnostic skills
to deal with these complex problems.
Cost implications of diabetic foot wounds and their treatment:
Cost implications are best summarized by the published data which
is detailed on the slides used in this talk. I will provide only the
highlights here and the slides are attached.
Cost of diabetic foot ulcers:
The cost to care for diabetic foot wounds depends on which wounds
are studied. For the purposes of this analysis only chronic wounds
are considered. Such wounds predict an additional cost of $14 000
per patient per year for 2 years, the same as the direct cost of an
amputation. Only one third are healed by conventional therapy. That
a comprehensive wound care program can heal 80% of these patients
has been demonstrated repeatedly. The costs are front end loaded,
but should be less than the average cost of conventional care in the
first year. Clinics able to achieve such results are generally
multidisciplinary. Their care is protocol driven and results
oriented. Their leaders are primarily diagnosticians and not
dressing merchants. Patient education features prominently in what
they do.
Cost of vascular reconstruction vs primary amputation:
The cost of revascularization, even in diabetics with
cardiovascular disease, is driven by the extent of the necrotic
tissue and not the operation or the other comorbidities. Vascular
patients with diabetes commonly require tibial bypasses and this
operation is outside of the scope of practice of most general
surgeons and cardiac surgeons not making vascular surgery a
specialty. These grafts require maintenance dictated by a graft
surveillance program. Surveillance studies may or may not be
considered a covered benefit but should be. All of this is
expensive. Primary amputation is more expensive, however, even when
only the direct costs of health care are considered. Amputations
have maintenance costs as well. The incidence of reamputation, new
amputations, and stump ulcerations is high in these patients.
Prosthetic costs approximate the cost of a new car every 3 or 4
years. Since most diabetic patients undergoing major amputation do
not regain their ability to walk, indirect costs of amputation are
even higher. Limb salvage vascular surgery is less expensive than
primary amputation.
Cost of specialized diabetic foot programs:
There are no easy answers to the medical management of diabetic
foot problems. Simply providing a "shoe benefit" is ineffective. An
effective program couples risk assessment with targeted
interventions. Such interventions may include education, extra depth
shoes, inserts, custom shoes, trimming nails and calluses, casting
and a host of others. High risk patients may need to see a
specialist on a monthly basis for routine care. The few available
studies of the cost effectiveness of this approach are summarized,
and are compelling. In Denver this service is best provided by the
podiatrists.
Diabetic foot wounds are a challenge. The best interventions are
the ones taken before the wound occurs. These interventions are
inexpensive and effective. For patients with chronic wounds,
however, comprehensive wound management programs, aggressive
revascularization strategies, and specialized foot care programs are
prudent financial investments.
Dr Brantigan wrote this article in December of 2000. |
