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Wound care costs amount to only a tiny fraction of aggregate annual health care dollars spent in the United States. Yet they still add up to substantial sums. National costs for treating pressure ulcers alone exceeded $1.355 billion in 1994, according to information gathered by the U.S. Agency for Health Care Policy and Research. Managing an individual chronic wound can cost from hundreds to tens of thousands of dollars. How do you know your wound care dollars are being put to the best use and that a particular wound care regimen is pulling its fiscal weight?
The answer is to understand that cost-effectiveness is an economic evaluation, says Laura Bolton, PhD, worldwide director of scientific affairs for wound and skin care at ConvaTec in Princeton, NJ. In this economic evaluation, alternative programs, services, or interventions are compared in terms of cost-per-unit clinical effect. For example, it takes into consideration the cost per life saved, cost per millimeter of blood pressure lowered, or cost per quality-adjusted life-year gained.
In wound care, cost-effectiveness analysis compares wound care strategies in terms of their costs-per-unit clinical effect or wound care outcome. These calculations must be specific to the patient care setting because cost and outcome variables differ for each, Bolton explains. "The cost to achieve a goal of care may be considered exorbitant in one patient care environment yet cost-effective in another," she and her colleagues write in a recent issue of Advances in Wound Care.1
To Bolton, the reasons for clarifying the cost-effectiveness of wound care interventions are clear. "Unless health care professionals are able to recommend research-based practices, untrained individuals will make the treatment-availability and cost-effectiveness decisions."1 Therefore, health care professionals need to understand, evaluate, and compare every aspect of wound care cost-effectiveness to select treatments that provide patients with the best and most efficient care possible. True cost-effective wound care is not just knowing the cost of a particular treatment but knowing the cost of achieving the desired outcome -– such as healing, for example. But understanding this concept is not enough. Clinicians must apply the practice to obtain hard numbers by which various treatment options can be evaluated.
Wound care literature to date mostly has addressed the costs of care, Bolton says. But knowing those costs is not commensurate with cost-effectiveness, which can be defined as the cost to achieve a "unit" of improvement or results, however that unit is measured. "You have to establish a ratio of costs to results," she says. Bolton acknowledges that research related to cost-effective wound care is limited, yet more such work is inevitable because reimbursement decisions will increasingly rely on cost-effectiveness data.
Two components cost and outcome are required to calculate a treatment’s cost-effectiveness. Cost, Bolton stresses, is not simply the sum of the costs of products used but the combination of direct costs and indirect costs. Direct costs include the following:
By far the greatest expenses are hospitalization and skilled caregiver time, followed by the costs related to complications and operating room time, Bolton says. Resist the temptation to reduce costs by purchasing lower-priced products without first evaluating their efficacy, she adds. That actually could increase rather than decrease overall costs if cheaper substitutes adversely affect treatment outcomes.
While most of the cost data can be gleaned from patient billing records, gathering outcome data requires more active research. Many facilities are already required by the Health Care Financing Administration to collect such information via the minimum data set.
One of the simplest outcome measures is the change of an ulcer’s dimensions. "If you’re lucky enough to have the use of an image analyzer, you can do a tracing of the wound and count the square centimeters of the area that’s been traced," Bolton says. "But that takes nursing time, which is at a premium."
The ultimate wound outcome is healing. However, many clinical settings require alternative outcomes measures, such as percent reduction in wound dimensions or area, percent reduction in pain, reduction in percent of the wound bed covered with necrotic tissue or fibrinous slough, time to return to normal activity levels, and reduction in frequency of wound infection. Regardless of the outcome measure being observed, cost-effectiveness calculations can be standardized only when baseline scores are contrasted against scores from subsequent assessments.
To standardize outcome measures, which reduces subjectivity and enables comparisons within a facility or among facilities within a system, one can use a computerized assessment to collect outcome data, Bolton says. She has used the Wound & Skin Intelligence System (WSIS), developed by Seattle-based Applied Health Science. The goal of the WSIS is twofold: to assess a patient’s risk for pressure ulcers and/or to document and monitor healing of existing wounds. The program also offers practitioners evidence-based treatment alternatives.
The use of an automated, accurate assessment tool encourages objective evaluations, which result in more accurate outcome data, Bolton says. To date, ConvaTec has assembled a database of more than 3,500 wound care cases using the WSIS. The WSIS applies the Braden Scale of Risk Assessment to evaluate the risk of developing a pressure ulcer or the Pressure Sore Status Tool to assess changes in wound status. The system also offers recommendations on a case-by-case basis. (For details on the WSIS, see story, at right.)
"The WSIS allows people to consistently document the length, width, and depth of a wound and record a series of wound parameters that have been tested for reliability and validated against clinical experience," Bolton explains. For assessing existing wounds, those parameters include measures of exudate, type and amount of necrotic tissue, granulation tissue formation, coverage by new epithelium, and surrounding skin redness signaling inflammation and possible further skin breakdown.
"Reliable, clinically valid outcome assessments are fundamental to cost-effectiveness studies. Unless you measure something about that wound, you can’t provide an accurate assessment for tracking results. Subjective feelings can’t be measured," Bolton adds.
A patient exhibits a pressure ulcer with an area of 12.5 cm2. After 12 days of treatment, the area of the wound has decreased to 5 cm2. Thus, the reduction in wound area is calculated as [(12.5 – 5.0) 12.5] x 100, or 60% over a 12-day period. Reduction per day equals 60% over 12 days, or 5% per day (equivalent to 35% per week). If direct and indirect costs total $175 per week, the cost-effectiveness of the treatment is $175 35%, or $5 per percent of wound area healed.
Comparing this measure to similarly derived measures from other treatment approaches to similar wounds gives practitioners a basis of cost comparison by which they can decide the most cost-effective options.
Bolton explains it this way: "You can choose some gold standard’ of care in your facility as your baseline, then switch to treatment X, measure how much it costs to achieve each percent of healing with treatment X, and determine which of the two treatments is more cost-effective. Even if one treatment is more expensive, it may be more cost-effective if it results in faster wound healing. A treatment that results in no or minimal healing is not going to be cost effective no matter how inexpensive it is. It isn’t cost effective if you don’t get results."
2101. Bolton LL, van Rijswijk L, Shaffer FA. Quality wound care equals cost-effective wound care: A clinical model. Advances in Wound Care. July/August 1997:33-38.