Is Noncontact Normothermic Wound Therapy Cost Effective for the Treatment of Stages 3 and 4 Pressure Ulcers?

Alex Macario, MD, MBA;1 Franklin Dexter, MD, PhD2

This is greater than the 45-percent healing rate at six months measured among patients with pressure ulcers at VA long-term care facilities.57 Rates of healing reported in that study are derived from administrative data and, as such, are likely to be underestimates of the true healing rate, which may explain why our model had a greater six-month healing rate. The underestimation may arise as patients whose ulcers healed and who then developed new pressure ulcers were considered not healed. Also, many patients had more than one ulcer and were not counted as healed unless all of their pressure ulcers had healed. Third, healing of pressure ulcers in patients that were discharged was not included. That study also found that 31 percent of patients with stage 4 ulcers would be healed at six months. In another study, a national nursing home chain similarly reported a 40-percent healing rate for stage 3 pressure ulcers and a 34-percent healing rate for stage 4.58 Both of these rates are within a few percentage points of what our model predicts.

     3. Our model predicts that the mean length of treatment for a stage 3 ulcer receiving standard care, from initial occurrence to complete healing, will equal 153 days. This is consistent with a wound closure rate of 0.1cm2/day as documented by Ferrell59 for a 16cm2 wound (as per our base case). Also, a study of long-term care patients with pressure ulcers found mean treatment length to equal 116 days.60

     Advanced wound care products compete with one another and with other medical treatments for reimbursement from federal and commercial payers. Thus, we also completed a second literature search to compare the efficacy of NNWT to topical negative pressure, another advanced wound care product.61 We found one prospective trial with a total of 24 participants that evaluated the effectiveness of topical negative pressure on 36 chronic wounds.62 However, this study did not report statistical analyses, and healing data for the subset of patients who had pressure ulcers was not reported. Additional well-controlled, blinded, “head-to-head” clinical trials, as well as studies of the use of NNWT in nonresearch protocol settings, are necessary.

     In our modeling, we assumed that transition probabilities from one health state to another remained constant as time went on (e.g., probability of healing after the first eight-week time period was equal to the probability of healing in the fourth eight-week time period). However, it may be that the efficacy of both standard and NNWT treatments decreases as a pressure ulcer ages. We simulated decreasing efficacy of both treatments as the pressure ulcer aged and found no significant impact on overall results.

     Costs, outcomes, and benefits can be analyzed from different points of view—the patient, the provider, the payer, or society as a whole.63 For example, the cost of a medical service to the payer (insurance company) equals the percentage of charges actually paid by the payer. However, the relevant cost to the patient is the out-of-pocket expense (not covered by insurance) plus other costs (e.g., inability to work) incurred due to illness. A different way to assign a cost for nursing services may have impacted the cost model. For example, from the facility’s perspective, nursing care time may be considered a fixed cost, as staff are paid regardless of whether there is one more or one less pressure ulcer to treat. However, we assumed that having a provider take care of a pressure ulcer is an incremental cost to society, as is commonly done in cost-effectiveness studies, to reflect that from society’s point of view, there is a cost for the provider’s time and expertise.

     Our computer simulation study has several limitations.


1. Bergstrom N, Braden B, Kemp M, et al. Multisite study of incidence of pressure ulcers and the relationship between risk level, demographic characteristics, diagnoses and prescription of preventive interventions. J Am Geriatr Soc 1996;44:22–30. 2. Langemo DK, Olson B, Hunter S, et al. Incidence of pressure sores in acute care, rehabilitation, extended care, home health, and hospice in one locale. Decubitus 1989; 2(2):42. 3. Weiler PG, Franzi C, Kecskes D. Pressure sores in nursing home patients. Aging 1990;2:267–75. 4. Brandeis GH, Morris JN, Nash DJ, Lipsitz LA. The epidemiology and natural history of pressure ulcers in elderly nursing home residents. J Am Med Assoc 1990;264:2905–9. 5. Berlowitz DR, Bezerra HQ, Brandeis GH, et al. Are we improving the quality of nursing home care: The case of pressure ulcers. J Am Geriatr Soc 2000;48:59–62. 6. Bergquist S, Frantz R. Pressure ulcers in community-based older adults receiving home healthcare. Prevalence, incidence, and associated risk factors. Adv Wound Care 1999;12(7):339–51. 7. Objective 1–16: Reduce the proportion of nursing home residents with pressure ulcers. Information accessed January 21, 2001. 8. Bello Y, Phillips T. Recent advances in wound healing. J Am Med Assoc 2000;283:716–8. 9. Gentzkow GD, Pollack SV, Kloth L, Stubbs HA. Improved healing of pressure ulcer using Dermapulse, a new electrical stimulant device. Wounds 1991;3:5:158–70. 10. Philbeck TE, Whittington KT, Millsap MH, et al. The clinical and cost effectiveness of externally applied negative pressure wound therapy in the treatment of wounds in home healthcare Medicare patients. Ost/Wound Manag 1999;45:41–50. 11. Ferrell BA, Keeler E, Siu AL, et al. Cost-effectiveness of low air-loss beds for treatment of pressure ulcers. J Gerontol A Biol Sci Med Sci 1995;50A:M141–6. 12. Xakellis G, Chrischillis E. Hydrocolloid versus saline gauze dressings in treating pressure ulcers: A cost-effectiveness analysis. Arch Phys Med Rehabil 1992;73:463–9. 13. Phillips TJ. New skin for old: Developments in biological skin substitutes. Arch Dermatol 1998;134:344–9. 14. Rees RS, Robson MC, Smiell JM, et al. Becaplermin gel in the treatment of pressure ulcers. Wound Rep Reg 1999;7:141–7. 15. Bergstrom N, Bennett MA, Carlson CE, et al. Treatment of pressure ulcers. Clinical Practice Guideline, No. 15. Rockville MD: U.S. Department of Health and Human Services. Public Health Service, Agency for Health Care Policy and Research. AHCPR Publication No. 95-0652; December 1994. 16. Ikeda T, Tayefeh F, Sessler Dl, et al. Local radiant heating increases subcutaneous oxygen tension. Amer J Surg 1998;175:33–7. 17. Plattner O, Akca O, Herbst F, et al. The influence of two surgical bandage systems on wound tissue oxygen tension. Arch Surg 2000;135(7):818–22. 18. Hunt TK, Hopf HW, West JM. A radiant heat bandage increases abdominal subcutaneous oxygen tension and temperature. Wound Rep Regen 1996;4:339–45. 19. Rabkin JM, Hunt TK. Local heat increases blood flow and oxygen tension in wounds. Arch Surg 1987;122:221–5. 20. Juhlin L, Civier A, Shroot S, et al. Effect of infrared radiation on the recoverable levels of free acid and prostaglandins in human forearm skin. J Invest Dermatol 1983;81:297–300. 21. Pai MP, Hunt TK. Effect of varying oxygen tension on healing of open wounds. Surg Gynecol Obstet 1972;135:756–8. 22. Hunt TK. The effect of varying ambient oxygen tensions on wound metabolism and collagen synthesis. Surg Gynecol Obstet 1972;135:561–7. 23. Jonsson K, Jensen JA, Goodson WH, et al. Tissue oxygenation anemia and perfusion in relation to wound healing in surgical patients. Ann Surg 1991;214:605–13. 24. Niinikoski J, Rajamaki A, Kulonen E. Healing of open wounds: Effects of oxygen, distributed blood supply, and hyperemia by infrared radiation. Acta Chir Scand 1971;137:399–401. 25. Jonsson K, Hunt TK, Mathes SJ. Oxygen as an isolated variable influences resistance to infection. Ann Surg 1988;208:783–7. 26. Park HY, Phillips TJ. The effect of heat on the inhibitory effects of chronic wound fluid on fibroblasts in vitro. Wounds 1998;10(6):189–92. 27. Xia Z, Sato A, Hughes M, Cherry GW. Stimulation of fibroblast growth in vitro by intermittent radiant warming. Wound Rep Regen 2000;8(2):138–44. 28. Cherry GW, Wilson J. The treatment of ambulatory venous ulcer patients with warming therapy. Ost/Wound Manag 1999;45(9):65–70. 29. Santilli SM, Valusek PA, Robinson C. Use of a noncontact radiant heat bandage for the treatment of chronic venous stasis ulcers. Adv Wound Care 1999;12:89–93. 30. Sonnenberg FA, Beck JR. Markov models in medical decision making: A practical guide. Med Decis Making 1993;13:322–38. 31. Russell L, Gold M, Siegel J, et al. The role of cost-effectiveness analysis in health and medicine: Panel on cost-effectiveness in health and medicine. J Am Med Assoc 1996:276;1172–7. 32. Cullum N, Deeks J, Sheldon TA, et al. The Cochrane Database of Systematic Reviews beds, mattresses, and cushions for pressure sore prevention and treatment. The Cochrane Collaboration 2000;Issue 4. 33. Cook DJ, Sackett DL, Spitzer WO. Methodological guidelines for systematic reviews of randomized control trials in healthcare from the Potsdam consultation on meta-analysis. J Clin Epidemiol 1995;48:167–71. 34. Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology: A proposal for reporting. J Am Med Assoc 2000;283:2008–12. 35. Price P. The challenge of outcome measures in chronic wounds. J Wound Care 1999; 8(6):306–8. 36. Kantor J, Margolis DJ. A multicentre study of percentage change in venous leg ulcer area as a prognostic index of healing at 24 weeks. Br J Dermatol 2000;142(5):960–4. 37. Honde C, Derks C, Tudor D. Local treatment of pressure sores in the elderly: Amino acid copolymer membrane versus hydrocolloid dressing. J Am Geriatr Soc 1994;42:1180–3. 38. Kramer JD, Kearney M. Patient, wound, and treatment characteristics associated with healing in pressure ulcers. Adv Skin Wound Care 2000;13:17–24. 39. Itoh M, Montemayor J, Matsumoto E. Accelerated wound healing of pressure ulcers by pulsed high peak power electromagnetic energy (Diapulse). Decubitus 1991;4:24–34. 40. Disa JJ, Carlton JM, Goldberg NH. Efficacy of operative cure in pressure sore patients. Plast Reconstr Surg 1992;89:272–8. 41. Thomson JS, Brooks RG. The economics of preventing and treating pressure ulcers: A pilot study. J Wound Care 1999;8:312–6. 42. Tengs TO, Wallace A. One thousand health-related quality-of-life estimates. Med Care 2000;38(6):583–637. 43. Franks PJ, Moffatt CJ. Quality-of-life issues in patients with chronic wounds. Wounds 1998;10:1E–10E. 44. Rosser R, Kind P. A scale of valuations of states of illness: Is there a social consensus? Int J Epidemiol 1978;7:347–58. 45. Kind P, Rosser R, Williams A. Valuation of quality of life: Some psychometric evidence. In: Jones-Lee MW (ed). The Value of Life and Safety. Amsterdam: North-Holland, 1982:159. 46. Torrance GW, Feeny DH, Furlong WJ, et al. Multiattribute utility function for a comprehensive health status classification: Health Utilities Index 2. Medical Care 1886;34:702–22. 47. US Department of Commerce, Bureau of the Census. Statistical Abstract of the United States, Expectation of Life and Expected Deaths. Washington, DC: US Government Printing Office; 1992. 48. Plan and operation of the Third National Health and Nutrition Examination Survey, 1988–94, Series 1: Programs and collection procedures. Vital Health Stat 1 1994;32:1–407. 49. Berlowitz D, Wilking S. The short-term outcome of pressure sores. J Am Geriatr Soc 1990;38:748–52. 50. Berlowitz DR, Brandeis GH, Anderson J, et al. Effect of pressure ulcers on the survival of long-term care residents. J Gerontol A Biol Sci Med Sci 1997;52:M106–10. 51. Mullahy J, Manning W. Valuing healthcare: Costs, benefits, and effectiveness of pharmaceuticals and other medical technologies. In: Sloan FA (ed). Statistical Issues in Cost-Effectiveness Analyses. New York, NY: Cambridge University Press, 1995:149–84. 52. Doubilet P, Begg C, Weinstein M, et al. Probabilitic sensitivity analysis using Monte-Carlo simulation. Med Dec Making 1985;5:157–77. 53. Kramer J, Kearney M. Patient, wound, and treatment characteristics associated with healing in pressure ulcers. Adv Skin Wound Care 2000;13:17–24. 54. Laupacis A, Feeny D, Detsky AS, Tugwell PX. How attractive does a new technology have to be to warrant adoption and utilization? Tentative guidelines for using clinical and economic evaluations. Can Med Assoc J 1992;146:473–81. 55. Hibbs P. The economics of pressure ulcer prevention. Decubitus 1989;2:32–8. 56. Frantz RA. Pressure ulcer costs in long-term care. Decubitus 1989;2:59–60. 57. Berlowitz DR, Brandeis GH, Anderson J, Brand HK. Predictors of pressure ulcer healing among long-term care residents. J Am Geriatr Soc 1997;45:1. 58. Brandeis GH, Morris JN, Nash DJ, Lipsitz LA. The epidemiology and natural history of pressure ulcers in elderly nursing home residents. J Am Med Assoc 1990;264:2905–9. 59. Ferrell B, Osterweil D, Christenson P. A randomized trial of low air-loss beds for treatment of pressure ulcers. J Am Med Assoc 1993;269:494–7. 60. Xakellis GC, Frantz R. The cost of healing pressure ulcers across multiple healthcare settings. Adv Wound Care 1996;9(6):6. 61. Flemming K, Cullum N. Electromagnetic therapy for the treatment of pressure sores. [Systematic Review] Cochrane Wounds Group. Cochrane Database of Systematic Reviews 2001;Issue 2. 62. Joseph E, Hamori CA, Bergman S, et al. A prospective, randomized trial of vaccum-assisted closure versus standard therapy of chronic nonhealing wounds. Wounds 2000;12(3):60–7. 63. Eisenberg JM. Clinical economics: A guide to economic analysis of clinical practices. J Am Med Assoc 1989;262:2879–86. 64. Bennett RG, O’Sullivan J, DeVito EM, Remsburg R. The increasing medical malpractice risk related to pressure ulcers in the United States. J Am Geriatr Soc 2000;48:73–81. 65. Mathias S, Prbil LA, Boyko W, Fastenau J. Health-related quality of life in venous leg ulcer patients successfully treated with Apligraf: A pilot study. Adv Wound Care 2000;13:76–8. 66. Berlowitz DR. Health-related quality of life of nursing home residents: Differences in patient and provider perceptions. J Am Geriatr Soc 1995;43:799–802. 67. Maklebust J, Margolis D. Session I: Pressure ulcers: Definition and assessment parameters. Adv Wound Care 1995;8:28-6–28-7. 68. Ferrel B, Osterweil D, Christenson P. A randomized trial of low air-loss beds for treatment of pressure ulcers. J Am Med Assoc 1993;269:494–7. 69. Groen HW, Groenier KH, Schuling J. Comparative study of a foam mattress and a water mattress. J Wound Care 1999l;8(7):333–5. 70. Xakellis G, Frantz RA, Lewis A, Harvey P. Cost-effectiveness of an intensive pressure ulcer prevention protocol in long-term care. Adv Wound Care 1998;11:22–9. 71. O’Brien SP, Gahtan V, Wind S, Kerstein M. What is the paradigm: Hospital or home healthcare for pressure ulcers? Am J Surg 1999;65(4):303–6. 72. Bergemann R, Lauterbach KW, et al. Economic evaluation of the treatment of chronic wounds. Pharmacoeconomics 1999;16:14:367–77. 73. Xakellis GC, Chrischilles EA. Hydrocolloid versus saline-gauze dressings in treating pressure ulcers: A cost-effectiveness analysis. Arch Phys Med Rehabil 1992;73(5):463–9. 74. Mosher BA, Cuddigan J, Thomas DR, Boudreau DM. Outcomes of four methods of debridement using a decision analysis methodology. Adv Wound Care 1999;12(2):81–8. 75. Ferrell BA, Keeler E, Siu AL, et al. Cost-effectiveness of low air-loss beds for treatment of pressure ulcers. J Gerontol A Biol Sci Med Sci 1995;50A:M141–6. 76. Allman RM, Damiano A, Strauss M. Pressure ulcer status and postdischarge resource utilization among older adults with activity limitations. Adv Wound Care 1996:9(2):38–44. 77. Hirshberg J, Rees R, Marchant B, Dean S. Osteomyelitis related to pressure ulcers: The cost of neglect. Adv Skin Wound Care 2000;13:25–9. 78. Allman R, Goode PS, Nickie B, et al. Pressure ulcers, hospital complications, and disease severity: Impact on hospital costs and length of stay. Adv Wound Care 1999;12:22–30. 79. Torrance G. Utility approach to measuring health related quality of life. J Chron Dis 1987;40:593–600. 80. Kloth L, Berman J, Dumit-Minkel S, et al. Effects of normothermic dressing on pressure ulcer healing. Adv Skin Wound Care 2000;13:69–74. 81. Whitney JD, Salvadalena G, Higa L, Mich M. Treatment of pressure ulcers with noncontact normothermic wound therapy: Healing and warming effects. J WOCN 2001,28:244–52. 82. Price P, Bale S, Crook H, Harding MB. The effect of a radiant heat dressing on pressure ulcers. J Wound Care 2000;9:201–5. 83. Kloth L, Nett M, Berman J, et al. A randomized comparison of healing rates between full-thickness pressure ulcers treated for 12 weeks with warming therapy and ulcers treated with standard care alone (abstract). Presentation. Las Vegas, Nevada: The 14th Annual Symposium on Advanced Wound Care, 2001.

Post new comment

  • Lines and paragraphs break automatically.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Use to create page breaks.

More information about formatting options

Enter the characters shown in the image.