Figure 1. Schematic organization of the wound care centers (Tübingen model).
Figure 2. The first page of the wound documentation program provides personal patient data, a localization diagram, and an automatically generated graph of the wound size during treatment.
Figure 3. The second page of the wound documentation program (visit documentation) includes wound characteristics, a photograph of the wound, wound size, and therapy. Wound size (area) is calculated on tracings that are scanned by a digitizer pad.
Figure 4. Distribution of the causes of 7051 problem wounds in the 10 wound care centers of the German Wound Net.
Figure 5. Life-table analyses of the calculated probability of healing within 2 years according to the effects of the grade of the wound (A), patient age (B), patient compliance (C), and the cause of the wound (D).
Coerper S, Wicke C, Pfeffer F, Köveker G, Becker H. Documentation of 7051 Chronic Wounds Using a New Computerized System Within a Network of Wound Care Centers. Arch Surg. 2004;139(3):251-258. doi:10.1001/archsurg.139.3.251
Wound care can be prospectively recorded on a large scale if a standardized wound documentation system is established. Based on such a documentation system, a network of specialized wound care centers can generate a large and valid database of wound characteristics, wound-healing dynamics, and wound care.
A clinical prospective analysis.
Ten German specialized surgical wound care centers.
Patients and Methods
In a 2-year pilot phase, 4175 patients with 7051 chronic nonhealing wounds were documented using a new computerized system and treated following defined standards.
A total of 1761 diabetic, 1349 venous, 1146 ischemic, 1079 pressure, and 759 postoperative nonhealing wounds and 957 ulcers with other causes were prospectively documented. Chronicity of ulceration was shown by the long wound duration of 433 days (range, 14-1867 days). Wound documentation was well integrated into daily practice, as shown by a mean ± SD documentation time of 5.7 ± 2.2 minutes per visit. A multivariate analysis of factors known to interfere with wound healing revealed significant effects of patient compliance, grading of wound depth, and patient age (P<.001 for all).
The German Wound Net achieved, for the first time, centralized and prospective documentation of more than 7000 chronic wounds treated according to defined guidelines. This new concept of a network of specialized wound care centers working with standardized treatment plans and prospective documentation of chronic wounds may open a new dimension for wound-healing studies and may represent an optimal platform for multicenter trials.
The incidence of chronic wounds is high, and it is continuously growing. It is well-known that ischemia, diabetes mellitus, chronic venous insufficiency, and pressure are frequent reasons for chronic nonhealing ulcers. In Germany, the number of patients with high-risk diabetic feet is estimated to be 800 000,1 and the prevalence of patients with venous disease is 12%.2 When these patients develop lower extremity ulcers, their lives are compromised by long hospitalization times, slow healing rates, and a high risk of recurrence, leading to high treatment costs. Chronic nonhealing wounds, therefore, represent not only a medical but also a social and economic problem. According to Gottrup et al,3 these so-called problem wounds are defined as wounds that are resistant to therapy; they provide an extra risk of morbidity and mortality and reduce the quality of life of the patient.
During the past decade, several experimental studies elucidated the pathophysiologic background of wound healing. These studies4- 7 implemented new therapeutic approaches, such as growth factor treatment, keratinocyte transfer, and application of living skin substitutes. These new treatment modalities, however, cannot be considered breakthroughs in the treatment of chronic wounds,5- 7 and despite these new therapeutic strategies, chronic wounds remain a major problem for the health care system.
We also have to address the problem of chronic wounds in another context. In Europe, and especially in Germany, there is a deficit in standardized wound care management. Different medical societies have published guidelines for wound care, but their acceptance and application in daily clinical practice must be questioned. Furthermore, the interdisciplinary aspect of the treatment of problem wounds has not been studied systematically.8- 11 The industry developed a plethora of different wound dressings. As a consequence, wound care today is much more focused on the right choice of wound dressing than on optimal and consequent diagnostic procedures and adequate treatment of the underlying disease.12
The major problem with evidence-based wound care is the lack of valid data. Most guidelines are established on experience and have not been evaluated systematically.
Based on these controversial issues, a discussion started about a new infrastructure to treat chronic wounds. In the United States, wound care centers in which wound care was standardized and regularly documented were established in the late 1980s.13 In Germany, the wound care center in Tübingen was the first to be established, in 1992, according to the American experience.14 In this center, wound care has, since then, been performed with an interdisciplinary approach and according to a standardized comprehensive wound care protocol. Following the Tübingen model, additional wound care centers have been created in Germany during the past 10 years.
In 1999, ten wound care centers in Germany joined their common interest of optimizing the care of chronic wounds and founded the German Wound Net. The primary goals of this network were the establishment of treatment standards and the prospective documentation of chronic wounds to gain prospective data on wound dynamics and wound care and to create a platform for multicenter studies of chronic wounds.
The German Wound Net was created in 3 steps: (1) cooperation partners were acquired and a basic organization was built, (2) a standardized computer-based documentation system was set up, and (3) treatment guidelines were defined.
The German Wound Net was founded in 1999 as a registered nonprofit organization (Wundnetz e.V.) of 10 surgical wound care centers. Each center specialized in the treatment of chronic wounds and was either a university-based or a university-affiliated community hospital. The centers already had an interdisciplinary approach for diagnosing and treating problem wounds. Figure 1 shows the schematic organization of the individual wound care centers. Patients with chronic wounds are usually treated in an ambulatory setting. Referrals to all relevant specialties are arranged. Inpatient treatment can be given to patients requiring invasive diagnostic procedures or major surgical interventions. Close cooperation with home care organizations and general practitioners optimizes the patient pathway. Each center agreed on the prospective documentation of all patients with problem wounds and on treatment according to the defined guidelines of the Wound Net.
A Web site (http://www.wundnetz.de) was created. At this stage, the Web page is written in German and represents a platform for physicians, patients, and industry partners. It provides information about Wound Net initiatives, current guidelines, and activities. Relevant statistical evaluations and links to published data are also included. Personal patient data do not appear on the Web platform.
Regular meetings were held to discuss the software of the wound documentation program until the first version of the program (wu:du: 1.0) was established and installed on the computers of each wound care center. Patient data had to be documented within a standardized system to allow valid prospective data collection and intercenter comparisons. Special software was created based on a commercially available database (Windows Data Access Objects; Microsoft Germany, Unterschleissheim, Germany). The structure of the program was developed using C++ (Lycos Germany, Guetersloh, Germany) and Visual Basic (Microsoft Germany). Hardware requirements include a personal computer, 64 MB of random access memory (a Pentium 200 processor or better), a digital photocamera (>2 million pixels), a port for a Smart Media Card (Viking Germany, Grossostheim, Germany), and a digitizer pad (Wacom Europe, Krefeld, Germany) for planimetric measurements.
The software was adapted to the routine working practice of the wound care centers. Patient data are entered individually and saved on the local server of each center. To initialize a new patient record, the personal patient data and the name and address of the referring physician have to be entered. Documentation is performed for each wound: the cause of the wound defined according to the German Wound Net guidelines (neuropathic diabetic ulceration, venous ulceration, peripheral arterial disease, pressure sore, etc), wound characterization, wound duration, risk assessment for amputation, and past treatment. Diagnostic and therapeutic procedures are documented in a separate window. Wound localization is documented in a wound localization diagram. Patient compliance is classified as good, acceptable, or poor at each visit, depending on the quality of dressing changes, the adequate use of supporting measures (such as compression therapy or off-loading devices), and reliability in keeping scheduled appointments at the wound care facility (Figure 2). Wound characteristics (amount and type of exudate, callus formation, undermining, maceration, etc) is assessed for each wound. The wound bed is characterized by documentation of the presence of granulation tissue and epithelium, nonviable or deficient tissue, infection or inflammation, moisture imbalance, and a nonadvancing or undermined epidermal margin.15 The presence of edema (yes or no) is evaluated clinically. The wound area is calculated from tracings obtained directly from the wound on Opsite foil (Smith and Nephew Germany, Hamburg, Germany), which are then scanned using a digitizer pad. Wound depth is measured using a probe, and the deepest tissue involved is documented (corium or subcutaneous tissue as grade 1, fascia or muscle as grade 2, and tendon or bone as grade 3) following a modified classification by Knighton et al.16 Wound infection is classified according to the following categories: no infection, superficial infection, deep tissue infection, and systemic infection. Current local therapy, results of microbial tests, supportive measures, and a pain score are documented (Figure 3). A digitized photograph of the wound is taken and transferred to the personal computer using the Smart Media Card. After documentation of these data, the treating physician adds specific comments and a treatment plan to the documented visit. Printouts of the visit are then generated for the patient's record and for the referring physician or the primary care institution.
The 10 wound care centers of the German Wound Net are all affiliated with surgical departments and have a special interest in the treatment of chronic wounds. The guidelines of the German Wound Net were adapted from published national and international guidelines for diabetic foot syndrome, chronic venous insufficiency, peripheral arterial disease, and pressure sores.10,11,17,18 One of the major goals of the German Wound Net is to standardize wound care and to evaluate its effect on healing and costs. The currently used guidelines are published on the Web site of the German Wound Net (http://www.wundnetz.de).
Patient data were entered into the local database of each site following the standard confidentiality policy of German hospitals. In Germany, no specific consent has to be signed for this documentation. For statistical analysis, the data were converted to anonymous records and sent to the central server of the German Wound Net. No personal data are shown on the public Web forum.
At this stage, the prospectively collected data can be evaluated individually per center or pooled for all centers. With a special statistical tool, each center can calculate healing rates. Cost calculations for quality control can be generated. For multicenter purposes, the data are converted to anonymous records and sent to the central server of the German Wound Net using a separate software tool.
In this first publication of data from the German Wound Net, we analyzed data collected from all 10 centers. For statistical analysis, data were entered into the SPPS database (SPSS Inc, Chicago, Ill) to calculate prediction of healing within the first 2 years of treatment using Kaplan-Meier analysis and the log-rank test. The time to complete healing, defined as the number of days until complete epithelialization, was analyzed using the Cox proportional hazards regression model, with patient age, wound grade, wound cause, and patient compliance as covariates.
In a 2-year pilot phase, the 10 centers of the German Wound Net prospectively documented 4175 patients with 7051 wounds. Follow-up treatment was documented in 32 830 visits. Each center had an individual focus regarding its patient population and the cause of ulceration. This led to a specific distribution of wound causes at each center (Figure 4). The individual centers documented 65 to 1205 patients in 2 years (Table 1). Wound duration before referral to the specialized wound care center was 433 days (range, 14-1867 days). Documentation included 1761 diabetic, 1349 venous, 1146 ischemic, 1079 pressure, and 759 postoperative nonhealing wounds and 957 ulcers with other causes, including vasculitis, osteomyelitis after trauma, radiation, and neuropathy not associated with diabetes mellitus. According to clinical examination using the filament test and palpation of peripheral foot pulses, diabetic foot ulcers were exclusively neuropathic in 30% of patients, exclusively ischemic in 13%, and both neuropathic and ischemic in 57%. Documentation time for each visit was a mean ± SD of 5.7 ± 2.2 minutes.
Multivariate statistical analysis of wound grade, patient age, patient compliance, and wound cause was performed. Healing was significantly faster in superficial ulcers than in those with bone or tendon involvement (P<.001). Age (≤70 vs >70 years) had a significant impact on healing, with older patients showing slower healing rates (P<.001). Patient compliance was also a significant factor regarding the probability of healing within the first 2 years of treatment (P<.001). The factor cause of the wound did not reach statistical significance (P = .47). Life-table analyses demonstrate the effects of wound grade, patient age, patient compliance, and wound cause on wound healing (Figure 5).
The documentation of medical treatment is mandatory by law,17,19 and it is useful for quality control in every medical institution. In this analysis, we showed, for the first time, that prospective evaluation of wound care in a large patient population is possible within a network of specialized wound care centers (the German Wound Net).
The key element of the German Wound Net is a specifically developed computerized wound documentation system.20 Only a few wound documentation systems have been published,21,22 and some have also been computerized, but none of these have ever been prospectively evaluated in a large patient population, to our knowledge. In a 2-year clinical study, Warren et al23 showed that a real-time electronic database for primary care medicine allows continuous and direct analysis of valid data. In the field of chronic wounds, the results of this study are a first step in this direction.
In this evaluation, we showed that the wound documentation system of the German Wound Net allows precise and standardized documentation of wounds. During development of the wound documentation software, we relied on the experience of previously published wound-healing studies. The system measures wound size and depth according to the studies published by Smiell et al18,24 by using tracings (wound area) and a probe (wound depth). This approach is easy, reproducible, and effective. Wound depth alone measured using a probe, however, does not always characterize the extent of the ulceration. Therefore, we also used a grading system, as modified by Knighton et al.16 Based on these measurements, we found a statistically significant effect of wound grade on the probability of healing.
At first glance, the time required for wound documentation at each visit seems high. The acceptance and speed of documentation, though, are increasing with time and experience. After a learning curve of 4 to 8 weeks, wound documentation can be performed within 5 to 6 minutes per visit. During the 2-year pilot phase, there was no increase in personnel costs. In a test run of 20 cases, documentation of the same wound by 3 different wound care nurses was not different (data not shown). After this pilot phase, we plan to conduct a multicenter study within the German Wound Net to investigate the reproducibility of wound documentation using the described system. Within this study, we also plan to analyze the extent of the standardization of wound care in the participating centers.
Within 2 years, the participating members of the German Wound Net documented and analyzed data from 4175 patients. These patients were referred to the centers of the German Wound Net with long-lasting chronic wounds, as demonstrated by a mean wound duration of more than 1 year before referral to the center.
The multivariate analysis of our first data set showed that patient age, wound grade, and patient compliance are independent factors that interfere with the healing of chronic wounds. The effect of aging has been described in previously published studies25,26 on animal and human healing. The data analysis showed that poor patient compliance is a significant factor that delays the healing of chronic wounds. This phenomenon has been described based on clinical observation in a study published by Gentzkow et al.27
Compared with other controlled wound-healing studies,16,18,28- 36 the calculated healing rates in the German Wound Net are high, especially if we consider the long wound duration. In a study of the efficacy and safety of becaplermin use on diabetic ulcers, Smiell et al18 report a healing rate of 35% within 20.1 weeks in the control group (168 patients treated according to standard care). The German Wound Net data include 1761 diabetic ulcers, and the probability of healing was 35% within 10 weeks. The prevalence of exclusively neuropathic diabetic foot ulcers in the analyzed patient population (30%) was lower than that in previously published data (70%).37 We assume that the predominance of patients with diabetic neuropathy associated with ischemia is because of the surgical orientation of the participating wound care centers.
The large database of prospective data developed by the German Wound Net can also be analyzed retrospectively. Although retrospective analyses do not have the same scientific impact as data from prospective studies, the large database gives us the chance to analyze homogeneous subgroups large enough for statistical evaluation.
The complete documentation of wound care, including each dressing change, has not been realized for all patients in the German Wound Net up to now because patients are also treated by general practitioners or home care organizations between control visits to the centers. It should be a goal for the future to create a documentation system that is used by all participants involved in wound care. Then, exact and realistic outcome measurements may be calculated to reveal useful data for efficacy and effectivity of any kind of treatment.38,39
Originally developed for use within the German health care system, the documentation system was designed to guarantee security and privacy of health information. The personalized documentation at each site takes into account the hospitals' local policies of computerized data safety. For statistical evaluation, only anonymous data are evaluated. No personal data appear on the online platform, and online documentation on the Web site is not possible. This format follows German legislation for ensuring the confidentiality of patients. Patient and referring physician acceptance of this system has been high. Specific criticism regarding the safety of the data analysis or the online publication of selected statistical evaluations has not been voiced in Germany.
The Web site (http://www.wundnetz.de) has been useful for primary care physicians. They can get additional information about standard wound care and are regularly informed about wound care meetings in their region. Referring physicians can contact a selected wound care center via e-mail if they face a specific wound care problem. This led to increased referral of patients to the specialized wound care centers of the German Wound Net. One of the missions of the German Wound Net, though, is to intensify care by primary care physicians. A diagnostic and therapeutic plan for the referring physicians is created and implemented by the centers within the first few visits.
The cooperation of specialized wound care centers, characterized by common guidelines and the use of the same standardized wound documentation system, makes the German Wound Net a unique platform. In this respect, it follows the call of the wound-healing organizations for a systemic approach to the management and education of ulcers.15 In the future, this infrastructure could be an ideal setting for running multicenter trials.40 The software will be extended with a study tool that is integrated into the documentation system. For each study, inclusion and exclusion criteria, study period, visit numbers, and special diagnostic and therapeutic procedures can be defined, and the screening of patients may then be performed automatically by the software. During the study, additional case record form documentation will not be necessary anymore, and data can then be exclusively recorded within the documentation program. Several control mechanisms for plausibility may be integrated to improve the quality of documentation. For international use, existing rules regarding patient confidentiality, such as the Health Insurance Portability and Accountability Act of 1996 in the United States, will have to be taken into account.
Within the German Wound Net, more than 7000 chronic wounds treated according to defined guidelines were prospectively documented in a centralized and standardized system. Significant factors for wound healing can be identified and monitored. This new concept of a network of specialized wound care centers working with standardized treatment plans and prospective documentation of chronic wounds may open new dimensions for wound-healing studies and may represent an optimal platform for national and international multicenter trials.
Corresponding author and reprints: Stephan Coerper, MD, Department of General Surgery, University Hospital Tübingen, Hoppe-Seyler Str 3, D-72076 Tübingen, Germany (e-mail: email@example.com).
Accepted for publication October 7, 2003.
Development of the documentation system of the German Wound Net was funded by Coloplast GmbH, Hamburg, Germany.
The following hospitals participate in the German Wound Net: Department of Trauma Care, City Hospital Berlin-Marzahn, Center for Spinal Cord Injuries (S. Becker, MD); Department of Trauma Care, Community Hospital Bietigheim-Ludwigsburg (R. Russ, MD); Department of General Surgery, St Johannes-Hospital Dortmund (E. Stein, MD); Department of General Surgery, University Hospital of München-Großhadern (E. Buttler, MD; G. Maiwald, MD, through June 2001); Department of General Surgery, University Hospital Rostock (F. Pfeffer, MD); Department of General Surgery, City Hospital of Sindelfingen (U. Lenz, MD); Department of General Surgery, City Hospital Schwerin (T. Sinow, MD); Department of General Surgery, University Hospital Tübingen (S. Coerper, MD); Department of General Surgery, University Hospital of Wuppertal (J. Schmidt, MD; V. D. Mohr, MD, through June 2001); and Department of General Surgery, University Hospital Würzburg (S. Debus, MD).
We thank Martin Jekov, Department of General Surgery, University of Rostock, for the development and maintenance of the wound documentation system.