Epidemiology of Chronic Wounds in Spain: Results of the First National Studies on Pressure and Leg Ulcer Prevalence

Acknowledgments: Mr. Soldevilla is the Director of the Grupo Nacional para el Estudio y Asesoramiento en Úlceras por Presión y Heridas Crónicas (GNEAUPP; the national pressure ulcer and chronic wound advisory panel); Mr. Torra is the former Deputy Director of the GNEAUPP; and Dr. Verdu, Mr. Rueda, and Mr. Martinez are members of the GNEAUPP steering committee.

Chronic wounds constitute a major health problem for the National Health Service and the patients who suffer with them. Pressure ulcers (PUs) and leg ulcers (LUs) are the most frequently seen chronic wounds at all healthcare levels.
A great profusion of literature deals with different aspects related to the epidemiology of chronic wounds, mostly pressure ulcers. These studies typically focus on local situations by means of methodological approaches, which make them difficult to compare with or include in broader analyses.¹ As for the epidemiology of the different types of leg ulcers, few data exist in the current literature that relates to figures obtained after studying larger populations, and those studies that do exist present distant views from the hypotheses in Spain, almost exclusively focusing on venous ulcers.
According to the current level of knowledge on this issue and the recommendations given by international interdisciplinary associations, such as the European Wound Management Association (EWMA), a successful approach to the problem of managing different types of chronic wounds includes the following objectives:²
• To achieve a deeper knowledge of the epidemiology of the different processes, as well as the main aspects of healthcare practice, related to chronic wounds and their economic impact
• To create the ideal teamwork-based environment for health professionals in charge of wound management to foster the integration, continuity, and contributions of various care levels
• To favor the creation of interdisciplinary research framework in areas related to etiopathogeny, causal treatment, chronic wound treatment, epidemiology, cost, and quality of life by defining organizational models to optimize integral treatment for these patients
• To draft and implement clinical practice guidelines based on the highest levels of evidence available
• To create contexts allowing an optimal content integration of promotion, health protection, and early diagnosis of high-risk situations.
Taking into account the need to obtain national figures of chronic wound prevalence in Spain, and in keeping with an epidemiological research line started by the Grupo Nacional para el Estudio y Asesoramiento en Úlceras por Presión y Heridas Crónicas (GNEAUPP; the Spanish national pressure ulcer and chronic wound advisory panel), which had initially led to a PU prevalence study³ in the Spanish autonomous region of La Rioja in 1999, it was suggested that 2 national studies on prevalence be conducted, one on PUs and another on LUs. The studies were supported by 2 unrestricted research grants, one awarded by Huntleigh Healthcare Spain for the study on PUs and another awarded by Smith & Nephew Spain for the study on LUs. The full versions of both studies were published by Spanish journals in 2003 and 2004, respectively.^4,5 This article summarizes the most relevant information derived from both studies in order to globally measure the problem of chronic wounds in Spain.

Methods

The aims of both studies were to obtain epidemiological indicators that would facilitate measurement of the PU and LU problem in Spain, help collect information about some aspects related to the main characteristics and treatment of these wounds, and provide information on the main characteristics of people with these wound types. For this reason and as a result of previous research, the authors conducted 2 point-prevalence national surveys based on an intentional sample. Two different questionnaires were prepared and validated by several GNEAUPP members.
In November 2001 (PU study) and October 2002 (LU study), 2,000 prevalence questionnaires were distributed to all the GNEAUPP members. Each questionnaire enclosed a postage-paid reply envelope. For the LU study, the Smith & Nephew wound care sales representatives distributed 2,000 additional questionnaires.
The questionnaires were directed to 3 possible respondent groups: primary healthcare professionals, hospital care professionals, and residential care professionals.
In these questionnaires, the authors asked:
• Primary healthcare professionals to describe their patients greater than age 14. In Spain, professionals working at a primary healthcare center are organized in pediatric care units (for patients age 0–13) and family medicine units (for patients age 14 and older). These professionals are generally responsible for treating their patients either at their health center or at patients’ homes.
• Hospital units or residential care professionals to describe the patients in their respective units who suffered from any PUs or LUs, depending on the study in question.
Information related to PU prevention or LU treatment as well as the main characteristics of these wounds was also requested.
In order to measure PU epidemiology, the GNEAUPP classification⁶ and epidemiological indicators guidelines⁷ were used. These indicators establish the definition of a pressure ulcer and their 4 possible stages based on the US National Pressure Ulcer Advisory Panel (NPUAP) recommendations. In the LU study, any vascular wounds with the loss of skin integrity in the area between the foot and the knee⁸ were considered LUs. Within this section, wounds were classified according to the following pathologies: venous, arterial, mixed, and diabetic foot ulcers.
The authors defined prevalence as “point prevalence” because information from respondents was obtained only in one moment when they completed the questionnaire. The deadline to return the questionnaires was 2 months after being sent. Point prevalence was calculated (in 2 different meanings) for primary healthcare, hospital, and residential units as follows:
• Crude prevalence (CP) = (all patients with PU/total number of patients studied) x 100.
The authors calculated the crude prevalence at each hospital or residential unit and then calculated the statistical mean of all units ± standard deviation (SD). In other words:
• Average prevalence (AP) (calculated only in hospitals and residential units) = (CP1 + CP2 +…+ CPn/total number of units) ± SD.
The information contained in the questionnaires was entered into a database and analyzed by the Chronic Wound Interdisciplinary Unit at Consorci Sanitari de Terrassa using the statistical program SPSS 10.0 (SPSS Inc, Chicago, Ill). Anonymity was guaranteed at all times, not only with the informing professionals but also with the patients and institutions involved in the study.

Results

Pressure ulcers. A total of 458 questionnaires were received before the deadline, which equalled a population sample of 347,250 persons. However, this population differed by institution.
The health professionals who completed the questionnaires described 1,214 patients with PUs (941 had complete information; this figure corresponds to 77.5% of the total number of prevailing PU patients). Data were reported on a total of 1,739 wounds.
PU prevalence at primary healthcare units. Regarding primary healthcare units, 176 questionnaires were analyzed corresponding to a study population of 335,235 people over age 14, ie, 0.96% of people over age 14 according to the statistic on Spanish population9 published on January 1, 2000.
Out of the 335,235 users over age 14 studied, 68,810 were greater than 65 years (20.25%) and 4,480 were being treated at home (6.51% of the users greater than 65 years and 1.39% of the users in the primary healthcare user lists). A total of 374 patients had PUs at this level, so crude PU prevalence in the patients treated at primary healthcare units group was estimated using 3 possible denominators:
• Home care patients CP = (374 PU patients/4,480) x 100 = 8.34%
• > 65 CP = (374 PU patients/68,810) x 100 = 0.54%
• > 14 CP = (374 PU patients/335,235) x 100 = 0.11%.
At this level, average prevalence was not calculated.
Complete data were reported for 343 patients with a PU that were treated at primary healthcare units (91.7% of the total prevailing PU patients at this care level), of whom 208 (60.6%) were women, 127 (37.0%) were men, and in 8 cases (2.3%) the patients’ sex was not specified. Table 1 summarizes the information related to the average age of patients and the rate of PU per patient based on their care level.
PU prevalence in hospitals. Regarding health professionals working in hospitals, 198 questionnaires were analyzed corresponding to a study population of 5,811 beds in acute care hospitals, ie, 4.34% of the patients treated in Spanish hospitals, according to data obtained by the authors from the National Hospital Catalogue. (This number of patients results from subtracting the patients in psychiatric and geriatric centers and/or long-term hospital patients from the total number of patients in the National Hospital Catalogue,¹⁰ updated on December 31, 2000.) At the time of the study, 5.483 patients were occupying these beds (an occupancy rate of 94.35%).
At this level, 452 patients had PUs. Crude PU prevalence was as follows:
• Acute care hospital units CP = (452 PU patients/5.483) x 100 = 8.24%.
The average PU prevalence data according to what the 198 hospital nursing units reported was 8.81% ± 10.21% (SD) (95% CI: 7.38; 10.24), with a minimum value of 0% and a maximum value of 45.45%. Table 2 summarizes the data related to PU prevalence at hospital units according to hospital and unit type.
Currently, there are data for 323 hospital PU patients (71.5% of the PU patients at this healthcare level), of whom 169 (52.3%) were women, 151 (46.7%) were men, and in 3 cases (0.9%) sex was unspecified.
PU prevalence at residential care centers. With regard to professionals working at residential care centers, 84 questionnaires were analyzed, providing information on 6,204 beds. Of those, 5,088 beds corresponded to geriatric centers, 601 to chronic patients, 30 to convalescence units, 16 to palliative units, and 266 to other types of units. At the time of the study, 5,961 patients were occupying these beds (an occupancy rate of 96.08%).
At this level, 388 patients had PUs. Crude PU prevalence was as follows:
• Residential care units CP = (388 PU patients/5,961) x 100 = 6.51%.
The average PU prevalence data according to what the 85 residential healthcare units reported was 7.6% ± 6.68% (SD) (95% CI: 6.15; 9.04), with a minimum value of 0% and a maximum value of 31.58%.
The reported information was derived from 275 patients with PUs treated at residential care centers, of whom 181 (65.8%) were women and 90 (32.7%) were men; in 4 cases (1.5%) sex was not specified.
Data on PUs (wounds). The reported information was derived from a total of 1,739 PUs—673 (38.7%) at primary healthcare units, 632 (36.3%) at hospitals, and 434 (24.9%) at residential care centers.
Of the total PUs, 311 cases (17.9%) were stage I ulcers, 583 (33.5%) were stage II, 511 (29.4%) were stage III, and 308 (17.7%) were stage IV. In 27 cases (1.5%), the stage was not specified.
Of the total PUs, 25.3% of the wounds were recurrent. Primary care patients accounted for 29.6% of the PUs, hospital patients 19%, and residential care center patients 27.8%. Table 3 summarizes where on the body these wounds were located. Table 4 illustrates the main wounds by body location and healthcare level, and Table 5 presents information related to the healthcare level where these wounds originally appeared.
Leg ulcers. During the established study period, a total number of 353 questionnaires were received; 222 (62.8% of the questionnaires) had been completed by primary healthcare professionals, 66 (18.7%) by health professionals in hospitals, and the remaining 65 (18.4%) by professionals at residential care centers. In order to analyze prevalence results, the questionnaires sent by hospital staff were not taken into account, as the authors could not establish a population denominator.
Leg ulcer prevalence at primary healthcare and residential care centers. With regard to primary healthcare units, the 222 questionnaires reported information about 450,163 people over age 14, ie, 1.23% of Spaniards over age 14 according to the statistic on Spanish population9 reported January 1, 2000. Of the total, 82,655 people were 65 years or older (18.63%) and 23,044 (5.11%) had diabetes.
Only crude prevalence was determined for LUs. Table 6 presents results related to LU prevalence in the population treated at primary healthcare units. Although the techniques employed in this study did not allow for determination of LU prevalence per age group, the extrapolation of the reported patients’ ages in the primary healthcare questionnaires allowed for the extrapolation of prevalence rate values based on wound type and patient age.
As for residential care units, 65 questionnaires were received with information related to 43 centers; in theory, these 65 questionnaires represent a population of 4,523 possible patients and a real figure of 4,124 patients (an occupancy rate of 91.2%).
Data on LUs (wounds). The 353 prevalence questionnaires received reported information about a total of 1,089 leg ulcers, of which 595 were venous ulcers, 78 were arterial ulcers, 187 were mixed etiology, and 224 were diabetic foot ulcers. In 5 cases, the ulcer type was not specified.
Venous ulcers. Data were collected for 595 venous ulcers (498 patients). Of the total, 67.2% of the venous ulcers affected women, and the remaining 32.8% affected men. Table 7 presents information related to patient age and wound area as well as patient age and number of ulcers according to the sex of the patient.
Of the total, 337 (56.9%) of the venous ulcers were recurrent. The average evolution time for recurrent venous ulcers is 395 ± 922 (SD) days (95% CI: 290–501; rank: 3–10.950 days), whereas the average evolution time corresponding to non-recurrent ulcers was 232 ± 712 (SD) days (95% CI: 129–335; rank: 5–7.430 days) (P = 0.039). People under age 65 represented 19.3% of those affected by venous ulcers.
It was surprising and noteworthy that only 18.2% of patients with venous ulcers received effective compression treatment. The compression systems used were crêpe bandages (58.6%), elastic stockings or socks (16.9%), multilayer systems (11.6%), cinch-tight compression bandages (10.5%), Unna boots (0.2%), and unspecified systems (2.1%).
Table 8 presents the results related to the frequency of weekly dressing changes, the dressing time per wound, and the weekly dressing time in relation to the use (or lack of use) of compression systems.
Arterial and mixed ulcers. Data were collected for 79 arterial ulcers on 75 patients. Of the total, 56.6% of the arterial ulcers affected women, and the remaining 43.4% affected men. In relation to mixed ulcers, information was collected for 187 wounds on 133 patients. Of these mixed ulcers, 56.75% affected women, and the remaining 43.25% affected men.
In this group of ulcers, 37.8% of arterial ulcers and 59.8% of mixed ulcers were recurrent.
In the case of recurrent arterial ulcers, the average evolution time for recurrent wounds was 221.6 ± 408.9 (SD) days (average 95% CI: 30–413; rank: 3–1,830 days), whereas the average evolution time for non-recurrent ulcers was 145.8 ± 261.4 (SD) days (average 95% CI: 60–232; rank: 2–1,524 days) (P = 0.393). As for recurrent mixed ulcers, the average evolution time for recurrent wounds was 719.5 ± 1,601 (SD) days (average 95% CI: 397–1,042; rank: 10–9,000 days), whereas the average evolution time for non-recurrent mixed ulcers was 222.8 ± 538.8 (SD) days (average 95% CI: 87–358; rank: 7–3,650) (P = 0.019).
Diabetic foot ulcers. Data were collected for 22 diabetic foot ulcers from 182 patients. Of these, 58.9% of the diabetic foot ulcers appeared in men and the remaining 41% in women.
In this group, 108 diabetic foot ulcers (52.94%) were recurrent. The average evolution time for recurrent wounds was 319.6 ± 438.5 (SD) days (average 95% CI: 228–411; rank: 10–2,190 days), whereas the average evolution time for non-recurrent ulcers was 122.1 ± 167.6 (SD) days (average 95% CI: 87–157; rank: 3–900 days) (P < 0.01).

Discussion

The number of returned questionnaires in both studies resulted in an important population scope, which provided an overall view of the PU and LU problem in Spain.
Mailing questionnaires proved to be highly useful and allowed the authors to employ the methodology of other studies on wide population scopes. Only one study in the scientific literature utilized this methodology for pressure ulcers, although the population scope was much smaller: 23,500 patients treated at home.^11,12
In the case of PUs, a main limitation is that most of the people who completed and returned questionnaires were GNEAUPP members. This limitation may lead one to believe the study is partially biased because GNEAUPP members would be more aware of the PU problem. On the other hand, individual professionals provided the prevalence data and not the institutions, leading the authors to conclude that the information is highly reliable. Institutions are generally reluctant to provide information about the PU problem.
International comparisons about PU prevalence usually produce contradictory results,^4,9 either due to the methodology employed in data collection or due to the different primary healthcare conditions in each country. As such, the present results will not be compared to other studies.
With regard to primary healthcare units, using the population treated by means of home care programs as a denominator allows for a better and more realistic description of the PU problem at this healthcare level than the data referred to the population older than 14 or 65, which hamper a full understanding of the problem, because most of these people are not at risk for PU development and people in home care programs are more similar to those in hospitals and residential care.^3,13
Although the final picture of the real situation regarding pressure ulcers might be biased, PUs currently constitute a major health problem in Spain, affecting patients and the national health service. The epidemiological indicators provide data that suggest PU prevention is not regarded as a priority yet, and although pressure ulcers primarily affect the aged, PU risk factors and their impact on younger age groups cannot be forgotten. The high wound evolution figures lead to consideration of a future scenario that accounts for:
• PU prevention
• The need to improve treatment protocols to reduce evolution time
• The need for different healthcare levels to coordinate with one another.
The number of questionnaires received on leg ulcers allowed the authors to work with a relevant study population (the number of people constituting the denominator of the prevalence indicators and the number of wounds). Almost 80% of the questionnaires were returned from community care units (primary health and residential care), which in Spain places the results of the present study in accordance with other studies’ results where most leg ulcers were treated at the community level.^14,15 Non-community settings (hospitals) constituted a low percentage of the questionnaires received, which might limit some aspects of the information related to this healthcare level.
According to the literature reviewed, the results of the present study on leg ulcer prevalence make this the largest community population studied with 450,000 people in comparison to 310,000 studied by O’Brien et al¹⁶ in Ireland (in 2000), 238,000 studied by Baker et al¹⁷ in Australia (in 1991), 270,000 studied by Nelzén et al¹⁸ in Sweden (in 1994), and 12,000 also studied in Sweden by Nelzén¹⁹ (in 1996).
As for leg ulcer prevalence in the community (all types), the 0.156% identified in Spain share the average results of the studies based on the community setting (Table 9).
Despite taking into account the great methodological variations existing in the studies on leg ulcer epidemiology,^20,21 the results of the present study differ from the more frequently quoted references in the specialist literature stating that leg ulcer prevalence affects approximately 1%–2% of the population.²² The present study results agree with more conservative studies,^23,24 presenting a prevalence of 0.15–0.8%.
The prevalence figures for the different types of leg ulcers greatly increase with patient age and directly link the problem of leg ulcers with the population’s increase in age.^25–27 The progressive aging of the population in Spain will certainly justify an increase in the total number of people with a leg ulcer and, therefore, must be met with a parallel increase in the healthcare units’ efforts to deal with such a problem. In order to achieve an overview of the leg ulcer problem, it is essential to point out that, as some authors suggest, for each open leg ulcer there are 2 healed ulcers at risk of recidivating.¹⁹
With regard to prevalence at residential care centers, the 3.56% identified in Spain in the present study is higher than the 2.5% (admitted to a residential care center) reported by Wipke-Tevis²⁸ in 2000, the only available study on this type of population.
Regarding the distribution of etiology, the number of mixed ulcers is outstanding, which is probably a result of inadequate wound diagnosis. Regardless, the distribution of etiology shares the average figures generally presented in the literature.
Literature on leg ulcer prevalence according to wound type is limited. The results of 1.6 venous ulcers per thousand in Nelzén’s study¹⁸ (in 1994) differ from the 0.9 per thousand in the present study. In the case of diabetic foot ulcers, the 0.53% prevalence in patients with diabetes in the present study is much smaller than the 3.5% also reported by Nelzén²⁹ (in 1993).
The ulcer and patient databases generated in the present study allow for handling of other relevant elements. For example, with venous ulcers, the average patient age (76.4 years) is slightly higher than the average patient age in other studies (72.1 in Ireland).¹⁶ The methodology of the present study does not allow for the determination of prevalence rate based on the age groups, although the extrapolation of data related to venous ulcers highlights that approximately 19.3% of venous ulcers affect people under age 65.
The distribution of venous ulcers by sex, two-thirds women and one-third men, coincides with the published studies to date.^18,19,30 It is important to underline that in contrast, the number of venous ulcers in men under age 65 almost doubles that of the women.
The average wound age, ie, the evolution time of the venous ulcers in the database, is high, which would directly coincide with limited use of effective compression systems.
Undoubtedly, more frequent use of compression systems would lead to higher compression figures, a considerable reduction in evolution times, greater effectiveness of the healthcare applied to this type of patient, and, therefore, lower cost of care and improved quality of life.^2,31–36 It is again worth mentioning that in men the evolution times are much longer than in women, even with a similar rate of compression use in both groups.
It is important to mention the high number of recurrent venous ulcers, which has been underlined in other studies,³⁷ as well as the significant statistical difference that exists between the evolution times of recurrent and non-recurrent wounds. Some authors, such as Moffatt,³⁸ directly relate the recurrence number with the use (or lack of use) of effective compression systems, in both treatment and prevention of wounds.
The arterial ulcer database shows a slight preponderance of men affected by these wounds compared to the number of women. The age of patients with an arterial ulcer is similar to the age of patients with other types of leg ulcers. Their evolution time is significantly shorter and does not exhibit much age- or sex-based difference. The average arterial ulcer evolutions are the shortest of all leg ulcer types studied.
Two factors stand out regarding diabetic foot ulcers—statistically significant differences regarding patient age (ulcers occur at a younger age in men) and wounds take longer to heal in women. The rate of men under age 65 with diabetic foot ulcers doubles the figure for women. The few number of references to diabetic foot ulcers in Spain might bias the definition of what constitutes a diabetic foot wound. As in many centers, this group of ulcers includes arterial wounds caused by the arteriopathy typically seen in patients with diabetes and diabetic wounds caused by neuropathy or plantar ulcers.

Conclusion

There are 2 possible limitations to the present study regarding leg ulcers: wound diagnosis is determined based on information supplied by healthcare professionals, and some scholars state that this may be regarded as an underestimation of the problem.³⁹ Others disagree, stating that a successful diagnosis allows for adjustment to prevalence-related data, such as Andersson²⁰ established when leg ulcer prevalence decreased from 2.15% to 1.05% when peripheral vascular assessment tests were performed. The authors’ data indicate that pressure and leg ulcers in Spain constitute a major health problem that is even more serious in older patients. Prevention of pressure ulcers is not yet considered to be a priority. In the case of venous ulcers, it is noteworthy that there is little use of effective compression therapy systems. A global approach to the pressure and leg ulcer problem in Spain is needed.