Explaining the national differences in pressure ulcer prevalence between the Netherlands and Germany – adjusted for personal risk factors and institutional quality indicators

Background Pressure ulcers have a known impact on quality of life as well as on morbidity and mortality of the persons affected. Remarkable differences in pressure ulcer prevalence between the Netherlands and Germany have been found during the last 6 years. This study explores to what extent the individual risk of the population and quality indicators of the institutions can explain the variation in national prevalence. Methods Data of a binational multi‐centred cross‐sectional study in 103 hospitals (n = 21 378 patients) and 129 nursing homes (n = 15 579 residents) were analysed using random effects regression models to calculate the differences in national prevalences within the nursing homes and hospitals, adjusted for personal risk for pressure ulcer and quality indicators. Results The prevalence of pressure ulcers among the at‐risk group (Bradenscore ≤20) in nursing homes was 30.8% in the Netherlands and 8.3% in Germany [OR: 4.9 (CI 95%: 4.2–5.7)]. In hospitals, the prevalence among the at‐risk group was 26.1% in the Netherlands and 21.2% in Germany [OR: 1.3 (CI 95%: 1.2–1.5)]. After adjusting for individual risk factors (age, gender, Bradenscore) as well as for quality structures (use of prevention and treatment protocols, experts groups, information leaflets, nurses training, central pressure ulcer statistics and regular updating of protocols), the chance of developing a pressure ulcer was 6.05 times higher (CI 95%: 4.0–9.2) in a Dutch nursing home than in a German nursing home. Within the hospitals, the OR for Dutch patients was 2.03 (CI 95%: 1.4–3.0). Conclusion A remarkable national variation exists in pressure ulcer prevalence and nursing practice. Neither the populations vulnerability for pressure ulcers nor pressure ulcer management as measured in this study could explain this national variation. Therefore, other risk factors should be taken into consideration. Additionally, it is possible that quality indicators are implemented in differing ways with varying levels of effectiveness. Therefore, further research is needed to examine prospectively and in more detail the reality of care within facilities in both countries.     

Quality improvement program to reduce the prevalence of pressure ulcers in an intensive care unit

BACKGROUND: Critically ill patients are at increased risk for pressure ulcers, which increase patients' morbidity and mortality. Quality improvement projects decrease the frequency of pressure ulcers. OBJECTIVES: To improve patients' outcomes by reducing the prevalence of pressure ulcers, identifying areas for improvement in prevention of pressure ulcers, and increasing the adoption of preventive strategies in an intensive care unit. METHOD: Quasi-experimental methods were used for this quality improvement project in which 563 surveys of patients' skin were performed during 22 audits conducted during a 26-month period. One-on-one clinical instruction was provided to bedside nurses during the surveys, and pressure ulcer data were displayed in the clinical area. RESULTS: The frequency of pressure ulcers of all stages showed an overall downward trend, and the prevalence decreased from 50% to 8%. The appropriate allocation of pressure-relieving devices increased from 75% up to 95% to 100%. The likely origin of the ulcer (ie, whether it was hospital or community acquired) and the anatomical site of the pressure ulcers did not change during the study period. CONCLUSIONS: This program was successful in reducing the prevalence of pressure ulcers among vulnerable intensive care patients and indicates that quality improvement is a highly effective formula for improving patients' outcomes that is easily implemented by using clinical expertise and existing resources.     

Variation in pressure ulcer prevalence and prevention in nursing homes: A multicenter study

AimTo estimate the prevalence of pressure ulcers in nursing homes and its variability, the frequency of use of preventive measures and treatment.BackgroundPressure ulcer is a frequent pathology across healthcare settings. Most pressure ulcers are preventable and are considered an important quality of care indicator.MethodsAssessments were done on a single day of November 2015 in nursing homes in Geneva, Switzerland. Of the 51 institutions (3824 patients) eligible, 33 homes agreed to participate, representing 2671 patients (69.8%).One referent nurse per nursing home received training on pressure ulcer detection. To estimate the residual variability in prevalence and in number of prevention measures, adjusted multilevel logistic regressions were used.ResultsPatients were on average 85.6 years old, with a median length of stay of 2.1 years. The overall prevalence was 5.7% but varied considerably, from 0% to 19.6%.The variability across nursing homes decreased slightly when taking into account patient-level and institution-level characteristics.In the adjusted models, pressure ulcers prevalence was significantly associated with Braden risk; number of preventive measures was significantly associated with nursing home size, and Braden risk, and marginally associated with length of stay.ConclusionsOverall prevalence of pressure ulcers was relatively low. While several prevention measures for patients at risk were taken, the correct use of all of them was rare.The variability in prevalence and in number of preventive measures across nursing homes was very high. Programmes focusing on the correct use of all recommended prevention measures could help reducing pressure ulcers prevalence.     

Pressure ulcer prevention in nursing homes: views and beliefs of enrolled nurses and other health care workers

Background. In the Netherlands much attention has been paid to pressure ulcer prevention. National guidelines on pressure ulcer prevention were developed in 1985 and adapted in 1992 at the request of a national organization for quality assurance in health care. Several studies indicate that nurses seem to be insufficiently informed about pressure ulcer preventive activities. There is, however, no information available about the reasons why nurses seem to be insufficiently informed. Aims and objectives. This study was planned to elucidate the views and beliefs of health care workers (especially enrolled nurses) in Dutch nursing homes about pressure ulcer prevention and about issues related with pressure ulcer prevention. Design. A qualitative study with semi‐structured, tape‐recorded interviews. Method. Interviews were conducted with enrolled nurses, team leaders, head nurses, staff nurses and physicians. The interviews were coded and analysed. Results. Analysis of the interviews revealed that today's pressure ulcer preventive activities are very much based on old traditions in nursing. It also showed that enrolled nurses have no intention to change the care they deliver with regard to pressure ulcer prevention. Conclusions. It is concluded that a systematic approach is necessary to change nursing thinking and acting with regard to pressure ulcer prevention. Relevance to clinical practice. This study gives an overview of the views and beliefs of health care workers (especially enrolled nurses) in Dutch nursing homes about pressure ulcer prevention. These views and beliefs can be used as a starting point for effective implementation of guidelines regarding the prevention of pressure ulcers.     

Effect of non-response bias in pressure ulcer prevalence studies

AIM: This paper reports a study to determine the prevalence of pressure ulcers in German hospitals and nursing homes for national and international comparison, and analyses the influence of non-response bias. BACKGROUND: Outcome rates are often used to evaluate provider performance. The prevalence of pressure ulcers is seen as a possible parameter of outcome healthcare quality. However, the results from different pressure ulcer prevalence studies cannot be compared, because there is no standardized methodology and terminology. Observed and published prevalence rates may reflect variations in quality of care, but differences could also relate to differences in case-mix or to random variation. METHODS: A point prevalence survey was carried out for 2002 and 2003 using data from 21,574 patients and residents in 147 different kinds of institutions throughout Germany. Participation rates and reasons for not participating in the study were documented. Non-responders were considered in different calculations to show the range of possible prevalence rate for a hypothetic 100% participation. RESULTS: In 2002 and 2003, the calculated prevalence rate (among participating persons at risk) in hospitals was 25.1% and 24.2% respectively, while in nursing homes it was 17.3% and 12.5% respectively. Non-response varied from 15.1% to 25.1%. The majority of non-responders in hospitals and nursing homes had not been willing to participate in the study. Based on different assumptions about the characteristics of the non-responders, we calculated minimum and maximum prevalence rates as if 100% participation was achieved. CONCLUSIONS: Calculating the non-response bias of prevalence rates is an inconvenient but necessary thing to do because its influence on calculated prevalence rates was high in this study. High participation rates in clinical studies will minimize non-response bias. If non-response cannot be avoided, the formula provided will help researchers calculate possible minimum and maximum prevalence rates for the total sample of both the responding and non-responding groups.     

Hospital pressure ulcer prevalence rates and number of raters

Aim. The purpose of this study was to evaluate the influence of different numbers of nurse raters conducting skin inspection (one or two) on observed pressure ulcer prevalence rates. Background. Pressure ulcer prevalence and incidence rates are important outcome measures for the quality of care. To ensure reliability and comparability of such rates standardisation of study methods is recommended. It is assumed that data accuracy can be improved if skin inspection is conducted by a team of two raters. Design. A secondary data analysis of pressure ulcer prevalence data was conducted. Method. Groups of hospital patients which were examined by one (n = 2420) or two raters (n = 15,009) were compared regarding demographic characteristics, pressure ulcer risk and pressure ulcer prevalence. Logistic regressions were conducted to examine the association between the number of raters (one or two) and the outcome pressure ulcer (yes/no). Results. Groups of one and two raters were comparable regarding demographic characteristics. There was no statistically significant difference regarding pressure ulcer prevalence between both groups (p = 0·222). There was no relation between the number of raters and the probability of identifying a pressure ulcer patient (p = 0·060). Conclusions. Pressure ulcer prevalence rates in the analysed studies were not affected by the number of raters. There seems to be no relation between the numbers of nurses conducting skin inspection and observed prevalence rates. Relevance to clinical practice. Conducting pressure ulcer prevalence studies require a lot of effort and personal costs. Provided that one nurse alone or a team of two nurses rate the existence of pressure ulcers equally it is no longer obligatory to have two raters. This would save resources. However, when patients are restricted in their mobility two nurses are recommended to provide assistance in patient turning.     

Differences in prevalence of pressure ulcers between the Netherlands and Germany--associations between risk, prevention and occurrence of pressure ulcers in hospitals and nursing homes

Aim. This study compares pressure ulcer prevalence and prevention activities in nursing homes and hospitals within two European countries. Background. Over three years stable differences have been found between the Netherlands (NL) and Germany (GER) with higher pressure ulcer rates in the NL. As previous analyses have shown, the differences cannot be entirely explained by differences in the population’s vulnerability to pressure ulcers because they still remain after risk adjustment. Therefore, the differences in prevalence must be caused by other factors. The purpose of this study is to analyse if any potential differences in preventive activities can account for the varying occurrence of pressure ulcers. Method. In both countries, nation-wide surveys were conducted annually using the same standardised questionnaires. Trained nurses examined all consenting patients of the voluntarily participating facilities. This examination included a skin assessment of the entire body. Data regarding risk factors, prevention and details about wounds were then collected. Results. In-patients of 29 German (n = 2531) and 71 Dutch (n = 10 098) nursing homes and 39 German (n = 8515) and 60 Dutch (n = 10 237) hospitals were investigated. The use of pressure-reducing devices was more common in the NL than in GER, but all other interventions were more frequently provided to German risk patients than to their Dutch counterparts. The pressure ulcer prevalence was significantly higher in the Dutch sample. After adjusting for gender, age, Braden Score and prevention, the probability of having a pressure ulcer was 8·1 times higher for Dutch nursing home residents than for German residents. Conclusion. Some of the variance in pressure ulcer prevalence between the two countries can be explained by varying pressure ulcer prevention. However, some remarkable differences still remain unexplained. Relevance to clinical practice. The extent of pressure ulcer prevention, especially repositioning and nutrition intervention provided to patients at risk, is not in accordance with international guidelines.     

Organizational correlates of the risk-adjusted pressure ulcer prevalence and subsequent survey deficiency citation in California nursing homes

Organizational correlates of the risk-adjusted pressure ulcer prevalence and subsequent deficiency citation in nursing homes are not known. The purpose of this study was to examine the relationships between these two outcomes and selected organizational variables, including total nurse staffing levels, specialization, centralization, nursing wages, and facility ownership. Secondary data analysis was conducted on a sample of 897 California nursing homes included in the 1996 On-line Survey Certification and Reporting system and the Office of Statewide Health Planning and Development financial disclosure reports of individual California nursing homes. Organizational variables explained a small amount of the variation (adjusted R2 = .04, p < .01). A higher PU prevalence was associated with lower licensed nurse centralization and facilities participating exclusively in the Medicaid program. Receipt of a deficiency was less likely in facilities having a higher total nurse staffing level (OR = .49, p < .001). It was more likely in facilities having a higher risk-adjusted PU prevalence (OR = 1.05, p < .001), more licensed nurses (OR = 2.74, p < .05), a size of 160 beds or more (OR = 1.93, p < .01), and survey teams from specific counties (OR ranging from 2.3 to 6.8, p < .05).     

Pressure ulcer: Prevention protocols and prevalence

Aims and objectives The aim of this paper is to analyse the protocols used in German hospitals and nursing homes for the prevention of pressure ulcers with regard to their contents and accordance with the national standard of the Deutsches Netzwerk für Qualitätsentwicklung in der Pflege (DNQP) and the European Pressure Ulcer Advisory Panel (EPUAP) and Royal College of Nursing (RCN) guidelines. Additionally, it is to show the relation between the existence and contents of the protocols of pressure ulcer prevention and pressure ulcer prevalence in the institutions. Methods On a fixed date trained nursing staff gathers data regarding the frequency of pressure ulcers during a prevalence survey. The existence of a pressure ulcer is established by physical examination after the risk assessment with the Braden‐Scale. The patient’s or resident’s informed consent is a precondition for his or her participation in the survey. The protocols are available as hard copies on paper or electronic files. Results Only two out of the 21 protocols developed in‐house are completely concurrent with the expert standard. The EPUAP and RCN guidelines include the aspect of training and further education that is missing in the in‐house protocols and the DNQP expert standard. Evaluation of the data reveals that there is no relation between the availability of protocols and pressure ulcer prevalence. Neither is there any relation between the contents and pressure ulcer prevalence. The institutions currently developing protocols have the lowest prevalence rates. Conclusion It is obvious that, while developing in‐house protocols, the discussion about pressure ulcer prevention has led to a higher problem awareness in nurses and thus to an increased attentiveness in daily nursing practice which then results in improved outcomes. Two years after its publication, the expert standard is still not very well known, therefore this concentrated form of the most up‐to‐date knowledge is not available to all nursing staff as a basis for evidence‐based practice. In addition, the sometimes outdated knowledge of nursing staff impedes the implementation of evidence‐based practice guidelines. A systematic implementation strategy that assists guidelines being applied in practice is therefore required.     

RN staffing time and outcomes of long-stay nursing home residents: pressure ulcers and other adverse outcomes are less likely as RNs spend more time on direct patient care

OBJECTIVE: A clear link has been demonstrated between lower nurse staffing levels in hospitals and adverse patient outcomes, but the results of studies of such relationships in long-term care facilities haven't been as clear. This study explored the time nurses spent in direct care and how it affected outcomes in long-stay (two weeks or longer) nursing home residents. METHODS: In a retrospective study of data collected as part of the National Pressure Ulcer Long-Term Study (NPULS), we analyzed data on 1,376 residents of 82 long-term care facilities whose lengths of stay were 14 days or longer, who were at risk of developing pressure ulcers but had none at study entry, and who had a Braden Scale score of 17 or less. Primary data came from residents' medical records during 12-week periods in 1996 and 1997. Dependent variables included development of pressure ulcer or urinary tract infection (UTI), weight loss, deterioration in the ability to perform activities of daily living (ADLs), and hospitalization. Independent variables included resident demographics, severity of illness, nutritional and incontinence interventions, medications, and nurse staffing time. RESULTS: More RN direct care time per resident per day (examined in 10-minute increments up to 30 to 40 minutes per resident per day) was associated with fewer pressure ulcers, hospitalizations, and UTIs; less weight loss, catheterization, and deterioration in the ability to perform ADLs; and greater use of oral standard medical nutritional supplements. More certified nursing assistant and licensed practical nurse time was associated with fewer pressure ulcers but did not improve other outcomes. CONCLUSIONS: The researchers controlled for important variables in long-stay nursing home residents at risk for pressure ulcers and found that more RN direct care time per resident per day was strongly associated with better outcomes. There's an urgent need for further research to confirm these findings and, if confirmed, for improving RN staffing in nursing homes to decrease avoidable adverse outcomes and suffering.     

Does the number of raters influence the pressure ulcer prevalence rate?

We analyzed data from pressure ulcer prevalence studies conducted in nursing homes between 2004 and 2006 concerning differences in the observed pressure ulcer prevalence rates while looking into the number of nurses conducting skin inspections (one or two). Results of the analysis revealed that the number of raters did not influence the observed pressure ulcer prevalence rate. Adequate preparation and training of ward nurses for data collection seem to be sufficient to achieve reliable data.     

Pressure ulcer prevention: education for nursing home staff

This article describes an education programme for a group of nurses working in several nursing homes located in different areas of the Midlands but each belonging to the same care group. The group's management team had identified that there were patients in the nursing homes who had severe pressure ulcers and that staff were not managing their care adequately in order for healing to occur. It has been identified that 'education is probably the single most effective way of reducing the incidence of pressure ulcers' (Department of Health (DoH), 1993). Although the various nursing homes were able to access the skills of clinical nurse specialists in tissue viability, severe pressure ulcers were failing to heal and nursing home staff requested additional education to help them address this problem. Nurses in the homes expressed a desire to gain a deeper knowledge of the problem, so they would be able to plan and implement appropriate care autonomously and thus raise the standard of pressure ulcer care provided in each home. This article discusses the implementation of a comprehensive education programme that contributed to raising the standards of patient care and to the professional self-worth of the nurses involved.     

Pressure ulcer prevalence in Europe: a pilot study

RATIONALE AND AIMS: Numerous prevalence studies have been conducted. The problem with these studies is that prevalence proportions cannot be compared with each other, because of differences in performance of each survey. There is no agreed standardized method for determining prevalence proportions. This study aimed to develop and pilot a uniform data collection instrument and methodology to measure the pressure ulcer prevalence and to get some insight into pressure ulcer prevalence across different patient groups in Europe. METHODS: Pressure ulcer experts from different European countries developed a data collection instrument, which included five categories of data: general data, patient data, risk assessment, skin observation and prevention. A convenience sample of university and general hospitals of Belgium, Italy, Portugal, UK and Sweden participated in the study. In each participating hospital, teams of two trained nurses who collected the data on the wards were established. All patients admitted before midnight on the day of the survey and older than 18 years were included. RESULTS: The data collection instrument and study procedure of the survey were found to be effective by all participants. 5947 patients were surveyed in 25 hospitals in five European countries. The pressure ulcer prevalence (grade 1-4) was 18.1% and if grade 1 ulcers were excluded, it was 10.5%. The sacrum and heels were the most affected locations. Only 9.7% of the patients in need of prevention received fully adequate preventive care. CONCLUSION: The methodology is sufficiently robust to measure and compare pressure ulcer prevalence in different countries. The pressure ulcer prevalence was higher than expected and relatively few patients received adequate prevention. This indicates that more attention to prevention is needed in Europe.     

Pressure ulcer prevalence and incidence in intensive care patients: a literature review

Background: Pressure ulcers remain a common health problem worldwide within the different health‐care settings, especially in intensive care settings. Aims: The aims of this were to systematically assess the recent prevalence and incidence of pressure ulcers in intensive care patients (2000–2005), the factors related to pressure ulcer prevalence and incidence and the methodological rigour of studies about pressure ulcer prevalence and incidence in intensive care patients. Methods: The research design involved a review of literature for the period of 2000 to 2005, focused on the prevalence and incidence of pressure ulcers in intensive care patients. Results: The analysis of published papers revealed variations in pressure ulcer prevalence in intensive care settings ranging from 4% in Denmark to 49% in Germany, while incidence ranged from 38% to 124%. There was a wide variation in the prevalence and incidence of pressure ulcers in intensive care patients as evidenced in the studies examined. There is also a gap between theory and practice in the prevention and treatment of pressure ulcers which needs to be addressed. Conclusion: Further research is needed regarding the effectiveness of nursing care on pressure ulcer development and into treatments that may successfully prevent their occurrence in intensive care patients.     

Exploring use of a clinical data repository containing international classification for nursing practice-based nursing practice data

To determine the usefulness of a clinical data repository for nursing, we conducted two studies (1) investigating the gaps between required nursing care time based on patient classification and actual nursing care time based on nurse staffing level and (2) exploring the practice variations of nurses by comparing nursing interventions documented to prevent and treat pressure ulcers. We reviewed the nursing records of 124,416 patients discharged from 2005 to 2007 to identify the gaps in nursing care time. We also reviewed records of 41,891 patients discharged in 2007 to identify those who had pressure ulcers or were at risk of pressure ulcers and analyzed the nursing interventions documented to prevent and treat pressure ulcers. The pediatric and geriatric units showed relatively high staffing needs and the trends of understaffing over time. For pressure ulcer care, nursing interventions vary by nursing unit. Position change was the most common nursing intervention documented except in the maternity unit, followed by ulcer wound care, use of devices, and nutritional assessment. This study showed that data in a clinical data repository can provide nurse managers and nurses with valuable information about nurse staffing and patient care.     

Comparison of two skin examination methods for grade 1 pressure ulcers

Aims and objectives. The purpose of this study was to find out whether the application of a transparent device for diagnosing grade 1 pressure ulcers influences grade 1 pressure ulcer prevalence rates and the total number of observed grade 1 pressure ulcers. Background. It is assumed that the accuracy of visual grade 1 pressure ulcer diagnosis is enhanced if a transparent device is used. Design. Quasi‐experimental. Method. Within a pressure ulcer prevalence study participating institutions were divided into groups at random. Data collecting nurses of the intervention group (n = 4667) applied a transparent disc. Data collecting nurses of the control group (n = 5095) conducted skin inspection using the ‘finger‐method’. Group comparisons were conducted. Relations between skin assessment methods and grade 1 pressure ulcer prevalence was analysed by logistic regressions. Results. Both groups were comparable regarding demographic characteristics. Grade 1 pressure ulcer prevalence in the intervention group was 3·9% and 7·1% in the control group (p<0·001). The total number of observed grade 1 pressure ulcers was 282 (intervention group) and 555 (control group). The chance to identify at least one grade 1 pressure ulcer increased when the ‘finger method’ was used (p<0·001). Conclusions. The use of a transparent disc influences the grade 1 pressure ulcer prevalence rates and the total number of observed grade 1 pressure ulcers. Relevance to clinical practice. Accurate identification of grade 1 pressure ulcers is important, because the development of those skin alterations indicate an urgent need for preventive measures. As the diagnosis of grade 1 pressure ulcers seems to be affected by the observation method, it is unknown which method is the more accurate. A study of diagnostic accuracy is needed to answer this question. It is recommended to report pressure ulcer prevalence rates including and excluding grade 1.     

The first national pressure ulcer prevalence survey in county council and municipality settings in Sweden

Aim To report data from the first national pressure ulcer prevalence survey in Sweden on prevalence, pressure ulcer categories, locations and preventive interventions for persons at risk for developing pressure ulcers. Methods A cross‐sectional research design was used in a total sample of 35 058 persons in hospitals and nursing homes. The methodology used was that recommended by the European Pressure Ulcer Advisory Panel. Results The prevalence of pressure ulcers was 16.6% in hospitals and 14.5% in nursing homes. Many persons at risk for developing pressure ulcers did not receive a pressure‐reducing mattress (23.3–27.9%) or planned repositioning in bed (50.2–57.5%). Conclusions Despite great effort on the national level to encourage the prevention of pressure ulcers, the prevalence is high. Public reporting and benchmarking are now available, evidence‐based guidelines have been disseminated and national goals have been set. Strategies for implementing practices outlined in the guidelines, meeting goals and changing attitudes must be further developed.     

A comparison of pressure ulcer prevalence rates in nursing homes in the Netherlands and Germany, adjusted for population characteristics

Annual pressure ulcer surveys in the Netherlands and Germany have shown remarkable differences in prevalence rates. We explored the differences between the two populations, and the degree to which these differences were associated with differences in prevalence. To this end, data from 48 Dutch and 45 German facilities (n = 9772) from 2003 were analyzed. The prevalence of pressure ulcers (excluding grade 1) was 12.5% in the Netherlands and 4.3% in Germany. After adjusting for age, sex, and other risk factors, the probability of developing a pressure ulcer of stage 2 or higher in Dutch nursing homes was three times greater than in German homes.     

Effects of education and experience on nurses' value of ulcer prevention

Few studies have focused on the value that nurses place on pressure ulcer prevention, even though values are a key determinant of a person's behaviour and actions. Previous studies have reported that the value that a nurse places on pressure ulcer prevention is linked to the skin care that they deliver. This article describes a study that was undertaken to determine the value that nurses place on pressure ulcer prevention, which also identified how this value is formed. The participants in this study (n=16), were recruited from non-acute adult medical wards of 14 hospitals in one NHS trust, and a university. Data was gathered via semi-structured interviews and interpreted through Straussian grounded theory. The findings of this study show how the participants underwent a transition from placing a low to a high value on pressure ulcer prevention and how this affected patient care. The key point in this transition appears to be an encounter with a patient with a high grade pressure ulcer, which caused the nurses to reappraise their values. Looking after patients with pressure ulcers seems to increase the value that a nurse places on pressure ulcer prevention. The education that nurses receive on pressure ulcer prevention only appears to alter their values when they have some experience of looking after patients with pressure ulcers.