Prevalence and Incidence Studies of Pressure Ulcers in Two Long-Term Care Facilities in Canada
Prevalence is a cross-sectional count of the number of cases of a medical condition at a specific point in time. Incidence is the number of new cases occurring over a given time period. A prevalence and incidence study is a combination of two studies that, when done consecutively, provides a facility with key statistics on patients with an existing medical condition and on those who acquire that condition during their stay.
Wide variation exists in the prevalence and incidence rates of pressure ulcers reported in the medical and nursing literature. The reasons for the variation in the rates are multiple; they include differences in the population of patients studied, differences in data collection and study methodology, and differences in the quality of care provided. Data collected from patients in tertiary care hospitals may not be comparable with data from residents in long-term care facilities (LTCFs).
The prevalence of pressure ulcers in the hospital setting ranges from 3.5% to 29.5%.1-5 The fourth National Pressure Ulcer Prevalence Survey recorded an overall prevalence of 10.1% (range 1.4% to 30.4%) in acute care hospitals. The authors noted that the prevalence had remained relatively constant throughout the four surveys that had been completed.5 However, other studies on hospital subpopulations have shown much higher prevalence rates for pressure ulcers that were as high as 60% in quadriplegic patients.6 Among people in long-term care settings, the prevalence of pressure ulcers ranges from 2.4% to 28%.7-12
The incidence of pressure ulcers in the hospital setting ranges from 2.7% to 29.5%.13-15 Higher incidence rates have been found in hospital subpopulations, such as elderly patients with femoral fractures where a 66% incidence was present.16 The incidence of pressure ulcers in the long-term care setting ranges from 4% to 24%.8,12,17-19 In a summary of data from studies of pressure ulcers in nursing homes, the incidence of pressure ulcers over a 4-week follow-up ranged from 10.8% to 13.3% for Stage II and greater ulcers, and rose to 28% when Stage I ulcers were included.11
Pressure ulcers predominate in the long-term care setting.20 Residents of LTCFs have high risk factors for developing pressure ulcers, such as decreased mobility, advanced age, decreased activity, malnutrition, and chronic medical conditions. The prevalence and incidence of pressure ulcers in LTCFs vary from one facility to another because of differences in staffing and case mix. A survey of pressure ulcers in Finland concluded that a lower educational level of healthcare personnel and a decrease in staff members were associated with an increased occurrence of pressure ulcers.20 Likewise, in a study on the occurrence of pressure ulcers in three nursing homes, the authors hypothesized that the interfacility differences in prevalence and incidence were probably due to differences in staffing patterns.12
Scant information is available in the medical literature regarding the prevalence and incidence of pressure ulcers in residents of LTCFs in Canada. One Canadian study found the overall prevalence of pressure ulcer in eight separate institutions to be 25.7%.21 This study included two LTCFs, but the prevalence of pressure ulcers in these individual facilities was not given. The present study was initiated to determine the prevalence and incidence of pressure ulcer specifically for residents of LTCFs in Canada.
Two LTCFs, separated by a distance of approximately 32 kilometers, were chosen for the study. The facilities are managed under the same regional authority, but each facility has its own staffing. Residents in these two facilities (95 residents in one facility, 92 residents in the other) were enrolled in the prevalence and incidence study for pressure ulcers. All residents of both facilities consented to take part in the study. No exclusion criteria were considered.
Data were collected using the Kinexus System developed by Kinetic Concepts Therapeutic Services (San Antonio, Tex.). Demographic data included age, gender, height, weight, skin color, support surface, location from which the patient was admitted, and the specific care unit. Medical information included the primary diagnosis, contributing factors for the development of pressure ulcers, and notation of skin breakdown on the nursing admission assessment. Consent for the study was obtained from the regional ethics board and from each resident in both facilities (or from family members where the resident was incapable of giving informed consent).
The attending physicians were notified. Staff of KCI Medical Canada were invited to participate in the study. The KCI staff had previous experience in assessing and treating pressure ulcers. Facility nurses also took part in the study; they were educated about the study to ensure consistency in data collection, skin inspection, and pressure ulcer staging. The study group was subdivided into three teams in each facility in order to complete each component of the study in a single day. Each team was comprised of one facility nurse, one healthcare aide, and one KCI member. The KCI staff participated in the study at both facilities. Each facility had its own nurses.
Demographic data, medical information, and possible contributing factors for pressure ulcers were collected by the team nurses at each facility for all residents. The prevalence study of pressure ulcers was conducted at both facilities in a single day. Each resident was assessed for the presence or absence of pressure ulcers, and the number of ulcers and their anatomical locations were recorded. Pressure ulcers were staged in accordance with National Pressure Ulcer Advisory Panel (NPUAP) criteria.22-24 The assessments were carried out jointly by facility nurses and KCI staff in their respective teams.
The incidence of pressure ulcers was determined in the remaining residents in each facility who did not have an ulcer at the time of the prevalence study. The incidence study was conducted after a period of 41 days in one LTCF and 42 days in the second facility. This time interval was selected as an appropriate time for the development of a pressure ulcer to occur while minimizing the possibility of drop-out due to transfer to other facilities, discharge home, or death. The residents who participated in the incidence study were assessed by the same teams who took part in the prevalence study. The presence or absence of pressure ulcers was documented for each resident. Detected ulcers were staged and their anatomical locations were recorded. None of the residents who were enrolled in the incidence study dropped out. The study teams carried out no other assessments during the incidence study period.
In the prevalence study, pressure ulcers were detected in 35 of the 95 residents in LTCF-1 and in 49 of the 92 residents in LTCF-2. Therefore, the prevalence of pressure ulcer was 36.8% in LTCF-1 and 53.2% in LTCF-2.
In the incidence study, pressure ulcers were detected in seven of 60 residents in LTCF-1 and in five of 43 residents in LTCF-2. Therefore, the incidence of pressure ulcer was 11.7% and 11.6%, respectively, in the two facilities.
Pressure ulcer staging in the prevalence study showed a predominance of Stage I and Stage II pressure ulcers (see Table I). Of the total number of ulcers in each facility, Stage I pressure ulcers accounted for 56.7% in LTCF-1 and 71.8% in LTCF-2; Stage II pressure ulcers were present in 31.3% and 24.5%, respectively. The remainder of the ulcers were Stage III (4.5% and 1.8%, respectively) except for some ulcers that were necrotic and could not be staged (7.5% and 1.8%, respectively). Several residents had two or more pressure ulcers.
Staging of the pressure ulcers in the incidence study showed a predominance of Stage I ulcers that accounted for 88.2% and 66.7% of the total number of ulcers in LTCF-1 and LTCF-2, respectively. The remainder of the ulcers were Stage II (see Table 2). Several residents had more than one pressure ulcer.
The anatomical locations of the pressure ulcers showed a widespread distribution in both the prevalence and incidence studies in the two LTCFs (see Tables 3 and 4). The ulcers were located at 22 sites in the prevalence study. The site most commonly involved with the pressure ulcers was the sacrum/coccyx area.
Collected data on the residents in the two facilities who were found to have pressure ulcers at the prevalence study were examined. Differences were noted in the primary medical diagnosis (see Table 5), contributing factors (see Table 6), and demographic data (see Table 7), which may help explain the difference in prevalence in the two facilities.
Pressure ulcer incidence is considered the marker of quality care within a facility, and is usually more accurate and sensitive data when compared to prevalence alone.25 A pressure ulcer incidence of less than 12% in each of the two LTCFs in this study compares favorably with other published data and suggests an equal and acceptable level of nursing care in both facilities.
The pressure ulcer prevalence rates of 36.8% and 53.2%, respectively, in the two LTCFs in this study are higher than in other published studies. Similar prevalence rates are more likely to be found in rehabilitation centers and facilities providing extended care. A breakdown of the Canadian pressure ulcer study, conducted in 1990, showed a prevalence of 30% for patients in a long-term care setting, which increased to 48% for extended care patients who were in an acute care setting.21
The present study included Stage I pressure ulcers, which may partly account for the higher prevalence. In 1989, the NPUAP revised its definition of pressure ulcers to include nonblanchable erythema of the intact skin (Stage I), and many studies before that year may not be comparable with later studies. The NPUAP further redefined its definition of Stage I pressure ulcers in 1998 to include changes that may occur in individuals with darkly pigmented skin.24 In the study under consideration here, a predominance of Stage I pressure ulcers was present in both LTCFs (see Table 1).
The disparity in the pressure ulcer prevalence rates between the two facilities in this study (38.8% versus 53.2%) is surprising in view of the similar incidence rates and the inference of equal and competent nursing care. It is unlikely that the difference in prevalence is due to inconsistent data collection or skin assessments because the same KCI staff participated in the study at both locations. A more plausible explanation for the difference in prevalence is the difference in case mix in the two facilities. When the primary medical diagnoses of the residents with pressure ulcers are examined, a greater variety of medical disorders in the facility with the higher prevalence rate is noted. Both facilities had a high proportion of residents with Alzheimer's disease (which was categorized under "other musculo/neuro"). However, the facility with the higher prevalence had a greater proportion of residents with specific medical disorders such as cerebrovascular accident, neuromuscular disease, congestive heart failure, diabetes mellitus, hypertension, and spinal cord injury (see Table 5). Moreover, comparison of the data on contributing factors for pressure ulcer shows that the facility with the higher prevalence had increased rates for known risk factors for pressure ulcer such as sensory loss (78% versus 11%), bedbound/bedrest (31% versus 11%), immobility (16% versus 6%), and peripheral vascular disease/poor circulation (37% versus 3%) (see Table 6). Further examination of the demographic data shows a higher rate of skin breakdown noted on the nursing admission assessment in the higher prevalence facility (12% versus 6%) (See Table 7).
Length of stay in a facility has been identified as a risk factor for pressure ulcer.21 In the present study, the length of stay possibly was longer in the higher prevalence facility because the other facility had been open for only 1 year when the study was conducted. However, the length of stay of residents was not recorded in the demographic data.
Although the results of these studies showed a pressure ulcer prevalence higher than published figures for the long-term care setting, the pressure ulcer incidence of less than 12% in each facility suggests an equal and acceptable level of nursing care in both facilities. The higher than expected prevalence rate may possibly be due to the use of the new guidelines for pressure ulcer staging. The disparity in the prevalence between the two LTCFs may be attributed to a difference in case mix. The findings of this study will be shared with the two participating facilities. Quality improvement activities may be initiated as a result of this study. A repeat prevalence and incidence study in the future will help determine the effectiveness of any new strategies of care that are implemented.
The authors wish to thank the facility staff who participated in the study and the staff of KCI Canada, Inc. for their assistance.
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