Risk Factors for Pressure Ulcers in Hospitalized Elderly without Significant Cognitive Impairment

Pressure ulcers (PU) are defined as skin breakdown and continuum of tissue damage of ischemic etiology secondary to high external pressure, which usually occurs over bony prominences.¹ Seventeen percent of hospitalized patients have or will end up having a PU. In the worldwide geriatric population, 71% of patients ≥ 70 years have PU.² According to Brazilian estimations, 14% of the population will be 60 years old or more by 2025.³ In Brazil, national policy considers elderly citizens to be 60 years old or older.⁴
Pressure ulcers are caused by intrinsic and extrinsic factors. The intrinsic factors include immobilization, cognitive deficit, chronic illness (eg, diabetes mellitus), poor nutrition, use of steroids, and aging.^5,6 There are 4 extrinsic factors that can cause these wounds—pressure, friction, humidity, and shear force. Pressure is a crucial factor in PU development. Pressure of 70 mmHg over a bony prominence for 2 hours or more is enough to cause an ischemic wound.¹ These factors might predispose a patient to PU development.
Several scales are used to analyze PU risk factors. One of these is the Braden Scale, which is based on PU physiology. The Braden Scale considers intensity and duration of pressure and tissue tolerance as critical determinants for PU development.⁷
Research shows that PU treatment is costly. A study conducted in the United States by the Agency for Healthcare Policy and Research found that PU treatment costs were more than $1.35 billion annually.⁸
The present study was formulated with the understanding of the prevalence of PUs in a growing geriatric population and its significant implication to the health care system. This study attempts to evaluate the risk factors for PUs in hospitalized elderly patients without significant cognitive impairment.

Methods

The present study was performed at a university hospital, Hospital das Clínicas Samuel Libânio (CHSL), in Pouso Alegre, Brazil.
The institution’s Ethics Committee approved the study protocol. It is a transverse, analytic, and controlled study.
Twenty elderly patients with a PU, age 60 years and older with no cognitive impairment were evaluated from July 2005 to February 2006. Twenty other hospitalized patients without PUs were assessed as a control group. All enrolled patients signed a consent form. Whenever patients had visual impairment or another disability that made writing difficult, their legal representatives signed the consent form. The patients were hospitalized for at least 24 hours and had 1 or more PU of various stages.
One researcher interviewed all patients. Clinical and demographic data were obtained. The MMSE⁹ was administered and a skin evaluation was performed. Pressure ulcers were documented and classified during the interview. Risk factors were assessed with the Braden Scale.⁷
The MMSE⁹ was used to exclude patients with significant cognitive impairment. The MMSE normal score was adjusted for the patients’ educational level as follows: no school = 13 points; 1 to 7 years of school ≥ 18 points; 8 or more years of school ≥ 26 points. The point total was 30.
Patients who did not reach the minimum score according to their level of education were excluded from the study.
Pressure ulcers were classified as Stage I–IV according to the National Pressure Ulcer Advisory Panel.¹⁰ Elderly patients with all stages of PUs were included in the study. Stage I is consistent with no blanched erythematic spot. Stage II is when partial skin thickness is lost involving the derma, and the epidermis is lost. Stage III is when all skin thickness is lost, compromising the adjacent muscular fascia. Stage IV is an extensive destruction of the skin with total loss of skin thickness, with important regional necrosis or with damage to tendons, articulations, and other structures.
The Braden Scale was used to assess PU risk factors. This scale is based on 6 subscales: sensorial perception, humidity, mobility, nutrition, friction, and shear force. Each subscale ranges from 1 to 4 points except for shear force and friction, which range from 1 to 3 points. Total scores vary from 6 to 23. The higher scores indicate low risk for developing PU.⁷ Patients with 18 points or less were considered at a higher risk for developing a PU.¹¹ This scale has been validated for use in Brazil.⁷
The chi-squared test¹² was used for data analysis in order to compare school grade and gender distribution between the study and the control groups. The Mann-Whitney test¹² was used on each of the subscales in order to compare the study and control groups according to the Braden Scale scores. A P value < 0.05 (or 5%) was considered significant.

Results

Twenty patients with a PU and the other 20 patients without a PU were analyzed, from July 2005 through February 2006.
Fourteen (70%) patients with a PU were women and 6 (30%) were men. The mean age was 71.5 (± 8.0) years. School grades varied from patients who never went to school (8, 40%), to patients with 1 to 4 years of school (12, 60%). The average score for the MMSE was 19.75 (± 3.2%).
In the control group, 10 (50%) patients were women and 10 (50%) were men. The average age was 70.3 (± 7.9) years. School grades also varied: 3 patients (15%) never went to school, 14 (70%) studied for 1 to 4 years, and the other 3 patients (15%) studied for more than 4 years. The average MMSE score was 22.8 (± 3.7).
The most frequent pre-existing diseases in the study group were hypertension, diabetes mellitus, dyslipidemia, and heart failure. The major causes of hospitalization in the study group were—hip fracture (5), heart failure (3), pneumonia (2), multiple traumas (2), pulmonary obstructive disease (2), hip arthroplasty (1), and other (5). Hypertension, diabetes mellitus, coronary disease, arrhythmias, and obstructive pulmonary disease were the major pre-existing diseases in the control group. The major causes of hospitalization in the control group were—pneumonia (3), cerebral vascular accident (3), hypertension (2), acute pyelonephritis (2), obstructive pulmonary disease (1), spinal cord compression (1), anemia (1), and other (5). The average number of medications was 4.8/patient/day in the study group versus 3.8 /patient/day in the control group.
The mean period of hospitalization for the study group was 23.2 (± 18.8) and 13 (± 10.4) days for the control group.
Twenty-six ulcers were observed among the 20 patients with a PU. Pressure ulcer classification and locations are shown in Table 1.
According to the Braden Scale, the average score was 15 (± 2.7) in the study group, and 20.15 (± 2.5) in the control group. Based on the Braden Scale, 18 (90%) patients scored 18 points after the addition of subscales. Three patients from the control group scored 18 points or less, thus, had a higher risk for developing a PU.
Table 2 shows the Braden Scale scores comparing the control group and the study group.

Discussion

Pressure ulcers are among the most common complications of older hospitalized patients. In general hospitals in Brazil a prevalence of 8% to 10% is observed.¹³ Patients with risk factors for developing PU must be identified in order to allow the adoption of specific preventive measures.^14,15 It is important to establish a preventive protocol that includes PU risk factor assessment, optimization of human and material resources, as well as reduction of the hospitalization costs.
Although there is no reference in the literature regarding a relationship between PUs and gender, the authors observed a greater occurrence of PUs in women.¹⁶ More cases of PUs were found among women than men, but gender is not thought to be a risk factor.¹⁶ In 2004, Blanes et al⁵ analyzed the relationship between age, gender, and PU risk factors. In a group of hospitalized patients with PUs, they found a mean age of 64 years—women were 67.9 years old and were slightly older than the men (60.4 years).
In the present study, the mean age among the elderly with a PU was 71.55 years. This is compatible with the literature, indicating a greater prevalence of chronic wounds in patients over 60 years old¹⁷ and that 71% of PU occurs in patients over age 70.2
A study conducted in a Finnish hospital found 164 patients with a PU—83% of the patients were age 65 or older.¹⁸
Older people are more susceptible to developing skin wounds because of age related skin changes.¹⁹ The dermal layer becomes thinner, epidermis vascularization, proliferation and thickness decreases. The skin’s properties, such as pain, sensibility, inflammatory answer, and barrier also decrease, making it more vulnerable to injury.¹⁹
Those who are more susceptible to PU development include older bed-ridden patients and those with cognitive impairment.²⁰ The major risk factor for developing geriatric syndromes among hospitalized patients (eg, a PU), is cognitive impairment.²¹ In the present study, the cognition aspect was not characterized as a risk factor—the older patients with no significant cognitive impairment according to the MMSE score and therefore the cognition aspect was not characterized as a risk factor.
Chronic illness, such as diabetes mellitus, immobilization, and age are intrinsic risk factors for PU.²² Hypertension, cerebral vascular accident, diabetes mellitus, heart failure, and obstructive pulmonary disease were the most frequently seen pre-existing diseases in both control and study groups. The daily use of medications is described as a contributing factor for PU occurrence.⁷ Anti-hypertensive agents can affect blood flow and decrease tissue perfusion, making tissues more susceptible to pressure.6–9
Pressure ulcers extend the hospitalization period by making patients recovery more difficult and increasing the risk for complications. It is estimated that 60,000 patients die each year due to PU-related complications, such as sepsis and osteomyelitis.²³ In a study by Blanes et al⁵ at a university hospital with 755 beds, all patients with PUs were hospitalized for an average of 33 days (hospital stays varied from 1 to 198 days). In the present study, the mean period of hospitalization was higher in the study group compared to the control group and had no statistical significance (P = 0.7868) but related to the presence of a pressure ulcer.
According to the literature, the Stage II PU is the most common and the predominant ulcer sites are the sacral, heel, and ischial regions.^5,18 In relation to ulcer stage, Stage I (26.9%) and Stage II (50%) were the most common in the present study.
According to Braden Scale results, the study group scored significantly lower than the control group. When the average scores and the median were compared (per the Braden Scale) they were significantly lower for the study group. A score of 18 used as the limit in this study allowed for the inclusion of 90% of the patients at risk for a PU, therefore making it possible to identify which factors can prevent the occurrence of new ulcers or exacerbation of pre-existing ulcers. Blanes et al⁵ found lower scores in all Braden Scale subscales.

Conclusion

General preventive measures for PUs begin with the identification of risk factors.²⁴ Most of these ulcers would not occur if health care professionals were more knowledgeable about the major characteristics of patients who develop PUs and PU risk evaluation scales, which would allow them to make an accurate prognosis and prevent possible PUs.
Health care professionals will then be able to develop more effective and preventive treatment plans for PUs if they become more knowledgeable about PU risk factors.
Data from the present study illustrate that older patients without significant cognitive impairment have increased risk factors for developing PUs. Major risk factors during the hospitalization period were humidity, activity, mobility, friction, and shear force.