Braden Subscales and Their Relationship to the Prevalence of Pressure Ulcers in Hospitalized Obese Patients

Abstract

Pressure ulcer development is a significant problem for any hospitalized patient, but the obese patient may be at higher risk for ulcer development. The purpose of this study was to examine the relationship of the individual Braden subscales to pressure-ulcer occurrence in the obese and non-obese hospitalized patient. Pressure-ulcer prevalence was slightly higher in the obese (17%) compared to the non-obese (14%). However, mean total Braden and Braden subscale scores were similar between the obese and non-obese. Although high-risk total Braden and Braden subscales, except for moisture, were significantly related to the occurrence of ulcer occurrence in both groups, high-risk total Braden score and mobility and friction/shear subscale scores were much more strongly related to ulcer occurrence in obese patients. Additionally, the prevalence of ulcers in obese patients with both high-risk mobility and friction/shear scores (79%) was much higher than in non-obese patients with both high-risk mobility and friction/shear scores (50%).

Introduction

Prevention of pressure ulcers (PU) in hospitalized patients is a major nursing problem. Literature dating back 60 years documents nursing's efforts to prevent breakdown and devise prevention strategies.¹ Currently, the estimated rate of hospital-acquired PU ranges from 7% to 9%.²

Preventing PU in obese patients is particularly challenging, as these patients may have difficulty regulating body heat and have increased risk for incontinence resulting in excess moisture.^3,4 Obese patients may have atypical pressure related to breakdown in skin folds due to poor blood supply in adipose tissue⁵ or from folds, tubes, and catheters. In addition, nurses and patients may have difficulty visualizing and inspecting high-risk areas leading to inadequate detection.⁶

There are few studies that have examined the rate of PU in obese patients. One study found that hospitalized morbidly obese patients (BMI ≥40) had twice the rate of PU occurrence (26%) than leaner patients⁷ but other studies suggest that obesity may have a protective value in PU development.^8,9

Turning and repositioning every 2 h has been the “gold standard” to prevent PUs, but this is particularly difficult in the case of the obese patient. The large body mass, as well as the patient's condition, may make it more difficult for the patient to move him/herself independently. The nurse generally requires assistive equipment to ambulate or transfer the patient from bed to chair or stretcher.¹⁰ In addition, carrying out routine nursing procedures such as moving the patient up in bed or ambulation requires more time and more staff members than the same activity carried out for the lean patient.¹¹ The latter may contribute to a lack of appropriate mobilization in the obese patient.

The most commonly used instrument to evaluate PU risk is the Braden Scale. This scale includes six subscales measuring the two primary etiologic factors in ulcer formation: intensity and duration of pressure and tissue tolerance for pressure. The first three subscales (sensory perception, activity, and mobility) assess clinical situations predisposing the patient to intense and prolonged pressure. The remaining subscales (nutrition, moisture, and friction/shear) assess factors adversely affecting tissue tolerance for pressure. The subscales are rated on a four-step scale from 1 = “least favorable (highest risk)” to 4 = “most favorable (least risk),” except for the friction/shear subscale, which is rated on a three-step scale. Scores range from 6 to 23, with lower scores indicating a greater risk for PU development. The instrument is administered by nurses trained in its use, and they assign the scores based on direct observation of the patient. The study reported here expands on the previous work⁷ by examining the relationship of Braden subscales to PU occurrence in obese and non-obese hospitalized patients.

Materials and Methods

Ulcer prevalence was obtained from a 24-h survey of hospitalized adult patients in March 2008. PU prevalence was collected by nurses trained in the identification and staging of PUs. Braden total scores and subscale scores available within 4 h of the PU assessment and patient height and weight were obtained from the electronic medical record. Patient height and weight data were used to compute body mass index (BMI) as the ratio of weight in kilograms to height in meters squared for each patient. Obesity was defined as a BMI of ≥30 kg/m². Braden subscale scores were categorized as high risk (scores of 1 or 2 on all subscales, except for a score of 1 on the friction/shear subscale) or low risk (scores >2 on 5 subscales and scores >1 on the friction/shear subscale). A high-risk total Braden score was defined as a score of ≤12. Mean comparisons between obese and non-obese patients were made with the independent-groups t-test, while comparisons of categorical variables between obese and non-obese patients were made using the chi-square test. Unadjusted odds ratios were computed to estimate the probability of ulcer occurrence from high-risk Braden total score and subscale scores. P values of <0.05 were deemed statistically significant.

Results

Complete data on PU occurrence and BMI were available on 326 adult patients. The average age of the total group was 60.4 (19–99), 49% were female, 135 (41%) were obese, and 50 (15.3%) had at least one Stage I PU. The average Braden total score for the group was 17.1 (2–23), with 24 (7%) having a high-risk Braden total score. For the 35 patients with a BMI of ≥40, the PU prevalence rate was 22.9%. There were no statistically significant differences between the obese and non-obese in terms of age, ulcer prevalence, high-risk Braden total score, or prevalence of high-risk Braden subscale scores, except for friction/shear (Table 1). There were no statistically significant differences between the mean total Braden and Braden subscale scores between the obese and non-obese.

Table 1.

Demographics, Braden Scale, and Ulcer Prevalence Information for Obese and Non-Obese Patients (N = 326)

	M (SD)/n (%)
	BMI <30 (n = 191)	BMI ≥30 (n = 135)	p
Age	61.8 (17.01)	58.5 (15.35)	0.08
Total Braden	17.0 (3.11)	17.2 (3.36)	0.59
Female gender	85 (44.7%)	76 (56.3%)	0.04
Ulcer prevalence	27 (14.1%)	23 (17.0%)	0.47
High-risk Braden scores
Sensory perception	27 (14.1%)	15 (11.1%)	0.42
Moisture	5 (2.6%)	1 (0.7%)	0.21
Activity	101 (52.9%)	62 (45.9%)	0.22
Mobility	51 (26.7%)	41 (30.4%)	0.47
Nutrition	64 (33.5%)	38 (13.3%)	0.30
Friction/shear	10 (5.3%)	18 (13.3%)	0.01
High-risk total Braden (≤12)	15 (7.9%)	9 (6.7%)	0.90

To investigate the ability of the Braden total score and the subscale scores, except for moisture, to predict PU occurrence in the obese and non-obese, unadjusted odds ratios were calculated for the total score and the subscale scores categorized into high- and low-risk dichotomies (Table 2). There were statistically significant odds ratios relating high risk to the probability of PU occurrence for both the obese and non-obese patients on the total score and all subscales except for nutrition. The odds ratio for obese patients with high-risk mobility scores was 4.4 times higher than for non-obese patients, high-risk friction/shear odds ratio was 3.9 times higher, and high-risk total score odds ratio was 1.9 times higher.

Table 2.

Unadjusted Odds Ratios Relating High Risk Braden Subscales and Total Braden to Pressure Ulcer Occurrence for Obese and Non-Obese Patients

	BMI < 30		BMI ≥ 30
High risk	Odds ratio	95% C.I.	Odds ratio	95% C.I.
Sensory perception	4.07	1.59–10.36	5.69	1.81–17.83
Activity	2.93	1.17–7.30	3.28	1.25–8.61
Mobility	4.44	1.91–10.34	19.43	6.00–62.90
Nutrition	1.72	0.75–3.94	1.46	0.56–3.79
Friction/shear	7.18	1.92–26.81	27.82	8.23–94.06
Total Braden	2.42	0.71–8.24	4.51	1.11–18.31

Discussion

PU development, particularly in hospitalized patients, is a serious problem. The recent Centers for Medicare and Medicaid Services ruling denying reimbursement to hospitals for Stage III and IV PU highlights even further the importance of this area.¹²

This study found that the prevalence of PU occurrence was slightly higher for obese patients. For patients with BMIs of ≥40, the prevalence rate was almost 23%. However, there were not enough patients with these higher BMIs to study as a single group. The major difference between the obese and non-obese was the more frequent occurrence of high friction/shear scores in obese patients (13.3%) than in non-obese patients (5.3%). Interestingly, even though the rate of high-risk mobility was similar in obese (30.4%) and non-obese (26.7%) patients, the difference in the proportion of those patients with PUs differed widely. Of the 51 non-obese patients with high-risk mobility scores, 15 (29.4%) had PUs compared to 19 (46.3%) of the 41 obese patients with high-risk mobility scores. Similarly, 5 (50%) of the 10 non-obese patients with high-risk friction/shear scores had PUs compared to 13 (72.2%) of the 18 obese patients with high-risk friction/shear scores.

When the associations of high-risk total score and subscale scores to ulcer occurrence were analyzed, significant odds ratios were found for sensory perception, activity, mobility, friction/shear subscales, and total score for both obese and non-obese patients. However, the association between mobility, friction/shear, and total score high risk was much stronger for obese patients than for the non-obese.

There was evidence that obese patients with both high-risk mobility and friction/shear scores had a higher prevalence of ulcers than non-obese patients with both high-risk scores. Eight (4.2%) of the non-obese patients had both high-risk mobility and friction/shear scores, and 14 (10.4%) of the obese patients had both high-risk scores. Of the 8 non-obese patients, 4 (50%) had ulcers compared to 11 (78.6%) of the 14 obese patients.

Conclusions

These data suggest that for obese patients it may be a combination of mobility and friction/shear that is the important risk factor for PU occurrence. Because of the cross-sectional nature of this study, we cannot determine whether the joint occurrence of high-risk mobility and friction/shear scores is the strongest predictor of PU development. A longitudinal study with a much larger sample size, in which Braden scores are collected on a cohort of obese and non-obese patients without PUs and followed to discharge or until a PU develops, would provide evidence on the predictive validity of the Braden subscale scores.

The cross-sectional nature of the study also did not allow differentiation between hospital-acquired PUs and PUs acquired prior to hospitalization or examination of skin changes over time. A longitudinal examination of patients' skin status would be more useful in determining when and under what conditions PUs develop.

Footnotes

Disclosure Statement

No competing financial interests exist.

References

Exton-Smith

, Norton

, McLaren

. An investigation of geriatric nursing problems in hospital. The National Corporation for the Care of Old People. Regent's Park: London, 1964.

Kring

. Reliability and validity of the Braden scale for predicting pressure ulcer risk. J Wound Ostomy Continence Nurs, 2007; 34:399–406.

Gallagher

. The challenges of obesity and skin integrity. Nurs Clin North Am, 2005; 40:325–336.

Hahler

. Morbid obesity: Aanursing care challenge. Dermatol Nurs, 2002; 14:249–256.

Pokorny

. Best practices lead in: skin physiology and diseases in the obese patient. Bar Nurs Surg Patient Care, 2008; 3:125–128.

Mathison

. Skin and wound care challenges in the hospitalized morbidly obese patient. Wound Care, 2003; 30:78–83.

Drake

, Swanson

, Baker

, Pokorny

, Rose

et al. The association of BMI and Braden total score on the occurrence of pressure ulcers. J Wound Ostomy Continence Nurs, 2010; 37:367–371.

Bates-Jensen

. Cadogan M, Osterwell D, Levy-Storms L, Jorge J, et al. The minimum data set pressure ulcer indicator: Does it reflect differences in care processes related to pressure ulcer prevention and treatment in nursing homes? J Am Geriatr Soc, 2003; 51:1203–1212.

Compher

, Kinosian

, Ratcliffe

, Baumgarten

. Obesity reduces the risk of pressure ulcers in elderly hospitalized patients. J Gerontol, 2007; 62a:1310–1312.

10.

Kramer

. WOC nurses as advocates for patients who are morbidly obese. J Wound Ostomy Continence Nurs, 2004; 31:379–387.

11.

Rose

, Baker

, Drake

et al. A comparison of nursing staffing requirements for the care of morbidly obese and non-obese patients in the acute care setting. Bar Nurs Surg Patient Care, 2007; 2:53–56.

12.

Centers for Medicare and Medicaid Services. Medicare & Medicaid Services. Medicare program: changes to the hospital inpatient prospective payment systems and fiscal year 2009 rates; payments for graduate medical education in certain emergency situations; changes to disclosure of physician ownership in hospitals and physician self-referral rules; updates to the long-term care prospective payment system; updates to certain IPPs-Excluded hospitals; and collection of information regarding financial relationships between hospitals. Fed Regist, 2008; 73:48434–49083. http://frwebgate.access.gpo.gov/cgi-bin/getpage.cgi. 2008 October 20.