Denis Anthony

Norton, Waterlow and Braden scores: a review of the literature and a comparison between the scores and clinical judgement

AIMS AND OBJECTIVES To consider the validity and reliability of risk assessment scales for pressure ulcers. BACKGROUND Pressure ulcers are a major problem worldwide. They cause morbidity and lead to mortality. Risk assessment scales have been available for nearly 50 years, but there is insufficient evidence to state with any certainty that they are useful. DESIGN A literature review and commentary. METHODS Bibliographic databases were searched for relevant papers, a critical review was completed on relevant papers. RESULTS There is contradictory evidence concerning the validity of risk assesment scales. The interaction of education, clinical judgement and use of risk assessment scales has not been fully explored. It is not known which of these is most important, nor whether combining them results in better patient care. CONCLUSIONS There is a need for further work. A study exploring the complex interaction of risk assessment scales, clinical judgement and education and training is introduced. RELEVANCE TO CLINICAL PRACTICE Nurses may be wasting their time conducting risk assessment scoring if clinical judgement and/or education are sufficient to assess pressure ulcers risk.

Do risk assessment scales for pressure ulcers work

Risk assessment scales are widely used to measure the risk of pressure ulcers in the clinical area. They have been subject to many validation studies; however these have focused on the predictive ability of the scales. We have conducted several studies that consider the validity of pressure ulcer risk assessment scales. We have reviewed these and revisited the data in some cases to conduct additional tests of validity presented for the first time in this paper. Based on these results, and a review of the literature, we have come to the conclusion that while the scales are probably reliable, and do assess risk: 1. Many of the components of risk assessment scales are not predictive of pressure ulcers. 2. There are other variables that are routinely available to clinicians that give additional predictive power. 3. The importance of components is not accurately reflected by their range of values. 4. Components are correlated and some components may be removed with no loss of predictive power. 5. There is no evidence the use of risk assessment scales reduces pressure ulcer incidence. The complexity of risk assessment scales does not appear to be warranted. There is evidence that clinical judgment is as effective in assessing risk as risk assessment scales. Reduction in pressure ulcer incidence after implementation of risk assessment tools is likely to be an example of the Hawthorn effect. We believe risk assessment scales are useful research tools, but may not be useful in clinical practice.

The impact of pressure ulcer risk assessment on patient outcomes among hospitalised patients.

AIMS AND OBJECTIVES To determine whether use of a risk assessment scale reduces nosocomial pressure ulcers. BACKGROUND There is contradictory evidence concerning the validity of risk assessment scales. The interaction of education, clinical judgement and use of risk assessment scales has not been fully explored. It is not known which of these is most important, nor whether combining them results in better patient care. DESIGN Pretest-posttest comparison. METHODS A risk assessment scale namely the Braden was implemented in a group of wards after appropriate education and training of staff in addition to mandatory wound care study days. Another group of staff received the same education programme but did not implement the risk assessment scale and a third group carried on with mandatory study days only. RESULTS Nosocomial Pressure Ulcer was reduced in all three groups, but the group that implemented the risk assessment scale showed no significant additional improvement. Allowing for age, gender, medical speciality, level of risk and other factors did not explain this lack of improvement. Clinical judgement seemed to be used by nurses to identify patients at high risk to implement appropriate risk reduction strategies such as use of pressure relieving beds. Clinical judgement was not significantly different from the risk assessment scale score in terms of risk evaluation. CONCLUSIONS It is questioned whether the routine use of a risk assessment scale is useful in reducing nosocomial pressure ulcer. It is suggested clinical judgement is as effective as a risk assessment scale in terms of assessing risk (though neither show good sensitivity and specificity) and determining appropriate care. RELEVANCE TO CLINICAL PRACTICE Clinical judgement may be as effective as employing a risk assessment scale to assess the risk of pressure ulcers. If this were true it would be simpler and release nursing time for other tasks.

An optimization of the Waterlow score using regression and artificial neural networks

Objectives: To optimize the ability of the Waterlow Scale to predict individuals vulnerable to developing pressure ulcers. Design: Prospective cohort study. Setting: Two acute care UK National Health Service (NHS) providers. Subjects: Four hundred and twenty-two inpatients across five specialities (general medicine, general surgery, orthopaedics, oncology and rehabilitation). Interventions: Waterlow scores recorded weekly for 14 days post admission to hospital. Main outcome measure: Development of a pressure ulcer. Results: Nonlinear analysis using neural networks did not outperform linear methods. Only five items out of 11 in the Waterlow Scale appeared to have any classification ability in this patient population. Conclusions: The Waterlow score when modelled as a linear equation appears as effective as more complicated nonlinear mappings using neural networks. Only a subset of the variables of the Waterlow Scale have predictive value in this patient population, but this is a different subset to those found in a previous study of a different client group (wheelchair users).

A regression analysis of the Waterlow score in pressure ulcer risk assessment

Objective: To explore the predictive value of the Waterlow score, and the subscores of age and gender. Design: Logistic regression analysis was conducted on the two subscores of the Waterlow score, and the residual Waterlow score with gender and age removed. Receiver operating characteristic (ROC) analysis gave a quantitative measure of the classification ability of the Waterlow score. Setting: Burton, UK. Subjects: All admissions over a five-year period to the District General Hospital, a total of 150 015 admissions of 82 691 patients. Interventions: None. Main outcome measures: Area under the ROC curve for significant (as determined by logistic regression) variables. Results: Data were inaccurate in at least 44.7% of the records, and analysis was conducted on the 43 735 records for which no errors were apparent. Nine hundred and fifty-four patients had a pressure ulcer on admission (2.1%); 277 developed a pressure ulcer (0.6%). The Waterlow score was predictive of pressure ulcers. Age was predictive, and gender was not found to be a significant predictor. Conclusions: The Waterlow score may be improved and simplified by removing gender from the scoring system.

An evaluation of current risk assessment scales for decubitus ulcer in general inpatients and wheelchair users

Objectives: To study the components of two risk assessment scales for decubitus ulcer risk, Waterlow and Braden, and of the Chailey score for the same purpose. Design: Experimental study of patients at risk of developing decubitus ulcers. Setting: The West Midlands and Yorkshire. Subjects: One hundred and fifty wheelchair users from the West Midlands and 9022 patients from a District General Hospital in York, the latter consisting of all admissions to the hospital in a four-month period. Interventions: Braden, Chailey scores (wheelchair users) and Waterlow scores (all subjects) measured. Main outcome measures: Development of a pressure sore, receiver operating characteristic (ROC) curves. Results: Waterlow outperformed Braden for classification of wheelchair patients with respect to decubitus ulcer. The Chailey score performed randomly in this group. The sensitivity and specificity as seen in ROC curves was different for Waterlow scores for wheelchair users and general patients, the latter being much better classified. Only three items out of 11 in the Waterlow score appeared to have any classification ability in the wheelchair group. Conclusions: Risk indicators used for general patients are probably poorly suited for wheelchair users. There is a need for large-scale predictive studies of wheelchair users and other groups to allow regression analysis of the subscales of risk indicators. From the provisional data of this study it appears that splitting patients by gender and into full and part-time wheelchair users classifies almost as well the much more complicated risk assessment tools currently available.

A comparison of Braden Q, Garvin and Glamorgan risk assessment scales in paediatrics

AIMS AND OBJECTIVES To compare three risk assessment scales with respect to predictive validity BACKGROUND In paediatrics there are several competing scales and at least ten published paediatric pressure ulcer risk assessment scales have been identified. However there are few studies exploring the validity of such scales, and none identified that compares paediatric risk assessment scales. DESIGN Cross sectional study METHODS Three risk assessment scales, Braden Q, Garvin and Glamorgan, were compared. The total scores and sub-scores were tested to determine if children with pressure ulcers were significantly different from those with no pressure ulcer. Logistic regression was conducted to determine if the probability of developing a pressure ulcer was a better predictor of development of pressure ulcer compared with the total score of each scale. Receiver operating characteristic curves were computed and the area under the curve used to compare the performance of the risk assessment scales. RESULTS Data from 236 children were collected. 71 were from children in eleven hospitals who were asked to provide data on children with pressure ulcers (although seventeen did not have a pressure ulcer) of whom five were deep (grade 4). A sample of 165 were from one hospital, of which seven had a pressure ulcer, none grade four. The Glamorgan risk assessment scale had a higher predictive ability than either the Braden Q or Garvin. The mobility sub-score of each of the risk assessment scales was the most predictive in each case. CONCLUSIONS The Glamorgan scale is the most valid of the three paediatric risk assessment scales studied in this population. Mobility alone may be as effective as employing the more complex risk assessment scale. RELEVANCE TO CLINICAL PRACTICE If a paediatric risk assessment scale is employed to predict risk, then unless it is valid, it may identify children who are not at risk and waste resources, or fail to identify children at risk possibly resulting in adverse health outcomes.

Health, lifestyle, belief and knowledge differences between two ethnic groups with specific reference to tobacco, diet and physical activity

AIMS   To compare physical activity levels, body mass index, habitual diet, tobacco use and prevalence of non-communicable disease between the two ethnic groups and to identify predictors for differences between groups. BACKGROUND   Tobacco use, poor diet and physical inactivity are major lifestyle risk factors for chronic cardiovascular diseases, certain cancers, diabetes and chronic lung diseases. There are higher risk and incidence of these diseases in some ethnic groups, for example Asians have higher incidence of diabetes. DESIGN   Cross sectional survey. METHODS   Cross sectional survey of Asians of Indian descent and white British adults conducted between October-December 2009. Main outcome variables were lifestyle behaviours and BMI. Self-reported disease diagnosis was also collected. In a regression analysis, predictors of outcome variables were demographic variables and beliefs/attitudes/knowledge towards lifestyle behaviours. RESULTS/FINDINGS   Body mass index, tobacco use and non-communicable disease (except diabetes) were lower in Indians. Indians reported lower physical activity levels and greater salt use than Whites. Tobacco use was higher in Whites, but knowledge, attitudes and beliefs were similar between Whites and Indians. CONCLUSION   Health risk behaviour and morbidity are different between the two ethnic groups. Gender, age, educational level, beliefs, attitudes and knowledge do not explain these differences. Health promotion that aims to improve knowledge will probably not work and innovative methods are needed to improve health in high risk groups.

An evaluation of serum albumin and the sub-scores of the Waterlow score in pressure ulcer risk assessment

BACKGROUND From previous work serum albumin is predictive of pressure ulcers over and above the Waterlow score. However the sub-scores of the Waterlow score were not available, and the accuracy of calculation of the total score was poor. This study has used sub-scores and is an order of magnitude larger. OBJECTIVES To compare serum albumin with Waterlow score as a predictive measure for pressure ulcers. DESIGN Retrospective analysis of hospital information support system. SETTINGS A district general hospital in Staffordshire. PARTICIPANTS Adult non-elective in-patients. METHODS Logistic regression and receiver operating characteristic. RESULTS The sub-scores of the Waterlow score were explored. While they constitute a multi-dimensional dataset, many were not found relevant to pressure ulcer risk in this population (non-elective in-patients). Some sub-scores were not recorded correctly, and body mass index (BMI) was particularly badly reported. Age was found to be as predictive of pressure ulcer as the more complex Waterlow score. Serum albumin was at least as good as the Waterlow score in risk assessment of pressure ulcers. Matching patients with pressure ulcers to patients with none, who had identical Waterlow sub-scores, confirmed serum albumin as a robust predictive value in pressure ulcers. CONCLUSION Risk assessing patients based on their age is as good as the more complex Waterlow score. Additional risk information can be gained from knowing the serum albumin value.

Serum albumin in risk assessment for Clostridium difficile.

We have examined serum albumin as a risk factor for Clostridium difficile-associated diarrhoea (CDAD). CDAD and serum albumin are related. In a series of studies of patients with C. difficile, it has been found that serum albumin is lower in patients with CDAD and that it is associated with refractoriness. A fall in serum albumin is associated with the onset of CDAD. There is a rationale since C. difficile toxin A in rats induces a leucocytedependent leakage of albumin from postcapillary venules. Toxin A increases vascular and mucosal permeability resulting in intralumen accumulation of serum albumin-rich fluid. We considered anonymised records of a sample of 9409 patients, aged >13 years, admitted nonelectively from 1 April 2006 to 30 November 2007 who had no pressure ulcer recorded on admission because pressure ulcers can reduce albumin. CDAD was diagnosed in 138 patients, of whom 37 were not tested until more than two days after admission. We excluded all patients tested in the first two days since they may have had CDAD on admission. Only four patients with a diagnosis of CDAD were aged <65 years, and we excluded patients aged <65 years from our analysis. Prior to data analysis, Caldicott Guardian and ethics opinions were sought and the study was deemed to be a service evaluation, not in need of a formal ethics approval. Binary logistic regression with CDAD as dependent variable, of serum albumin, haemoglobin, sodium, gender and age with the forward conditional method gave the inverse of serum albumin, hypoalbuminaemia and age as significant. Using receiver operating characteristic, serum albumin (inverted, as low values are associated with cases) showed a greater area under the curve as a classifier of CDAD than age, but hypoalbuminaemia alone was similar (Figure 1). While serum albumin is slightly superior to a binary split into normal and abnormally low albumin, the latter has the advantage of simplicity. It is easy to interpret and is objective. About 90% of cases are in 10% of the sample who are elderly and hypoalbuminaemic. Since serum albumin is increasingly used routinely on admission, this may be a useful screening tool. Serum albumin with age (both objective and easy to interpret) is sensitive and specific and, in our sample, suggested that 10% were at risk. Concentrating infection control measures on this subgroup could be more efficient than using the current risk tool that focuses on age and antibiotic use. This would be especially useful in planned admission cases where albumin could be measured in assessment clinics. We have previously shown the Waterlow score to be useful in assessment of risk for CDAD. This is non-invasive and can be