Exploring Factors Associated with Pressure Ulcers: A Data Mining Approach

Raju, D, Su, X, Patrician, P, Loan, L, McCarthy, M


Background: Pressure ulcers are associated with a nearly three-fold increase in in-hospital mortality. It is essential to investigate how other factors besides the Braden scale could enhance the prediction of pressure ulcers. Data mining modeling techniques can be beneficial to conduct this type of analysis. Data mining techniques have been applied extensively in health care, but are not widely used in nursing research.
Purpose: To remedy this methodological gap, this paper will review, explain, and compare several data mining models to examine patient level factors associated with pressure ulcers based on a four year study from military hospitals in the United States.
Methods: The variables included in the analysis are easily accessible demographic information and medical measurements. Logistic regression, decision trees, random forests, and multivariate adaptive regression splines were compared based on their performance and interpretability.
Results: The random forests model had the highest accuracy (C-statistic) with the following variables, in order of importance, ranked highest in predicting pressure ulcers: days in the hospital, serum albumin, age, blood urea nitrogen, and total Braden score.
Conclusion: Data mining, particularly, random forests are useful in predictive modeling. It is important for hospitals and health care systems to use their own data over time for pressure ulcer risk prediction, to develop risk models based upon more than the total Braden score, and specific to their patient population.

Link to ScienceDirect.com

Using Item Response Theory Models to Evaluate the Practice Environment Scale

Raju, Dheeraj; Su, Xiaogang; Patrician, Patricia A.


Background and Purpose: The purpose of this article is to introduce different types of item response theory models and to demonstrate their usefulness by evaluating the Practice Environment Scale. Methods: Item response theory models such as constrained and unconstrained graded response model, partial credit model, Rasch model, and one-parameter logistic model are demonstrated. The Akaike information criterion (AIC) and Bayesian information criterion (BIC) indices are used as model selection criterion. Results: The unconstrained graded response and partial credit models indicated the best fit for the data. Almost all items in the instrument performed well. Conclusions: Although most of the items strongly measure the construct, there are a few items that could be eliminated without substantially altering the instrument. The analysis revealed that the instrument may function differently when administered to different unit types.

Link to Springer Publishing

The role of physical distribution services as determinants of product returns in Internet retailing

Rao, S, E, Rabinovich, & Raju, D.


Pressure continues to build on Internet retailers to squeeze out inefficiencies from their day-to-day operations. One major source of such inefficiencies is product returns. Indeed, product returns in Internet retailing have been shown to be, on average, as high as 22% of sales. Yet, most retailers accept them as a necessary cost of doing business. This is not surprising since many retailers do not have a clear understanding of the causes of product returns. While it is known that return policies of retailers, along with product attributes, are two important factors related to product return incidents, little is known about which aspects of the online retail transaction make such a purchase more return-prone. In the current study, we seek to address this issue. We use a large data set of customer purchases and returns to identify how process attributes in physical distribution service (PDS) influence product returns. The first attribute involves perceptions of scarcity conditions in inventory availability among consumers when retailers reveal to consumers information on inventory levels for the products that they intend to buy. Our results show that orders in which items are sold when these conditions are revealed to shoppers have a higher likelihood of being returned than orders in which these conditions are not revealed. While prior research has argued that inventory scarcity perceptions have an effect on purchases, our findings suggest that they are also related to the likelihood of these purchases being returned. The second attribute involves the reliability in the delivery of orders to consumers. We find that the likelihood of orders being returned depends on the consistency between retailer promises of timeliness in the delivery of orders and the actual delivery performance of the orders. Moreover, we find that the effect that consistency in the delivery has in the likelihood of returns, is stronger for orders that involve promises for expedited delivery than for orders with less expeditious promises. That is, although the occurrence of returns depends on the delays in the delivery of orders to consumers relative to the initial promises made by the retailers, this effect is more notable for orders that involve promises of fast delivery.

Link to ScienceDirect.com

Dr. David Vance’s ability to develop and maintain his vector of research is well illustrated in a recent publication with co-authors from the Departments of Psychology and Medicine (Gerontology) at UAB, Pariya Fazeli, Lesley Ross, Virginia Wadley and Karlene Ball in the Journal of the Association of Nurses in AIDS Care.  The article entitled “Speed of processing training with middle-age and older adults with HIV:  A pilot study” examines the efficacy and feasibility of using a cognitive remediation therapy which has proven results in improving speed of processing in the geriatric population and applying it to middle-aged patients with HIV who experience similar deficits.

The advent of improved pharmacological therapies (ART) has resulted in a dramatic shift in the age distribution of patients with HIV.  Currently, more than 25% of patients with HIV in the United States are aged 50 or older and It is expected that this will increase to nearly 50% by 2015.  As a result of both the disease and the treatment, however, patients with HIV are particularly vulnerable to age-related medical and cognitive changes and may experience them at an earlier age than is typical.  Cognitive changes in older patients with HIV are particularly important as they influence factors such as adherence to a complex medication regimen, financial management, activities of daily living, and even driving.  Speed of processing is one example of a cognitive process that is known to be affected in both the aging and the HIV populations.

Speed of processing training has been used for over a decade in older adults.  It has been shown to improve both speed of processing itself and to generalize to other areas of cognition.  In addition, older adults who have completed speed of processing training have shown other benefits including improved self-reported health, reduced depression scores, improved performance on activities of daily living and safer driving  These benefits have persisted for up to five years following training.

Dr. Vance’s current study involved comparing an intervention group which received speed of processing training to a control group which did not.  The intervention consisted of playing four computer games designed to tap speed of processing and visual attention by requiring the participant to identify both central and peripheral stimuli on a computer screen.  The games involve four levels of difficulty and automatically adjust either up or down so that players are always near the threshold of their ability.  The intervention condition consisted of 22 subjects with a mean age of 51.5 years while the control condition consisted of 24 subjects who did not differ demographically from the intervention group.  Both groups of subjects received a brief neuropsychological examination prior to the intervention and again following the training. 

Analysis of the neuropsychological test results revealed that subjects who received the speed of processing training showed improvement on the Useful Field of Vistion test (which is a measure of speed of processing) and the Timed Activities of Daily Living test (which is a measure of everyday functioning).  Participants also indicated that they felt the training had resulted in useful improvements.  In conclusion, cognitive remediation therapies such as speed of processing training are feasible and effective, cost effective and medically acceptable for improving cognitive abilities in HIV patients with neurologic sequelae or accelerated aging.  This work reflects Dr. Vance’s vector of research on maintaining and improving cognition in vulnerable populations.


Article summary by Jennifer Frank, PhD (jfranf@uab.edu)